diff options
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
| -rw-r--r-- | drivers/tty/serial/stm32-usart.c | 2095 |
1 files changed, 1636 insertions, 459 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 033856287ca2..ad06b760cfca 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1,16 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) Maxime Coquelin 2015 + * Copyright (C) STMicroelectronics SA 2017 * Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com> - * Gerald Baeza <gerald.baeza@st.com> - * License terms: GNU General Public License (GPL), version 2 + * Gerald Baeza <gerald.baeza@foss.st.com> + * Erwan Le Ray <erwan.leray@foss.st.com> * * Inspired by st-asc.c from STMicroelectronics (c) */ -#if defined(CONFIG_SERIAL_STM32_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) -#define SUPPORT_SYSRQ -#endif - +#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/console.h> #include <linux/delay.h> @@ -23,8 +22,10 @@ #include <linux/module.h> #include <linux/of.h> #include <linux/of_platform.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> +#include <linux/pm_wakeirq.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/spinlock.h> @@ -32,17 +33,91 @@ #include <linux/tty_flip.h> #include <linux/tty.h> +#include "serial_mctrl_gpio.h" #include "stm32-usart.h" -static void stm32_stop_tx(struct uart_port *port); -static void stm32_transmit_chars(struct uart_port *port); + +/* Register offsets */ +static struct stm32_usart_info __maybe_unused stm32f4_info = { + .ofs = { + .isr = 0x00, + .rdr = 0x04, + .tdr = 0x04, + .brr = 0x08, + .cr1 = 0x0c, + .cr2 = 0x10, + .cr3 = 0x14, + .gtpr = 0x18, + .rtor = UNDEF_REG, + .rqr = UNDEF_REG, + .icr = UNDEF_REG, + .presc = UNDEF_REG, + .hwcfgr1 = UNDEF_REG, + }, + .cfg = { + .uart_enable_bit = 13, + .has_7bits_data = false, + } +}; + +static struct stm32_usart_info __maybe_unused stm32f7_info = { + .ofs = { + .cr1 = 0x00, + .cr2 = 0x04, + .cr3 = 0x08, + .brr = 0x0c, + .gtpr = 0x10, + .rtor = 0x14, + .rqr = 0x18, + .isr = 0x1c, + .icr = 0x20, + .rdr = 0x24, + .tdr = 0x28, + .presc = UNDEF_REG, + .hwcfgr1 = UNDEF_REG, + }, + .cfg = { + .uart_enable_bit = 0, + .has_7bits_data = true, + .has_swap = true, + } +}; + +static struct stm32_usart_info __maybe_unused stm32h7_info = { + .ofs = { + .cr1 = 0x00, + .cr2 = 0x04, + .cr3 = 0x08, + .brr = 0x0c, + .gtpr = 0x10, + .rtor = 0x14, + .rqr = 0x18, + .isr = 0x1c, + .icr = 0x20, + .rdr = 0x24, + .tdr = 0x28, + .presc = 0x2c, + .hwcfgr1 = 0x3f0, + }, + .cfg = { + .uart_enable_bit = 0, + .has_7bits_data = true, + .has_swap = true, + .has_wakeup = true, + .has_fifo = true, + } +}; + +static void stm32_usart_stop_tx(struct uart_port *port); +static void stm32_usart_transmit_chars(struct uart_port *port); +static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch); static inline struct stm32_port *to_stm32_port(struct uart_port *port) { return container_of(port, struct stm32_port, port); } -static void stm32_set_bits(struct uart_port *port, u32 reg, u32 bits) +static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits) { u32 val; @@ -51,7 +126,7 @@ static void stm32_set_bits(struct uart_port *port, u32 reg, u32 bits) writel_relaxed(val, port->membase + reg); } -static void stm32_clr_bits(struct uart_port *port, u32 reg, u32 bits) +static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits) { u32 val; @@ -60,486 +135,1183 @@ static void stm32_clr_bits(struct uart_port *port, u32 reg, u32 bits) writel_relaxed(val, port->membase + reg); } -static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res, - bool threaded) +static unsigned int stm32_usart_tx_empty(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - enum dma_status status; - struct dma_tx_state state; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - *sr = readl_relaxed(port->membase + ofs->isr); + if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC) + return TIOCSER_TEMT; + + return 0; +} + +static void stm32_usart_rs485_rts_enable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } +} + +static void stm32_usart_rs485_rts_disable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } +} + +static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE, + u32 delay_DDE, u32 baud) +{ + u32 rs485_deat_dedt; + u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT); + bool over8; + + *cr3 |= USART_CR3_DEM; + over8 = *cr1 & USART_CR1_OVER8; + + *cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK); + + if (over8) + rs485_deat_dedt = delay_ADE * baud * 8; + else + rs485_deat_dedt = delay_ADE * baud * 16; - if (threaded && stm32_port->rx_ch) { - status = dmaengine_tx_status(stm32_port->rx_ch, - stm32_port->rx_ch->cookie, - &state); - if ((status == DMA_IN_PROGRESS) && - (*last_res != state.residue)) - return 1; + rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000); + rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ? + rs485_deat_dedt_max : rs485_deat_dedt; + rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) & + USART_CR1_DEAT_MASK; + *cr1 |= rs485_deat_dedt; + + if (over8) + rs485_deat_dedt = delay_DDE * baud * 8; + else + rs485_deat_dedt = delay_DDE * baud * 16; + + rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000); + rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ? + rs485_deat_dedt_max : rs485_deat_dedt; + rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) & + USART_CR1_DEDT_MASK; + *cr1 |= rs485_deat_dedt; +} + +static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485conf) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_config *cfg = &stm32_port->info->cfg; + u32 usartdiv, baud, cr1, cr3; + bool over8; + + stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + + if (rs485conf->flags & SER_RS485_ENABLED) { + cr1 = readl_relaxed(port->membase + ofs->cr1); + cr3 = readl_relaxed(port->membase + ofs->cr3); + usartdiv = readl_relaxed(port->membase + ofs->brr); + usartdiv = usartdiv & GENMASK(15, 0); + over8 = cr1 & USART_CR1_OVER8; + + if (over8) + usartdiv = usartdiv | (usartdiv & GENMASK(4, 0)) + << USART_BRR_04_R_SHIFT; + + baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv); + stm32_usart_config_reg_rs485(&cr1, &cr3, + rs485conf->delay_rts_before_send, + rs485conf->delay_rts_after_send, + baud); + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) + cr3 &= ~USART_CR3_DEP; else - return 0; - } else if (*sr & USART_SR_RXNE) { - return 1; + cr3 |= USART_CR3_DEP; + + writel_relaxed(cr3, port->membase + ofs->cr3); + writel_relaxed(cr1, port->membase + ofs->cr1); + + if (!port->rs485_rx_during_tx_gpio) + rs485conf->flags |= SER_RS485_RX_DURING_TX; + + } else { + stm32_usart_clr_bits(port, ofs->cr3, + USART_CR3_DEM | USART_CR3_DEP); + stm32_usart_clr_bits(port, ofs->cr1, + USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK); } + + stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + + /* Adjust RTS polarity in case it's driven in software */ + if (stm32_usart_tx_empty(port)) + stm32_usart_rs485_rts_disable(port); + else + stm32_usart_rs485_rts_enable(port); + return 0; } -static unsigned long -stm32_get_char(struct uart_port *port, u32 *sr, int *last_res) +static int stm32_usart_init_rs485(struct uart_port *port, + struct platform_device *pdev) +{ + struct serial_rs485 *rs485conf = &port->rs485; + + rs485conf->flags = 0; + rs485conf->delay_rts_before_send = 0; + rs485conf->delay_rts_after_send = 0; + + if (!pdev->dev.of_node) + return -ENODEV; + + return uart_get_rs485_mode(port); +} + +static bool stm32_usart_rx_dma_started(struct stm32_port *stm32_port) +{ + return stm32_port->rx_ch ? stm32_port->rx_dma_busy : false; +} + +static void stm32_usart_rx_dma_terminate(struct stm32_port *stm32_port) +{ + dmaengine_terminate_async(stm32_port->rx_ch); + stm32_port->rx_dma_busy = false; +} + +static int stm32_usart_dma_pause_resume(struct stm32_port *stm32_port, + struct dma_chan *chan, + enum dma_status expected_status, + int dmaengine_pause_or_resume(struct dma_chan *), + bool stm32_usart_xx_dma_started(struct stm32_port *), + void stm32_usart_xx_dma_terminate(struct stm32_port *)) +{ + struct uart_port *port = &stm32_port->port; + enum dma_status dma_status; + int ret; + + if (!stm32_usart_xx_dma_started(stm32_port)) + return -EPERM; + + dma_status = dmaengine_tx_status(chan, chan->cookie, NULL); + if (dma_status != expected_status) + return -EAGAIN; + + ret = dmaengine_pause_or_resume(chan); + if (ret) { + dev_err(port->dev, "DMA failed with error code: %d\n", ret); + stm32_usart_xx_dma_terminate(stm32_port); + } + return ret; +} + +static int stm32_usart_rx_dma_pause(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch, + DMA_IN_PROGRESS, dmaengine_pause, + stm32_usart_rx_dma_started, + stm32_usart_rx_dma_terminate); +} + +static int