diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_port.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 3426 |
1 files changed, 3426 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c new file mode 100644 index 000000000000..719faf92aa8a --- /dev/null +++ b/drivers/tty/serial/8250/8250_port.c @@ -0,0 +1,3426 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Base port operations for 8250/16550-type serial ports + * + * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. + * Split from 8250_core.c, Copyright (C) 2001 Russell King. + * + * A note about mapbase / membase + * + * mapbase is the physical address of the IO port. + * membase is an 'ioremapped' cookie. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/irq.h> +#include <linux/console.h> +#include <linux/gpio/consumer.h> +#include <linux/sysrq.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/tty.h> +#include <linux/ratelimit.h> +#include <linux/tty_flip.h> +#include <linux/serial.h> +#include <linux/serial_8250.h> +#include <linux/nmi.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/pm_runtime.h> +#include <linux/ktime.h> + +#include <asm/io.h> +#include <asm/irq.h> + +#include "8250.h" + +/* + * Here we define the default xmit fifo size used for each type of UART. + */ +static const struct serial8250_config uart_config[] = { + [PORT_UNKNOWN] = { + .name = "unknown", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_8250] = { + .name = "8250", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_16450] = { + .name = "16450", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_16550] = { + .name = "16550", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_16550A] = { + .name = "16550A", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO, + }, + [PORT_CIRRUS] = { + .name = "Cirrus", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_16650] = { + .name = "ST16650", + .fifo_size = 1, + .tx_loadsz = 1, + .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, + }, + [PORT_16650V2] = { + .name = "ST16650V2", + .fifo_size = 32, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | + UART_FCR_T_TRIG_00, + .rxtrig_bytes = {8, 16, 24, 28}, + .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, + }, + [PORT_16750] = { + .name = "TI16750", + .fifo_size = 64, + .tx_loadsz = 64, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 | + UART_FCR7_64BYTE, + .rxtrig_bytes = {1, 16, 32, 56}, + .flags = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE, + }, + [PORT_STARTECH] = { + .name = "Startech", + .fifo_size = 1, + .tx_loadsz = 1, + }, + [PORT_16C950] = { + .name = "16C950/954", + .fifo_size = 128, + .tx_loadsz = 128, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01, + .rxtrig_bytes = {16, 32, 112, 120}, + /* UART_CAP_EFR breaks billionon CF bluetooth card. */ + .flags = UART_CAP_FIFO | UART_CAP_SLEEP, + }, + [PORT_16654] = { + .name = "ST16654", + .fifo_size = 64, + .tx_loadsz = 32, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | + UART_FCR_T_TRIG_10, + .rxtrig_bytes = {8, 16, 56, 60}, + .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, + }, + [PORT_16850] = { + .name = "XR16850", + .fifo_size = 128, + .tx_loadsz = 128, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, + }, + [PORT_RSA] = { + .name = "RSA", + .fifo_size = 2048, + .tx_loadsz = 2048, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11, + .flags = UART_CAP_FIFO, + }, + [PORT_NS16550A] = { + .name = "NS16550A", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO | UART_NATSEMI, + }, + [PORT_XSCALE] = { + .name = "XScale", + .fifo_size = 32, + .tx_loadsz = 32, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE, + }, + [PORT_OCTEON] = { + .name = "OCTEON", + .fifo_size = 64, + .tx_loadsz = 64, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO, + }, + [PORT_U6_16550A] = { + .name = "U6_16550A", + .fifo_size = 64, + .tx_loadsz = 64, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, + [PORT_TEGRA] = { + .name = "Tegra", + .fifo_size = 32, + .tx_loadsz = 8, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | + UART_FCR_T_TRIG_01, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO | UART_CAP_RTOIE, + }, + [PORT_XR17D15X] = { + .name = "XR17D15X", + .fifo_size = 64, + .tx_loadsz = 64, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR | + UART_CAP_SLEEP, + }, + [PORT_XR17V35X] = { + .name = "XR17V35X", + .fifo_size = 256, + .tx_loadsz = 256, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 | + UART_FCR_T_TRIG_11, + .flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR | + UART_CAP_SLEEP, + }, + [PORT_LPC3220] = { + .name = "LPC3220", + .fifo_size = 64, + .tx_loadsz = 32, + .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO | + UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00, + .flags = UART_CAP_FIFO, + }, + [PORT_BRCM_TRUMANAGE] = { + .name = "TruManage", + .fifo_size = 1, + .tx_loadsz = 1024, + .flags = UART_CAP_HFIFO, + }, + [PORT_8250_CIR] = { + .name = "CIR port" + }, + [PORT_ALTR_16550_F32] = { + .name = "Altera 16550 FIFO32", + .fifo_size = 32, + .tx_loadsz = 32, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 8, 16, 30}, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, + [PORT_ALTR_16550_F64] = { + .name = "Altera 16550 FIFO64", + .fifo_size = 64, + .tx_loadsz = 64, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 16, 32, 62}, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, + [PORT_ALTR_16550_F128] = { + .name = "Altera 16550 FIFO128", + .fifo_size = 128, + .tx_loadsz = 128, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 32, 64, 126}, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, + /* + * tx_loadsz is set to 63-bytes instead of 64-bytes to implement + * workaround of errata A-008006 which states that tx_loadsz should + * be configured less than Maximum supported fifo bytes. + */ + [PORT_16550A_FSL64] = { + .name = "16550A_FSL64", + .fifo_size = 64, + .tx_loadsz = 63, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 | + UART_FCR7_64BYTE, + .flags = UART_CAP_FIFO | UART_CAP_NOTEMT, + }, + [PORT_RT2880] = { + .name = "Palmchip BK-3103", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO, + }, + [PORT_DA830] = { + .name = "TI DA8xx/66AK2x", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO | + UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, + [PORT_MTK_BTIF] = { + .name = "MediaTek BTIF", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | + UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT, + .flags = UART_CAP_FIFO, + }, + [PORT_NPCM] = { + .name = "Nuvoton 16550", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 | + UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO, + }, + [PORT_SUNIX] = { + .name = "Sunix", + .fifo_size = 128, + .tx_loadsz = 128, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 32, 64, 112}, + .flags = UART_CAP_FIFO | UART_CAP_SLEEP, + }, + [PORT_ASPEED_VUART] = { + .name = "ASPEED VUART", + .fifo_size = 16, + .tx_loadsz = 16, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00, + .rxtrig_bytes = {1, 4, 8, 14}, + .flags = UART_CAP_FIFO, + }, + [PORT_MCHP16550A] = { + .name = "MCHP16550A", + .fifo_size = 256, + .tx_loadsz = 256, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01, + .rxtrig_bytes = {2, 66, 130, 194}, + .flags = UART_CAP_FIFO, + }, + [PORT_BCM7271] = { + .name = "Broadcom BCM7271 UART", + .fifo_size = 32, + .tx_loadsz = 32, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01, + .rxtrig_bytes = {1, 8, 16, 30}, + .flags = UART_CAP_FIFO | UART_CAP_AFE, + }, +}; + +/* Uart divisor latch read */ +static u32 default_serial_dl_read(struct uart_8250_port *up) +{ + /* Assign these in pieces to truncate any bits above 7. */ + unsigned char dll = serial_in(up, UART_DLL); + unsigned char dlm = serial_in(up, UART_DLM); + + return dll | dlm << 8; +} + +/* Uart divisor latch write */ +static void default_serial_dl_write(struct uart_8250_port *up, u32 value) +{ + serial_out(up, UART_DLL, value & 0xff); + serial_out(up, UART_DLM, value >> 8 & 0xff); +} + +#ifdef CONFIG_HAS_IOPORT +static u32 hub6_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + outb(p->hub6 - 1 + offset, p->iobase); + return inb(p->iobase + 1); +} + +static void hub6_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + outb(p->hub6 - 1 + offset, p->iobase); + outb(value, p->iobase + 1); +} +#endif /* CONFIG_HAS_IOPORT */ + +static u32 mem_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + return readb(p->membase + offset); +} + +static void mem_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + writeb(value, p->membase + offset); +} + +static void mem16_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + writew(value, p->membase + offset); +} + +static u32 mem16_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + return readw(p->membase + offset); +} + +static void mem32_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + writel(value, p->membase + offset); +} + +static u32 mem32_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + return readl(p->membase + offset); +} + +static void mem32be_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + iowrite32be(value, p->membase + offset); +} + +static u32 mem32be_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + return ioread32be(p->membase + offset); +} + +#ifdef CONFIG_HAS_IOPORT +static u32 io_serial_in(struct uart_port *p, unsigned int offset) +{ + offset = offset << p->regshift; + return inb(p->iobase + offset); +} + +static void io_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ + offset = offset << p->regshift; + outb(value, p->iobase + offset); +} +#endif +static u32 no_serial_in(struct uart_port *p, unsigned int offset) +{ + return ~0U; +} + +static void no_serial_out(struct uart_port *p, unsigned int offset, u32 value) +{ +} + +static int serial8250_default_handle_irq(struct uart_port *port); + +static void set_io_from_upio(struct uart_port *p) +{ + struct uart_8250_port *up = up_to_u8250p(p); + + up->dl_read = default_serial_dl_read; + up->dl_write = default_serial_dl_write; + + switch (p->iotype) { +#ifdef CONFIG_HAS_IOPORT + case UPIO_HUB6: + p->serial_in = hub6_serial_in; + p->serial_out = hub6_serial_out; + break; +#endif + + case UPIO_MEM: + p->serial_in = mem_serial_in; + p->serial_out = mem_serial_out; + break; + + case UPIO_MEM16: + p->serial_in = mem16_serial_in; + p->serial_out = mem16_serial_out; + break; + + case UPIO_MEM32: + p->serial_in = mem32_serial_in; + p->serial_out = mem32_serial_out; + break; + + case UPIO_MEM32BE: + p->serial_in = mem32be_serial_in; + p->serial_out = mem32be_serial_out; + break; +#ifdef CONFIG_HAS_IOPORT + case UPIO_PORT: + p->serial_in = io_serial_in; + p->serial_out = io_serial_out; + break; +#endif + default: + WARN(p->iotype != UPIO_PORT || p->iobase, + "Unsupported UART type %x\n", p->iotype); + p->serial_in = no_serial_in; + p->serial_out = no_serial_out; + } + /* Remember loaded iotype */ + up->cur_iotype = p->iotype; + p->handle_irq = serial8250_default_handle_irq; +} + +static void +serial_port_out_sync(struct uart_port *p, int offset, int value) +{ + switch (p->iotype) { + case UPIO_MEM: + case UPIO_MEM16: + case UPIO_MEM32: + case UPIO_MEM32BE: + case UPIO_AU: + p->serial_out(p, offset, value); + p->serial_in(p, UART_LCR); /* safe, no side-effects */ + break; + default: + p->serial_out(p, offset, value); + } +} + +/* + * FIFO support. + */ +static void serial8250_clear_fifos(struct uart_8250_port *p) +{ + if (p->capabilities & UART_CAP_FIFO) { + serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO); + serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO | + UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); + serial_out(p, UART_FCR, 0); + } +} + +static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t); +static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t); + +void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p) +{ + serial8250_clear_fifos(p); + serial_out(p, UART_FCR, p->fcr); +} +EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos); + +void serial8250_rpm_get(struct uart_8250_port *p) +{ + if (!