diff options
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
| -rw-r--r-- | drivers/tty/serial/stm32-usart.c | 1637 |
1 files changed, 1637 insertions, 0 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c new file mode 100644 index 000000000..9377da1e9 --- /dev/null +++ b/drivers/tty/serial/stm32-usart.c @@ -0,0 +1,1637 @@ +// 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> + * + * Inspired by st-asc.c from STMicroelectronics (c) + */ + +#include <linux/clk.h> +#include <linux/console.h> +#include <linux/delay.h> +#include <linux/dma-direction.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/irq.h> +#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> +#include <linux/sysrq.h> +#include <linux/tty_flip.h> +#include <linux/tty.h> + +#include "serial_mctrl_gpio.h" +#include "stm32-usart.h" + +static void stm32_usart_stop_tx(struct uart_port *port); +static void stm32_usart_transmit_chars(struct uart_port *port); + +static inline struct stm32_port *to_stm32_port(struct uart_port *port) +{ + return container_of(port, struct stm32_port, port); +} + +static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits) +{ + u32 val; + + val = readl_relaxed(port->membase + reg); + val |= bits; + writel_relaxed(val, port->membase + reg); +} + +static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits) +{ + u32 val; + + val = readl_relaxed(port->membase + reg); + val &= ~bits; + writel_relaxed(val, port->membase + reg); +} + +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; + + 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 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)); + + port->rs485 = *rs485conf; + + rs485conf->flags |= SER_RS485_RX_DURING_TX; + + 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; + rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND; + } else { + cr3 |= USART_CR3_DEP; + rs485conf->flags |= SER_RS485_RTS_AFTER_SEND; + } + + writel_relaxed(cr3, port->membase + ofs->cr3); + writel_relaxed(cr1, port->membase + ofs->cr1); + } 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)); + + return 0; +} + +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 int stm32_usart_pending_rx(struct uart_port *port, u32 *sr, + int *last_res, bool threaded) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + enum dma_status status; + struct dma_tx_state state; + + *sr = readl_relaxed(port->membase + ofs->isr); + + 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; + else + return 0; + } else if (*sr & USART_SR_RXNE) { + return 1; + } + return 0; +} + +static unsigned long stm32_usart_get_char(struct uart_port *port, u32 *sr, + int *last_res) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long c; + + if (stm32_port->rx_ch) { + c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--]; + if ((*last_res) == 0) + *last_res = RX_BUF_L; + } else { + c = readl_relaxed(port->membase + ofs->rdr); + /* apply RDR data mask */ + c &= stm32_port->rdr_mask; + } + + return c; +} + +static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) +{ + struct tty_port *tport = &port->state->port; + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long c; + u32 sr; + char flag; + + spin_lock(&port->lock); + + while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res, + threaded)) { + sr |= USART_SR_DUMMY_RX; + flag = TTY_NORMAL; + + /* + * 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(port, &sr, &stm32_port->last_res); + port->icount.rx++; + if (sr & USART_SR_ERR_MASK) { + if (sr & USART_SR_ORE) { + port->icount.overrun++; + } else if (sr & USART_SR_PE) { + port->icount.parity++; + } else if (sr & USART_SR_FE) { + /* 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_PE) { + flag = TTY_PARITY; + } else if (sr & USART_SR_FE) { + if (!c) + flag = TTY_BREAK; + else + flag = TTY_FRAME; + } + } + + if (uart_handle_sysrq_char(port, c)) + continue; + uart_insert_char(port, sr, USART_SR_ORE, c, flag); + } + + spin_unlock(&port->lock); + + tty_flip_buffer_push(tport); +} + +static void stm32_usart_tx_dma_complete(void *arg) +{ + struct uart_port *port = arg; + struct stm32_port *stm32port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + unsigned long flags; + + dmaengine_terminate_async(stm32port->tx_ch); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + stm32port->tx_dma_busy = false; + + /* Let's see if we have pending data to send */ + spin_lock_irqsave(&port->lock, flags); + stm32_usart_transmit_chars(port); + spin_unlock_irqrestore(&port->lock, 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_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE); + else + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE); +} + +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 (stm32_port->fifoen) + 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_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 circ_buf *xmit = &port->state->xmit; + + if (stm32_port->tx_dma_busy) { + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + stm32_port->tx_dma_busy = false; + } + + while (!uart_circ_empty(xmit)) { + /* Check that TDR is empty before filling FIFO */ + if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) + break; + writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + } + + /* rely on TXE irq (mask or unmask) for sending remaining data */ + if (uart_circ_empty(xmit)) + 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); + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + struct circ_buf *xmit = &port->state->xmit; + struct dma_async_tx_descriptor *desc = NULL; + unsigned int count, i; + + if (stm32port->tx_dma_busy) + return; + + stm32port->tx_dma_busy = true; + + count = uart_circ_chars_pending(xmit); + + if (count > TX_BUF_L) + count = TX_BUF_L; + + 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 (one > count) + one = count; + two = count - one; + + memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one); + if (two) + memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two); + } + + desc = dmaengine_prep_slave_single(stm32port->tx_ch, + stm32port->tx_dma_buf, + count, + DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT); + + if (!desc) + goto fallback_err; + + desc->callback = stm32_usart_tx_dma_complete; + desc->callback_param = port; + + /* Push current DMA TX transaction in the pending queue */ + if (dma_submit_error(dmaengine_submit(desc))) { + /* dma no yet started, safe to free resources */ + dmaengine_terminate_async(stm32port->tx_ch); + goto fallback_err; + } + + /* Issue pending DMA TX requests */ + dma_async_issue_pending(stm32port->tx_ch); + + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT); + + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); + port->icount.tx += count; + return; + +fallback_err: + for (i = count; i > 0; i--) + stm32_usart_transmit_chars_pio(port); +} + +static void stm32_usart_transmit_chars(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + struct circ_buf *xmit = &port->state->xmit; + u32 isr; + int ret; + + if (port->x_char) { + if (stm32_port->tx_dma_busy) + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + + /* 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_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT); + return; + } + + if (uart_circ_empty(xmit) || 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_usart_transmit_chars_dma(port); + else + stm32_usart_transmit_chars_pio(port); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + stm32_usart_tx_interrupt_disable(port); +} + +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); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + u32 sr; + + sr = readl_relaxed(port->membase + ofs->isr); + + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) + writel_relaxed(USART_ICR_RTOCF, + port->membase + ofs->icr); + + 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); + } + + if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch)) + stm32_usart_receive_chars(port, false); + + if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) { + spin_lock(&port->lock); + stm32_usart_transmit_chars(port); + spin_unlock(&port->lock); + } + + if (stm32_port->rx_ch) + return IRQ_WAKE_THREAD; + else + return IRQ_HANDLED; +} + +static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) +{ + struct uart_port *port = ptr; + struct stm32_port *stm32_port = to_stm32_port(port); + + if (stm32_port->rx_ch) + stm32_usart_receive_chars(port, true); + + return IRQ_HANDLED; +} + +static unsigned int stm32_usart_tx_empty(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_TC) + return TIOCSER_TEMT; + + return 0; +} + +static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + 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); + + mctrl_gpio_set(stm32_port->gpios, mctrl); +} + +static unsigned int stm32_usart_get_mctrl(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + unsigned int ret; + + /* This routine is used to get signals of: DCD, DSR, RI, and CTS */ + ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; + + return mctrl_gpio_get(stm32_port->gpios, &ret); +} + +static void stm32_usart_enable_ms(struct uart_port *port) +{ + mctrl_gpio_enable_ms(to_stm32_port(port)->gpios); +} + +static void stm32_usart_disable_ms(struct uart_port *port) +{ + mctrl_gpio_disable_ms(to_stm32_port(port)->gpios); +} + +/* Transmit stop */ +static void stm32_usart_stop_tx(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + stm32_usart_tx_interrupt_disable(port); + + if (rs485conf->flags & SER_RS485_ENABLED) { + 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); + } + } +} + +/* There are probably characters waiting to be transmitted. */ +static void stm32_usart_start_tx(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + struct circ_buf *xmit = &port->state->xmit; + + if (uart_circ_empty(xmit) && !port->x_char) + return; + + if (rs485conf->flags & SER_RS485_ENABLED) { + 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); + } + } + + stm32_usart_transmit_chars(port); +} + +/* Throttle the remote when input buffer is about to overflow. */ +static void