stm32_usart_rx_dma_resume(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch, + DMA_PAUSED, dmaengine_resume, + stm32_usart_rx_dma_started, + stm32_usart_rx_dma_terminate); +} + +/* Return true when data is pending (in pio mode), and false when no data is pending. */ +static bool stm32_usart_pending_rx_pio(struct uart_port *port, u32 *sr) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - unsigned long c; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - if (stm32_port->rx_ch) { - c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--]; - if ((*last_res) == 0) - *last_res = RX_BUF_L; - return c; - } else { - return readl_relaxed(port->membase + ofs->rdr); + *sr = readl_relaxed(port->membase + ofs->isr); + /* Get pending characters in RDR or FIFO */ + if (*sr & USART_SR_RXNE) { + /* Get all pending characters from the RDR or the FIFO when using interrupts */ + if (!stm32_usart_rx_dma_started(stm32_port)) + return true; + + /* Handle only RX data errors when using DMA */ + if (*sr & USART_SR_ERR_MASK) + return true; } + + return false; } -static void stm32_receive_chars(struct uart_port *port, bool threaded) +static u8 stm32_usart_get_char_pio(struct uart_port *port) { - struct tty_port *tport = &port->state->port; struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; unsigned long c; - u32 sr; - char flag; - static int last_res = RX_BUF_L; - if (port->irq_wake) - pm_wakeup_event(tport->tty->dev, 0); + c = readl_relaxed(port->membase + ofs->rdr); + /* Apply RDR data mask */ + c &= stm32_port->rdr_mask; + + return c; +} + +static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned int size = 0; + u32 sr; + u8 c, flag; - while (stm32_pending_rx(port, &sr, &last_res, threaded)) { + while (stm32_usart_pending_rx_pio(port, &sr)) { sr |= USART_SR_DUMMY_RX; - c = stm32_get_char(port, &sr, &last_res); flag = TTY_NORMAL; - port->icount.rx++; + /* + * Status bits has to be cleared before reading the RDR: + * In FIFO mode, reading the RDR will pop the next data + * (if any) along with its status bits into the SR. + * Not doing so leads to misalignement between RDR and SR, + * and clear status bits of the next rx data. + * + * Clear errors flags for stm32f7 and stm32h7 compatible + * devices. On stm32f4 compatible devices, the error bit is + * cleared by the sequence [read SR - read DR]. + */ + if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG) + writel_relaxed(sr & USART_SR_ERR_MASK, + port->membase + ofs->icr); + + c = stm32_usart_get_char_pio(port); + port->icount.rx++; + size++; if (sr & USART_SR_ERR_MASK) { - if (sr & USART_SR_LBD) { - port->icount.brk++; - if (uart_handle_break(port)) - continue; - } else if (sr & USART_SR_ORE) { - if (ofs->icr != UNDEF_REG) - writel_relaxed(USART_ICR_ORECF, - port->membase + - ofs->icr); + if (sr & USART_SR_ORE) { port->icount.overrun++; } else if (sr & USART_SR_PE) { port->icount.parity++; } else if (sr & USART_SR_FE) { - port->icount.frame++; + /* Break detection if character is null */ + if (!c) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } else { + port->icount.frame++; + } } sr &= port->read_status_mask; - if (sr & USART_SR_LBD) - flag = TTY_BREAK; - else if (sr & USART_SR_PE) + if (sr & USART_SR_PE) { flag = TTY_PARITY; - else if (sr & USART_SR_FE) - flag = TTY_FRAME; + } else if (sr & USART_SR_FE) { + if (!c) + flag = TTY_BREAK; + else + flag = TTY_FRAME; + } } - if (uart_handle_sysrq_char(port, c)) + if (uart_prepare_sysrq_char(port, c)) continue; uart_insert_char(port, sr, USART_SR_ORE, c, flag); } - spin_unlock(&port->lock); - tty_flip_buffer_push(tport); - spin_lock(&port->lock); + return size; } -static void stm32_tx_dma_complete(void *arg) +static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size) { - struct uart_port *port = arg; - struct stm32_port *stm32port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32port->info->ofs; - unsigned int isr; - int ret; + struct stm32_port *stm32_port = to_stm32_port(port); + struct tty_port *ttyport = &stm32_port->port.state->port; + unsigned char *dma_start; + int dma_count, i; - ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, - isr, - (isr & USART_SR_TC), - 10, 100000); + dma_start = stm32_port->rx_buf + (RX_BUF_L - stm32_port->last_res); - if (ret) - dev_err(port->dev, "terminal count not set\n"); + /* + * Apply rdr_mask on buffer in order to mask parity bit. + * This loop is useless in cs8 mode because DMA copies only + * 8 bits and already ignores parity bit. + */ + if (!(stm32_port->rdr_mask == (BIT(8) - 1))) + for (i = 0; i < dma_size; i++) + *(dma_start + i) &= stm32_port->rdr_mask; + + dma_count = tty_insert_flip_string(ttyport, dma_start, dma_size); + port->icount.rx += dma_count; + if (dma_count != dma_size) + port->icount.buf_overrun++; + stm32_port->last_res -= dma_count; + if (stm32_port->last_res == 0) + stm32_port->last_res = RX_BUF_L; +} - if (ofs->icr == UNDEF_REG) - stm32_clr_bits(port, ofs->isr, USART_SR_TC); - else - stm32_set_bits(port, ofs->icr, USART_CR_TC); +static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + unsigned int dma_size, size = 0; + + /* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */ + if (stm32_port->rx_dma_state.residue > stm32_port->last_res) { + /* Conditional first part: from last_res to end of DMA buffer */ + dma_size = stm32_port->last_res; + stm32_usart_push_buffer_dma(port, dma_size); + size = dma_size; + } - stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT); - stm32port->tx_dma_busy = false; + dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue; + stm32_usart_push_buffer_dma(port, dma_size); + size += dma_size; - /* Let's see if we have pending data to send */ - stm32_transmit_chars(port); + return size; } -static void stm32_transmit_chars_pio(struct uart_port *port) +static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - struct circ_buf *xmit = &port->state->xmit; - unsigned int isr; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + enum dma_status rx_dma_status; + u32 sr; + unsigned int size = 0; + + if (stm32_usart_rx_dma_started(stm32_port) || force_dma_flush) { + rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch, + stm32_port->rx_ch->cookie, + &stm32_port->rx_dma_state); + if (rx_dma_status == DMA_IN_PROGRESS || + rx_dma_status == DMA_PAUSED) { + /* Empty DMA buffer */ + size = stm32_usart_receive_chars_dma(port); + sr = readl_relaxed(port->membase + ofs->isr); + if (sr & USART_SR_ERR_MASK) { + /* Disable DMA request line */ + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); + + /* Switch to PIO mode to handle the errors */ + size += stm32_usart_receive_chars_pio(port); + + /* Switch back to DMA mode */ + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR); + } + } else { + /* Disable RX DMA */ + stm32_usart_rx_dma_terminate(stm32_port); + /* Fall back to interrupt mode */ + dev_dbg(port->dev, "DMA error, fallback to irq mode\n"); + size = stm32_usart_receive_chars_pio(port); + } + } else { + size = stm32_usart_receive_chars_pio(port); + } + + return size; +} + +static void stm32_usart_rx_dma_complete(void *arg) +{ + struct uart_port *port = arg; + struct tty_port *tport = &port->state->port; + unsigned int size; + unsigned long flags; + + uart_port_lock_irqsave(port, &flags); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) + tty_flip_buffer_push(tport); +} + +static int stm32_usart_rx_dma_start_or_resume(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct dma_async_tx_descriptor *desc; + enum dma_status rx_dma_status; int ret; - if (stm32_port->tx_dma_busy) { - stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT); - stm32_port->tx_dma_busy = false; + if (stm32_port->throttled) + return 0; + + if (stm32_port->rx_dma_busy) { + rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch, + stm32_port->rx_ch->cookie, + NULL); + if (rx_dma_status == DMA_IN_PROGRESS) + return 0; + + if (rx_dma_status == DMA_PAUSED && !stm32_usart_rx_dma_resume(stm32_port)) + return 0; + + dev_err(port->dev, "DMA failed : status error.