(p->capabilities & UART_CAP_RPM)) + return; + pm_runtime_get_sync(p->port.dev); +} +EXPORT_SYMBOL_GPL(serial8250_rpm_get); + +void serial8250_rpm_put(struct uart_8250_port *p) +{ + if (!(p->capabilities & UART_CAP_RPM)) + return; + pm_runtime_mark_last_busy(p->port.dev); + pm_runtime_put_autosuspend(p->port.dev); +} +EXPORT_SYMBOL_GPL(serial8250_rpm_put); + +/** + * serial8250_em485_init() - put uart_8250_port into rs485 emulating + * @p: uart_8250_port port instance + * + * The function is used to start rs485 software emulating on the + * &struct uart_8250_port* @p. Namely, RTS is switched before/after + * transmission. The function is idempotent, so it is safe to call it + * multiple times. + * + * The caller MUST enable interrupt on empty shift register before + * calling serial8250_em485_init(). This interrupt is not a part of + * 8250 standard, but implementation defined. + * + * The function is supposed to be called from .rs485_config callback + * or from any other callback protected with p->port.lock spinlock. + * + * See also serial8250_em485_destroy() + * + * Return 0 - success, -errno - otherwise + */ +static int serial8250_em485_init(struct uart_8250_port *p) +{ + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&p->port.lock); + + if (p->em485) + goto deassert_rts; + + p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC); + if (!p->em485) + return -ENOMEM; + + hrtimer_setup(&p->em485->stop_tx_timer, &serial8250_em485_handle_stop_tx, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + hrtimer_setup(&p->em485->start_tx_timer, &serial8250_em485_handle_start_tx, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + p->em485->port = p; + p->em485->active_timer = NULL; + p->em485->tx_stopped = true; + +deassert_rts: + if (p->em485->tx_stopped) + p->rs485_stop_tx(p, true); + + return 0; +} + +/** + * serial8250_em485_destroy() - put uart_8250_port into normal state + * @p: uart_8250_port port instance + * + * The function is used to stop rs485 software emulating on the + * &struct uart_8250_port* @p. The function is idempotent, so it is safe to + * call it multiple times. + * + * The function is supposed to be called from .rs485_config callback + * or from any other callback protected with p->port.lock spinlock. + * + * See also serial8250_em485_init() + */ +void serial8250_em485_destroy(struct uart_8250_port *p) +{ + if (!p->em485) + return; + + hrtimer_cancel(&p->em485->start_tx_timer); + hrtimer_cancel(&p->em485->stop_tx_timer); + + kfree(p->em485); + p->em485 = NULL; +} +EXPORT_SYMBOL_GPL(serial8250_em485_destroy); + +struct serial_rs485 serial8250_em485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | + SER_RS485_TERMINATE_BUS | SER_RS485_RX_DURING_TX, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, +}; +EXPORT_SYMBOL_GPL(serial8250_em485_supported); + +/** + * serial8250_em485_config() - generic ->rs485_config() callback + * @port: uart port + * @termios: termios structure + * @rs485: rs485 settings + * + * Generic callback usable by 8250 uart drivers to activate rs485 settings + * if the uart is incapable of driving RTS as a Transmit Enable signal in + * hardware, relying on software emulation instead. + */ +int serial8250_em485_config(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* + * Both serial8250_em485_init() and serial8250_em485_destroy() + * are idempotent. + */ + if (rs485->flags & SER_RS485_ENABLED) + return serial8250_em485_init(up); + + serial8250_em485_destroy(up); + return 0; +} +EXPORT_SYMBOL_GPL(serial8250_em485_config); + +/* + * These two wrappers ensure that enable_runtime_pm_tx() can be called more than + * once and disable_runtime_pm_tx() will still disable RPM because the fifo is + * empty and the HW can idle again. + */ +static void serial8250_rpm_get_tx(struct uart_8250_port *p) +{ + unsigned char rpm_active; + + if (!(p->capabilities & UART_CAP_RPM)) + return; + + rpm_active = xchg(&p->rpm_tx_active, 1); + if (rpm_active) + return; + pm_runtime_get_sync(p->port.dev); +} + +static void serial8250_rpm_put_tx(struct uart_8250_port *p) +{ + unsigned char rpm_active; + + if (!(p->capabilities & UART_CAP_RPM)) + return; + + rpm_active = xchg(&p->rpm_tx_active, 0); + if (!rpm_active) + return; + pm_runtime_mark_last_busy(p->port.dev); + pm_runtime_put_autosuspend(p->port.dev); +} + +/* + * IER sleep support. UARTs which have EFRs need the "extended + * capability" bit enabled. Note that on XR16C850s, we need to + * reset LCR to write to IER. + */ +static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) +{ + unsigned char lcr = 0, efr = 0; + + guard(serial8250_rpm)(p); + + if (!(p->capabilities & UART_CAP_SLEEP)) + return; + + /* Synchronize UART_IER access against the console. */ + guard(uart_port_lock_irq)(&p->port); + + if (p->capabilities & UART_CAP_EFR) { + lcr = serial_in(p, UART_LCR); + efr = serial_in(p, UART_EFR); + serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B); + serial_out(p, UART_EFR, UART_EFR_ECB); + serial_out(p, UART_LCR, 0); + } + serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0); + if (p->capabilities & UART_CAP_EFR) { + serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B); + serial_out(p, UART_EFR, efr); + serial_out(p, UART_LCR, lcr); + } +} + +/* Clear the interrupt registers. */ +static void serial8250_clear_interrupts(struct uart_port *port) +{ + serial_port_in(port, UART_LSR); + serial_port_in(port, UART_RX); + serial_port_in(port, UART_IIR); + serial_port_in(port, UART_MSR); +} + +static void serial8250_clear_IER(struct uart_8250_port *up) +{ + if (up->capabilities & UART_CAP_UUE) + serial_out(up, UART_IER, UART_IER_UUE); + else + serial_out(up, UART_IER, 0); +} + +/* + * This is a quickie test to see how big the FIFO is. + * It doesn't work at all the time, more's the pity. + */ +static int size_fifo(struct uart_8250_port *up) +{ + unsigned char old_fcr, old_mcr, old_lcr; + u32 old_dl; + int count; + + old_lcr = serial_in(up, UART_LCR); + serial_out(up, UART_LCR, 0); + old_fcr = serial_in(up, UART_FCR); + old_mcr = serial8250_in_MCR(up); + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | + UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); + serial8250_out_MCR(up, UART_MCR_LOOP); + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); + old_dl = serial_dl_read(up); + serial_dl_write(up, 0x0001); + serial_out(up, UART_LCR, UART_LCR_WLEN8); + for (count = 0; count < 256; count++) + serial_out(up, UART_TX, count); + mdelay(20);/* FIXME - schedule_timeout */ + for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) && + (count < 256); count++) + serial_in(up, UART_RX); + serial_out(up, UART_FCR, old_fcr); + serial8250_out_MCR(up, old_mcr); + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); + serial_dl_write(up, old_dl); + serial_out(up, UART_LCR, old_lcr); + + return count; +} + +/* + * Read UART ID using the divisor method - set DLL and DLM to zero + * and the revision will be in DLL and device type in DLM. We + * preserve the device state across this. + */ +static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p) +{ + unsigned char old_lcr; + unsigned int id, old_dl; + + old_lcr = serial_in(p, UART_LCR); + serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A); + old_dl = serial_dl_read(p); + serial_dl_write(p, 0); + id = serial_dl_read(p); + serial_dl_write(p, old_dl); + + serial_out(p, UART_LCR, old_lcr); + + return id; +} + +/* + * This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's. + * When this function is called we know it is at least a StarTech + * 16650 V2, but it might be one of several StarTech UARTs, or one of + * its clones. (We treat the broken original StarTech 16650 V1 as a + * 16550, and why not? Startech doesn't seem to even acknowledge its + * existence.) + * + * What evil have men's minds wrought... + */ +static void autoconfig_has_efr(struct uart_8250_port *up) +{ + unsigned int id1, id2, id3, rev; + + /* + * Everything with an EFR has SLEEP + */ + up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP; + + /* + * First we check to see if it's an Oxford Semiconductor UART. + * + * If we have to do this here because some non-National + * Semiconductor clone chips lock up if you try writing to the + * LSR register (which serial_icr_read does) + */ + + /* + * Check for Oxford Semiconductor 16C950. + * + * EFR [4] must be set else this test fails. + * + * This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca) + * claims that it's needed for 952 dual UART's (which are not + * recommended for new designs). + */ + up->acr = 0; + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + serial_out(up, UART_EFR, UART_EFR_ECB); + serial_out(up, UART_LCR, 0x00); + id1 = serial_icr_read(up, UART_ID1); + id2 = serial_icr_read(up, UART_ID2); + id3 = serial_icr_read(up, UART_ID3); + rev = serial_icr_read(up, UART_REV); + + if (id1 == 0x16 && id2 == 0xC9 && + (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) { + up->port.type = PORT_16C950; + + /* + * Enable work around for the Oxford Semiconductor 952 rev B + * chip which causes it to seriously miscalculate baud rates + * when DLL is 0. + */ + if (id3 == 0x52 && rev == 0x01) + up->bugs |= UART_BUG_QUOT; + return; + } + + /* + * We check for a XR16C850 by setting DLL and DLM to 0, and then + * reading back DLL and DLM. The chip type depends on the DLM + * value read back: + * 0x10 - XR16C850 and the DLL contains the chip revision. + * 0x12 - XR16C2850. + * 0x14 - XR16C854. + */ + id1 = autoconfig_read_divisor_id(up); + + id2 = id1 >> 8; + if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) { + up->port.type = PORT_16850; + return; + } + + /* + * It wasn't an XR16C850. + * + * We distinguish between the '654 and the '650 by counting + * how many bytes are in the FIFO. I'm using this for now, + * since that's the technique that was sent to me in the + * serial driver update, but I'm not convinced this works. + * I've had problems doing this in the past. -TYT + */ + if (size_fifo(up) == 64) + up->port.type = PORT_16654; + else + up->port.type = PORT_16650V2; +} + +/* + * We detected a chip without a FIFO. Only two fall into + * this category - the original 8250 and the 16450. The + * 16450 has a scratch register (accessible with LCR=0) + */ +static void autoconfig_8250(struct uart_8250_port *up) +{ + unsigned char scratch, status1, status2; + + up->port.type = PORT_8250; + + scratch = serial_in(up, UART_SCR); + serial_out(up, UART_SCR, 0xa5); + status1 = serial_in(up, UART_SCR); + serial_out(up, UART_SCR, 0x5a); + status2 = serial_in(up, UART_SCR); + serial_out(up, UART_SCR, scratch); + + if (status1 == 0xa5 && status2 == 0x5a) + up->port.type = PORT_16450; +} + +static int broken_efr(struct uart_8250_port *up) +{ + /* + * Exar ST16C2550 "A2" devices incorrectly detect as + * having an EFR, and report an ID of 0x0201. See + * http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html + */ + if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16) + return 1; + + return 0; +} + +/* + * We know that the chip has FIFOs. Does it have an EFR? The + * EFR is located in the same register position as the IIR and + * we know the top two bits of the IIR are currently set. The + * EFR should contain zero. Try to read the EFR. + */ +static void autoconfig_16550a(struct uart_8250_port *up) +{ + unsigned char status1, status2; + unsigned int iersave; + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&up->port.lock); + + up->port.type = PORT_16550A; + up->capabilities |= UART_CAP_FIFO; + + if (!IS_ENABLED(CONFIG_SERIAL_8250_16550A_VARIANTS) && + !