1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) Maxime Coquelin 2015
4 * Copyright (C) STMicroelectronics SA 2017
5 * Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com>
6 * Gerald Baeza <gerald.baeza@foss.st.com>
7 * Erwan Le Ray <erwan.leray@foss.st.com>
9 * Inspired by st-asc.c from STMicroelectronics (c)
12 #include <linux/bitfield.h>
13 #include <linux/clk.h>
14 #include <linux/console.h>
15 #include <linux/delay.h>
16 #include <linux/dma-direction.h>
17 #include <linux/dmaengine.h>
18 #include <linux/dma-mapping.h>
20 #include <linux/iopoll.h>
21 #include <linux/irq.h>
22 #include <linux/module.h>
24 #include <linux/of_platform.h>
25 #include <linux/pinctrl/consumer.h>
26 #include <linux/platform_device.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/pm_wakeirq.h>
29 #include <linux/serial_core.h>
30 #include <linux/serial.h>
31 #include <linux/spinlock.h>
32 #include <linux/sysrq.h>
33 #include <linux/tty_flip.h>
34 #include <linux/tty.h>
36 #include "serial_mctrl_gpio.h"
37 #include "stm32-usart.h"
40 /* Register offsets */
41 static struct stm32_usart_info __maybe_unused stm32f4_info = {
58 .uart_enable_bit = 13,
59 .has_7bits_data = false,
63 static struct stm32_usart_info __maybe_unused stm32f7_info = {
81 .has_7bits_data = true,
86 static struct stm32_usart_info __maybe_unused stm32h7_info = {
103 .uart_enable_bit = 0,
104 .has_7bits_data = true,
111 static void stm32_usart_stop_tx(struct uart_port *port);
112 static void stm32_usart_transmit_chars(struct uart_port *port);
113 static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
115 static inline struct stm32_port *to_stm32_port(struct uart_port *port)
117 return container_of(port, struct stm32_port, port);
120 static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits)
124 val = readl_relaxed(port->membase + reg);
126 writel_relaxed(val, port->membase + reg);
129 static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits)
133 val = readl_relaxed(port->membase + reg);
135 writel_relaxed(val, port->membase + reg);
138 static unsigned int stm32_usart_tx_empty(struct uart_port *port)
140 struct stm32_port *stm32_port = to_stm32_port(port);
141 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
143 if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
149 static void stm32_usart_rs485_rts_enable(struct uart_port *port)
151 struct stm32_port *stm32_port = to_stm32_port(port);
152 struct serial_rs485 *rs485conf = &port->rs485;
154 if (stm32_port->hw_flow_control ||
155 !(rs485conf->flags & SER_RS485_ENABLED))
158 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
159 mctrl_gpio_set(stm32_port->gpios,
160 stm32_port->port.mctrl | TIOCM_RTS);
162 mctrl_gpio_set(stm32_port->gpios,
163 stm32_port->port.mctrl & ~TIOCM_RTS);
167 static void stm32_usart_rs485_rts_disable(struct uart_port *port)
169 struct stm32_port *stm32_port = to_stm32_port(port);
170 struct serial_rs485 *rs485conf = &port->rs485;
172 if (stm32_port->hw_flow_control ||
173 !(rs485conf->flags & SER_RS485_ENABLED))
176 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
177 mctrl_gpio_set(stm32_port->gpios,
178 stm32_port->port.mctrl & ~TIOCM_RTS);
180 mctrl_gpio_set(stm32_port->gpios,
181 stm32_port->port.mctrl | TIOCM_RTS);
185 static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
186 u32 delay_DDE, u32 baud)
189 u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
192 *cr3 |= USART_CR3_DEM;
193 over8 = *cr1 & USART_CR1_OVER8;
195 *cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
198 rs485_deat_dedt = delay_ADE * baud * 8;
200 rs485_deat_dedt = delay_ADE * baud * 16;
202 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
203 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
204 rs485_deat_dedt_max : rs485_deat_dedt;
205 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
207 *cr1 |= rs485_deat_dedt;
210 rs485_deat_dedt = delay_DDE * baud * 8;
212 rs485_deat_dedt = delay_DDE * baud * 16;
214 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
215 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
216 rs485_deat_dedt_max : rs485_deat_dedt;
217 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
219 *cr1 |= rs485_deat_dedt;
222 static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios,
223 struct serial_rs485 *rs485conf)
225 struct stm32_port *stm32_port = to_stm32_port(port);
226 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
227 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
228 u32 usartdiv, baud, cr1, cr3;
231 stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
233 if (rs485conf->flags & SER_RS485_ENABLED) {
234 cr1 = readl_relaxed(port->membase + ofs->cr1);
235 cr3 = readl_relaxed(port->membase + ofs->cr3);
236 usartdiv = readl_relaxed(port->membase + ofs->brr);
237 usartdiv = usartdiv & GENMASK(15, 0);
238 over8 = cr1 & USART_CR1_OVER8;
241 usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
242 << USART_BRR_04_R_SHIFT;
244 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
245 stm32_usart_config_reg_rs485(&cr1, &cr3,
246 rs485conf->delay_rts_before_send,
247 rs485conf->delay_rts_after_send,
250 if (rs485conf->flags & SER_RS485_RTS_ON_SEND)
251 cr3 &= ~USART_CR3_DEP;
253 cr3 |= USART_CR3_DEP;
255 writel_relaxed(cr3, port->membase + ofs->cr3);
256 writel_relaxed(cr1, port->membase + ofs->cr1);
258 if (!port->rs485_rx_during_tx_gpio)
259 rs485conf->flags |= SER_RS485_RX_DURING_TX;
262 stm32_usart_clr_bits(port, ofs->cr3,
263 USART_CR3_DEM | USART_CR3_DEP);
264 stm32_usart_clr_bits(port, ofs->cr1,
265 USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
268 stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
270 /* Adjust RTS polarity in case it's driven in software */
271 if (stm32_usart_tx_empty(port))
272 stm32_usart_rs485_rts_disable(port);
274 stm32_usart_rs485_rts_enable(port);
279 static int stm32_usart_init_rs485(struct uart_port *port,
280 struct platform_device *pdev)
282 struct serial_rs485 *rs485conf = &port->rs485;
284 rs485conf->flags = 0;
285 rs485conf->delay_rts_before_send = 0;
286 rs485conf->delay_rts_after_send = 0;
288 if (!pdev->dev.of_node)
291 return uart_get_rs485_mode(port);