\n"); + stm32_usart_rx_dma_terminate(stm32_port); } - ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, - isr, - (isr & USART_SR_TXE), - 10, 100); + stm32_port->rx_dma_busy = true; - if (ret) - dev_err(port->dev, "tx empty not set\n"); + stm32_port->last_res = RX_BUF_L; + /* Prepare a DMA cyclic transaction */ + desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch, + stm32_port->rx_dma_buf, + RX_BUF_L, RX_BUF_P, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(port->dev, "rx dma prep cyclic failed\n"); + stm32_port->rx_dma_busy = false; + return -ENODEV; + } + + desc->callback = stm32_usart_rx_dma_complete; + desc->callback_param = port; + + /* Push current DMA transaction in the pending queue */ + ret = dma_submit_error(dmaengine_submit(desc)); + if (ret) { + dmaengine_terminate_sync(stm32_port->rx_ch); + stm32_port->rx_dma_busy = false; + return ret; + } + + /* Issue pending DMA requests */ + dma_async_issue_pending(stm32_port->rx_ch); + + return 0; +} + +static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port) +{ + dmaengine_terminate_async(stm32_port->tx_ch); + stm32_port->tx_dma_busy = false; +} + +static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port) +{ + /* + * We cannot use the function "dmaengine_tx_status" to know the + * status of DMA. This function does not show if the "dma complete" + * callback of the DMA transaction has been called. So we prefer + * to use "tx_dma_busy" flag to prevent dual DMA transaction at the + * same time. + */ + return stm32_port->tx_dma_busy; +} - stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE); +static int stm32_usart_tx_dma_pause(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch, + DMA_IN_PROGRESS, dmaengine_pause, + stm32_usart_tx_dma_started, + stm32_usart_tx_dma_terminate); +} - writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr); - xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); - port->icount.tx++; +static int stm32_usart_tx_dma_resume(struct stm32_port *stm32_port) +{ + return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch, + DMA_PAUSED, dmaengine_resume, + stm32_usart_tx_dma_started, + stm32_usart_tx_dma_terminate); } -static void stm32_transmit_chars_dma(struct uart_port *port) +static void stm32_usart_tx_dma_complete(void *arg) { + struct uart_port *port = arg; struct stm32_port *stm32port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32port->info->ofs; - struct circ_buf *xmit = &port->state->xmit; - struct dma_async_tx_descriptor *desc = NULL; - dma_cookie_t cookie; - unsigned int count, i; + unsigned long flags; - if (stm32port->tx_dma_busy) - return; + stm32_usart_tx_dma_terminate(stm32port); - stm32port->tx_dma_busy = true; + /* Let's see if we have pending data to send */ + uart_port_lock_irqsave(port, &flags); + stm32_usart_transmit_chars(port); + uart_port_unlock_irqrestore(port, flags); +} + +static void stm32_usart_tx_interrupt_enable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + /* + * Enables TX FIFO threashold irq when FIFO is enabled, + * or TX empty irq when FIFO is disabled + */ + if (stm32_port->fifoen && stm32_port->txftcfg >= 0) + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE); + else + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE); +} + +static void stm32_usart_tc_interrupt_enable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - count = uart_circ_chars_pending(xmit); + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TCIE); +} - if (count > TX_BUF_L) - count = TX_BUF_L; +static void stm32_usart_tx_interrupt_disable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - if (xmit->tail < xmit->head) { - memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count); - } else { - size_t one = UART_XMIT_SIZE - xmit->tail; - size_t two; + if (stm32_port->fifoen && stm32_port->txftcfg >= 0) + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE); + else + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE); +} + +static void stm32_usart_tc_interrupt_disable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE); +} + +static void stm32_usart_transmit_chars_pio(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + struct tty_port *tport = &port->state->port; + + while (1) { + unsigned char ch; - if (one > count) - one = count; - two = count - one; + /* Check that TDR is empty before filling FIFO */ + if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) + break; - memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one); - if (two) - memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two); + if (!uart_fifo_get(port, &ch)) + break; + + writel_relaxed(ch, port->membase + ofs->tdr); } + /* rely on TXE irq (mask or unmask) for sending remaining data */ + if (kfifo_is_empty(&tport->xmit_fifo)) + stm32_usart_tx_interrupt_disable(port); + else + stm32_usart_tx_interrupt_enable(port); +} + +static void stm32_usart_transmit_chars_dma(struct uart_port *port) +{ + struct stm32_port *stm32port = to_stm32_port(port); + struct tty_port *tport = &port->state->port; + struct dma_async_tx_descriptor *desc = NULL; + unsigned int count; + int ret; + + if (stm32_usart_tx_dma_started(stm32port)) { + ret = stm32_usart_tx_dma_resume(stm32port); + if (ret < 0 && ret != -EAGAIN) + goto fallback_err; + return; + } + + count = kfifo_out_peek(&tport->xmit_fifo, &stm32port->tx_buf[0], + TX_BUF_L); + desc = dmaengine_prep_slave_single(stm32port->tx_ch, stm32port->tx_dma_buf, count, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); - if (!desc) { - for (i = count; i > 0; i--) - stm32_transmit_chars_pio(port); - return; - } + if (!desc) + goto fallback_err; + + /* + * Set "tx_dma_busy" flag. This flag will be released when + * dmaengine_terminate_async will be called. This flag helps + * transmit_chars_dma not to start another DMA transaction + * if the callback of the previous is not yet called. + */ + stm32port->tx_dma_busy = true; - desc->callback = stm32_tx_dma_complete; + desc->callback = stm32_usart_tx_dma_complete; desc->callback_param = port; /* Push current DMA TX transaction in the pending queue */ - cookie = dmaengine_submit(desc); + /* DMA no yet started, safe to free resources */ + ret = dma_submit_error(dmaengine_submit(desc)); + if (ret) { + dev_err(port->dev, "DMA failed with error code: %d\n", ret); + stm32_usart_tx_dma_terminate(stm32port); + goto fallback_err; + } /* Issue pending DMA TX requests */ dma_async_issue_pending(stm32port->tx_ch); - stm32_clr_bits(port, ofs->isr, USART_SR_TC); - stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT); + uart_xmit_advance(port, count); + + return; - xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); - port->icount.tx += count; +fallback_err: + stm32_usart_transmit_chars_pio(port); } -static void stm32_transmit_chars(struct uart_port *port) +static void stm32_usart_transmit_chars(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - struct circ_buf *xmit = &port->state->xmit; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + struct tty_port *tport = &port->state->port; + u32 isr; + int ret; + + if (!stm32_port->hw_flow_control && + port->rs485.flags & SER_RS485_ENABLED && + (port->x_char || + !(kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)))) { + stm32_usart_tc_interrupt_disable(port); + stm32_usart_rs485_rts_enable(port); + } if (port->x_char) { - if (stm32_port->tx_dma_busy) - stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + /* dma terminate may have been called in case of dma pause failure */ + stm32_usart_tx_dma_pause(stm32_port); + + /* Check that TDR is empty before filling FIFO */ + ret = + readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, + (isr & USART_SR_TXE), + 10, 1000); + if (ret) + dev_warn(port->dev, "1 character may be erased\n"); + writel_relaxed(port->x_char, port->membase + ofs->tdr); port->x_char = 0; port->icount.tx++; - if (stm32_port->tx_dma_busy) - stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT); - return; - } - if (uart_tx_stopped(port)) { - stm32_stop_tx(port); + /* dma terminate may have been called in case of dma resume failure */ + stm32_usart_tx_dma_resume(stm32_port); return; } - if (uart_circ_empty(xmit)) { - stm32_stop_tx(port); + if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) { + stm32_usart_tx_interrupt_disable(port); return; } + if (ofs->icr == UNDEF_REG) + stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC); + else + writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr); + if (stm32_port->tx_ch) - stm32_transmit_chars_dma(port); + stm32_usart_transmit_chars_dma(port); else - stm32_transmit_chars_pio(port); + stm32_usart_transmit_chars_pio(port); - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port); - if (uart_circ_empty(xmit)) - stm32_stop_tx(port); + if (kfifo_is_empty(&tport->xmit_fifo)) { + stm32_usart_tx_interrupt_disable(port); + if (!stm32_port->hw_flow_control && + port->rs485.flags & SER_RS485_ENABLED) { + stm32_usart_tc_interrupt_enable(port); + } + } } -static irqreturn_t stm32_interrupt(int irq, void *ptr) +static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) { struct uart_port *port = ptr; + struct tty_port *tport = &port->state->port; struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; - - spin_lock(&port->lock); + unsigned int size; + irqreturn_t ret = IRQ_NONE; sr = readl_relaxed(port->membase + ofs->isr); - if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch)) - stm32_receive_chars(port, false); + if (!stm32_port->hw_flow_control && + port->rs485.flags & SER_RS485_ENABLED && + (sr & USART_SR_TC)) { + stm32_usart_tc_interrupt_disable(port); + stm32_usart_rs485_rts_disable(port); + ret = IRQ_HANDLED; + } - if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) - stm32_transmit_chars(port); + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) { + writel_relaxed(USART_ICR_RTOCF, + port->membase + ofs->icr); + ret = IRQ_HANDLED; + } - spin_unlock(&port->lock); + if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) { + /* Clear wake up flag and disable wake up interrupt */ + writel_relaxed(USART_ICR_WUCF, + port->membase + ofs->icr); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); + if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) + pm_wakeup_event(tport->tty->dev, 0); + ret = IRQ_HANDLED; + } - if (stm32_port->rx_ch) - return IRQ_WAKE_THREAD; - else - return IRQ_HANDLED; + /* + * rx errors in dma mode has to be handled ASAP to avoid overrun as the DMA request + * line has been masked by HW and rx data are stacking in FIFO. + */ + if (!stm32_port->throttled) { + if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) || + ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) { + uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) + tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; + } + } + + if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) { + uart_port_lock(port); + stm32_usart_transmit_chars(port); + uart_port_unlock(port); + ret = IRQ_HANDLED; + } + + /* Receiver timeout irq for DMA RX */ + if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) { + uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) + tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; + } + + return ret; } -static irqreturn_t stm32_threaded_interrupt(int irq, void *ptr) +static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl) { - struct uart_port *port = ptr; struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - spin_lock(&port->lock); - - if (stm32_port->rx_ch) - stm32_receive_chars(port, true); - - spin_unlock(&port->lock); + if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE); + else + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE); - return IRQ_HANDLED; + mctrl_gpio_set(stm32_port->gpios, mctrl); } -static unsigned int stm32_tx_empty(struct uart_port *port) +static unsigned int stm32_usart_get_mctrl(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned int ret; + + /* This routine is used to get signals of: DCD, DSR, RI, and CTS */ + ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; - return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE; + return mctrl_gpio_get(stm32_port->gpios, &ret); } -static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl) +static void stm32_usart_enable_ms(struct uart_port *port) { - struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - - if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) - stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE); - else - stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE); + mctrl_gpio_enable_ms(to_stm32_port(port)->gpios); } -static unsigned int stm32_get_mctrl(struct uart_port *port) +static void stm32_usart_disable_ms(struct uart_port *port) { - /* This routine is used to get signals of: DCD, DSR, RI, and CTS */ - return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; + mctrl_gpio_disable_ms_sync(to_stm32_port(port)->gpios); } /* Transmit stop */ -static void stm32_stop_tx(struct uart_port *port) +static void stm32_usart_stop_tx(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE); + stm32_usart_tx_interrupt_disable(port); + + /* dma terminate may have been called in case of dma pause failure */ + stm32_usart_tx_dma_pause(stm32_port); + + stm32_usart_rs485_rts_disable(port); } /* There are probably characters waiting to be transmitted. */ -static void stm32_start_tx(struct uart_port *port) +static void stm32_usart_start_tx(struct uart_port *port) { - struct circ_buf *xmit = &port->state->xmit; + struct tty_port *tport = &port->state->port; - if (uart_circ_empty(xmit)) + if (kfifo_is_empty(&tport->xmit_fifo) && !port->x_char) return; - stm32_transmit_chars(port); + stm32_usart_rs485_rts_enable(port); + + stm32_usart_transmit_chars(port); +} + +/* Flush the transmit buffer. */ +static void stm32_usart_flush_buffer(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + + if (stm32_port->tx_ch) + stm32_usart_tx_dma_terminate(stm32_port); } /* Throttle the remote when input buffer is about to overflow. */ -static void stm32_throttle(struct uart_port *port) +static void stm32_usart_throttle(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); - stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); + + /* + * Pause DMA transfer, so the RX data gets queued into the FIFO. + * Hardware flow control is triggered when RX FIFO is full. + */ + stm32_usart_rx_dma_pause(stm32_port); + + stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq); + if (stm32_port->cr3_irq) + stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq); + + stm32_port->throttled = true; + uart_port_unlock_irqrestore(port, flags); } /* Unthrottle the remote, the input buffer can now accept data. */ -static void stm32_unthrottle(struct uart_port *port) +static void stm32_usart_unthrottle(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); - stm32_set_bits(port, ofs->cr1, USART_CR1_RXNEIE); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); + stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq); + if (stm32_port->cr3_irq) + stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq); + + stm32_port->throttled = false; + + /* + * Switch back to DMA mode (resume DMA). + * Hardware flow control is stopped when FIFO is not full any more. + */ + if (stm32_port->rx_ch) + stm32_usart_rx_dma_start_or_resume(port); + + uart_port_unlock_irqrestore(port, flags); } /* Receive stop */ -static void stm32_stop_rx(struct uart_port *port) +static void stm32_usart_stop_rx(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + /* Disable DMA request line. */ + stm32_usart_rx_dma_pause(stm32_port); - stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE); + stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq); + if (stm32_port->cr3_irq) + stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq); } -/* Handle breaks - ignored by us */ -static void stm32_break_ctl(struct uart_port *port, int break_state) +static void stm32_usart_break_ctl(struct uart_port *port, int break_state) { + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + + uart_port_lock_irqsave(port, &flags); + + if (break_state) + stm32_usart_set_bits(port, ofs->rqr, USART_RQR_SBKRQ); + else + stm32_usart_clr_bits(port, ofs->rqr, USART_RQR_SBKRQ); + + uart_port_unlock_irqrestore(port, flags); } -static int stm32_startup(struct uart_port *port) +static int stm32_usart_startup(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_config *cfg = &stm32_port->info->cfg; const char *name = to_platform_device(port->dev)->name; u32 val; int ret; - ret = request_threaded_irq(port->irq, stm32_interrupt, - stm32_threaded_interrupt, - IRQF_NO_SUSPEND, name, port); + ret = request_irq(port->irq, stm32_usart_interrupt, + IRQF_NO_SUSPEND, name, port); if (ret) return ret; - val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE; - stm32_set_bits(port, ofs->cr1, val); + if (stm32_port->swap) { + val = readl_relaxed(port->membase + ofs->cr2); + val |= USART_CR2_SWAP; + writel_relaxed(val, port->membase + ofs->cr2); + } + stm32_port->throttled = false; + + /* RX FIFO Flush */ + if (ofs->rqr != UNDEF_REG) + writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr); + + if (stm32_port->rx_ch) { + ret = stm32_usart_rx_dma_start_or_resume(port); + if (ret) { + free_irq(port->irq, port); + return ret; + } + } + + /* RX enabling */ + val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit); + stm32_usart_set_bits(port, ofs->cr1, val); return 0; } -static void stm32_shutdown(struct uart_port *port) +static void stm32_usart_shutdown(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - struct stm32_usart_config *cfg = &stm32_port->info->cfg; - u32 val; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_config *cfg = &stm32_port->info->cfg; + u32 val, isr; + int ret; + + if (stm32_usart_tx_dma_started(stm32_port)) + stm32_usart_tx_dma_terminate(stm32_port); + + if (stm32_port->tx_ch) + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + + /* Disable modem control interrupts */ + stm32_usart_disable_ms(port); - val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE; + val = USART_CR1_TXEIE | USART_CR1_TE; + val |= stm32_port->cr1_irq | USART_CR1_RE; val |= BIT(cfg->uart_enable_bit); - stm32_clr_bits(port, ofs->cr1, val); + if (stm32_port->fifoen) + val |= USART_CR1_FIFOEN; + + ret = readl_relaxed_poll_timeout(port->membase + ofs->isr, + isr, (isr & USART_SR_TC), + 10, 100000); + + /* Send the TC error message only when ISR_TC is not set */ + if (ret) + dev_err(port->dev, "Transmission is not complete\n"); + + /* Disable RX DMA. */ + if (stm32_port->rx_ch) { + stm32_usart_rx_dma_terminate(stm32_port); + dmaengine_synchronize(stm32_port->rx_ch); + } + + /* flush