(up->port.flags & UPF_FULL_PROBE)) + return; + + /* + * Check for presence of the EFR when DLAB is set. + * Only ST16C650V1 UARTs pass this test. + */ + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); + if (serial_in(up, UART_EFR) == 0) { + serial_out(up, UART_EFR, 0xA8); + if (serial_in(up, UART_EFR) != 0) { + up->port.type = PORT_16650; + up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP; + } else { + serial_out(up, UART_LCR, 0); + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | + UART_FCR7_64BYTE); + status1 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750; + serial_out(up, UART_FCR, 0); + serial_out(up, UART_LCR, 0); + + if (status1 == UART_IIR_FIFO_ENABLED_16750) + up->port.type = PORT_16550A_FSL64; + } + serial_out(up, UART_EFR, 0); + return; + } + + /* + * Maybe it requires 0xbf to be written to the LCR. + * (other ST16C650V2 UARTs, TI16C752A, etc) + */ + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) { + autoconfig_has_efr(up); + return; + } + + /* + * Check for a National Semiconductor SuperIO chip. + * Attempt to switch to bank 2, read the value of the LOOP bit + * from EXCR1. Switch back to bank 0, change it in MCR. Then + * switch back to bank 2, read it from EXCR1 again and check + * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2 + */ + serial_out(up, UART_LCR, 0); + status1 = serial8250_in_MCR(up); + serial_out(up, UART_LCR, 0xE0); + status2 = serial_in(up, 0x02); /* EXCR1 */ + + if (!((status2 ^ status1) & UART_MCR_LOOP)) { + serial_out(up, UART_LCR, 0); + serial8250_out_MCR(up, status1 ^ UART_MCR_LOOP); + serial_out(up, UART_LCR, 0xE0); + status2 = serial_in(up, 0x02); /* EXCR1 */ + serial_out(up, UART_LCR, 0); + serial8250_out_MCR(up, status1); + + if ((status2 ^ status1) & UART_MCR_LOOP) { + unsigned short quot; + + serial_out(up, UART_LCR, 0xE0); + + quot = serial_dl_read(up); + quot <<= 3; + + if (ns16550a_goto_highspeed(up)) + serial_dl_write(up, quot); + + serial_out(up, UART_LCR, 0); + + up->port.uartclk = 921600*16; + up->port.type = PORT_NS16550A; + up->capabilities |= UART_NATSEMI; + return; + } + } + + /* + * No EFR. Try to detect a TI16750, which only sets bit 5 of + * the IIR when 64 byte FIFO mode is enabled when DLAB is set. + * Try setting it with and without DLAB set. Cheap clones + * set bit 5 without DLAB set. + */ + serial_out(up, UART_LCR, 0); + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE); + status1 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750; + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO); + + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE); + status2 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750; + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO); + + serial_out(up, UART_LCR, 0); + + if (status1 == UART_IIR_FIFO_ENABLED_16550A && + status2 == UART_IIR_FIFO_ENABLED_16750) { + up->port.type = PORT_16750; + up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP; + return; + } + + /* + * Try writing and reading the UART_IER_UUE bit (b6). + * If it works, this is probably one of the Xscale platform's + * internal UARTs. + * We're going to explicitly set the UUE bit to 0 before + * trying to write and read a 1 just to make sure it's not + * already a 1 and maybe locked there before we even start. + */ + iersave = serial_in(up, UART_IER); + serial_out(up, UART_IER, iersave & ~UART_IER_UUE); + if (!(serial_in(up, UART_IER) & UART_IER_UUE)) { + /* + * OK it's in a known zero state, try writing and reading + * without disturbing the current state of the other bits. + */ + serial_out(up, UART_IER, iersave | UART_IER_UUE); + if (serial_in(up, UART_IER) & UART_IER_UUE) { + /* + * It's an Xscale. + * We'll leave the UART_IER_UUE bit set to 1 (enabled). + */ + up->port.type = PORT_XSCALE; + up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE; + return; + } + } + serial_out(up, UART_IER, iersave); + + /* + * We distinguish between 16550A and U6 16550A by counting + * how many bytes are in the FIFO. + */ + if (up->port.type == PORT_16550A && size_fifo(up) == 64) { + up->port.type = PORT_U6_16550A; + up->capabilities |= UART_CAP_AFE; + } +} + +/* + * This routine is called by rs_init() to initialize a specific serial + * port. It determines what type of UART chip this serial port is + * using: 8250, 16450, 16550, 16550A. The important question is + * whether or not this UART is a 16550A or not, since this will + * determine whether or not we can use its FIFO features or not. + */ +static void autoconfig(struct uart_8250_port *up) +{ + unsigned char status1, scratch, scratch2, scratch3; + unsigned char save_lcr, save_mcr; + struct uart_port *port = &up->port; + unsigned long flags; + unsigned int old_capabilities; + + if (!port->iobase && !port->mapbase && !port->membase) + return; + + /* + * We really do need global IRQs disabled here - we're going to + * be frobbing the chips IRQ enable register to see if it exists. + * + * Synchronize UART_IER access against the console. + */ + uart_port_lock_irqsave(port, &flags); + + up->capabilities = 0; + up->bugs = 0; + + if (!(port->flags & UPF_BUGGY_UART)) { + /* + * Do a simple existence test first; if we fail this, + * there's no point trying anything else. + * + * 0x80 is used as a nonsense port to prevent against + * false positives due to ISA bus float. The + * assumption is that 0x80 is a non-existent port; + * which should be safe since include/asm/io.h also + * makes this assumption. + * + * Note: this is safe as long as MCR bit 4 is clear + * and the device is in "PC" mode. + */ + scratch = serial_in(up, UART_IER); + serial_out(up, UART_IER, 0); +#if defined(__i386__) && defined(CONFIG_HAS_IOPORT) + outb(0xff, 0x080); +#endif + /* + * Mask out IER[7:4] bits for test as some UARTs (e.g. TL + * 16C754B) allow only to modify them if an EFR bit is set. + */ + scratch2 = serial_in(up, UART_IER) & UART_IER_ALL_INTR; + serial_out(up, UART_IER, UART_IER_ALL_INTR); +#if defined(__i386__) && defined(CONFIG_HAS_IOPORT) + outb(0, 0x080); +#endif + scratch3 = serial_in(up, UART_IER) & UART_IER_ALL_INTR; + serial_out(up, UART_IER, scratch); + if (scratch2 != 0 || scratch3 != UART_IER_ALL_INTR) { + /* + * We failed; there's nothing here + */ + uart_port_unlock_irqrestore(port, flags); + return; + } + } + + save_mcr = serial8250_in_MCR(up); + save_lcr = serial_in(up, UART_LCR); + + /* + * Check to see if a UART is really there. Certain broken + * internal modems based on the Rockwell chipset fail this + * test, because they apparently don't implement the loopback + * test mode. So this test is skipped on the COM 1 through + * COM 4 ports. This *should* be safe, since no board + * manufacturer would be stupid enough to design a board + * that conflicts with COM 1-4 --- we hope! + */ + if (!(port->flags & UPF_SKIP_TEST)) { + serial8250_out_MCR(up, UART_MCR_LOOP | UART_MCR_OUT2 | UART_MCR_RTS); + status1 = serial_in(up, UART_MSR) & UART_MSR_STATUS_BITS; + serial8250_out_MCR(up, save_mcr); + if (status1 != (UART_MSR_DCD | UART_MSR_CTS)) { + uart_port_unlock_irqrestore(port, flags); + return; + } + } + + /* + * We're pretty sure there's a port here. Lets find out what + * type of port it is. The IIR top two bits allows us to find + * out if it's 8250 or 16450, 16550, 16550A or later. This + * determines what we test for next. + * + * We also initialise the EFR (if any) to zero for later. The + * EFR occupies the same register location as the FCR and IIR. + */ + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + serial_out(up, UART_EFR, 0); + serial_out(up, UART_LCR, 0); + + serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO); + + switch (serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED) { + case UART_IIR_FIFO_ENABLED_8250: + autoconfig_8250(up); + break; + case UART_IIR_FIFO_ENABLED_16550: + port->type = PORT_16550; + break; + case UART_IIR_FIFO_ENABLED_16550A: + autoconfig_16550a(up); + break; + default: + port->type = PORT_UNKNOWN; + break; + } + + rsa_autoconfig(up); + + serial_out(up, UART_LCR, save_lcr); + + port->fifosize = uart_config[up->port.type].fifo_size; + old_capabilities = up->capabilities; + up->capabilities = uart_config[port->type].flags; + up->tx_loadsz = uart_config[port->type].tx_loadsz; + + if (port->type != PORT_UNKNOWN) { + /* + * Reset the UART. + */ + rsa_reset(up); + serial8250_out_MCR(up, save_mcr); + serial8250_clear_fifos(up); + serial_in(up, UART_RX); + serial8250_clear_IER(up); + } + + uart_port_unlock_irqrestore(port, flags); + + /* + * Check if the device is a Fintek F81216A + */ + if (port->type == PORT_16550A && port->iotype == UPIO_PORT) + fintek_8250_probe(up); + + if (up->capabilities != old_capabilities) { + dev_warn(port->dev, "detected caps %08x should be %08x\n", + old_capabilities, up->capabilities); + } +} + +static void autoconfig_irq(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + unsigned char save_mcr, save_ier; + unsigned char save_ICP = 0; + unsigned int ICP = 0; + unsigned long irqs; + int irq; + + if (port->flags & UPF_FOURPORT) { + ICP = (port->iobase & 0xfe0) | 0x1f; + save_ICP = inb_p(ICP); + outb_p(0x80, ICP); + inb_p(ICP); + } + + /* forget possible initially masked and pending IRQ */ + probe_irq_off(probe_irq_on()); + save_mcr = serial8250_in_MCR(up); + /* Synchronize UART_IER access against the console. */ + scoped_guard(uart_port_lock_irq, port) + save_ier = serial_in(up, UART_IER); + serial8250_out_MCR(up, UART_MCR_OUT1 | UART_MCR_OUT2); + + irqs = probe_irq_on(); + serial8250_out_MCR(up, 0); + udelay(10); + if (port->flags & UPF_FOURPORT) { + serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS); + } else { + serial8250_out_MCR(up, + UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2); + } + /* Synchronize UART_IER access against the console. */ + scoped_guard(uart_port_lock_irq, port) + serial_out(up, UART_IER, UART_IER_ALL_INTR); + serial8250_clear_interrupts(port); + serial_out(up, UART_TX, 