294 static bool stm32_usart_rx_dma_started(struct stm32_port *stm32_port)
296 return stm32_port->rx_ch ? stm32_port->rx_dma_busy : false;
299 static void stm32_usart_rx_dma_terminate(struct stm32_port *stm32_port)
301 dmaengine_terminate_async(stm32_port->rx_ch);
302 stm32_port->rx_dma_busy = false;
305 static int stm32_usart_dma_pause_resume(struct stm32_port *stm32_port,
306 struct dma_chan *chan,
307 enum dma_status expected_status,
308 int dmaengine_pause_or_resume(struct dma_chan *),
309 bool stm32_usart_xx_dma_started(struct stm32_port *),
310 void stm32_usart_xx_dma_terminate(struct stm32_port *))
312 struct uart_port *port = &stm32_port->port;
313 enum dma_status dma_status;
316 if (!stm32_usart_xx_dma_started(stm32_port))
319 dma_status = dmaengine_tx_status(chan, chan->cookie, NULL);
320 if (dma_status != expected_status)
323 ret = dmaengine_pause_or_resume(chan);
325 dev_err(port->dev, "DMA failed with error code: %d\n", ret);
326 stm32_usart_xx_dma_terminate(stm32_port);
331 static int stm32_usart_rx_dma_pause(struct stm32_port *stm32_port)
333 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
334 DMA_IN_PROGRESS, dmaengine_pause,
335 stm32_usart_rx_dma_started,
336 stm32_usart_rx_dma_terminate);
339 static int stm32_usart_rx_dma_resume(struct stm32_port *stm32_port)
341 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
342 DMA_PAUSED, dmaengine_resume,
343 stm32_usart_rx_dma_started,
344 stm32_usart_rx_dma_terminate);
347 /* Return true when data is pending (in pio mode), and false when no data is pending. */
348 static bool stm32_usart_pending_rx_pio(struct uart_port *port, u32 *sr)
350 struct stm32_port *stm32_port = to_stm32_port(port);
351 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
353 *sr = readl_relaxed(port->membase + ofs->isr);
354 /* Get pending characters in RDR or FIFO */
355 if (*sr & USART_SR_RXNE) {
356 /* Get all pending characters from the RDR or the FIFO when using interrupts */
357 if (!stm32_usart_rx_dma_started(stm32_port))
360 /* Handle only RX data errors when using DMA */
361 if (*sr & USART_SR_ERR_MASK)
368 static u8 stm32_usart_get_char_pio(struct uart_port *port)
370 struct stm32_port *stm32_port = to_stm32_port(port);
371 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
374 c = readl_relaxed(port->membase + ofs->rdr);
375 /* Apply RDR data mask */
376 c &= stm32_port->rdr_mask;
381 static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port)
383 struct stm32_port *stm32_port = to_stm32_port(port);
384 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
385 unsigned int size = 0;
389 while (stm32_usart_pending_rx_pio(port, &sr)) {
390 sr |= USART_SR_DUMMY_RX;
394 * Status bits has to be cleared before reading the RDR:
395 * In FIFO mode, reading the RDR will pop the next data
396 * (if any) along with its status bits into the SR.
397 * Not doing so leads to misalignement between RDR and SR,
398 * and clear status bits of the next rx data.
400 * Clear errors flags for stm32f7 and stm32h7 compatible
401 * devices. On stm32f4 compatible devices, the error bit is
402 * cleared by the sequence [read SR - read DR].
404 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
405 writel_relaxed(sr & USART_SR_ERR_MASK,
406 port->membase + ofs->icr);
408 c = stm32_usart_get_char_pio(port);
411 if (sr & USART_SR_ERR_MASK) {
412 if (sr & USART_SR_ORE) {
413 port->icount.overrun++;
414 } else if (sr & USART_SR_PE) {
415 port->icount.parity++;
416 } else if (sr & USART_SR_FE) {
417 /* Break detection if character is null */
420 if (uart_handle_break(port))
423 port->icount.frame++;
427 sr &= port->read_status_mask;
429 if (sr & USART_SR_PE) {
431 } else if (sr & USART_SR_FE) {
439 if (uart_prepare_sysrq_char(port, c))
441 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
447 static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size)
449 struct stm32_port *stm32_port = to_stm32_port(port);
450 struct tty_port *ttyport = &stm32_port->port.state->port;
451 unsigned char *dma_start;
454 dma_start = stm32_port->rx_buf + (RX_BUF_L - stm32_port->last_res);
457 * Apply rdr_mask on buffer in order to mask parity bit.
458 * This loop is useless in cs8 mode because DMA copies only
459 * 8 bits and already ignores parity bit.
461 if (!(stm32_port->rdr_mask == (BIT(8) - 1)))
462 for (i = 0; i < dma_size; i++)
463 *(dma_start + i) &= stm32_port->rdr_mask;
465 dma_count = tty_insert_flip_string(ttyport, dma_start, dma_size);
466 port->icount.rx += dma_count;
467 if (dma_count != dma_size)
468 port->icount.buf_overrun++;
469 stm32_port->last_res -= dma_count;
470 if (stm32_port->last_res == 0)
471 stm32_port->last_res = RX_BUF_L;
474 static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port)
476 struct stm32_port *stm32_port = to_stm32_port(port);
477 unsigned int dma_size, size = 0;
479 /* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */
480 if (stm32_port->rx_dma_state.residue > stm32_port->last_res) {
481 /* Conditional first part: from last_res to end of DMA buffer */
482 dma_size = stm32_port->last_res;
483 stm32_usart_push_buffer_dma(port, dma_size);
487 dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue;
488 stm32_usart_push_buffer_dma(port, dma_size);
494 static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush)
496 struct stm32_port *stm32_port = to_stm32_port(port);
497 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
498 enum dma_status rx_dma_status;
500 unsigned int size = 0;
502 if (stm32_usart_rx_dma_started(stm32_port) || force_dma_flush) {
503 rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
504 stm32_port->rx_ch->cookie,
505 &stm32_port->rx_dma_state);
506 if (rx_dma_status == DMA_IN_PROGRESS ||
507 rx_dma_status == DMA_PAUSED) {
508 /* Empty DMA buffer */
509 size = stm32_usart_receive_chars_dma(port);
510 sr = readl_relaxed(port->membase + ofs->isr);
511 if (sr & USART_SR_ERR_MASK) {
512 /* Disable DMA request line */
513 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
515 /* Switch to PIO mode to handle the errors */
516 size += stm32_usart_receive_chars_pio(port);
518 /* Switch back to DMA mode */
519 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
