diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_of.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_of.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c new file mode 100644 index 000000000000..9799356b65f7 --- /dev/null +++ b/drivers/tty/serial/8250/8250_of.c @@ -0,0 +1,374 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Serial Port driver for Open Firmware platform devices + * + * Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp. + */ + +#include <linux/bits.h> +#include <linux/console.h> +#include <linux/math.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/serial_core.h> +#include <linux/serial_reg.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/of_platform.h> +#include <linux/pm_runtime.h> +#include <linux/clk.h> +#include <linux/reset.h> +#include <linux/notifier.h> + +#include "8250.h" + +struct of_serial_info { + struct clk *clk; + struct clk *bus_clk; + struct reset_control *rst; + int type; + int line; + struct notifier_block clk_notifier; +}; + +/* Nuvoton NPCM timeout register */ +#define UART_NPCM_TOR 7 +#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */ + +static int npcm_startup(struct uart_port *port) +{ + /* + * Nuvoton calls the scratch register 'UART_TOR' (timeout + * register). Enable it, and set TIOC (timeout interrupt + * comparator) to be 0x20 for correct operation. + */ + serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20); + + return serial8250_do_startup(port); +} + +/* Nuvoton NPCM UARTs have a custom divisor calculation */ +static unsigned int npcm_get_divisor(struct uart_port *port, unsigned int baud, + unsigned int *frac) +{ + return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2; +} + +static int npcm_setup(struct uart_port *port) +{ + port->get_divisor = npcm_get_divisor; + port->startup = npcm_startup; + return 0; +} + +static inline struct of_serial_info *clk_nb_to_info(struct notifier_block *nb) +{ + return container_of(nb, struct of_serial_info, clk_notifier); +} + +static int of_platform_serial_clk_notifier_cb(struct notifier_block *nb, unsigned long event, + void *data) +{ + struct of_serial_info *info = clk_nb_to_info(nb); + struct uart_8250_port *port8250 = serial8250_get_port(info->line); + struct clk_notifier_data *ndata = data; + + if (event == POST_RATE_CHANGE) { + serial8250_update_uartclk(&port8250->port, ndata->new_rate); + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + +/* + * Fill a struct uart_port for a given device node + */ +static int of_platform_serial_setup(struct platform_device *ofdev, + int type, struct uart_8250_port *up, + struct of_serial_info *info) +{ + struct resource resource; + struct device *dev = &ofdev->dev; + struct device_node *np = dev->of_node; + struct uart_port *port = &up->port; + u32 spd; + int ret; + + memset(port, 0, sizeof(*port)); + + pm_runtime_enable(&ofdev->dev); + pm_runtime_get_sync(&ofdev->dev); + + ret = of_address_to_resource(np, 0, &resource); + if (ret) { + dev_err_probe(dev, ret, "invalid address\n"); + goto err_pmruntime; + } + + port->dev = &ofdev->dev; + port->flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE; + spin_lock_init(&port->lock); + + if (resource_type(&resource) == IORESOURCE_IO) { + port->iobase = resource.start; + } else { + port->mapbase = resource.start; + port->mapsize = resource_size(&resource); + port->flags |= UPF_IOREMAP; + } + + ret = uart_read_and_validate_port_properties(port); + if (ret) + goto err_pmruntime; + + /* Get clk rate through clk driver if present */ + if (!port->uartclk) { + struct clk *bus_clk; + + bus_clk = devm_clk_get_optional_enabled(dev, "bus"); + if (IS_ERR(bus_clk)) { + ret = dev_err_probe(dev, PTR_ERR(bus_clk), "failed to get bus clock\n"); + goto err_pmruntime; + } + + /* If the bus clock is required, core clock must be named */ + info->clk = devm_clk_get_enabled(dev, bus_clk ? "core" : NULL); + if (IS_ERR(info->clk)) { + ret = dev_err_probe(dev, PTR_ERR(info->clk), "failed to get clock\n"); + goto err_pmruntime; + } + + info->bus_clk = bus_clk; + port->uartclk = clk_get_rate(info->clk); + } + /* If current-speed was set, then try not to change it. */ + if (of_property_read_u32(np, "current-speed", &spd) == 0) + port->custom_divisor = port->uartclk / (16 * spd); + + /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */ + if (of_device_is_compatible(np, "mrvl,mmp-uart")) + port->regshift = 2; + + info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL); + if (IS_ERR(info->rst)) { + ret = PTR_ERR(info->rst); + goto err_pmruntime; + } + + ret = reset_control_deassert(info->rst); + if (ret) + goto err_pmruntime; + + port->type = type; + port->rs485_config = serial8250_em485_config; + port->rs485_supported = serial8250_em485_supported; + up->rs485_start_tx = serial8250_em485_start_tx; + up->rs485_stop_tx = serial8250_em485_stop_tx; + + switch (type) { + case PORT_RT2880: + ret = rt288x_setup(port); + break; + case PORT_NPCM: + ret = npcm_setup(port); + break; + default: + /* Nothing to do */ + ret = 0; + break; + } + if (ret) + goto err_pmruntime; + + if (IS_REACHABLE(CONFIG_SERIAL_8250_FSL) && + (of_device_is_compatible(np, "fsl,ns16550") || + of_device_is_compatible(np, "fsl,16550-FIFO64"))) { + port->handle_irq = fsl8250_handle_irq; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); + } + + return 