0xFF); + udelay(20); + irq = probe_irq_off(irqs); + + serial8250_out_MCR(up, save_mcr); + /* Synchronize UART_IER access against the console. */ + scoped_guard(uart_port_lock_irq, port) + serial_out(up, UART_IER, save_ier); + + if (port->flags & UPF_FOURPORT) + outb_p(save_ICP, ICP); + + port->irq = (irq > 0) ? irq : 0; +} + +static void serial8250_stop_rx(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&port->lock); + + guard(serial8250_rpm)(up); + + up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); + serial_port_out(port, UART_IER, up->ier); +} + +/** + * serial8250_em485_stop_tx() - generic ->rs485_stop_tx() callback + * @p: uart 8250 port + * @toggle_ier: true to allow enabling receive interrupts + * + * Generic callback usable by 8250 uart drivers to stop rs485 transmission. + */ +void serial8250_em485_stop_tx(struct uart_8250_port *p, bool toggle_ier) +{ + unsigned char mcr = serial8250_in_MCR(p); + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&p->port.lock); + + if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND) + mcr |= UART_MCR_RTS; + else + mcr &= ~UART_MCR_RTS; + serial8250_out_MCR(p, mcr); + + /* + * Empty the RX FIFO, we are not interested in anything + * received during the half-duplex transmission. + * Enable previously disabled RX interrupts. + */ + if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) { + serial8250_clear_and_reinit_fifos(p); + + if (toggle_ier) { + p->ier |= UART_IER_RLSI | UART_IER_RDI; + serial_port_out(&p->port, UART_IER, p->ier); + } + } +} +EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx); + +static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t) +{ + struct uart_8250_em485 *em485 = container_of(t, struct uart_8250_em485, + stop_tx_timer); + struct uart_8250_port *p = em485->port; + + guard(serial8250_rpm)(p); + guard(uart_port_lock_irqsave)(&p->port); + + if (em485->active_timer == &em485->stop_tx_timer) { + p->rs485_stop_tx(p, true); + em485->active_timer = NULL; + em485->tx_stopped = true; + } + + return HRTIMER_NORESTART; +} + +static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec) +{ + hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL); +} + +static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay) +{ + struct uart_8250_em485 *em485 = p->em485; + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&p->port.lock); + + stop_delay += (u64)p->port.rs485.delay_rts_after_send * NSEC_PER_MSEC; + + /* + * rs485_stop_tx() is going to set RTS according to config + * AND flush RX FIFO if required. + */ + if (stop_delay > 0) { + em485->active_timer = &em485->stop_tx_timer; + hrtimer_start(&em485->stop_tx_timer, ns_to_ktime(stop_delay), HRTIMER_MODE_REL); + } else { + p->rs485_stop_tx(p, true); + em485->active_timer = NULL; + em485->tx_stopped = true; + } +} + +static inline void __stop_tx(struct uart_8250_port *p) +{ + struct uart_8250_em485 *em485 = p->em485; + + if (em485) { + u16 lsr = serial_lsr_in(p); + u64 stop_delay = 0; + + if (!(lsr & UART_LSR_THRE)) + return; + /* + * To provide required timing and allow FIFO transfer, + * __stop_tx_rs485() must be called only when both FIFO and + * shift register are empty. The device driver should either + * enable interrupt on TEMT or set UART_CAP_NOTEMT that will + * enlarge stop_tx_timer by the tx time of one frame to cover + * for emptying of the shift register. + */ + if (!(lsr & UART_LSR_TEMT)) { + if (!(p->capabilities & UART_CAP_NOTEMT)) + return; + /* + * RTS might get deasserted too early with the normal + * frame timing formula. It seems to suggest THRE might + * get asserted already during tx of the stop bit + * rather than after it is fully sent. + * Roughly estimate 1 extra bit here with / 7. + */ + stop_delay = p->port.frame_time + DIV_ROUND_UP(p->port.frame_time, 7); + } + + __stop_tx_rs485(p, stop_delay); + } + + if (serial8250_clear_THRI(p)) + serial8250_rpm_put_tx(p); +} + +static void serial8250_stop_tx(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + guard(serial8250_rpm)(up); + __stop_tx(up); + + /* + * We really want to stop the transmitter from sending. + */ + if (port->type == PORT_16C950) { + up->acr |= UART_ACR_TXDIS; + serial_icr_write(up, UART_ACR, up->acr); + } +} + +static inline void __start_tx(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + if (up->dma && !up->dma->tx_dma(up)) + return; + + if (serial8250_set_THRI(up)) { + if (up->bugs & UART_BUG_TXEN) { + u16 lsr = serial_lsr_in(up); + + if (lsr & UART_LSR_THRE) + serial8250_tx_chars(up); + } + } + + /* + * Re-enable the transmitter if we disabled it. + */ + if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) { + up->acr &= ~UART_ACR_TXDIS; + serial_icr_write(up, UART_ACR, up->acr); + } +} + +/** + * serial8250_em485_start_tx() - generic ->rs485_start_tx() callback + * @up: uart 8250 port + * @toggle_ier: true to allow disabling receive interrupts + * + * Generic callback usable by 8250 uart drivers to start rs485 transmission. + * Assumes that setting the RTS bit in the MCR register means RTS is high. + * (Some chips use inverse semantics.) Further assumes that reception is + * stoppable by disabling the UART_IER_RDI interrupt. (Some chips set the + * UART_LSR_DR bit even when UART_IER_RDI is disabled, foiling this approach.) + */ +void serial8250_em485_start_tx(struct uart_8250_port *up, bool toggle_ier) +{ + unsigned char mcr = serial8250_in_MCR(up); + + if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX) && toggle_ier) + serial8250_stop_rx(&up->port); + + if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND) + mcr |= UART_MCR_RTS; + else + mcr &= ~UART_MCR_RTS; + serial8250_out_MCR(up, mcr); +} +EXPORT_SYMBOL_GPL(serial8250_em485_start_tx); + +/* Returns false, if start_tx_timer was setup to defer TX start */ +static bool start_tx_rs485(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct uart_8250_em485 *em485 = up->em485; + + /* + * While serial8250_em485_handle_stop_tx() is a noop if + * em485->active_timer != &em485->stop_tx_timer, it might happen that + * the timer is still armed and triggers only after the current bunch of + * chars is send and em485->active_timer == &em485->stop_tx_timer again. + * So cancel the timer. There is still a theoretical race condition if + * the timer is already running and only comes around to check for + * em485->active_timer when &em485->stop_tx_timer is armed again. + */ + if (em485->active_timer == &em485->stop_tx_timer) + hrtimer_try_to_cancel(&em485->stop_tx_timer); + + em485->active_timer = NULL; + + if (em485->tx_stopped) { + em485->tx_stopped = false; + + up->rs485_start_tx(up, true); + + if (up->port.rs485.delay_rts_before_send > 0) { + em485->active_timer = &em485->start_tx_timer; + start_hrtimer_ms(&em485->start_tx_timer, + up->port.rs485.delay_rts_before_send); + return false; + } + } + + return true; +} + +static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t) +{ + struct uart_8250_em485 *em485 = container_of(t, struct uart_8250_em485, + start_tx_timer); + struct uart_8250_port *p = em485->port; + + guard(uart_port_lock_irqsave)(&p->port); + + if (em485->active_timer == &em485->start_tx_timer) { + __start_tx(&p->port); + em485->active_timer = NULL; + } + + return HRTIMER_NORESTART; +} + +static void serial8250_start_tx(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct uart_8250_em485 *em485 = up->em485; + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&port->lock); + + if (!port->x_char && kfifo_is_empty(&port->state->port.xmit_fifo)) + return; + + serial8250_rpm_get_tx(up); + + if (em485) { + if ((em485->active_timer == &em485->start_tx_timer) || + !start_tx_rs485(port)) + return; + } + __start_tx(port); +} + +static void serial8250_throttle(struct uart_port *port) +{ + port->throttle(port); +} + +static void serial8250_unthrottle(struct uart_port *port) +{ + port->unthrottle(port); +} + +static void serial8250_disable_ms(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&port->lock); + + /* no MSR capabilities */ + if (up->bugs & UART_BUG_NOMSR) + return; + + mctrl_gpio_disable_ms_no_sync(up->gpios); + + up->ier &= ~UART_IER_MSI; + serial_port_out(port, UART_IER, up->ier); +} + +static void serial8250_enable_ms(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* Port locked to synchronize UART_IER access against the console. */ + lockdep_assert_held_once(&port->lock); + + /* no MSR capabilities */ + if (up->bugs & UART_BUG_NOMSR) + return; + + mctrl_gpio_enable_ms(up->gpios); + + up->ier |= UART_IER_MSI; + + guard(serial8250_rpm)(up); + serial_port_out(port, UART_IER, up->ier); +} + +void serial8250_read_char(struct uart_8250_port *up, u16 lsr) +{ + struct uart_port *port = &up->port; + u8 ch, flag = TTY_NORMAL; + + if (likely(lsr & UART_LSR_DR)) + ch = serial_in(up, UART_RX); + else + /* + * Intel 82571 has a Serial Over Lan device that will + * set UART_LSR_BI without setting UART_LSR_DR when + * it receives a break. To avoid reading from the + * receive buffer without UART_LSR_DR bit set, we + * just force the read character to be 0 + */ + ch = 0; + + port->icount.rx++; + + lsr |= up->lsr_saved_flags; + up->lsr_saved_flags = 0; + + if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) { + if (lsr & UART_LSR_BI) { + lsr &= ~(UART_LSR_FE | UART_LSR_PE); + port->icount.brk++; + /* + * We do the SysRQ and SAK checking + * here because otherwise the break + * may get masked by ignore_status_mask + * or read_status_mask. + */ + if (uart_handle_break(port)) + return; + } else if (lsr & UART_LSR_PE) + port->icount.parity++; + else if (lsr & UART_LSR_FE) + port->icount.frame++; + if (lsr & UART_LSR_OE) + port->icount.overrun++; + + /* + * Mask off conditions which should be ignored. + */ + lsr &= port->read_status_mask; + + if (lsr & UART_LSR_BI) { + dev_dbg(port->dev, "handling break\n"); + flag = TTY_BREAK; + } else if (lsr & UART_LSR_PE) + flag = TTY_PARITY; + else if (lsr & UART_LSR_FE) + flag = TTY_FRAME; + } + if (uart_prepare_sysrq_char(port, ch)) + return; + + uart_insert_char(port, lsr, UART_LSR_OE, ch, flag); +} +EXPORT_SYMBOL_GPL(serial8250_read_char); + +/* + * serial8250_rx_chars - Read characters. The first LSR value must be passed in. + * + * Returns LSR bits. The caller should rely only on non-Rx related LSR bits + * (such as THRE) because the LSR value might come from an already consumed + * character. + */ +u16 serial8250_rx_chars(struct uart_8250_port *up, u16 lsr) +{ + struct uart_port *port = &up->port; + int max_count = 256; + + do { + serial8250_read_char(up, lsr); + if (--max_count == 0) + break; + lsr = serial_in(up, UART_LSR); + } while (lsr & (UART_LSR_DR | UART_LSR_BI)); + + tty_flip_buffer_push(&port->state->port); + return lsr; +} +EXPORT_SYMBOL_GPL(serial8250_rx_chars); + +void serial8250_tx_chars(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + struct tty_port *tport = &port->state->port; + int count; + + if (port->x_char) { + uart_xchar_out(port, UART_TX); + return; + } + if (uart_tx_stopped(port)) { + serial8250_stop_tx(port); + return; + } + if (kfifo_is_empty(&tport->xmit_fifo)) { + __stop_tx(up); + return; + } + + count = up->tx_loadsz; + do { + unsigned char c; + + if (!uart_fifo_get(port, &c)) + break; + + serial_out(up, UART_TX, c); + if (up->bugs & UART_BUG_TXRACE) { + /* + * The Aspeed BMC virtual UARTs have a bug where data + * may get stuck in the BMC's Tx FIFO from bursts of + * writes on the APB interface. + * + * Delay back-to-back writes by a read cycle to avoid + * stalling the VUART. Read a register that won't have + * side-effects and discard the result. + */ + serial_in(up, UART_SCR); + } + + if ((up->capabilities & UART_CAP_HFIFO) && + !uart_lsr_tx_empty(serial_in(up, UART_LSR))) + break; + /* The BCM2835 MINI UART THRE bit is really a not-full bit. */ + if ((up->capabilities & UART_CAP_MINI) && + !