523 stm32_usart_rx_dma_terminate(stm32_port);
524 /* Fall back to interrupt mode */
525 dev_dbg(port->dev, "DMA error, fallback to irq mode\n");
526 size = stm32_usart_receive_chars_pio(port);
529 size = stm32_usart_receive_chars_pio(port);
535 static void stm32_usart_rx_dma_complete(void *arg)
537 struct uart_port *port = arg;
538 struct tty_port *tport = &port->state->port;
542 uart_port_lock_irqsave(port, &flags);
543 size = stm32_usart_receive_chars(port, false);
544 uart_unlock_and_check_sysrq_irqrestore(port, flags);
546 tty_flip_buffer_push(tport);
549 static int stm32_usart_rx_dma_start_or_resume(struct uart_port *port)
551 struct stm32_port *stm32_port = to_stm32_port(port);
552 struct dma_async_tx_descriptor *desc;
553 enum dma_status rx_dma_status;
556 if (stm32_port->throttled)
559 if (stm32_port->rx_dma_busy) {
560 rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
561 stm32_port->rx_ch->cookie,
563 if (rx_dma_status == DMA_IN_PROGRESS)
566 if (rx_dma_status == DMA_PAUSED && !stm32_usart_rx_dma_resume(stm32_port))
569 dev_err(port->dev, "DMA failed : status error.\n");
570 stm32_usart_rx_dma_terminate(stm32_port);
573 stm32_port->rx_dma_busy = true;
575 stm32_port->last_res = RX_BUF_L;
576 /* Prepare a DMA cyclic transaction */
577 desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch,
578 stm32_port->rx_dma_buf,
583 dev_err(port->dev, "rx dma prep cyclic failed\n");
584 stm32_port->rx_dma_busy = false;
588 desc->callback = stm32_usart_rx_dma_complete;
589 desc->callback_param = port;
591 /* Push current DMA transaction in the pending queue */
592 ret = dma_submit_error(dmaengine_submit(desc));
594 dmaengine_terminate_sync(stm32_port->rx_ch);
595 stm32_port->rx_dma_busy = false;
599 /* Issue pending DMA requests */
600 dma_async_issue_pending(stm32_port->rx_ch);
605 static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port)
607 dmaengine_terminate_async(stm32_port->tx_ch);
608 stm32_port->tx_dma_busy = false;
611 static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port)
614 * We cannot use the function "dmaengine_tx_status" to know the
615 * status of DMA. This function does not show if the "dma complete"
616 * callback of the DMA transaction has been called. So we prefer
617 * to use "tx_dma_busy" flag to prevent dual DMA transaction at the
620 return stm32_port->tx_dma_busy;
623 static int stm32_usart_tx_dma_pause(struct stm32_port *stm32_port)
625 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
626 DMA_IN_PROGRESS, dmaengine_pause,
627 stm32_usart_tx_dma_started,
628 stm32_usart_tx_dma_terminate);
631 static int stm32_usart_tx_dma_resume(struct stm32_port *stm32_port)
633 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
634 DMA_PAUSED, dmaengine_resume,
635 stm32_usart_tx_dma_started,
636 stm32_usart_tx_dma_terminate);
639 static void stm32_usart_tx_dma_complete(void *arg)
641 struct uart_port *port = arg;
642 struct stm32_port *stm32port = to_stm32_port(port);
645 stm32_usart_tx_dma_terminate(stm32port);
647 /* Let's see if we have pending data to send */
648 uart_port_lock_irqsave(port, &flags);
649 stm32_usart_transmit_chars(port);
650 uart_port_unlock_irqrestore(port, flags);
653 static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
655 struct stm32_port *stm32_port = to_stm32_port(port);
656 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
659 * Enables TX FIFO threashold irq when FIFO is enabled,
660 * or TX empty irq when FIFO is disabled
662 if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
663 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
665 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
668 static void stm32_usart_tc_interrupt_enable(struct uart_port *port)
670 struct stm32_port *stm32_port = to_stm32_port(port);
671 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
673 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TCIE);
676 static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
678 struct stm32_port *stm32_port = to_stm32_port(port);
679 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
681 if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
682 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
684 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
687 static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
689 struct stm32_port *stm32_port = to_stm32_port(port);
690 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
692 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE);
695 static void stm32_usart_transmit_chars_pio(struct uart_port *port)
697 struct stm32_port *stm32_port = to_stm32_port(port);
698 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
699 struct circ_buf *xmit = &port->state->xmit;
701 while (!uart_circ_empty(xmit)) {
702 /* Check that TDR is empty before filling FIFO */
703 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
705 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
706 uart_xmit_advance(port, 1);
709 /* rely on TXE irq (mask or unmask) for sending remaining data */
710 if (uart_circ_empty(xmit))
711 stm32_usart_tx_interrupt_disable(port);
713 stm32_usart_tx_interrupt_enable(port);
716 static void stm32_usart_transmit_chars_dma(struct uart_port *port)
718 struct stm32_port *stm32port = to_stm32_port(port);
719 struct circ_buf *xmit = &port->state->xmit;
720 struct dma_async_tx_descriptor *desc = NULL;
724 if (stm32_usart_tx_dma_started(stm32port)) {
725 ret = stm32_usart_tx_dma_resume(stm32port);
726 if (ret < 0 && ret != -EAGAIN)
731 count = uart_circ_chars_pending(xmit);
733 if (count > TX_BUF_L)
736 if (xmit->tail < xmit->head) {
737 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
739 size_t one = UART_XMIT_SIZE - xmit->tail;
746 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
748 memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
751 desc = dmaengine_prep_slave_single(stm32port->tx_ch,
752 stm32port->tx_dma_buf,
761 * Set "tx_dma_busy" flag. This flag will be released when
762 * dmaengine_terminate_async will be called. This flag helps
763 * transmit_chars_dma not to start another DMA transaction
764 * if the callback of the previous is not yet called.