stm32_usart_throttle(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + 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); + + spin_unlock_irqrestore(&port->lock, flags); +} + +/* Unthrottle the remote, the input buffer can now accept data. */ +static void stm32_usart_unthrottle(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + + spin_lock_irqsave(&port->lock, 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); + + spin_unlock_irqrestore(&port->lock, flags); +} + +/* Receive stop */ +static void stm32_usart_stop_rx(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, 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_usart_break_ctl(struct uart_port *port, int break_state) +{ +} + +static int stm32_usart_startup(struct uart_port *port) +{ + 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; + const char *name = to_platform_device(port->dev)->name; + u32 val; + int ret; + + ret = request_threaded_irq(port->irq, stm32_usart_interrupt, + stm32_usart_threaded_interrupt, + IRQF_ONESHOT | IRQF_NO_SUSPEND, + name, port); + if (ret) + return ret; + + /* RX FIFO Flush */ + if (ofs->rqr != UNDEF_REG) + writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr); + + /* 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_usart_shutdown(struct uart_port *port) +{ + 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 val, isr; + int ret; + + /* Disable modem control interrupts */ + stm32_usart_disable_ms(port); + + val = USART_CR1_TXEIE | USART_CR1_TE; + val |= stm32_port->cr1_irq | USART_CR1_RE; + val |= BIT(cfg->uart_enable_bit); + if (stm32_port->fifoen) + val |= USART_CR1_FIFOEN; + + ret = readl_relaxed_poll_timeout(port->membase + ofs->isr, + isr, (isr & USART_SR_TC), + 10, 100000); + + if (ret) + dev_err(port->dev, "transmission complete not set\n"); + + /* 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 unsigned int stm32_usart_get_databits(struct ktermios *termios) +{ + unsigned int bits; + + tcflag_t cflag = termios->c_cflag; + + switch (cflag & CSIZE) { + /* + * CSIZE settings are not necessarily supported in hardware. + * CSIZE unsupported configurations are handled here to set word length + * to 8 bits word as default configuration and to print debug message. + */ + case CS5: + bits = 5; + break; + case CS6: + bits = 6; + break; + case CS7: + bits = 7; + break; + /* default including CS8 */ + default: + bits = 8; + break; + } + + return bits; +} + +static void stm32_usart_set_termios(struct uart_port *port, + struct ktermios *termios, + struct ktermios *old) +{ + 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; + struct serial_rs485 *rs485conf = &port->rs485; + unsigned int baud, bits; + u32 usartdiv, mantissa, fraction, oversampling; + tcflag_t cflag = termios->c_cflag; + u32 cr1, cr2, cr3, isr; + 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); + + spin_lock_irqsave(&port->lock, 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); + + /* 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 = 0; + + /* Tx and RX FIFO configuration */ + cr3 = readl_relaxed(port->membase + ofs->cr3); + cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE; + if (stm32_port->fifoen) { + cr3 &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK); + cr3 |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT; + cr3 |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT; + } + + if (cflag & CSTOPB) + cr2 |= USART_CR2_STOP_2B; + + bits = stm32_usart_get_databits(termios); + stm32_port->rdr_mask = (BIT(bits) - 1); + + if (cflag & PARENB) { + bits++; + cr1 |= USART_CR1_PCE; + } + + /* + * 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)) { + 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; + /* Not using dma, enable fifo threshold irq */ + if (!stm32_port->rx_ch) + 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 | USART_CR3_RTSE; + } + + usartdiv = DIV_ROUND_CLOSEST(port->uartclk, 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; + 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; + writel_relaxed(mantissa | fraction, port->membase + ofs->brr); + + uart_update_timeout(port, cflag, baud); + + port->read_status_mask = USART_SR_ORE; + 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_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_FE; + /* + * If we're ignoring parity and break indicators, + * ignore overruns too (for real raw support). + */ + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= USART_SR_ORE; + } + + /* Ignore all characters if CREAD is not set */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= USART_SR_DUMMY_RX; + + if (stm32_port->rx_ch) + cr3 |= USART_CR3_DMAR; + + 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->wakeirq > 0) { + 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); + + stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + spin_unlock_irqrestore(&port->lock, 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_usart_type(struct uart_port *port) +{ + return (port->type == PORT_STM32) ? DRIVER_NAME : NULL; +} + +static