(serial_in(up, UART_LSR) & UART_LSR_THRE)) + break; + } while (--count > 0); + + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) + uart_write_wakeup(port); + + /* + * With RPM enabled, we have to wait until the FIFO is empty before the + * HW can go idle. So we get here once again with empty FIFO and disable + * the interrupt and RPM in __stop_tx() + */ + if (kfifo_is_empty(&tport->xmit_fifo) && + !(up->capabilities & UART_CAP_RPM)) + __stop_tx(up); +} +EXPORT_SYMBOL_GPL(serial8250_tx_chars); + +/* Caller holds uart port lock */ +unsigned int serial8250_modem_status(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + unsigned int status = serial_in(up, UART_MSR); + + status |= up->msr_saved_flags; + up->msr_saved_flags = 0; + if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI && + port->state != NULL) { + if (status & UART_MSR_TERI) + port->icount.rng++; + if (status & UART_MSR_DDSR) + port->icount.dsr++; + if (status & UART_MSR_DDCD) + uart_handle_dcd_change(port, status & UART_MSR_DCD); + if (status & UART_MSR_DCTS) + uart_handle_cts_change(port, status & UART_MSR_CTS); + + wake_up_interruptible(&port->state->port.delta_msr_wait); + } + + return status; +} +EXPORT_SYMBOL_GPL(serial8250_modem_status); + +static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) +{ + switch (iir & 0x3f) { + case UART_IIR_THRI: + /* + * Postpone DMA or not decision to IIR_RDI or IIR_RX_TIMEOUT + * because it's impossible to do an informed decision about + * that with IIR_THRI. + * + * This also fixes one known DMA Rx corruption issue where + * DR is asserted but DMA Rx only gets a corrupted zero byte + * (too early DR?). + */ + return false; + case UART_IIR_RDI: + if (!up->dma->rx_running) + break; + fallthrough; + case UART_IIR_RLSI: + case UART_IIR_RX_TIMEOUT: + serial8250_rx_dma_flush(up); + return true; + } + return up->dma->rx_dma(up); +} + +/* + * This handles the interrupt from one port. + */ +int serial8250_handle_irq(struct uart_port *port, unsigned int iir) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct tty_port *tport = &port->state->port; + bool skip_rx = false; + unsigned long flags; + u16 status; + + if (iir & UART_IIR_NO_INT) + return 0; + + uart_port_lock_irqsave(port, &flags); + + status = serial_lsr_in(up); + + /* + * If port is stopped and there are no error conditions in the + * FIFO, then don't drain the FIFO, as this may lead to TTY buffer + * overflow. Not servicing, RX FIFO would trigger auto HW flow + * control when FIFO occupancy reaches preset threshold, thus + * halting RX. This only works when auto HW flow control is + * available. + */ + if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) && + (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) && + !(up->ier & (UART_IER_RLSI | UART_IER_RDI))) + skip_rx = true; + + if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) { + struct irq_data *d; + + d = irq_get_irq_data(port->irq); + if (d && irqd_is_wakeup_set(d)) + pm_wakeup_event(tport->tty->dev, 0); + if (!up->dma || handle_rx_dma(up, iir)) + status = serial8250_rx_chars(up, status); + } + serial8250_modem_status(up); + if ((status & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) { + if (!up->dma || up->dma->tx_err) + serial8250_tx_chars(up); + else if (!up->dma->tx_running) + __stop_tx(up); + } + + uart_unlock_and_check_sysrq_irqrestore(port, flags); + + return 1; +} +EXPORT_SYMBOL_GPL(serial8250_handle_irq); + +static int serial8250_default_handle_irq(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int iir; + + guard(serial8250_rpm)(up); + + iir = serial_port_in(port, UART_IIR); + return serial8250_handle_irq(port, iir); +} + +/* + * Newer 16550 compatible parts such as the SC16C650 & Altera 16550 Soft IP + * have a programmable TX threshold that triggers the THRE interrupt in + * the IIR register. In this case, the THRE interrupt indicates the FIFO + * has space available. Load it up with tx_loadsz bytes. + */ +static int serial8250_tx_threshold_handle_irq(struct uart_port *port) +{ + unsigned int iir = serial_port_in(port, UART_IIR); + + /* TX Threshold IRQ triggered so load up FIFO */ + if ((iir & UART_IIR_ID) == UART_IIR_THRI) { + struct uart_8250_port *up = up_to_u8250p(port); + + guard(uart_port_lock_irqsave)(port); + serial8250_tx_chars(up); + } + + iir = serial_port_in(port, UART_IIR); + return serial8250_handle_irq(port, iir); +} + +static unsigned int serial8250_tx_empty(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + guard(serial8250_rpm)(up); + guard(uart_port_lock_irqsave)(port); + + if (!serial8250_tx_dma_running(up) && uart_lsr_tx_empty(serial_lsr_in(up))) + return TIOCSER_TEMT; + + return 0; +} + +unsigned int serial8250_do_get_mctrl(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int status; + unsigned int val; + + scoped_guard(serial8250_rpm, up) + status = serial8250_modem_status(up); + + val = serial8250_MSR_to_TIOCM(status); + if (up->gpios) + return mctrl_gpio_get(up->gpios, &val); + + return val; +} +EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl); + +static unsigned int serial8250_get_mctrl(struct uart_port *port) +{ + if (port->get_mctrl) + return port->get_mctrl(port); + return serial8250_do_get_mctrl(port); +} + +void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned char mcr; + + mcr = serial8250_TIOCM_to_MCR(mctrl); + + mcr |= up->mcr; + + serial8250_out_MCR(up, mcr); +} +EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl); + +static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + if (port->rs485.flags & SER_RS485_ENABLED) + return; + + if (port->set_mctrl) + port->set_mctrl(port, mctrl); + else + serial8250_do_set_mctrl(port, mctrl); +} + +static void serial8250_break_ctl(struct uart_port *port, int break_state) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + guard(serial8250_rpm)(up); + guard(uart_port_lock_irqsave)(port); + + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_port_out(port, UART_LCR, up->lcr); +} + +/* Returns true if @bits were set, false on timeout */ +static bool wait_for_lsr(struct uart_8250_port *up, int bits) +{ + unsigned int status, tmout; + + /* + * Wait for a character to be sent. Fallback to a safe default + * timeout value if @frame_time is not available. + */ + if (up->port.frame_time) + tmout = up->port.frame_time * 2 / NSEC_PER_USEC; + else + tmout = 10000; + + for (;;) { + status = serial_lsr_in(up); + + if ((status & bits) == bits) + break; + if (--tmout == 0) + break; + udelay(1); + touch_nmi_watchdog(); + } + + return (tmout != 0); +} + +/* Wait for transmitter and holding register to empty with timeout */ +static void wait_for_xmitr(struct uart_8250_port *up, int bits) +{ + unsigned int tmout; + + wait_for_lsr(up, bits); + + /* Wait up to 1s for flow control if necessary */ + if (up->port.flags & UPF_CONS_FLOW) { + for (tmout = 1000000; tmout; tmout--) { + unsigned int msr = serial_in(up, UART_MSR); + up->msr_saved_flags |= msr & MSR_SAVE_FLAGS; + if (msr & UART_MSR_CTS) + break; + udelay(1); + touch_nmi_watchdog(); + } + } +} + +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context. + */ + +static int serial8250_get_poll_char(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + u16 lsr; + + guard(serial8250_rpm)(up); + + lsr = serial_port_in(port, UART_LSR); + if (!(lsr & UART_LSR_DR)) + return NO_POLL_CHAR; + + return serial_port_in(port, UART_RX); +} + + +static void serial8250_put_poll_char(struct uart_port *port, + unsigned char c) +{ + unsigned int ier; + struct uart_8250_port *up = up_to_u8250p(port); + + /* + * Normally the port is locked to synchronize UART_IER access + * against the console. However, this function is only used by + * KDB/KGDB, where it may not be possible to acquire the port + * lock because all other CPUs are quiesced. The quiescence + * should allow safe lockless usage here. + */ + + guard(serial8250_rpm)(up); + /* + * First save the IER then disable the interrupts + */ + ier = serial_port_in(port, UART_IER); + serial8250_clear_IER(up); + + wait_for_xmitr(up, UART_LSR_BOTH_EMPTY); + /* + * Send the character out. + */ + serial_port_out(port, UART_TX, c); + + /* + * Finally, wait for transmitter to become empty + * and restore the IER + */ + wait_for_xmitr(up, UART_LSR_BOTH_EMPTY); + serial_port_out(port, UART_IER, ier); +} + +#endif /* CONFIG_CONSOLE_POLL */ + +static void serial8250_startup_special(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + switch (port->type) { + case PORT_16C950: { + /* + * Wake up and initialize UART + * + * Synchronize UART_IER access against the console. + */ + guard(uart_port_lock_irqsave)(port); + up->acr = 0; + serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B); + serial_port_out(port, UART_EFR, UART_EFR_ECB); + serial_port_out(port, UART_IER, 0); + serial_port_out(port, UART_LCR, 0); + serial_icr_write(up, UART_CSR, 0); /* Reset the UART */ + serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B); + serial_port_out(port, UART_EFR, UART_EFR_ECB); + serial_port_out(port, UART_LCR, 0); + break; + } + case PORT_DA830: + /* + * Reset the port + * + * Synchronize UART_IER access against the console. + */ + scoped_guard(uart_port_lock_irqsave, port) { + serial_port_out(port, UART_IER, 0); + serial_port_out(port, UART_DA830_PWREMU_MGMT, 0); + } + mdelay(10); + + /* Enable Tx, Rx and free run mode */ + serial_port_out(port, UART_DA830_PWREMU_MGMT, + UART_DA830_PWREMU_MGMT_UTRST | + UART_DA830_PWREMU_MGMT_URRST | + UART_DA830_PWREMU_MGMT_FREE); + break; + case PORT_RSA: + rsa_enable(up); + break; + } +} + +static void serial8250_set_TRG_levels(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + switch (port->type) { + /* For a XR16C850, we need to set the trigger levels */ + case PORT_16850: { + u8 fctr; + + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + + fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX); + fctr |= UART_FCTR_TRGD; + serial_port_out(port, UART_FCTR, fctr | UART_FCTR_RX); + serial_port_out(port, UART_TRG, UART_TRG_96); + serial_port_out(port, UART_FCTR, fctr | UART_FCTR_TX); + serial_port_out(port, UART_TRG, UART_TRG_96); + + serial_port_out(port, UART_LCR, 0); + break; + } + /* For the Altera 16550 variants, set TX threshold trigger level. */ + case PORT_ALTR_16550_F32: + case PORT_ALTR_16550_F64: + case PORT_ALTR_16550_F128: + if (port->fifosize <= 1) + return; + + /* Bounds checking of TX threshold (valid 0 to fifosize-2) */ + if (up->tx_loadsz < 2 || up->tx_loadsz > port->fifosize) { + dev_err(port->dev, "TX FIFO Threshold