766 stm32port->tx_dma_busy = true;
768 desc->callback = stm32_usart_tx_dma_complete;
769 desc->callback_param = port;
771 /* Push current DMA TX transaction in the pending queue */
772 /* DMA no yet started, safe to free resources */
773 ret = dma_submit_error(dmaengine_submit(desc));
775 dev_err(port->dev, "DMA failed with error code: %d\n", ret);
776 stm32_usart_tx_dma_terminate(stm32port);
780 /* Issue pending DMA TX requests */
781 dma_async_issue_pending(stm32port->tx_ch);
783 uart_xmit_advance(port, count);
788 stm32_usart_transmit_chars_pio(port);
791 static void stm32_usart_transmit_chars(struct uart_port *port)
793 struct stm32_port *stm32_port = to_stm32_port(port);
794 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
795 struct circ_buf *xmit = &port->state->xmit;
799 if (!stm32_port->hw_flow_control &&
800 port->rs485.flags & SER_RS485_ENABLED &&
802 !(uart_circ_empty(xmit) || uart_tx_stopped(port)))) {
803 stm32_usart_tc_interrupt_disable(port);
804 stm32_usart_rs485_rts_enable(port);
808 /* dma terminate may have been called in case of dma pause failure */
809 stm32_usart_tx_dma_pause(stm32_port);
811 /* Check that TDR is empty before filling FIFO */
813 readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
815 (isr & USART_SR_TXE),
818 dev_warn(port->dev, "1 character may be erased\n");
820 writel_relaxed(port->x_char, port->membase + ofs->tdr);
824 /* dma terminate may have been called in case of dma resume failure */
825 stm32_usart_tx_dma_resume(stm32_port);
829 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
830 stm32_usart_tx_interrupt_disable(port);
834 if (ofs->icr == UNDEF_REG)
835 stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC);
837 writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
839 if (stm32_port->tx_ch)
840 stm32_usart_transmit_chars_dma(port);
842 stm32_usart_transmit_chars_pio(port);
844 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
845 uart_write_wakeup(port);
847 if (uart_circ_empty(xmit)) {
848 stm32_usart_tx_interrupt_disable(port);
849 if (!stm32_port->hw_flow_control &&
850 port->rs485.flags & SER_RS485_ENABLED) {
851 stm32_usart_tc_interrupt_enable(port);
856 static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
858 struct uart_port *port = ptr;
859 struct tty_port *tport = &port->state->port;
860 struct stm32_port *stm32_port = to_stm32_port(port);
861 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
865 sr = readl_relaxed(port->membase + ofs->isr);
867 if (!stm32_port->hw_flow_control &&
868 port->rs485.flags & SER_RS485_ENABLED &&
869 (sr & USART_SR_TC)) {
870 stm32_usart_tc_interrupt_disable(port);
871 stm32_usart_rs485_rts_disable(port);
874 if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
875 writel_relaxed(USART_ICR_RTOCF,
876 port->membase + ofs->icr);
878 if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
879 /* Clear wake up flag and disable wake up interrupt */
880 writel_relaxed(USART_ICR_WUCF,
881 port->membase + ofs->icr);
882 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
883 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
884 pm_wakeup_event(tport->tty->dev, 0);
888 * rx errors in dma mode has to be handled ASAP to avoid overrun as the DMA request
889 * line has been masked by HW and rx data are stacking in FIFO.
891 if (!stm32_port->throttled) {
892 if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) ||
893 ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) {
894 uart_port_lock(port);
895 size = stm32_usart_receive_chars(port, false);
896 uart_unlock_and_check_sysrq(port);
898 tty_flip_buffer_push(tport);
902 if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
903 uart_port_lock(port);
904 stm32_usart_transmit_chars(port);
905 uart_port_unlock(port);
908 /* Receiver timeout irq for DMA RX */
909 if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) {
910 uart_port_lock(port);
911 size = stm32_usart_receive_chars(port, false);
912 uart_unlock_and_check_sysrq(port);
914 tty_flip_buffer_push(tport);
920 static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
922 struct stm32_port *stm32_port = to_stm32_port(port);
923 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
925 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
926 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE);
928 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
930 mctrl_gpio_set(stm32_port->gpios, mctrl);
933 static unsigned int stm32_usart_get_mctrl(struct uart_port *port)
935 struct stm32_port *stm32_port = to_stm32_port(port);
938 /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
939 ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
941 return mctrl_gpio_get(stm32_port->gpios, &ret);
944 static void stm32_usart_enable_ms(struct uart_port *port)
946 mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
949 static void stm32_usart_disable_ms(struct uart_port *port)
951 mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
955 static void stm32_usart_stop_tx(struct uart_port *port)
957 struct stm32_port *stm32_port = to_stm32_port(port);
959 stm32_usart_tx_interrupt_disable(port);
961 /* dma terminate may have been called in case of dma pause failure */
962 stm32_usart_tx_dma_pause(stm32_port);
964 stm32_usart_rs485_rts_disable(port);
967 /* There are probably characters waiting to be transmitted. */
968 static void stm32_usart_start_tx(struct uart_port *port)
970 struct circ_buf *xmit = &port->state->xmit;
972 if (uart_circ_empty(xmit) && !port->x_char) {
973 stm32_usart_rs485_rts_disable(port);
977 stm32_usart_rs485_rts_enable(port);
979 stm32_usart_transmit_chars(port);
982 /* Flush the transmit buffer. */
983 static void stm32_usart_flush_buffer(struct uart_port *port)
985 struct stm32_port *stm32_port = to_stm32_port(port);
987 if (stm32_port->tx_ch)
988 stm32_usart_tx_dma_terminate(stm32_port);
991 /* Throttle the remote when input buffer is about to overflow. */
992 static void stm32_usart_throttle(struct uart_port *port)
994 struct stm32_port *stm32_port = to_stm32_port(port);
995 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
998 uart_port_lock_irqsave(port, &flags);
1001 * Pause DMA transfer, so the RX data gets queued into the FIFO.
1002 * Hardware flow control is triggered when RX FIFO is full.
1004 stm32_usart_rx_dma_pause(stm32_port);
1006 stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1007 if (stm32_port->cr3_irq)
1008 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1010 stm32_port->throttled = true;
1011 uart_port_unlock_irqrestore(port, flags);
1014 /* Unthrottle the remote, the input buffer can now accept data. */
1015 static void stm32_usart_unthrottle(struct uart_port *port)
1017 struct stm32_port *stm32_port = to_stm32_port(port);
1018 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1019 unsigned long flags;
1021 uart_port_lock_irqsave(port, &flags);
1022 stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
1023 if (stm32_port->cr3_irq)
1024 stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
1026 stm32_port->throttled = false;
1029 * Switch back to DMA mode (resume DMA).
1030 * Hardware flow control is stopped when FIFO is not full any more.