void stm32_usart_release_port(struct uart_port *port) +{ +} + +static int stm32_usart_request_port(struct uart_port *port) +{ + return 0; +} + +static void stm32_usart_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) + port->type = PORT_STM32; +} + +static int +stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + /* No user changeable parameters */ + return -EINVAL; +} + +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); + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + const struct stm32_usart_config *cfg = &stm32port->info->cfg; + unsigned long flags = 0; + + switch (state) { + case UART_PM_STATE_ON: + pm_runtime_get_sync(port->dev); + break; + case UART_PM_STATE_OFF: + spin_lock_irqsave(&port->lock, flags); + stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + spin_unlock_irqrestore(&port->lock, flags); + pm_runtime_put_sync(port->dev); + break; + } +} + +static const struct uart_ops stm32_uart_ops = { + .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, + .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, +}; + +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; + + ret = platform_get_irq(pdev, 0); + if (ret <= 0) + return ret ? : -ENODEV; + + port->iotype = UPIO_MEM; + port->flags = UPF_BOOT_AUTOCONF; + port->ops = &stm32_uart_ops; + port->dev = &pdev->dev; + port->fifosize = stm32port->info->cfg.fifosize; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE); + port->irq = ret; + port->rs485_config = stm32_usart_config_rs485; + + ret = stm32_usart_init_rs485(port, pdev); + if (ret) + return ret; + + if (stm32port->info->cfg.has_wakeup) { + stm32port->wakeirq = platform_get_irq_optional(pdev, 1); + if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO) + return stm32port->wakeirq ? : -ENODEV; + } + + stm32port->fifoen = stm32port->info->cfg.has_fifo; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + port->membase = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(port->membase)) + return PTR_ERR(port->membase); + port->mapbase = res->start; + + spin_lock_init(&port->lock); + + stm32port->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(stm32port->clk)) + return PTR_ERR(stm32port->clk); + + /* Ensure that clk rate is correct by enabling the clk */ + ret = clk_prepare_enable(stm32port->clk); + if (ret) + return ret; + + stm32port->port.uartclk = clk_get_rate(stm32port->clk); + if (!stm32port->port.uartclk) { + ret = -EINVAL; + goto err_clk; + } + + 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" 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_usart_of_get_port(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + int id; + + if (!np) + return NULL; + + id = of_alias_get_id(np, "serial"); + 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") /*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-uart", .data = &stm32f4_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_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; + int ret; + + /* + * Using DMA and threaded handler for the console could lead to + * deadlocks. + */ + if (uart_console(port)) + return -ENODEV; + + /* 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; + } + + /* Configure DMA channel */ + memset(&config, 0, sizeof(config)); + config.src_addr = port->mapbase + ofs->rdr; + config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + + 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; + } + + /* 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 */ + ret = dma_submit_error(dmaengine_submit(desc)); + if (ret) { + dmaengine_terminate_sync(stm32port->rx_ch); + goto config_err; + } + + /* 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 int stm32_usart_of_dma_tx_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; + 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; + } + + /* Configure DMA channel */ + memset(&config, 0, sizeof(config)); + config.dst_addr = port->mapbase + ofs->tdr; + config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + + 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; + } + + 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_usart_serial_probe(struct platform_device *pdev) +{ + struct stm32_port *stm32port; + int ret; + + stm32port = stm32_usart_of_get_port(pdev); + if (!stm32port) + return -ENODEV; + + stm32port->info = of_device_get_match_data(&pdev->dev); + if (!stm32port->info) + return -EINVAL; + + ret = stm32_usart_init_port(stm32port, pdev); + if (ret) + return ret; + + if (stm32port->wakeirq > 0) { + ret = device_init_wakeup(&pdev->dev, true); + if (ret) + goto err_uninit; + + ret = dev_pm_set_dedicated_wake_irq(&pdev->dev, + stm32port->wakeirq); + if (ret) + goto err_nowup; + + device_set_wakeup_enable(&pdev->dev, false); + } + + ret = stm32_usart_of_dma_rx_probe(stm32port, pdev); + if (ret) + dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n"); + + ret = stm32_usart_of_dma_tx_probe(stm32port, pdev); + if (ret) + dev_info(&pdev->dev, "interrupt mode used 