errors, skipping\n"); + return; + } + serial_port_out(port, UART_ALTR_AFR, UART_ALTR_EN_TXFIFO_LW); + serial_port_out(port, UART_ALTR_TX_LOW, port->fifosize - up->tx_loadsz); + port->handle_irq = serial8250_tx_threshold_handle_irq; + break; + } +} + +static void serial8250_THRE_test(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + bool iir_noint1, iir_noint2; + + if (!port->irq) + return; + + if (up->port.flags & UPF_NO_THRE_TEST) + return; + + if (port->irqflags & IRQF_SHARED) + disable_irq_nosync(port->irq); + + /* + * Test for UARTs that do not reassert THRE when the transmitter is idle and the interrupt + * has already been cleared. Real 16550s should always reassert this interrupt whenever the + * transmitter is idle and the interrupt is enabled. Delays are necessary to allow register + * changes to become visible. + * + * Synchronize UART_IER access against the console. + */ + scoped_guard(uart_port_lock_irqsave, port) { + wait_for_xmitr(up, UART_LSR_THRE); + serial_port_out_sync(port, UART_IER, UART_IER_THRI); + udelay(1); /* allow THRE to set */ + iir_noint1 = serial_port_in(port, UART_IIR) & UART_IIR_NO_INT; + serial_port_out(port, UART_IER, 0); + serial_port_out_sync(port, UART_IER, UART_IER_THRI); + udelay(1); /* allow a working UART time to re-assert THRE */ + iir_noint2 = serial_port_in(port, UART_IIR) & UART_IIR_NO_INT; + serial_port_out(port, UART_IER, 0); + } + + if (port->irqflags & IRQF_SHARED) + enable_irq(port->irq); + + /* + * If the interrupt is not reasserted, or we otherwise don't trust the iir, setup a timer to + * kick the UART on a regular basis. + */ + if ((!iir_noint1 && iir_noint2) || up->port.flags & UPF_BUG_THRE) + up->bugs |= UART_BUG_THRE; +} + +static void serial8250_init_mctrl(struct uart_port *port) +{ + if (port->flags & UPF_FOURPORT) { + if (!port->irq) + port->mctrl |= TIOCM_OUT1; + } else { + /* Most PC uarts need OUT2 raised to enable interrupts. */ + if (port->irq) + port->mctrl |= TIOCM_OUT2; + } + + serial8250_set_mctrl(port, port->mctrl); +} + +static void serial8250_iir_txen_test(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + bool lsr_temt, iir_noint; + + if (port->quirks & UPQ_NO_TXEN_TEST) + return; + + /* Do a quick test to see if we receive an interrupt when we enable the TX irq. */ + serial_port_out(port, UART_IER, UART_IER_THRI); + lsr_temt = serial_port_in(port, UART_LSR) & UART_LSR_TEMT; + iir_noint = serial_port_in(port, UART_IIR) & UART_IIR_NO_INT; + serial_port_out(port, UART_IER, 0); + + /* + * Serial over Lan (SoL) hack: + * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be used for Serial Over + * Lan. Those chips take a longer time than a normal serial device to signalize that a + * transmission data was queued. Due to that, the above test generally fails. One solution + * would be to delay the reading of iir. However, this is not reliable, since the timeout is + * variable. So, in case of UPQ_NO_TXEN_TEST, let's just don't test if we receive TX irq. + * This way, we'll never enable UART_BUG_TXEN. + */ + if (lsr_temt && iir_noint) { + if (!(up->bugs & UART_BUG_TXEN)) { + up->bugs |= UART_BUG_TXEN; + dev_dbg(port->dev, "enabling bad tx status workarounds\n"); + } + return; + } + + /* FIXME: why is this needed? */ + up->bugs &= ~UART_BUG_TXEN; +} + +static void serial8250_initialize(struct uart_port *port) +{ + guard(uart_port_lock_irqsave)(port); + serial_port_out(port, UART_LCR, UART_LCR_WLEN8); + + serial8250_init_mctrl(port); + serial8250_iir_txen_test(port); +} + +int serial8250_do_startup(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + int retval; + + if (!port->fifosize) + port->fifosize = uart_config[port->type].fifo_size; + if (!up->tx_loadsz) + up->tx_loadsz = uart_config[port->type].tx_loadsz; + if (!up->capabilities) + up->capabilities = uart_config[port->type].flags; + up->mcr = 0; + + if (port->iotype != up->cur_iotype) + set_io_from_upio(port); + + guard(serial8250_rpm)(up); + + serial8250_startup_special(port); + + /* + * Clear the FIFO buffers and disable them. + * (they will be reenabled in set_termios()) + */ + serial8250_clear_fifos(up); + + serial8250_clear_interrupts(port); + + /* + * At this point, there's no way the LSR could still be 0xff; + * if it is, then bail out, because there's likely no UART + * here. + */ + if (!(port->flags & UPF_BUGGY_UART) && + (serial_port_in(port, UART_LSR) == 0xff)) { + dev_info_ratelimited(port->dev, "LSR safety check engaged!\n"); + return -ENODEV; + } + + serial8250_set_TRG_levels(port); + + /* Check if we need to have shared IRQs */ + if (port->irq && (up->port.flags & UPF_SHARE_IRQ)) + up->port.irqflags |= IRQF_SHARED; + + retval = up->ops->setup_irq(up); + if (retval) + return retval; + + serial8250_THRE_test(port); + + up->ops->setup_timer(up); + + serial8250_initialize(port); + + /* + * Clear the interrupt registers again for luck, and clear the + * saved flags to avoid getting false values from polling + * routines or the previous session. + */ + serial8250_clear_interrupts(port); + up->lsr_saved_flags = 0; + up->msr_saved_flags = 0; + + /* + * Request DMA channels for both RX and TX. + */ + if (up->dma) { + const char *msg = NULL; + + if (uart_console(port)) + msg = "forbid DMA for kernel console"; + else if (serial8250_request_dma(up)) + msg = "failed to request DMA"; + if (msg) { + dev_warn_ratelimited(port->dev, "%s\n", msg); + up->dma = NULL; + } + } + + /* + * Set the IER shadow for rx interrupts but defer actual interrupt + * enable until after the FIFOs are enabled; otherwise, an already- + * active sender can swamp the interrupt handler with "too much work". + */ + up->ier = UART_IER_RLSI | UART_IER_RDI; + + if (port->flags & UPF_FOURPORT) { + unsigned int icp; + /* + * Enable interrupts on the AST Fourport board + */ + icp = (port->iobase & 0xfe0) | 0x01f; + outb_p(0x80, icp); + inb_p(icp); + } + + return 0; +} +EXPORT_SYMBOL_GPL(serial8250_do_startup); + +static int serial8250_startup(struct uart_port *port) +{ + if (port->startup) + return port->startup(port); + return serial8250_do_startup(port); +} + +void serial8250_do_shutdown(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + serial8250_rpm_get(up); + /* + * Disable interrupts from this port + * + * Synchronize UART_IER access against the console. + */ + scoped_guard(uart_port_lock_irqsave, port) { + up->ier = 0; + serial_port_out(port, UART_IER, 0); + } + + synchronize_irq(port->irq); + + if (up->dma) + serial8250_release_dma(up); + + scoped_guard(uart_port_lock_irqsave, port) { + if (port->flags & UPF_FOURPORT) { + /* reset interrupts on the AST Fourport board */ + inb((port->iobase & 0xfe0) | 0x1f); + port->mctrl |= TIOCM_OUT1; + } else + port->mctrl &= ~TIOCM_OUT2; + + serial8250_set_mctrl(port, port->mctrl); + } + + /* + * Disable break condition and FIFOs + */ + serial_port_out(port, UART_LCR, + serial_port_in(port, UART_LCR) & ~UART_LCR_SBC); + serial8250_clear_fifos(up); + + rsa_disable(up); + + /* + * Read data port to reset things, and then unlink from + * the IRQ chain. + */ + serial_port_in(port, UART_RX); + serial8250_rpm_put(up); + + up->ops->release_irq(up); +} +EXPORT_SYMBOL_GPL(serial8250_do_shutdown); + +static void serial8250_shutdown(struct uart_port *port) +{ + if (port->shutdown) + port->shutdown(port); + else + serial8250_do_shutdown(port); +} + +static void serial8250_flush_buffer(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + if (up->dma) + serial8250_tx_dma_flush(up); +} + +static unsigned int serial8250_do_get_divisor(struct uart_port *port, unsigned int baud) +{ + upf_t magic_multiplier = port->flags & UPF_MAGIC_MULTIPLIER; + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int quot; + + /* + * Handle magic divisors for baud rates above baud_base on SMSC + * Super I/O chips. We clamp custom rates from clk/6 and clk/12 + * up to clk/4 (0x8001) and clk/8 (0x8002) respectively. These + * magic divisors actually reprogram the baud rate generator's + * reference clock derived from chips's 14.318MHz clock input. + * + * Documentation claims that with these magic divisors the base + * frequencies of 7.3728MHz and 3.6864MHz are used respectively + * for the extra baud rates of 460800bps and 230400bps rather + * than the usual base frequency of 1.8462MHz. However empirical + * evidence contradicts that. + * + * Instead bit 7 of the DLM register (bit 15 of the divisor) is + * effectively used as a clock prescaler selection bit for the + * base frequency of 7.3728MHz, always used. If set to 0, then + * the base frequency is divided by 4 for use by the Baud Rate + * Generator, for the usual arrangement where the value of 1 of + * the divisor produces the baud rate of 115200bps. Conversely, + * if set to 1 and high-speed operation has been enabled with the + * Serial Port Mode Register in the Device Configuration Space, + * then the base frequency is supplied directly to the Baud Rate + * Generator, so for the divisor values of 0x8001, 0x8002, 0x8003, + * 0x8004, etc. the respective baud rates produced are 460800bps, + * 230400bps, 153600bps, 115200bps, etc. + * + * In all cases only low 15 bits of the divisor are used to divide + * the baud base and therefore 32767 is the maximum divisor value + * possible, even though documentation says that the programmable + * Baud Rate Generator is capable of dividing the internal PLL + * clock by any divisor from 1 to 65535. + */ + if (magic_multiplier && baud >= port->uartclk / 6) + quot = 0x8001; + else if (magic_multiplier && baud >= port->uartclk / 12) + quot = 0x8002; + else + quot = uart_get_divisor(port, baud); + + /* + * Oxford Semi 952 rev B workaround + */ + if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0) + quot++; + + return quot; +} + +static unsigned int serial8250_get_divisor(struct uart_port *port, + unsigned int baud, + unsigned int *frac) +{ + if (port->get_divisor) + return port->get_divisor(port, baud, frac); + + return serial8250_do_get_divisor(port, baud); +} + +static unsigned char serial8250_compute_lcr(struct uart_8250_port *up, tcflag_t c_cflag) +{ + u8 lcr = UART_LCR_WLEN(tty_get_char_size(c_cflag)); + + if (c_cflag & CSTOPB) + lcr |= UART_LCR_STOP; + if (c_cflag & PARENB) + lcr |= UART_LCR_PARITY; + if (!