1032 if (stm32_port->rx_ch)
1033 stm32_usart_rx_dma_start_or_resume(port);
1035 uart_port_unlock_irqrestore(port, flags);
1039 static void stm32_usart_stop_rx(struct uart_port *port)
1041 struct stm32_port *stm32_port = to_stm32_port(port);
1042 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1044 /* Disable DMA request line. */
1045 stm32_usart_rx_dma_pause(stm32_port);
1047 stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1048 if (stm32_port->cr3_irq)
1049 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1052 static void stm32_usart_break_ctl(struct uart_port *port, int break_state)
1054 struct stm32_port *stm32_port = to_stm32_port(port);
1055 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1056 unsigned long flags;
1058 spin_lock_irqsave(&port->lock, flags);
1061 stm32_usart_set_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1063 stm32_usart_clr_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1065 spin_unlock_irqrestore(&port->lock, flags);
1068 static int stm32_usart_startup(struct uart_port *port)
1070 struct stm32_port *stm32_port = to_stm32_port(port);
1071 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1072 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1073 const char *name = to_platform_device(port->dev)->name;
1077 ret = request_irq(port->irq, stm32_usart_interrupt,
1078 IRQF_NO_SUSPEND, name, port);
1082 if (stm32_port->swap) {
1083 val = readl_relaxed(port->membase + ofs->cr2);
1084 val |= USART_CR2_SWAP;
1085 writel_relaxed(val, port->membase + ofs->cr2);
1089 if (ofs->rqr != UNDEF_REG)
1090 writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
1092 if (stm32_port->rx_ch) {
1093 ret = stm32_usart_rx_dma_start_or_resume(port);
1095 free_irq(port->irq, port);
1101 val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
1102 stm32_usart_set_bits(port, ofs->cr1, val);
1107 static void stm32_usart_shutdown(struct uart_port *port)
1109 struct stm32_port *stm32_port = to_stm32_port(port);
1110 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1111 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1115 if (stm32_usart_tx_dma_started(stm32_port))
1116 stm32_usart_tx_dma_terminate(stm32_port);
1118 if (stm32_port->tx_ch)
1119 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1121 /* Disable modem control interrupts */
1122 stm32_usart_disable_ms(port);
1124 val = USART_CR1_TXEIE | USART_CR1_TE;
1125 val |= stm32_port->cr1_irq | USART_CR1_RE;
1126 val |= BIT(cfg->uart_enable_bit);
1127 if (stm32_port->fifoen)
1128 val |= USART_CR1_FIFOEN;
1130 ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
1131 isr, (isr & USART_SR_TC),
1134 /* Send the TC error message only when ISR_TC is not set */
1136 dev_err(port->dev, "Transmission is not complete\n");
1138 /* Disable RX DMA. */
1139 if (stm32_port->rx_ch) {
1140 stm32_usart_rx_dma_terminate(stm32_port);
1141 dmaengine_synchronize(stm32_port->rx_ch);
1144 /* flush RX & TX FIFO */
1145 if (ofs->rqr != UNDEF_REG)
1146 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1147 port->membase + ofs->rqr);
1149 stm32_usart_clr_bits(port, ofs->cr1, val);
1151 free_irq(port->irq, port);
1154 static const unsigned int stm32_usart_presc_val[] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256};
1156 static void stm32_usart_set_termios(struct uart_port *port,
1157 struct ktermios *termios,
1158 const struct ktermios *old)
1160 struct stm32_port *stm32_port = to_stm32_port(port);
1161 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1162 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1163 struct serial_rs485 *rs485conf = &port->rs485;
1164 unsigned int baud, bits, uart_clk, uart_clk_pres;
1165 u32 usartdiv, mantissa, fraction, oversampling;
1166 tcflag_t cflag = termios->c_cflag;
1167 u32 cr1, cr2, cr3, isr, brr, presc;
1168 unsigned long flags;
1171 if (!stm32_port->hw_flow_control)
1174 uart_clk = clk_get_rate(stm32_port->clk);
1176 baud = uart_get_baud_rate(port, termios, old, 0, uart_clk / 8);
1178 uart_port_lock_irqsave(port, &flags);
1180 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
1182 (isr & USART_SR_TC),
1185 /* Send the TC error message only when ISR_TC is not set. */
1187 dev_err(port->dev, "Transmission is not complete\n");
1189 /* Stop serial port and reset value */
1190 writel_relaxed(0, port->membase + ofs->cr1);
1192 /* flush RX & TX FIFO */
1193 if (ofs->rqr != UNDEF_REG)
1194 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1195 port->membase + ofs->rqr);
1197 cr1 = USART_CR1_TE | USART_CR1_RE;
1198 if (stm32_port->fifoen)
1199 cr1 |= USART_CR1_FIFOEN;
1200 cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
1202 /* Tx and RX FIFO configuration */
1203 cr3 = readl_relaxed(port->membase + ofs->cr3);
1204 cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
1205 if (stm32_port->fifoen) {
1206 if (stm32_port->txftcfg >= 0)
1207 cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
1208 if (stm32_port->rxftcfg >= 0)
1209 cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
1213 cr2 |= USART_CR2_STOP_2B;
1215 bits = tty_get_char_size(cflag);
1216 stm32_port->rdr_mask = (BIT(bits) - 1);
1218 if (cflag & PARENB) {
1220 cr1 |= USART_CR1_PCE;
1224 * Word length configuration:
1225 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
1226 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
1227 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
1228 * M0 and M1 already cleared by cr1 initialization.
1231 cr1 |= USART_CR1_M0;
1232 } else if ((bits == 7) && cfg->has_7bits_data) {
1233 cr1 |= USART_CR1_M1;
1234 } else if (bits != 8) {
1235 dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
1239 termios->c_cflag = cflag;
1241 if (cflag & PARENB) {
1243 cr1 |= USART_CR1_M0;
1247 if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
1248 (stm32_port->fifoen &&
1249 stm32_port->rxftcfg >= 0))) {
1251 bits = bits + 3; /* 1 start bit + 2 stop bits */
1253 bits = bits + 2; /* 1 start bit + 1 stop bit */
1255 /* RX timeout irq to occur after last stop bit + bits */
1256 stm32_port->cr1_irq = USART_CR1_RTOIE;
1257 writel_relaxed(bits, port->membase + ofs->rtor);
1258 cr2 |= USART_CR2_RTOEN;
1260 * Enable fifo threshold irq in two cases, either when there is no DMA, or when
1261 * wake up over usart, from low power until the DMA gets re-enabled by resume.
1263 stm32_port->cr3_irq = USART_CR3_RXFTIE;
1266 cr1 |= stm32_port->cr1_irq;
1267 cr3 |= stm32_port->cr3_irq;
1270 cr1 |= USART_CR1_PS;
1272 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
1273 if (cflag & CRTSCTS) {
1274 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
1275 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
1278 for (presc = 0; presc <= USART_PRESC_MAX; presc++) {
1279 uart_clk_pres = DIV_ROUND_CLOSEST(uart_clk, stm32_usart_presc_val[presc]);
1280 usartdiv = DIV_ROUND_CLOSEST(uart_clk_pres, baud);
1283 * The USART supports 16 or 8 times oversampling.
1284 * By default we prefer 16 times oversampling, so that the receiver
1285 * has a better tolerance to clock deviations.
1286 * 8 times oversampling is only used to achieve higher speeds.