RX & TX FIFO */ + if (ofs->rqr != UNDEF_REG) + writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ, + port->membase + ofs->rqr); + + stm32_usart_clr_bits(port, ofs->cr1, val); free_irq(port->irq, port); } -static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, - struct ktermios *old) +static const unsigned int stm32_usart_presc_val[] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256}; + +static void stm32_usart_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - struct stm32_usart_config *cfg = &stm32_port->info->cfg; - unsigned int baud; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_config *cfg = &stm32_port->info->cfg; + struct serial_rs485 *rs485conf = &port->rs485; + unsigned int baud, bits, uart_clk, uart_clk_pres; u32 usartdiv, mantissa, fraction, oversampling; tcflag_t cflag = termios->c_cflag; - u32 cr1, cr2, cr3; + u32 cr1, cr2, cr3, isr, brr, presc; unsigned long flags; + int ret; if (!stm32_port->hw_flow_control) cflag &= ~CRTSCTS; - baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8); + uart_clk = clk_get_rate(stm32_port->clk); + + baud = uart_get_baud_rate(port, termios, old, 0, uart_clk / 8); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); + + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, + (isr & USART_SR_TC), + 10, 100000); + + /* Send the TC error message only when ISR_TC is not set. */ + if (ret) + dev_err(port->dev, "Transmission is not complete\n"); /* Stop serial port and reset value */ writel_relaxed(0, port->membase + ofs->cr1); - cr1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE; - cr1 |= BIT(cfg->uart_enable_bit); - cr2 = 0; - cr3 = 0; + /* flush RX & TX FIFO */ + if (ofs->rqr != UNDEF_REG) + writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ, + port->membase + ofs->rqr); + + cr1 = USART_CR1_TE | USART_CR1_RE; + if (stm32_port->fifoen) + cr1 |= USART_CR1_FIFOEN; + cr2 = stm32_port->swap ? USART_CR2_SWAP : 0; + + /* Tx and RX FIFO configuration */ + cr3 = readl_relaxed(port->membase + ofs->cr3); + cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE; + if (stm32_port->fifoen) { + if (stm32_port->txftcfg >= 0) + cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT; + if (stm32_port->rxftcfg >= 0) + cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT; + } if (cflag & CSTOPB) cr2 |= USART_CR2_STOP_2B; + bits = tty_get_char_size(cflag); + stm32_port->rdr_mask = (BIT(bits) - 1); + if (cflag & PARENB) { + bits++; cr1 |= USART_CR1_PCE; - if ((cflag & CSIZE) == CS8) { - if (cfg->has_7bits_data) - cr1 |= USART_CR1_M0; - else - cr1 |= USART_CR1_M; + } + + /* + * Word length configuration: + * CS8 + parity, 9 bits word aka [M1:M0] = 0b01 + * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10 + * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00 + * M0 and M1 already cleared by cr1 initialization. + */ + if (bits == 9) { + cr1 |= USART_CR1_M0; + } else if ((bits == 7) && cfg->has_7bits_data) { + cr1 |= USART_CR1_M1; + } else if (bits != 8) { + dev_dbg(port->dev, "Unsupported data bits config: %u bits\n" + , bits); + cflag &= ~CSIZE; + cflag |= CS8; + termios->c_cflag = cflag; + bits = 8; + if (cflag & PARENB) { + bits++; + cr1 |= USART_CR1_M0; } } + if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch || + (stm32_port->fifoen && + stm32_port->rxftcfg >= 0))) { + if (cflag & CSTOPB) + bits = bits + 3; /* 1 start bit + 2 stop bits */ + else + bits = bits + 2; /* 1 start bit + 1 stop bit */ + + /* RX timeout irq to occur after last stop bit + bits */ + stm32_port->cr1_irq = USART_CR1_RTOIE; + writel_relaxed(bits, port->membase + ofs->rtor); + cr2 |= USART_CR2_RTOEN; + /* + * Enable fifo threshold irq in two cases, either when there is no DMA, or when + * wake up over usart, from low power until the DMA gets re-enabled by resume. + */ + stm32_port->cr3_irq = USART_CR3_RXFTIE; + } + + cr1 |= stm32_port->cr1_irq; + cr3 |= stm32_port->cr3_irq; + if (cflag & PARODD) cr1 |= USART_CR1_PS; port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); if (cflag & CRTSCTS) { port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; - cr3 |= USART_CR3_CTSE; + cr3 |= USART_CR3_CTSE | USART_CR3_RTSE; } - usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud); + for (presc = 0; presc <= USART_PRESC_MAX; presc++) { + uart_clk_pres = DIV_ROUND_CLOSEST(uart_clk, stm32_usart_presc_val[presc]); + usartdiv = DIV_ROUND_CLOSEST(uart_clk_pres, baud); - /* - * The USART supports 16 or 8 times oversampling. - * By default we prefer 16 times oversampling, so that the receiver - * has a better tolerance to clock deviations. - * 8 times oversampling is only used to achieve higher speeds. - */ - if (usartdiv < 16) { - oversampling = 8; - stm32_set_bits(port, ofs->cr1, USART_CR1_OVER8); - } else { - oversampling = 16; - stm32_clr_bits(port, ofs->cr1, USART_CR1_OVER8); + /* + * The USART supports 16 or 8 times oversampling. + * By default we prefer 16 times oversampling, so that the receiver + * has a better tolerance to clock deviations. + * 8 times oversampling is only used to achieve higher speeds. + */ + if (usartdiv < 16) { + oversampling = 8; + cr1 |= USART_CR1_OVER8; + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8); + } else { + oversampling = 16; + cr1 &= ~USART_CR1_OVER8; + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8); + } + + mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT; + fraction = usartdiv % oversampling; + brr = mantissa | fraction; + + if (FIELD_FIT(USART_BRR_MASK, brr)) { + if (ofs->presc != UNDEF_REG) { + port->uartclk = uart_clk_pres; + writel_relaxed(presc, port->membase + ofs->presc); + } else if (presc) { + /* We need a prescaler but we don't have it (STM32F4, STM32F7) */ + dev_err(port->dev, + "unable to set baudrate, input clock is too high"); + } + break; + } else if (presc == USART_PRESC_MAX) { + /* Even with prescaler and brr at max value we can't set baudrate */ + dev_err(port->dev, "unable to set baudrate, input clock is too high"); + break; + } } - mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT; - fraction = usartdiv % oversampling; - writel_relaxed(mantissa | fraction, port->membase + ofs->brr); + writel_relaxed(brr, port->membase + ofs->brr); uart_update_timeout(port, cflag, baud); @@ -547,14 +1319,14 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, if (termios->c_iflag & INPCK) port->read_status_mask |= USART_SR_PE | USART_SR_FE; if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) - port->read_status_mask |= USART_SR_LBD; + port->read_status_mask |= USART_SR_FE; /* Characters to ignore */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask = USART_SR_PE | USART_SR_FE; if (termios->c_iflag & IGNBRK) { - port->ignore_status_mask |= USART_SR_LBD; + port->ignore_status_mask |= USART_SR_FE; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). @@ -567,101 +1339,258 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= USART_SR_DUMMY_RX; - if (stm32_port->rx_ch) + if (stm32_port->rx_ch) { + /* + * Setup DMA to collect only valid data and enable error irqs. + * This also enables break reception when using DMA. + */ + cr1 |= USART_CR1_PEIE; + cr3 |= USART_CR3_EIE; cr3 |= USART_CR3_DMAR; + cr3 |= USART_CR3_DDRE; + } + + if (stm32_port->tx_ch) + cr3 |= USART_CR3_DMAT; + + if (rs485conf->flags & SER_RS485_ENABLED) { + stm32_usart_config_reg_rs485(&cr1, &cr3, + rs485conf->delay_rts_before_send, + rs485conf->delay_rts_after_send, + baud); + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + cr3 &= ~USART_CR3_DEP; + rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND; + } else { + cr3 |= USART_CR3_DEP; + rs485conf->flags |= SER_RS485_RTS_AFTER_SEND; + } + + } else { + cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP); + cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK); + } + + /* Configure wake up from low power on start bit detection */ + if (stm32_port->wakeup_src) { + cr3 &= ~USART_CR3_WUS_MASK; + cr3 |= USART_CR3_WUS_START_BIT; + } writel_relaxed(cr3, port->membase + ofs->cr3); writel_relaxed(cr2, port->membase + ofs->cr2); writel_relaxed(cr1, port->membase + ofs->cr1); - spin_unlock_irqrestore(&port->lock, flags); + stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + uart_port_unlock_irqrestore(port, flags); + + /* Handle modem control interrupts */ + if (UART_ENABLE_MS(port, termios->c_cflag)) + stm32_usart_enable_ms(port); + else + stm32_usart_disable_ms(port); } -static const char *stm32_type(struct uart_port *port) +static const char *stm32_usart_type(struct uart_port *port) { return (port->type == PORT_STM32) ? DRIVER_NAME : NULL; } -static void stm32_release_port(struct uart_port *port) +static void stm32_usart_release_port(struct uart_port *port) { } -static int stm32_request_port(struct uart_port *port) +static int stm32_usart_request_port(struct