0; +err_pmruntime: + pm_runtime_put_sync(&ofdev->dev); + pm_runtime_disable(&ofdev->dev); + return ret; +} + +/* + * Try to register a serial port + */ +static int of_platform_serial_probe(struct platform_device *ofdev) +{ + struct of_serial_info *info; + struct uart_8250_port port8250; + unsigned int port_type; + u32 tx_threshold; + int ret; + + if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) && + of_device_is_compatible(ofdev->dev.of_node, "brcm,bcm7271-uart")) + return -ENODEV; + + port_type = (unsigned long)of_device_get_match_data(&ofdev->dev); + if (port_type == PORT_UNKNOWN) + return -EINVAL; + + if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas")) + return -EBUSY; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (info == NULL) + return -ENOMEM; + + memset(&port8250, 0, sizeof(port8250)); + ret = of_platform_serial_setup(ofdev, port_type, &port8250, info); + if (ret) + goto err_free; + + if (port8250.port.fifosize) + port8250.capabilities = UART_CAP_FIFO; + + /* Check for TX FIFO threshold & set tx_loadsz */ + if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold", + &tx_threshold) == 0) && + (tx_threshold < port8250.port.fifosize)) + port8250.tx_loadsz = port8250.port.fifosize - tx_threshold; + + if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control")) + port8250.capabilities |= UART_CAP_AFE; + + if (of_property_read_u32(ofdev->dev.of_node, + "overrun-throttle-ms", + &port8250.overrun_backoff_time_ms) != 0) + port8250.overrun_backoff_time_ms = 0; + + ret = serial8250_register_8250_port(&port8250); + if (ret < 0) + goto err_dispose; + + info->type = port_type; + info->line = ret; + platform_set_drvdata(ofdev, info); + + if (info->clk) { + info->clk_notifier.notifier_call = of_platform_serial_clk_notifier_cb; + ret = clk_notifier_register(info->clk, &info->clk_notifier); + if (ret) { + dev_err_probe(port8250.port.dev, ret, "Failed to set the clock notifier\n"); + goto err_unregister; + } + } + + return 0; +err_unregister: + serial8250_unregister_port(info->line); +err_dispose: + pm_runtime_put_sync(&ofdev->dev); + pm_runtime_disable(&ofdev->dev); +err_free: + kfree(info); + return ret; +} + +/* + * Release a line + */ +static void of_platform_serial_remove(struct platform_device *ofdev) +{ + struct of_serial_info *info = platform_get_drvdata(ofdev); + + if (info->clk) + clk_notifier_unregister(info->clk, &info->clk_notifier); + + serial8250_unregister_port(info->line); + + reset_control_assert(info->rst); + pm_runtime_put_sync(&ofdev->dev); + pm_runtime_disable(&ofdev->dev); + kfree(info); +} + +#ifdef CONFIG_PM_SLEEP +static int of_serial_suspend(struct device *dev) +{ + struct of_serial_info *info = dev_get_drvdata(dev); + struct uart_8250_port *port8250 = serial8250_get_port(info->line); + struct uart_port *port = &port8250->port; + + serial8250_suspend_port(info->line); + + if (!uart_console(port) || console_suspend_enabled) { + pm_runtime_put_sync(dev); + clk_disable_unprepare(info->clk); + clk_disable_unprepare(info->bus_clk); + } + return 0; +} + +static int of_serial_resume(struct device *dev) +{ + struct of_serial_info *info = dev_get_drvdata(dev); + struct uart_8250_port *port8250 = serial8250_get_port(info->line); + struct uart_port *port = &port8250->port; + + if (!uart_console(port) || console_suspend_enabled) { + pm_runtime_get_sync(dev); + clk_prepare_enable(info->bus_clk); + clk_prepare_enable(info->clk); + } + + serial8250_resume_port(info->line); + + return 0; +} +#endif +static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); + +/* + * A few common types, add more as needed. + */ +static const struct of_device_id of_platform_serial_table[] = { + { .compatible = "ns8250", .data = (void *)PORT_8250, }, + { .compatible = "ns16450", .data = (void *)PORT_16450, }, + { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, + { .compatible = "ns16550", .data = (void *)PORT_16550, }, + { .compatible = "ns16750", .data = (void *)PORT_16750, }, + { .compatible = "ns16850", .data = (void *)PORT_16850, }, + { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, }, + { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, }, + { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, }, + { .compatible = "altr,16550-FIFO32", + .data = (void *)PORT_ALTR_16550_F32, }, + { .compatible = "altr,16550-FIFO64", + .data = (void *)PORT_ALTR_16550_F64, }, + { .compatible = "altr,16550-FIFO128", + .data = (void *)PORT_ALTR_16550_F128, }, + { .compatible = "fsl,16550-FIFO64", + .data = (void *)PORT_16550A_FSL64, }, + { .compatible = "mediatek,mtk-btif", + .data = (void *)PORT_MTK_BTIF, }, + { .compatible = "mrvl,mmp-uart", + .data = (void *)PORT_XSCALE, }, + { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, }, + { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, }, + { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, }, + { /* end of list */ }, +}; +MODULE_DEVICE_TABLE(of, of_platform_serial_table); + +static struct platform_driver of_platform_serial_driver = { + .driver = { + .name = "of_serial", + .of_match_table = of_platform_serial_table, + .pm = &of_serial_pm_ops, + }, + .probe = of_platform_serial_probe, + .remove = of_platform_serial_remove, +}; + +module_platform_driver(of_platform_serial_driver); + +MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); |