1288 if (usartdiv < 16) {
1290 cr1 |= USART_CR1_OVER8;
1291 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8);
1294 cr1 &= ~USART_CR1_OVER8;
1295 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
1298 mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
1299 fraction = usartdiv % oversampling;
1300 brr = mantissa | fraction;
1302 if (FIELD_FIT(USART_BRR_MASK, brr)) {
1303 if (ofs->presc != UNDEF_REG) {
1304 port->uartclk = uart_clk_pres;
1305 writel_relaxed(presc, port->membase + ofs->presc);
1307 /* We need a prescaler but we don't have it (STM32F4, STM32F7) */
1309 "unable to set baudrate, input clock is too high");
1312 } else if (presc == USART_PRESC_MAX) {
1313 /* Even with prescaler and brr at max value we can't set baudrate */
1314 dev_err(port->dev, "unable to set baudrate, input clock is too high");
1319 writel_relaxed(brr, port->membase + ofs->brr);
1321 uart_update_timeout(port, cflag, baud);
1323 port->read_status_mask = USART_SR_ORE;
1324 if (termios->c_iflag & INPCK)
1325 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
1326 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1327 port->read_status_mask |= USART_SR_FE;
1329 /* Characters to ignore */
1330 port->ignore_status_mask = 0;
1331 if (termios->c_iflag & IGNPAR)
1332 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
1333 if (termios->c_iflag & IGNBRK) {
1334 port->ignore_status_mask |= USART_SR_FE;
1336 * If we're ignoring parity and break indicators,
1337 * ignore overruns too (for real raw support).
1339 if (termios->c_iflag & IGNPAR)
1340 port->ignore_status_mask |= USART_SR_ORE;
1343 /* Ignore all characters if CREAD is not set */
1344 if ((termios->c_cflag & CREAD) == 0)
1345 port->ignore_status_mask |= USART_SR_DUMMY_RX;
1347 if (stm32_port->rx_ch) {
1349 * Setup DMA to collect only valid data and enable error irqs.
1350 * This also enables break reception when using DMA.
1352 cr1 |= USART_CR1_PEIE;
1353 cr3 |= USART_CR3_EIE;
1354 cr3 |= USART_CR3_DMAR;
1355 cr3 |= USART_CR3_DDRE;
1358 if (stm32_port->tx_ch)
1359 cr3 |= USART_CR3_DMAT;
1361 if (rs485conf->flags & SER_RS485_ENABLED) {
1362 stm32_usart_config_reg_rs485(&cr1, &cr3,
1363 rs485conf->delay_rts_before_send,
1364 rs485conf->delay_rts_after_send,
1366 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
1367 cr3 &= ~USART_CR3_DEP;
1368 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
1370 cr3 |= USART_CR3_DEP;
1371 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
1375 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
1376 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
1379 /* Configure wake up from low power on start bit detection */
1380 if (stm32_port->wakeup_src) {
1381 cr3 &= ~USART_CR3_WUS_MASK;
1382 cr3 |= USART_CR3_WUS_START_BIT;
1385 writel_relaxed(cr3, port->membase + ofs->cr3);
1386 writel_relaxed(cr2, port->membase + ofs->cr2);
1387 writel_relaxed(cr1, port->membase + ofs->cr1);
1389 stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1390 uart_port_unlock_irqrestore(port, flags);
1392 /* Handle modem control interrupts */
1393 if (UART_ENABLE_MS(port, termios->c_cflag))
1394 stm32_usart_enable_ms(port);
1396 stm32_usart_disable_ms(port);
1399 static const char *stm32_usart_type(struct uart_port *port)
1401 return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
1404 static void stm32_usart_release_port(struct uart_port *port)
1408 static int stm32_usart_request_port(struct uart_port *port)
1413 static void stm32_usart_config_port(struct uart_port *port, int flags)
1415 if (flags & UART_CONFIG_TYPE)
1416 port->type = PORT_STM32;
1420 stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser)
1422 /* No user changeable parameters */
1426 static void stm32_usart_pm(struct uart_port *port, unsigned int state,
1427 unsigned int oldstate)
1429 struct stm32_port *stm32port = container_of(port,
1430 struct stm32_port, port);
1431 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1432 const struct stm32_usart_config *cfg = &stm32port->info->cfg;
1433 unsigned long flags;
1436 case UART_PM_STATE_ON:
1437 pm_runtime_get_sync(port->dev);
1439 case UART_PM_STATE_OFF:
1440 uart_port_lock_irqsave(port, &flags);
1441 stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1442 uart_port_unlock_irqrestore(port, flags);
1443 pm_runtime_put_sync(port->dev);
1448 #if defined(CONFIG_CONSOLE_POLL)
1450 /* Callbacks for characters polling in debug context (i.e. KGDB). */
1451 static int stm32_usart_poll_init(struct uart_port *port)
1453 struct stm32_port *stm32_port = to_stm32_port(port);
1455 return clk_prepare_enable(stm32_port->clk);
1458 static int stm32_usart_poll_get_char(struct uart_port *port)
1460 struct stm32_port *stm32_port = to_stm32_port(port);
1461 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1463 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE))
1464 return NO_POLL_CHAR;
1466 return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask;
1469 static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch)
1471 stm32_usart_console_putchar(port, ch);
1473 #endif /* CONFIG_CONSOLE_POLL */
1475 static const struct uart_ops stm32_uart_ops = {
1476 .tx_empty = stm32_usart_tx_empty,
1477 .set_mctrl = stm32_usart_set_mctrl,
1478 .get_mctrl = stm32_usart_get_mctrl,
1479 .stop_tx = stm32_usart_stop_tx,
1480 .start_tx = stm32_usart_start_tx,
1481 .throttle = stm32_usart_throttle,
1482 .unthrottle = stm32_usart_unthrottle,
1483 .stop_rx = stm32_usart_stop_rx,
1484 .enable_ms = stm32_usart_enable_ms,
1485 .break_ctl = stm32_usart_break_ctl,
1486 .startup = stm32_usart_startup,
1487 .shutdown = stm32_usart_shutdown,
1488 .flush_buffer = stm32_usart_flush_buffer,
1489 .set_termios = stm32_usart_set_termios,
1490 .pm = stm32_usart_pm,
1491 .type = stm32_usart_type,
1492 .release_port = stm32_usart_release_port,
1493 .request_port = stm32_usart_request_port,
1494 .config_port = stm32_usart_config_port,
1495 .verify_port = stm32_usart_verify_port,
1496 #if defined(CONFIG_CONSOLE_POLL)
1497 .poll_init = stm32_usart_poll_init,
1498 .poll_get_char = stm32_usart_poll_get_char,
1499 .poll_put_char = stm32_usart_poll_put_char,
1500 #endif /* CONFIG_CONSOLE_POLL */
1503 struct stm32_usart_thresh_ratio {
1508 static const struct stm32_usart_thresh_ratio stm32h7_usart_fifo_thresh_cfg[] = {
1509 {1, 8}, {1, 4}, {1, 2}, {3, 4}, {7, 8}, {1, 1} };
1511 static int stm32_usart_get_thresh_value(u32 fifo_size, int index)
1513 return fifo_size * stm32h7_usart_fifo_thresh_cfg[index].mul /
1514 stm32h7_usart_fifo_thresh_cfg[index].div;