uart_port *port) { return 0; } -static void stm32_config_port(struct uart_port *port, int flags) +static void stm32_usart_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) port->type = PORT_STM32; } static int -stm32_verify_port(struct uart_port *port, struct serial_struct *ser) +stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser) { /* No user changeable parameters */ return -EINVAL; } -static void stm32_pm(struct uart_port *port, unsigned int state, - unsigned int oldstate) +static void stm32_usart_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) { struct stm32_port *stm32port = container_of(port, struct stm32_port, port); - struct stm32_usart_offsets *ofs = &stm32port->info->ofs; - struct stm32_usart_config *cfg = &stm32port->info->cfg; - unsigned long flags = 0; + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + const struct stm32_usart_config *cfg = &stm32port->info->cfg; + unsigned long flags; switch (state) { case UART_PM_STATE_ON: - clk_prepare_enable(stm32port->clk); + pm_runtime_get_sync(port->dev); break; case UART_PM_STATE_OFF: - spin_lock_irqsave(&port->lock, flags); - stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); - spin_unlock_irqrestore(&port->lock, flags); - clk_disable_unprepare(stm32port->clk); + uart_port_lock_irqsave(port, &flags); + stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + uart_port_unlock_irqrestore(port, flags); + pm_runtime_put_sync(port->dev); break; } } +#if defined(CONFIG_CONSOLE_POLL) + + /* Callbacks for characters polling in debug context (i.e. KGDB). */ +static int stm32_usart_poll_init(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + + return clk_prepare_enable(stm32_port->clk); +} + +static int stm32_usart_poll_get_char(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE)) + return NO_POLL_CHAR; + + return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask; +} + +static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch) +{ + stm32_usart_console_putchar(port, ch); +} +#endif /* CONFIG_CONSOLE_POLL */ + static const struct uart_ops stm32_uart_ops = { - .tx_empty = stm32_tx_empty, - .set_mctrl = stm32_set_mctrl, - .get_mctrl = stm32_get_mctrl, - .stop_tx = stm32_stop_tx, - .start_tx = stm32_start_tx, - .throttle = stm32_throttle, - .unthrottle = stm32_unthrottle, - .stop_rx = stm32_stop_rx, - .break_ctl = stm32_break_ctl, - .startup = stm32_startup, - .shutdown = stm32_shutdown, - .set_termios = stm32_set_termios, - .pm = stm32_pm, - .type = stm32_type, - .release_port = stm32_release_port, - .request_port = stm32_request_port, - .config_port = stm32_config_port, - .verify_port = stm32_verify_port, + .tx_empty = stm32_usart_tx_empty, + .set_mctrl = stm32_usart_set_mctrl, + .get_mctrl = stm32_usart_get_mctrl, + .stop_tx = stm32_usart_stop_tx, + .start_tx = stm32_usart_start_tx, + .throttle = stm32_usart_throttle, + .unthrottle = stm32_usart_unthrottle, + .stop_rx = stm32_usart_stop_rx, + .enable_ms = stm32_usart_enable_ms, + .break_ctl = stm32_usart_break_ctl, + .startup = stm32_usart_startup, + .shutdown = stm32_usart_shutdown, + .flush_buffer = stm32_usart_flush_buffer, + .set_termios = stm32_usart_set_termios, + .pm = stm32_usart_pm, + .type = stm32_usart_type, + .release_port = stm32_usart_release_port, + .request_port = stm32_usart_request_port, + .config_port = stm32_usart_config_port, + .verify_port = stm32_usart_verify_port, +#if defined(CONFIG_CONSOLE_POLL) + .poll_init = stm32_usart_poll_init, + .poll_get_char = stm32_usart_poll_get_char, + .poll_put_char = stm32_usart_poll_put_char, +#endif /* CONFIG_CONSOLE_POLL */ +}; + +struct stm32_usart_thresh_ratio { + int mul; + int div; +}; + +static const struct stm32_usart_thresh_ratio stm32h7_usart_fifo_thresh_cfg[] = { + {1, 8}, {1, 4}, {1, 2}, {3, 4}, {7, 8}, {1, 1} }; + +static int stm32_usart_get_thresh_value(u32 fifo_size, int index) +{ + return fifo_size * stm32h7_usart_fifo_thresh_cfg[index].mul / + stm32h7_usart_fifo_thresh_cfg[index].div; +} + +static int stm32_usart_get_ftcfg(struct platform_device *pdev, struct stm32_port *stm32port, + const char *p, int *ftcfg) +{ + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + u32 bytes, i, cfg8; + int fifo_size; + + if (WARN_ON(ofs->hwcfgr1 == UNDEF_REG)) + return 1; + + cfg8 = FIELD_GET(USART_HWCFGR1_CFG8, + readl_relaxed(stm32port->port.membase + ofs->hwcfgr1)); + + /* On STM32H7, hwcfgr is not present, so returned value will be 0 */ + fifo_size = cfg8 ? 1 << cfg8 : STM32H7_USART_FIFO_SIZE; + + /* DT option to get RX & TX FIFO threshold (default to half fifo size) */ + if (of_property_read_u32(pdev->dev.of_node, p, &bytes)) + bytes = fifo_size / 2; + + if (bytes < stm32_usart_get_thresh_value(fifo_size, 0)) { + *ftcfg = -EINVAL; + return fifo_size; + } + + for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) { + if (stm32_usart_get_thresh_value(fifo_size, i) >= bytes) + break; + } + if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg)) + i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1; + + dev_dbg(&pdev->dev, "%s set to %d/%d bytes\n", p, + stm32_usart_get_thresh_value(fifo_size, i), fifo_size); + + *ftcfg = i; + return fifo_size; +} + +static void stm32_usart_deinit_port(struct stm32_port *stm32port) +{ + clk_disable_unprepare(stm32port->clk); +} + +static const struct serial_rs485 stm32_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | + SER_RS485_RX_DURING_TX, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, }; -static int stm32_init_port(struct stm32_port *stm32port, - struct platform_device *pdev) +static int stm32_usart_init_port(struct stm32_port *stm32port, + struct platform_device *pdev) { struct uart_port *port = &stm32port->port; struct resource *res; - int ret; + int ret, irq; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; port->iotype = UPIO_MEM; port->flags = UPF_BOOT_AUTOCONF; port->ops = &stm32_uart_ops; port->dev = &pdev->dev; - port->irq = platform_get_irq(pdev, 0); + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE); + port->irq = irq; + port->rs485_config = stm32_usart_config_rs485; + port->rs485_supported = stm32_rs485_supported; - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - port->membase = devm_ioremap_resource(&pdev->dev, res); + ret = stm32_usart_init_rs485(port, pdev); + if (ret) + return ret; + + stm32port->wakeup_src = stm32port->info->cfg.has_wakeup && + of_property_read_bool(pdev->dev.of_node, "wakeup-source"); + + stm32port->swap = stm32port->info->cfg.has_swap && + of_property_read_bool(pdev->dev.of_node, "rx-tx-swap"); + + port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res); if (IS_ERR(port->membase)) return PTR_ERR(port->membase); port->mapbase = res->start; @@ -678,13 +1607,48 @@ static int stm32_init_port(struct stm32_port *stm32port, return ret; stm32port->port.uartclk = clk_get_rate(stm32port->clk); - if (!stm32port->port.uartclk) + if (!stm32port->port.uartclk) { ret = -EINVAL; + goto err_clk; + } + + stm32port->fifoen = stm32port->info->cfg.has_fifo; + if (stm32port->fifoen) { + stm32_usart_get_ftcfg(pdev, stm32port, "rx-threshold", &stm32port->rxftcfg); + port->fifosize = stm32_usart_get_ftcfg(pdev, stm32port, "tx-threshold", + &stm32port->txftcfg); + } else { + port->fifosize = 1; + } + + stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0); + if (IS_ERR(stm32port->gpios)) { + ret = PTR_ERR(stm32port->gpios); + goto err_clk; + } + + /* + * Both CTS/RTS gpios and "st,hw-flow-ctrl" (deprecated) or "uart-has-rtscts" + * properties should not be specified. + */ + if (stm32port->hw_flow_control) { + if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) || + mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) { + dev_err(&pdev->dev, "Conflicting RTS/CTS config\n"); + ret = -EINVAL; + goto err_clk; + } + } + + return ret; + +err_clk: + clk_disable_unprepare(stm32port->clk); return ret; } -static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev) +static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; int id; @@ -693,54 +1657,57 @@ static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev) return NULL; id = of_alias_get_id(np, "serial"); - if (id < 0) - id = 0; + if (id < 0) { + dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id); + return NULL; + } if (WARN_ON(id >= STM32_MAX_PORTS)) return NULL; - stm32_ports[id].hw_flow_control = of_property_read_bool(np, - "st,hw-flow-ctrl"); + stm32_ports[id].hw_flow_control = + of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ || + of_property_read_bool (np, "uart-has-rtscts"); stm32_ports[id].port.line = id; + stm32_ports[id].cr1_irq = USART_CR1_RXNEIE; + stm32_ports[id].cr3_irq = 0; + stm32_ports[id].last_res = RX_BUF_L; return &stm32_ports[id]; } #ifdef CONFIG_OF static const struct of_device_id stm32_match[] = { - { .compatible = "st,stm32-usart", .data = &stm32f4_info}, { .compatible = "st,stm32-uart", .data = &stm32f4_info}, - { .compatible = "st,stm32f7-usart", .data = &stm32f7_info}, { .compatible = "st,stm32f7-uart", .data = &stm32f7_info}, + { .compatible = "st,stm32h7-uart", .data = &stm32h7_info}, {}, }; MODULE_DEVICE_TABLE(of, stm32_match); #endif -static int stm32_of_dma_rx_probe(struct stm32_port *stm32port, - struct platform_device *pdev) +static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port, + struct platform_device *pdev) { - struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + if (stm32port->rx_buf) + dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf, + stm32port->rx_dma_buf); +} + +static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, + struct platform_device *pdev) +{ + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; struct uart_port *port = &stm32port->port; struct device *dev = &pdev->dev; struct dma_slave_config config; - struct dma_async_tx_descriptor *desc = NULL; - dma_cookie_t cookie; int ret; - /* Request DMA RX channel */ - stm32port->rx_ch = dma_request_slave_channel(dev, "rx"); - if (!stm32port->rx_ch) { - dev_info(dev, "rx dma alloc failed\n"); - return -ENODEV; - } - stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L, - &stm32port->rx_dma_buf, - GFP_KERNEL); - if (!stm32port->rx_buf) { - ret = -ENOMEM; - goto alloc_err; - } + stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L, + &stm32port->rx_dma_buf, + GFP_KERNEL); + if (!stm32port->rx_buf) + return -ENOMEM; /* Configure DMA channel */ memset(&config, 0, sizeof(config)); @@ -750,69 +1717,35 @@ static int stm32_of_dma_rx_probe(struct stm32_port *stm32port, ret = dmaengine_slave_config(stm32port->rx_ch, &config); if (ret < 0) { dev_err(dev, "rx dma channel config failed\n"); - ret = -ENODEV; - goto config_err; - } - - /* Prepare a DMA cyclic transaction */ - desc = dmaengine_prep_dma_cyclic(stm32port->rx_ch, - stm32port->rx_dma_buf, - RX_BUF_L, RX_BUF_P, DMA_DEV_TO_MEM, - DMA_PREP_INTERRUPT); - if (!desc) { - dev_err(dev, "rx dma prep cyclic failed\n"); - ret = -ENODEV; - goto config_err; + stm32_usart_of_dma_rx_remove(stm32port, pdev); + return ret; } - /* No callback as dma buffer is drained on usart interrupt */ - desc->callback = NULL; - desc->callback_param = NULL; - - /* Push current DMA transaction in the pending queue */ - cookie = dmaengine_submit(desc); - - /* Issue pending DMA requests */ - dma_async_issue_pending(stm32port->rx_ch); - return 0; +} -config_err: - dma_free_coherent(&pdev->dev, - RX_BUF_L, stm32port->rx_buf, - stm32port->rx_dma_buf); - -alloc_err: - dma_release_channel(stm32port->rx_ch); - stm32port->rx_ch = NULL; - - return ret; +static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port, + struct platform_device *pdev) +{ + if (stm32port->tx_buf) + dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf, + stm32port->tx_dma_buf); } -static int stm32_of_dma_tx_probe(struct stm32_port *stm32port, - struct platform_device *pdev) +static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port, + struct platform_device *pdev) { - struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; struct uart_port *port = &stm32port->port; struct device *dev = &pdev->dev; struct dma_slave_config config; int ret; - stm32port->tx_dma_busy = false; - - /* Request DMA TX channel */ - stm32port->tx_ch = dma_request_slave_channel(dev, "tx"); - if (!stm32port->tx_ch) { - dev_info(dev, "tx dma alloc failed\n"); - return -ENODEV; - } - stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L, - &stm32port->tx_dma_buf, - GFP_KERNEL); - if (!stm32port->tx_buf) { - ret = -ENOMEM; - goto alloc_err; - } + stm32port->tx_buf = dma_alloc_coherent(dev, TX_BUF_L, + &stm32port->tx_dma_buf, + GFP_KERNEL); + if (!stm32port->tx_buf) + return -ENOMEM; /* Configure DMA channel */ memset(&config, 0, sizeof(config)); @@ -822,122 +1755,189 @@ static int stm32_of_dma_tx_probe(struct stm32_port *stm32port, ret = dmaengine_slave_config(stm32port->tx_ch, &config); if (ret < 0) { dev_err(dev, "tx dma channel config failed\n"); - ret = -ENODEV; - goto config_err; + stm32_usart_of_dma_tx_remove(stm32port, pdev); + return ret; } return 0; - -config_err: - dma_free_coherent(&pdev->dev, - TX_BUF_L, stm32port->tx_buf, - stm32port->tx_dma_buf); - -alloc_err: - dma_release_channel(stm32port->tx_ch); - stm32port->tx_ch = NULL; - - return ret; } -static int stm32_serial_probe(struct platform_device *pdev) +static int stm32_usart_serial_probe(struct platform_device *pdev) { - const struct of_device_id *match; struct stm32_port *stm32port; int ret; - stm32port = stm32_of_get_stm32_port(pdev); + stm32port = stm32_usart_of_get_port(pdev); if (!stm32port) return -ENODEV; - match = of_match_device(stm32_match, &pdev->dev); - if (match && match->data) - stm32port->info = (struct stm32_usart_info *)match->data; - else + stm32port->info = of_device_get_match_data(&pdev->dev); + if (!stm32port->info) return -EINVAL; - ret = stm32_init_port(stm32port, pdev); - if (ret) - return ret; + stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx"); + if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) + return -EPROBE_DEFER; - ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port); - if (ret) - return ret; + /* Fall back in interrupt mode for any non-deferral error */ + if (IS_ERR(stm32port->rx_ch)) + stm32port->rx_ch = NULL; - ret = stm32_of_dma_rx_probe(stm32port, pdev); - if (ret) - dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n"); + stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx"); + if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto err_dma_rx; + } + /* Fall back in interrupt mode for any non-deferral error */ + if (IS_ERR(stm32port->tx_ch)) + stm32port->tx_ch = NULL; - ret = stm32_of_dma_tx_probe(stm32port, pdev); + ret = stm32_usart_init_port(stm32port, pdev); if (ret) - dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n"); + goto err_dma_tx; + + if (stm32port->wakeup_src) { + device_set_wakeup_capable(&pdev->dev, true); + ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq); + if (ret) + goto err_deinit_port; + } + + if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) { + /* Fall back in interrupt mode */ + dma_release_channel(stm32port->rx_ch); + stm32port->rx_ch = NULL; + } + + if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) { + /* Fall back in interrupt mode */ + dma_release_channel(stm32port->tx_ch); + stm32port->tx_ch = NULL; + } + + if (!stm32port->rx_ch) + dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n"); + if (!stm32port->tx_ch) + dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n"); platform_set_drvdata(pdev, &stm32port->port); + pm_runtime_get_noresume(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + + ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port); + if (ret) + goto err_port; + + pm_runtime_put_sync(&pdev->dev); + return 0; + +err_port: + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); + + if (stm32port->tx_ch) + stm32_usart_of_dma_tx_remove(stm32port, pdev); + if (stm32port->rx_ch) + stm32_usart_of_dma_rx_remove(stm32port, pdev); + + if (stm32port->wakeup_src) + dev_pm_clear_wake_irq(&pdev->dev); + +err_deinit_port: + if (stm32port->wakeup_src) + device_set_wakeup_capable(&pdev->dev, false); + + stm32_usart_deinit_port(stm32port); + +err_dma_tx: + if (stm32port->tx_ch) + dma_release_channel(stm32port->tx_ch); + +err_dma_rx: + if (stm32port->rx_ch) + dma_release_channel(stm32port->rx_ch); + + return ret; } -static int stm32_serial_remove(struct platform_device *pdev) +static void stm32_usart_serial_remove(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + u32 cr3; - stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR); + pm_runtime_get_sync(&pdev->dev); + uart_remove_one_port(&stm32_usart_driver, port); - if (stm32_port->rx_ch) - dma_release_channel(stm32_port->rx_ch); - - if (stm32_port->rx_dma_buf) - dma_free_coherent(&pdev->dev, - RX_BUF_L, stm32_port->rx_buf, - stm32_port->rx_dma_buf); + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); - stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_PEIE); - if (stm32_port->tx_ch) + if (stm32_port->tx_ch) { + stm32_usart_of_dma_tx_remove(stm32_port, pdev); dma_release_channel(stm32_port->tx_ch); + } - if (stm32_port->tx_dma_buf) - dma_free_coherent(&pdev->dev, - TX_BUF_L, stm32_port->tx_buf, - stm32_port->tx_dma_buf); + if (stm32_port->rx_ch) { + stm32_usart_of_dma_rx_remove(stm32_port, pdev); + dma_release_channel(stm32_port->rx_ch); + } - clk_disable_unprepare(stm32_port->clk); + cr3 = readl_relaxed(port->membase + ofs->cr3); + cr3 &= ~USART_CR3_EIE; + cr3 &= ~USART_CR3_DMAR; + cr3 &= ~USART_CR3_DMAT; + cr3 &= ~USART_CR3_DDRE; + writel_relaxed(cr3, port->membase + ofs->cr3); - return uart_remove_one_port(&stm32_usart_driver, port); -} + if (stm32_port->wakeup_src) { + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); + } + stm32_usart_deinit_port(stm32_port); +} -#ifdef CONFIG_SERIAL_STM32_CONSOLE -static void stm32_console_putchar(struct uart_port *port, int ch) +static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch) { struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - - while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) - cpu_relax(); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + u32 isr; + int ret; + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr, + (isr & USART_SR_TXE), 100, + STM32_USART_TIMEOUT_USEC); + if (ret != 0) { + dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret); + return; + } writel_relaxed(ch, port->membase + ofs->tdr); } -static void stm32_console_write(struct console *co, const char *s, unsigned cnt) +#ifdef CONFIG_SERIAL_STM32_CONSOLE +static void stm32_usart_console_write(struct console *co, const char *s, + unsigned int cnt) { struct uart_port *port = &stm32_ports[co->index].port; struct stm32_port *stm32_port = to_stm32_port(port); - struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - struct stm32_usart_config *cfg = &stm32_port->info->cfg; + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + const struct stm32_usart_config *cfg = &stm32_port->info->cfg; unsigned long flags; u32 old_cr1, new_cr1; int locked = 1; - local_irq_save(flags); - if (port->sysrq) - locked = 0; - else if (oops_in_progress) - locked = spin_trylock(&port->lock); + if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); else - spin_lock(&port->lock); + uart_port_lock_irqsave(port, &flags); /* Save and disable interrupts, enable the transmitter */ old_cr1 = readl_relaxed(port->membase + ofs->cr1); @@ -945,17 +1945,16 @@ static void stm32_console_write(struct console *co, const char *s, unsigned cnt) new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit); writel_relaxed(new_cr1, port->membase + ofs->cr1); - uart_console_write(port, s, cnt, stm32_console_putchar); + uart_console_write(port, s, cnt, stm32_usart_console_putchar); /* Restore interrupt state */ writel_relaxed(old_cr1, port->membase + ofs->cr1); if (locked) - spin_unlock(&port->lock); - local_irq_restore(flags); + uart_port_unlock_irqrestore(port, flags); } -static int stm32_console_setup(struct console *co, char *options) +static int stm32_usart_console_setup(struct console *co, char *options) { struct stm32_port *stm32port; int baud = 9600; @@ -974,7 +1973,7 @@ static int stm32_console_setup(struct console *co, char *options) * this to be called during the uart port registration when the * driver gets probed and the port should be mapped at that point. */ - if (stm32port->port.mapbase == 0 || stm32port->port.membase == NULL) + if (stm32port->port.mapbase == 0 || !stm32port->port.membase) return -ENXIO; if (options) @@ -986,8 +1985,8 @@ static int stm32_console_setup(struct console *co, char *options) static struct console stm32_console = { .name = STM32_SERIAL_NAME, .device = uart_console_device, - .write = stm32_console_write, - .setup = stm32_console_setup, + .write = stm32_usart_console_write, + .setup = stm32_usart_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &stm32_usart_driver, @@ -999,6 +1998,57 @@ static struct console stm32_console = { #define STM32_SERIAL_CONSOLE NULL #endif /* CONFIG_SERIAL_STM32_CONSOLE */ +#ifdef CONFIG_SERIAL_EARLYCON +static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch) +{ + struct stm32_usart_info *info = port->private_data; + + while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE)) + cpu_relax(); + + writel_relaxed(ch, port->membase + info->ofs.tdr); +} + +static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count) +{ + struct earlycon_device *device = console->data; + struct uart_port *port = &device->port; + + uart_console_write(port, s, count, early_stm32_usart_console_putchar); +} + +static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32h7_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32f7_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options) +{ + if (!(device->port.membase || device->port.iobase)) + return -ENODEV; + device->port.private_data = &stm32f4_info; + device->con->write = early_stm32_serial_write; + return 0; +} + +OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup); +OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup); +OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup); +#endif /* CONFIG_SERIAL_EARLYCON */ + static struct uart_driver stm32_usart_driver = { .driver_name = DRIVER_NAME, .dev_name = STM32_SERIAL_NAME, @@ -1008,16 +2058,143 @@ static struct uart_driver stm32_usart_driver = { .cons = STM32_SERIAL_CONSOLE, }; +static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port, + bool enable) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + struct tty_port *tport = &port->state->port; + int ret; + unsigned int size = 0; + unsigned long flags; + + if (!stm32_port->wakeup_src || !tty_port_initialized(tport)) + return 0; + + /* + * Enable low-power wake-up and wake-up irq if argument is set to + * "enable", disable low-power wake-up and wake-up irq otherwise + */ + if (enable) { + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM); + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE); + mctrl_gpio_enable_irq_wake(stm32_port->gpios); + + /* + * When DMA is used for reception, it must be disabled before + * entering low-power mode and re-enabled when exiting from + * low-power mode. + */ + if (stm32_port->rx_ch) { + uart_port_lock_irqsave(port, &flags); + /* Poll data from DMA RX buffer if any */ + if (!stm32_usart_rx_dma_pause(stm32_port)) + size += stm32_usart_receive_chars(port, true); + stm32_usart_rx_dma_terminate(stm32_port); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) + tty_flip_buffer_push(tport); + } + + /* Poll data from RX FIFO if any */ + stm32_usart_receive_chars(port, false); + } else { + if (stm32_port->rx_ch) { + ret = stm32_usart_rx_dma_start_or_resume(port); + if (ret) + return ret; + } + mctrl_gpio_disable_irq_wake(stm32_port->gpios); + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); + } + + return 0; +} + +static int __maybe_unused stm32_usart_serial_suspend(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + int ret; + + uart_suspend_port(&stm32_usart_driver, port); + + if (device_may_wakeup(dev) || device_wakeup_path(dev)) { + ret = stm32_usart_serial_en_wakeup(port, true); + if (ret) + return ret; + } + + /* + * When "no_console_suspend" is enabled, keep the pinctrl default state + * and rely on bootloader stage to restore this state upon resume. + * Otherwise, apply the idle or sleep states depending on wakeup + * capabilities. + */ + if (console_suspend_enabled || !uart_console(port)) { + if (device_may_wakeup(dev) || device_wakeup_path(dev)) + pinctrl_pm_select_idle_state(dev); + else + pinctrl_pm_select_sleep_state(dev); + } + + return 0; +} + +static int __maybe_unused stm32_usart_serial_resume(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + int ret; + + pinctrl_pm_select_default_state(dev); + + if (device_may_wakeup(dev) || device_wakeup_path(dev)) { + ret = stm32_usart_serial_en_wakeup(port, false); + if (ret) + return ret; + } + + return uart_resume_port(&stm32_usart_driver, port); +} + +static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + struct stm32_port *stm32port = container_of(port, + struct stm32_port, port); + + clk_disable_unprepare(stm32port->clk); + + return 0; +} + +static int __maybe_unused stm32_usart_runtime_resume(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + struct stm32_port *stm32port = container_of(port, + struct stm32_port, port); + + return clk_prepare_enable(stm32port->clk); +} + +static const struct dev_pm_ops stm32_serial_pm_ops = { + SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend, + stm32_usart_runtime_resume, NULL) + SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend, + stm32_usart_serial_resume) +}; + static struct platform_driver stm32_serial_driver = { - .probe = stm32_serial_probe, - .remove = stm32_serial_remove, + .probe = stm32_usart_serial_probe, + .remove = stm32_usart_serial_remove, .driver = { .name = DRIVER_NAME, + .pm = &stm32_serial_pm_ops, .of_match_table = of_match_ptr(stm32_match), }, }; -static int __init usart_init(void) +static int __init stm32_usart_init(void) { static char banner[] __initdata = "STM32 USART driver initialized"; int ret; @@ -1035,14 +2212,14 @@ static int __init usart_init(void) return ret; } -static void __exit usart_exit(void) +static void __exit stm32_usart_exit(void) { platform_driver_unregister(&stm32_serial_driver); uart_unregister_driver(&stm32_usart_driver); } -module_init(usart_init); -module_exit(usart_exit); +module_init(stm32_usart_init); +module_exit(stm32_usart_exit); MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver"); |