(c_cflag & PARODD)) + lcr |= UART_LCR_EPAR; + if (c_cflag & CMSPAR) + lcr |= UART_LCR_SPAR; + + return lcr; +} + +void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud, + unsigned int quot) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* Workaround to enable 115200 baud on OMAP1510 internal ports */ + if (is_omap1510_8250(up)) { + if (baud == 115200) { + quot = 1; + serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1); + } else + serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0); + } + + /* + * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2, + * otherwise just set DLAB + */ + if (up->capabilities & UART_NATSEMI) + serial_port_out(port, UART_LCR, 0xe0); + else + serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB); + + serial_dl_write(up, quot); +} +EXPORT_SYMBOL_GPL(serial8250_do_set_divisor); + +static void serial8250_set_divisor(struct uart_port *port, unsigned int baud, + unsigned int quot, unsigned int quot_frac) +{ + if (port->set_divisor) + port->set_divisor(port, baud, quot, quot_frac); + else + serial8250_do_set_divisor(port, baud, quot); +} + +static unsigned int serial8250_get_baud_rate(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ + unsigned int tolerance = port->uartclk / 100; + unsigned int min; + unsigned int max; + + /* + * Handle magic divisors for baud rates above baud_base on SMSC + * Super I/O chips. Enable custom rates of clk/4 and clk/8, but + * disable divisor values beyond 32767, which are unavailable. + */ + if (port->flags & UPF_MAGIC_MULTIPLIER) { + min = port->uartclk / 16 / UART_DIV_MAX >> 1; + max = (port->uartclk + tolerance) / 4; + } else { + min = port->uartclk / 16 / UART_DIV_MAX; + max = (port->uartclk + tolerance) / 16; + } + + /* + * Ask the core to calculate the divisor for us. + * Allow 1% tolerance at the upper limit so uart clks marginally + * slower than nominal still match standard baud rates without + * causing transmission errors. + */ + return uart_get_baud_rate(port, termios, old, min, max); +} + +/* + * Note in order to avoid the tty port mutex deadlock don't use the next method + * within the uart port callbacks. Primarily it's supposed to be utilized to + * handle a sudden reference clock rate change. + */ +void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk) +{ + struct tty_port *tport = &port->state->port; + + scoped_guard(tty_port_tty, tport) { + struct tty_struct *tty = scoped_tty(); + + guard(rwsem_write)(&tty->termios_rwsem); + guard(mutex)(&tport->mutex); + + if (port->uartclk == uartclk) + return; + + port->uartclk = uartclk; + + if (!tty_port_initialized(tport)) + return; + + serial8250_do_set_termios(port, &tty->termios, NULL); + + return; + } + guard(mutex)(&tport->mutex); + port->uartclk = uartclk; +} +EXPORT_SYMBOL_GPL(serial8250_update_uartclk); + +static void serial8250_set_mini(struct uart_port *port, struct ktermios *termios) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + if (!(up->capabilities & UART_CAP_MINI)) + return; + + termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR); + + tcflag_t csize = termios->c_cflag & CSIZE; + if (csize == CS5 || csize == CS6) { + termios->c_cflag &= ~CSIZE; + termios->c_cflag |= CS7; + } +} + +static void serial8250_set_trigger_for_slow_speed(struct uart_port *port, struct ktermios *termios, + unsigned int baud) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + if (!(up->capabilities & UART_CAP_FIFO)) + return; + if (port->fifosize <= 1) + return; + if (baud >= 2400) + return; + if (up->dma) + return; + + up->fcr &= ~UART_FCR_TRIGGER_MASK; + up->fcr |= UART_FCR_TRIGGER_1; +} + +/* + * MCR-based auto flow control. When AFE is enabled, RTS will be deasserted when the receive FIFO + * contains more characters than the trigger, or the MCR RTS bit is cleared. + */ +static void serial8250_set_afe(struct uart_port *port, struct ktermios *termios) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + if (!(up->capabilities & UART_CAP_AFE)) + return; + + up->mcr &= ~UART_MCR_AFE; + if (termios->c_cflag & CRTSCTS) + up->mcr |= UART_MCR_AFE; +} + +static void serial8250_set_errors_and_ignores(struct uart_port *port, struct ktermios *termios) +{ + /* + * Specify which conditions may be considered for error handling and the ignoring of + * characters. The actual ignoring of characters only occurs if the bit is set in + * @ignore_status_mask as well. + */ + port->read_status_mask = UART_LSR_OE | UART_LSR_DR; + if (termios->c_iflag & INPCK) + port->read_status_mask |= UART_LSR_FE | UART_LSR_PE; + if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) + port->read_status_mask |= UART_LSR_BI; + + /* Characters to ignore */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE; + if (termios->c_iflag & IGNBRK) { + port->ignore_status_mask |= UART_LSR_BI; + /* + * If we're ignoring parity and break indicators, ignore overruns too (for real raw + * support). + */ + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART_LSR_OE; + } + + /* ignore all characters if CREAD is not set */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= UART_LSR_DR; +} + +static void serial8250_set_ier(struct uart_port *port, struct ktermios *termios) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* CTS flow control flag and modem status interrupts */ + up->ier &= ~UART_IER_MSI; + if (!(up->bugs & UART_BUG_NOMSR) && UART_ENABLE_MS(&up->port, termios->c_cflag)) + up->ier |= UART_IER_MSI; + if (up->capabilities & UART_CAP_UUE) + up->ier |= UART_IER_UUE; + if (up->capabilities & UART_CAP_RTOIE) + up->ier |= UART_IER_RTOIE; + + serial_port_out(port, UART_IER, up->ier); +} + +static void serial8250_set_efr(struct uart_port *port, struct ktermios *termios) +{ + struct uart_8250_port *up = up_to_u8250p(port); + u8 efr_reg = UART_EFR; + u8 efr = 0; + + if (!(up->capabilities & UART_CAP_EFR)) + return; + + /* + * TI16C752/Startech hardware flow control. FIXME: + * - TI16C752 requires control thresholds to be set. + * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled. + */ + if (termios->c_cflag & CRTSCTS) + efr |= UART_EFR_CTS; + + if (port->flags & UPF_EXAR_EFR) + efr_reg = UART_XR_EFR; + + serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B); + serial_port_out(port, efr_reg, efr); +} + +static void serial8250_set_fcr(struct uart_port *port, struct ktermios *termios) +{ + struct uart_8250_port *up = up_to_u8250p(port); + bool is_16750 = port->type == PORT_16750; + + if (is_16750) + serial_port_out(port, UART_FCR, up->fcr); + + /* + * LCR DLAB must be reset to enable 64-byte FIFO mode. If the FCR is written without DLAB + * set, this mode will be disabled. + */ + serial_port_out(port, UART_LCR, up->lcr); + + if (is_16750) + return; + + /* emulated UARTs (Lucent Venus 167x) need two steps */ + if (up->fcr & UART_FCR_ENABLE_FIFO) + serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO); + + serial_port_out(port, UART_FCR, up->fcr); +} + +void +serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int baud, quot, frac = 0; + u8 lcr; + + serial8250_set_mini(port, termios); + lcr = serial8250_compute_lcr(up, termios->c_cflag); + baud = serial8250_get_baud_rate(port, termios, old); + quot = serial8250_get_divisor(port, baud, &frac); + + /* + * Ok, we're now changing the port state. Do it with interrupts disabled. + * + * Synchronize UART_IER access against the console. + */ + scoped_guard(serial8250_rpm, up) { + guard(uart_port_lock_irqsave)(port); + + up->lcr = lcr; + serial8250_set_trigger_for_slow_speed(port, termios, baud); + serial8250_set_afe(port, termios); + uart_update_timeout(port, termios->c_cflag, baud); + serial8250_set_errors_and_ignores(port, termios); + serial8250_set_ier(port, termios); + serial8250_set_efr(port, termios); + serial8250_set_divisor(port, baud, quot, frac); + serial8250_set_fcr(port, termios); + serial8250_set_mctrl(port, port->mctrl); + } + + /* Don't rewrite B0 */ + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); +} +EXPORT_SYMBOL(serial8250_do_set_termios); + +static void +serial8250_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + if (port->set_termios) + port->set_termios(port, termios, old); + else + serial8250_do_set_termios(port, termios, old); +} + +void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios) +{ + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; + guard(uart_port_lock_irq)(port); + serial8250_enable_ms(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { + guard(uart_port_lock_irq)(port); + serial8250_disable_ms(port); + } + } +} +EXPORT_SYMBOL_GPL(serial8250_do_set_ldisc); + +static void +serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios) +{ + if (port->set_ldisc) + port->set_ldisc(port, termios); + else + serial8250_do_set_ldisc(port, termios); +} + +void serial8250_do_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) +{ + struct uart_8250_port *p = up_to_u8250p(port); + + serial8250_set_sleep(p, state != 0); +} +EXPORT_SYMBOL(serial8250_do_pm); + +static void +serial8250_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) +{ + if (port->pm) + port->pm(port, state, oldstate); + else + serial8250_do_pm(port, state, oldstate); +} + +static unsigned int serial8250_port_size(struct uart_8250_port *pt) +{ + if (pt->port.mapsize) + return pt->port.mapsize; + if (is_omap1_8250(pt)) + return 0x16 << pt->port.regshift; + + return 8 << pt->port.regshift; +} + +/* + * Resource handling. + */ +static int serial8250_request_std_resource(struct uart_8250_port *up) +{ + unsigned int size = serial8250_port_size(up); + struct uart_port *port = &up->port; + + switch (port->iotype) { + case UPIO_AU: + case UPIO_TSI: + case UPIO_MEM32: + case UPIO_MEM32BE: + case UPIO_MEM16: + case UPIO_MEM: + if (!port->mapbase) + return -EINVAL; + + if (!request_mem_region(port->mapbase, size, "serial")) + return -EBUSY; + + if (port->flags & UPF_IOREMAP) { + port->membase = ioremap(port->mapbase, size); + if (!port->membase) { + release_mem_region(port->mapbase, size); + return -ENOMEM; + } + } + return 0; + case UPIO_HUB6: + case UPIO_PORT: + if (!request_region(port->iobase, size, "serial")) + return -EBUSY; + return 0; + case UPIO_UNKNOWN: + break; + } + + return 0; +} + +static void serial8250_release_std_resource(struct uart_8250_port *up) +{ + unsigned int size = serial8250_port_size(up); + struct uart_port *port = &up->port; + + switch (port->iotype) { + case UPIO_AU: + case UPIO_TSI: + case UPIO_MEM32: + case UPIO_MEM32BE: + case UPIO_MEM16: + case UPIO_MEM: + if (!port->mapbase) + break; + + if (port->flags & UPF_IOREMAP) { + iounmap(port->membase); + port->membase = NULL; + } + + release_mem_region(port->mapbase, size); + break; + + case UPIO_HUB6: + case UPIO_PORT: + release_region(port->iobase, size); + break; + case UPIO_UNKNOWN: + break; + } +} + +static void serial8250_release_port(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + serial8250_release_std_resource(up); +} + +static int serial8250_request_port(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + return serial8250_request_std_resource(up); +} + +static int fcr_get_rxtrig_bytes(struct uart_8250_port *up) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + unsigned char bytes; + + bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)]; + + return bytes ? bytes : -EOPNOTSUPP; +} + +static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + int i; + + if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)]) + return -EOPNOTSUPP; + + for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) { + if (bytes < conf_type->rxtrig_bytes[i]) + /* Use the nearest lower value */ + return (--i) << UART_FCR_R_TRIG_SHIFT; + } + + return UART_FCR_R_TRIG_11; +} + +static int do_get_rxtrig(struct tty_port *port) +{ + struct uart_state *state = container_of(port, struct uart_state, port); + struct uart_port *uport = state->uart_port; + struct uart_8250_port *up = up_to_u8250p(uport); + + if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1) + return -EINVAL; + + return fcr_get_rxtrig_bytes(up); +} + +static int do_serial8250_get_rxtrig(struct tty_port *port) +{ + int rxtrig_bytes; + + mutex_lock(&port->mutex); + rxtrig_bytes = do_get_rxtrig(port); + mutex_unlock(&port->mutex); + + return rxtrig_bytes; +} + +static ssize_t rx_trig_bytes_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct tty_port *port = dev_get_drvdata(dev); + int rxtrig_bytes; + + rxtrig_bytes = do_serial8250_get_rxtrig(port); + if (rxtrig_bytes < 0) + return rxtrig_bytes; + + return sysfs_emit(buf, "%d\n", rxtrig_bytes); +} + +static int do_set_rxtrig(struct tty_port *port, unsigned char bytes) +{ + struct uart_state *state = container_of(port, struct uart_state, port); + struct uart_port *uport = state->uart_port; + struct uart_8250_port *up = up_to_u8250p(uport); + int rxtrig; + + if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1) + return -EINVAL; + + rxtrig = bytes_to_fcr_rxtrig(up, bytes); + if (rxtrig < 0) + return rxtrig; + + serial8250_clear_fifos(up); + up->fcr &= ~UART_FCR_TRIGGER_MASK; + up->fcr |= (unsigned char)rxtrig; + serial_out(up, UART_FCR, up->fcr); + return 0; +} + +static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes) +{ + int ret; + + mutex_lock(&port->mutex); + ret = do_set_rxtrig(port, bytes); + mutex_unlock(&port->mutex); + + return ret; +} + +static ssize_t rx_trig_bytes_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct tty_port *port = dev_get_drvdata(dev); + unsigned char bytes; + int ret; + + if (!count) + return -EINVAL; + + ret = kstrtou8(buf, 10, &bytes); + if (ret < 0) + return ret; + + ret = do_serial8250_set_rxtrig(port, bytes); + if (ret < 0) + return ret; + + return count; +} + +static DEVICE_ATTR_RW(rx_trig_bytes); + +static struct attribute *serial8250_dev_attrs[] = { + &dev_attr_rx_trig_bytes.attr, + NULL +}; + +static struct attribute_group serial8250_dev_attr_group = { + .attrs = serial8250_dev_attrs, +}; + +static void register_dev_spec_attr_grp(struct uart_8250_port *up) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + + if (conf_type->rxtrig_bytes[0]) + up->port.attr_group = &serial8250_dev_attr_group; +} + +static void serial8250_config_port(struct uart_port *port, int flags) +{ + struct uart_8250_port *up = up_to_u8250p(port); + int ret; + + /* + * Find the region that we can probe for. This in turn + * tells us whether we can probe for the type of port. + */ + ret = serial8250_request_std_resource(up); + if (ret < 0) + return; + + if (port->iotype != up->cur_iotype) + set_io_from_upio(port); + + if (flags & UART_CONFIG_TYPE) + autoconfig(up); + + /* HW bugs may trigger IRQ while IIR == NO_INT */ + if (port->type == PORT_TEGRA) + up->bugs |= UART_BUG_NOMSR; + + if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ) + autoconfig_irq(up); + + if (port->type == PORT_UNKNOWN) + serial8250_release_std_resource(up); + + register_dev_spec_attr_grp(up); + up->fcr = uart_config[up->port.type].fcr; +} + +static int +serial8250_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + if (ser->irq >= irq_get_nr_irqs() || ser->irq < 0 || + ser->baud_base < 9600 || ser->type < PORT_UNKNOWN || + ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS || + ser->type == PORT_STARTECH) + return -EINVAL; + return 0; +} + +static const char *serial8250_type(struct uart_port *port) +{ + int type = port->type; + + if (type >= ARRAY_SIZE(uart_config)) + type = 0; + return uart_config[type].name; +} + +static const struct uart_ops serial8250_pops = { + .tx_empty = serial8250_tx_empty, + .set_mctrl = serial8250_set_mctrl, + .get_mctrl = serial8250_get_mctrl, + .stop_tx = serial8250_stop_tx, + .start_tx = serial8250_start_tx, + .throttle = serial8250_throttle, + .unthrottle = serial8250_unthrottle, + .stop_rx = serial8250_stop_rx, + .enable_ms = serial8250_enable_ms, + .break_ctl = serial8250_break_ctl, + .startup = serial8250_startup, + .shutdown = serial8250_shutdown, + .flush_buffer = serial8250_flush_buffer, + .set_termios = serial8250_set_termios, + .set_ldisc = serial8250_set_ldisc, + .pm = serial8250_pm, + .type = serial8250_type, + .release_port = serial8250_release_port, + .request_port = serial8250_request_port, + .config_port = serial8250_config_port, + .verify_port = serial8250_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif +}; + +void serial8250_init_port(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + + spin_lock_init(&port->lock); + port->ctrl_id = 0; + port->pm = NULL; + port->ops = &serial8250_pops; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); + + up->cur_iotype = UPIO_UNKNOWN; +} +EXPORT_SYMBOL_GPL(serial8250_init_port); + +void serial8250_set_defaults(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + + if (up->port.flags & UPF_FIXED_TYPE) { + unsigned int type = up->port.type; + + if (!up->port.fifosize) + up->port.fifosize = uart_config[type].fifo_size; + if (!up->tx_loadsz) + up->tx_loadsz = uart_config[type].tx_loadsz; + if (!up->capabilities) + up->capabilities = uart_config[type].flags; + } + + set_io_from_upio(port); + + /* default dma handlers */ + if (up->dma) { + if (!up->dma->tx_dma) + up->dma->tx_dma = serial8250_tx_dma; + if (!up->dma->rx_dma) + up->dma->rx_dma = serial8250_rx_dma; + } +} +EXPORT_SYMBOL_GPL(serial8250_set_defaults); + +#ifdef CONFIG_SERIAL_8250_CONSOLE + +static void serial8250_console_putchar(struct uart_port *port, unsigned char ch) +{ + serial_port_out(port, UART_TX, ch); +} + +static void serial8250_console_wait_putchar(struct uart_port *port, unsigned char ch) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + wait_for_xmitr(up, UART_LSR_THRE); + serial8250_console_putchar(port, ch); +} + +/* + * Restore serial console when h/w power-off detected + */ +static void serial8250_console_restore(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + struct ktermios termios; + unsigned int baud, quot, frac = 0; + + termios.c_cflag = port->cons->cflag; + termios.c_ispeed = port->cons->ispeed; + termios.c_ospeed = port->cons->ospeed; + if (port->state->port.tty && termios.c_cflag == 0) { + termios.c_cflag = port->state->port.tty->termios.c_cflag; + termios.c_ispeed = port->state->port.tty->termios.c_ispeed; + termios.c_ospeed = port->state->port.tty->termios.c_ospeed; + } + + baud = serial8250_get_baud_rate(port, &termios, NULL); + quot = serial8250_get_divisor(port, baud, &frac); + + serial8250_set_divisor(port, baud, quot, frac); + serial_port_out(port, UART_LCR, up->lcr); + serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS); +} + +static void fifo_wait_for_lsr(struct uart_8250_port *up, unsigned int count) +{ + unsigned int i; + + for (i = 0; i < count; i++) { + if (wait_for_lsr(up, UART_LSR_THRE)) + return; + } +} + +/* + * Print a string to the serial port using the device FIFO + * + * It sends fifosize bytes and then waits for the fifo + * to get empty. + */ +static void serial8250_console_fifo_write(struct uart_8250_port *up, + const char *s, unsigned int count) +{ + const char *end = s + count; + unsigned int fifosize = up->tx_loadsz; + struct uart_port *port = &up->port; + unsigned int tx_count = 0; + bool cr_sent = false; + unsigned int i; + + while (s != end) { + /* Allow timeout for each byte of a possibly full FIFO */ + fifo_wait_for_lsr(up, fifosize); + + for (i = 0; i < fifosize && s != end; ++i) { + if (*s == '\n' && !cr_sent) { + serial8250_console_putchar(port, '\r'); + cr_sent = true; + } else { + serial8250_console_putchar(port, *s++); + cr_sent = false; + } + } + tx_count = i; + } + + /* + * Allow timeout for each byte written since the caller will only wait + * for UART_LSR_BOTH_EMPTY using the timeout of a single character + */ + fifo_wait_for_lsr(up, tx_count); +} + +/* + * Print a string to the serial port trying not to disturb + * any possible real use of the port... + * + * The console_lock must be held when we get here. + * + * Doing runtime PM is really a bad idea for the kernel console. + * Thus, we assume the function is called when device is powered up. + */ +void serial8250_console_write(struct uart_8250_port *up, const char *s, + unsigned int count) +{ + struct uart_8250_em485 *em485 = up->em485; + struct uart_port *port = &up->port; + unsigned long flags; + unsigned int ier, use_fifo; + int locked = 1; + + touch_nmi_watchdog(); + + if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); + else + uart_port_lock_irqsave(port, &flags); + + /* + * First save the IER then disable the interrupts + */ + ier = serial_port_in(port, UART_IER); + serial8250_clear_IER(up); + + /* check scratch reg to see if port powered off during system sleep */ + if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { + serial8250_console_restore(up); + up->canary = 0; + } + + if (em485) { + if (em485->tx_stopped) + up->rs485_start_tx(up, false); + mdelay(port->rs485.delay_rts_before_send); + } + + use_fifo = (up->capabilities & UART_CAP_FIFO) && + /* + * BCM283x requires to check the fifo + * after each byte. + */ + !(up->capabilities & UART_CAP_MINI) && + /* + * tx_loadsz contains the transmit fifo size + */ + up->tx_loadsz > 1 && + (up->fcr & UART_FCR_ENABLE_FIFO) && + port->state && + test_bit(TTY_PORT_INITIALIZED, &port->state->port.iflags) && + /* + * After we put a data in the fifo, the controller will send + * it regardless of the CTS state. Therefore, only use fifo + * if we don't use control flow. + */ + !(up->port.flags & UPF_CONS_FLOW); + + if (likely(use_fifo)) + serial8250_console_fifo_write(up, s, count); + else + uart_console_write(port, s, count, serial8250_console_wait_putchar); + + /* + * Finally, wait for transmitter to become empty + * and restore the IER + */ + wait_for_xmitr(up, UART_LSR_BOTH_EMPTY); + + if (em485) { + mdelay(port->rs485.delay_rts_after_send); + if (em485->tx_stopped) + up->rs485_stop_tx(up, false); + } + + serial_port_out(port, UART_IER, ier); + + /* + * The receive handling will happen properly because the + * receive ready bit will still be set; it is not cleared + * on read. However, modem control will not, we must + * call it if we have saved something in the saved flags + * while processing with interrupts off. + */ + if (up->msr_saved_flags) + serial8250_modem_status(up); + + if (locked) + uart_port_unlock_irqrestore(port, flags); +} + +static unsigned int probe_baud(struct uart_port *port) +{ + unsigned char lcr, dll, dlm; + unsigned int quot; + + lcr = serial_port_in(port, UART_LCR); + serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB); + dll = serial_port_in(port, UART_DLL); + dlm = serial_port_in(port, UART_DLM); + serial_port_out(port, UART_LCR, lcr); + + quot = (dlm << 8) | dll; + return (port->uartclk / 16) / quot; +} + +int serial8250_console_setup(struct uart_port *port, char *options, bool probe) +{ + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + int ret; + + if (!port->iobase && !port->membase) + return -ENODEV; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + else if (probe) + baud = probe_baud(port); + + ret = uart_set_options(port, port->cons, baud, parity, bits, flow); + if (ret) + return ret; + + if (port->dev) + pm_runtime_get_sync(port->dev); + + return 0; +} + +int serial8250_console_exit(struct uart_port *port) +{ + if (port->dev) + pm_runtime_put_sync(port->dev); + + return 0; +} + +#endif /* CONFIG_SERIAL_8250_CONSOLE */ + +MODULE_DESCRIPTION("Base port operations for 8250/16550-type serial ports"); +MODULE_LICENSE("GPL"); |