1517 static int stm32_usart_get_ftcfg(struct platform_device *pdev, struct stm32_port *stm32port,
1518 const char *p, int *ftcfg)
1520 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1524 if (WARN_ON(ofs->hwcfgr1 == UNDEF_REG))
1527 cfg8 = FIELD_GET(USART_HWCFGR1_CFG8,
1528 readl_relaxed(stm32port->port.membase + ofs->hwcfgr1));
1530 /* On STM32H7, hwcfgr is not present, so returned value will be 0 */
1531 fifo_size = cfg8 ? 1 << cfg8 : STM32H7_USART_FIFO_SIZE;
1533 /* DT option to get RX & TX FIFO threshold (default to half fifo size) */
1534 if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
1535 bytes = fifo_size / 2;
1537 if (bytes < stm32_usart_get_thresh_value(fifo_size, 0)) {
1542 for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) {
1543 if (stm32_usart_get_thresh_value(fifo_size, i) >= bytes)
1546 if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
1547 i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
1549 dev_dbg(&pdev->dev, "%s set to %d/%d bytes\n", p,
1550 stm32_usart_get_thresh_value(fifo_size, i), fifo_size);
1556 static void stm32_usart_deinit_port(struct stm32_port *stm32port)
1558 clk_disable_unprepare(stm32port->clk);
1561 static const struct serial_rs485 stm32_rs485_supported = {
1562 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
1563 SER_RS485_RX_DURING_TX,
1564 .delay_rts_before_send = 1,
1565 .delay_rts_after_send = 1,
1568 static int stm32_usart_init_port(struct stm32_port *stm32port,
1569 struct platform_device *pdev)
1571 struct uart_port *port = &stm32port->port;
1572 struct resource *res;
1575 irq = platform_get_irq(pdev, 0);
1579 port->iotype = UPIO_MEM;
1580 port->flags = UPF_BOOT_AUTOCONF;
1581 port->ops = &stm32_uart_ops;
1582 port->dev = &pdev->dev;
1583 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
1585 port->rs485_config = stm32_usart_config_rs485;
1586 port->rs485_supported = stm32_rs485_supported;
1588 ret = stm32_usart_init_rs485(port, pdev);
1592 stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
1593 of_property_read_bool(pdev->dev.of_node, "wakeup-source");
1595 stm32port->swap = stm32port->info->cfg.has_swap &&
1596 of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
1598 port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
1599 if (IS_ERR(port->membase))
1600 return PTR_ERR(port->membase);
1601 port->mapbase = res->start;
1603 spin_lock_init(&port->lock);
1605 stm32port->clk = devm_clk_get(&pdev->dev, NULL);
1606 if (IS_ERR(stm32port->clk))
1607 return PTR_ERR(stm32port->clk);
1609 /* Ensure that clk rate is correct by enabling the clk */
1610 ret = clk_prepare_enable(stm32port->clk);
1614 stm32port->port.uartclk = clk_get_rate(stm32port->clk);
1615 if (!stm32port->port.uartclk) {
1620 stm32port->fifoen = stm32port->info->cfg.has_fifo;
1621 if (stm32port->fifoen) {
1622 stm32_usart_get_ftcfg(pdev, stm32port, "rx-threshold", &stm32port->rxftcfg);
1623 port->fifosize = stm32_usart_get_ftcfg(pdev, stm32port, "tx-threshold",
1624 &stm32port->txftcfg);
1629 stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
1630 if (IS_ERR(stm32port->gpios)) {
1631 ret = PTR_ERR(stm32port->gpios);
1636 * Both CTS/RTS gpios and "st,hw-flow-ctrl" (deprecated) or "uart-has-rtscts"
1637 * properties should not be specified.
1639 if (stm32port->hw_flow_control) {
1640 if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
1641 mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
1642 dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
1651 clk_disable_unprepare(stm32port->clk);
1656 static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
1658 struct device_node *np = pdev->dev.of_node;
1664 id = of_alias_get_id(np, "serial");
1666 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
1670 if (WARN_ON(id >= STM32_MAX_PORTS))
1673 stm32_ports[id].hw_flow_control =
1674 of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
1675 of_property_read_bool (np, "uart-has-rtscts");
1676 stm32_ports[id].port.line = id;
1677 stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
1678 stm32_ports[id].cr3_irq = 0;
1679 stm32_ports[id].last_res = RX_BUF_L;
1680 return &stm32_ports[id];
1684 static const struct of_device_id stm32_match[] = {
1685 { .compatible = "st,stm32-uart", .data = &stm32f4_info},
1686 { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1687 { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1691 MODULE_DEVICE_TABLE(of, stm32_match);
1694 static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
1695 struct platform_device *pdev)
1697 if (stm32port->rx_buf)
1698 dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
1699 stm32port->rx_dma_buf);
1702 static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
1703 struct platform_device *pdev)
1705 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1706 struct uart_port *port = &stm32port->port;
1707 struct device *dev = &pdev->dev;
1708 struct dma_slave_config config;
1711 stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
1712 &stm32port->rx_dma_buf,
1714 if (!stm32port->rx_buf)
1717 /* Configure DMA channel */
1718 memset(&config, 0, sizeof(config));
1719 config.src_addr = port->mapbase + ofs->rdr;
1720 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1722 ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1724 dev_err(dev, "rx dma channel config failed\n");
1725 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1732 static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
1733 struct platform_device *pdev)
1735 if (stm32port->tx_buf)
1736 dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
1737 stm32port->tx_dma_buf);
1740 static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
1741 struct platform_device *pdev)
1743 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1744 struct uart_port *port = &stm32port->port;
1745 struct device *dev = &pdev->dev;
1746 struct dma_slave_config config;
1749 stm32port->tx_buf = dma_alloc_coherent(dev, TX_BUF_L,
1750 &stm32port->tx_dma_buf,
1752 if (!stm32port->tx_buf)
1755 /* Configure DMA channel */
1756 memset(&config, 0, sizeof(config));
1757 config.dst_addr = port->mapbase + ofs->tdr;
1758 config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1760 ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1762 dev_err(dev, "tx dma channel config failed\n");
1763 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1770 static int stm32_usart_serial_probe(struct platform_device *pdev)
1772 struct stm32_port *stm32port;
1775 stm32port = stm32_usart_of_get_port(pdev);
1779 stm32port->info = of_device_get_match_data(&pdev->dev);