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->rx_ch) { + dmaengine_terminate_async(stm32port->rx_ch); + dma_release_channel(stm32port->rx_ch); + } + + if (stm32port->rx_dma_buf) + dma_free_coherent(&pdev->dev, + RX_BUF_L, stm32port->rx_buf, + stm32port->rx_dma_buf); + + if (stm32port->tx_ch) { + dmaengine_terminate_async(stm32port->tx_ch); + dma_release_channel(stm32port->tx_ch); + } + + if (stm32port->tx_dma_buf) + dma_free_coherent(&pdev->dev, + TX_BUF_L, stm32port->tx_buf, + stm32port->tx_dma_buf); + + if (stm32port->wakeirq > 0) + dev_pm_clear_wake_irq(&pdev->dev); + +err_nowup: + if (stm32port->wakeirq > 0) + device_init_wakeup(&pdev->dev, false); + +err_uninit: + clk_disable_unprepare(stm32port->clk); + + return ret; +} + +static int 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); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + int err; + + pm_runtime_get_sync(&pdev->dev); + err = uart_remove_one_port(&stm32_usart_driver, port); + if (err) + return(err); + + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); + + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); + + if (stm32_port->rx_ch) { + dmaengine_terminate_async(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); + + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); + + if (stm32_port->tx_ch) { + dmaengine_terminate_async(stm32_port->tx_ch); + 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->wakeirq > 0) { + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); + } + + clk_disable_unprepare(stm32_port->clk); + + return 0; +} + +#ifdef CONFIG_SERIAL_STM32_CONSOLE +static void stm32_usart_console_putchar(struct uart_port *port, int ch) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) + cpu_relax(); + + writel_relaxed(ch, port->membase + ofs->tdr); +} + +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); + 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); + else + spin_lock(&port->lock); + + /* Save and disable interrupts, enable the transmitter */ + old_cr1 = readl_relaxed(port->membase + ofs->cr1); + new_cr1 = old_cr1 & ~USART_CR1_IE_MASK; + 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_usart_console_putchar); + + /* Restore interrupt state */ + writel_relaxed(old_cr1, port->membase + ofs->cr1); + + if (locked) + spin_unlock(&port->lock); + local_irq_restore(flags); +} + +static int stm32_usart_console_setup(struct console *co, char *options) +{ + struct stm32_port *stm32port; + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (co->index >= STM32_MAX_PORTS) + return -ENODEV; + + stm32port = &stm32_ports[co->index]; + + /* + * This driver does not support early console initialization + * (use ARM early printk support instead), so we only expect + * 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) + return -ENXIO; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(&stm32port->port, co, baud, parity, bits, flow); +} + +static struct console stm32_console = { + .name = STM32_SERIAL_NAME, + .device = uart_console_device, + .write = stm32_usart_console_write, + .setup = stm32_usart_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &stm32_usart_driver, +}; + +#define STM32_SERIAL_CONSOLE (&stm32_console) + +#else +#define STM32_SERIAL_CONSOLE NULL +#endif /* CONFIG_SERIAL_STM32_CONSOLE */ + +static struct uart_driver stm32_usart_driver = { + .driver_name = DRIVER_NAME, + .dev_name = STM32_SERIAL_NAME, + .major = 0, + .minor = 0, + .nr = STM32_MAX_PORTS, + .cons = STM32_SERIAL_CONSOLE, +}; + +static void __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; + + if (stm32_port->wakeirq <= 0) + return; + + /* + * 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); + } else { + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); + } +} + +static int __maybe_unused stm32_usart_serial_suspend(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + + uart_suspend_port(&stm32_usart_driver, port); + + if (device_may_wakeup(dev)) + stm32_usart_serial_en_wakeup(port, true); + else + stm32_usart_serial_en_wakeup(port, false); + + /* + * 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)) + 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); + + pinctrl_pm_select_default_state(dev); + + if (device_may_wakeup(dev)) + stm32_usart_serial_en_wakeup(port, false); + + 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_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 stm32_usart_init(void) +{ + static char banner[] __initdata = "STM32 USART driver initialized"; + int ret; + + pr_info("%s\n", banner); + + ret = uart_register_driver(&stm32_usart_driver); + if (ret) + return ret; + + ret = platform_driver_register(&stm32_serial_driver); + if (ret) + uart_unregister_driver(&stm32_usart_driver); + + return ret; +} + +static void __exit stm32_usart_exit(void) +{ + platform_driver_unregister(&stm32_serial_driver); + uart_unregister_driver(&stm32_usart_driver); +} + +module_init(stm32_usart_init); +module_exit(stm32_usart_exit); + +MODULE_ALIAS("platform:" DRIVER_NAME); +MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver"); +MODULE_LICENSE("GPL v2"); |