1780 if (!stm32port->info)
1783 stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
1784 if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER)
1785 return -EPROBE_DEFER;
1787 /* Fall back in interrupt mode for any non-deferral error */
1788 if (IS_ERR(stm32port->rx_ch))
1789 stm32port->rx_ch = NULL;
1791 stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
1792 if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
1793 ret = -EPROBE_DEFER;
1796 /* Fall back in interrupt mode for any non-deferral error */
1797 if (IS_ERR(stm32port->tx_ch))
1798 stm32port->tx_ch = NULL;
1800 ret = stm32_usart_init_port(stm32port, pdev);
1804 if (stm32port->wakeup_src) {
1805 device_set_wakeup_capable(&pdev->dev, true);
1806 ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
1808 goto err_deinit_port;
1811 if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
1812 /* Fall back in interrupt mode */
1813 dma_release_channel(stm32port->rx_ch);
1814 stm32port->rx_ch = NULL;
1817 if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
1818 /* Fall back in interrupt mode */
1819 dma_release_channel(stm32port->tx_ch);
1820 stm32port->tx_ch = NULL;
1823 if (!stm32port->rx_ch)
1824 dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
1825 if (!stm32port->tx_ch)
1826 dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
1828 platform_set_drvdata(pdev, &stm32port->port);
1830 pm_runtime_get_noresume(&pdev->dev);
1831 pm_runtime_set_active(&pdev->dev);
1832 pm_runtime_enable(&pdev->dev);
1834 ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1838 pm_runtime_put_sync(&pdev->dev);
1843 pm_runtime_disable(&pdev->dev);
1844 pm_runtime_set_suspended(&pdev->dev);
1845 pm_runtime_put_noidle(&pdev->dev);
1847 if (stm32port->tx_ch)
1848 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1849 if (stm32port->rx_ch)
1850 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1852 if (stm32port->wakeup_src)
1853 dev_pm_clear_wake_irq(&pdev->dev);
1856 if (stm32port->wakeup_src)
1857 device_set_wakeup_capable(&pdev->dev, false);
1859 stm32_usart_deinit_port(stm32port);
1862 if (stm32port->tx_ch)
1863 dma_release_channel(stm32port->tx_ch);
1866 if (stm32port->rx_ch)
1867 dma_release_channel(stm32port->rx_ch);
1872 static void stm32_usart_serial_remove(struct platform_device *pdev)
1874 struct uart_port *port = platform_get_drvdata(pdev);
1875 struct stm32_port *stm32_port = to_stm32_port(port);
1876 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1879 pm_runtime_get_sync(&pdev->dev);
1880 uart_remove_one_port(&stm32_usart_driver, port);
1882 pm_runtime_disable(&pdev->dev);
1883 pm_runtime_set_suspended(&pdev->dev);
1884 pm_runtime_put_noidle(&pdev->dev);
1886 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_PEIE);
1888 if (stm32_port->tx_ch) {
1889 stm32_usart_of_dma_tx_remove(stm32_port, pdev);
1890 dma_release_channel(stm32_port->tx_ch);
1893 if (stm32_port->rx_ch) {
1894 stm32_usart_of_dma_rx_remove(stm32_port, pdev);
1895 dma_release_channel(stm32_port->rx_ch);
1898 cr3 = readl_relaxed(port->membase + ofs->cr3);
1899 cr3 &= ~USART_CR3_EIE;
1900 cr3 &= ~USART_CR3_DMAR;
1901 cr3 &= ~USART_CR3_DMAT;
1902 cr3 &= ~USART_CR3_DDRE;
1903 writel_relaxed(cr3, port->membase + ofs->cr3);
1905 if (stm32_port->wakeup_src) {
1906 dev_pm_clear_wake_irq(&pdev->dev);
1907 device_init_wakeup(&pdev->dev, false);
1910 stm32_usart_deinit_port(stm32_port);
1913 static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
1915 struct stm32_port *stm32_port = to_stm32_port(port);
1916 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1920 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr,
1921 (isr & USART_SR_TXE), 100,
1922 STM32_USART_TIMEOUT_USEC);
1924 dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret);
1927 writel_relaxed(ch, port->membase + ofs->tdr);
1930 #ifdef CONFIG_SERIAL_STM32_CONSOLE
1931 static void stm32_usart_console_write(struct console *co, const char *s,
1934 struct uart_port *port = &stm32_ports[co->index].port;
1935 struct stm32_port *stm32_port = to_stm32_port(port);
1936 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1937 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1938 unsigned long flags;
1939 u32 old_cr1, new_cr1;
1942 if (oops_in_progress)
1943 locked = uart_port_trylock_irqsave(port, &flags);
1945 uart_port_lock_irqsave(port, &flags);
1947 /* Save and disable interrupts, enable the transmitter */
1948 old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1949 new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1950 new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit);
1951 writel_relaxed(new_cr1, port->membase + ofs->cr1);
1953 uart_console_write(port, s, cnt, stm32_usart_console_putchar);
1955 /* Restore interrupt state */
1956 writel_relaxed(old_cr1, port->membase + ofs->cr1);
1959 uart_port_unlock_irqrestore(port, flags);
1962 static int stm32_usart_console_setup(struct console *co, char *options)
1964 struct stm32_port *stm32port;
1970 if (co->index >= STM32_MAX_PORTS)
1973 stm32port = &stm32_ports[co->index];
1976 * This driver does not support early console initialization
1977 * (use ARM early printk support instead), so we only expect
1978 * this to be called during the uart port registration when the
1979 * driver gets probed and the port should be mapped at that point.
1981 if (stm32port->port.mapbase == 0 || !stm32port->port.membase)
1985 uart_parse_options(options, &baud, &parity, &bits, &flow);
1987 return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1990 static struct console stm32_console = {
1991 .name = STM32_SERIAL_NAME,
1992 .device = uart_console_device,
1993 .write = stm32_usart_console_write,
1994 .setup = stm32_usart_console_setup,
1995 .flags = CON_PRINTBUFFER,
1997 .data = &stm32_usart_driver,
2000 #define STM32_SERIAL_CONSOLE (&stm32_console)
2003 #define STM32_SERIAL_CONSOLE NULL
2004 #endif /* CONFIG_SERIAL_STM32_CONSOLE */
2006 #ifdef CONFIG_SERIAL_EARLYCON
2007 static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
2009 struct stm32_usart_info *info = port->private_data;
2011 while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE))
2014 writel_relaxed(ch, port->membase + info->ofs.tdr);
2017 static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count)
2019 struct earlycon_device *device = console->data;
2020 struct uart_port *port = &device->port;
2022 uart_console_write(port, s, count, early_stm32_usart_console_putchar);
2025 static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options)
2027 if (!(device->port.membase || device->port.iobase))
2029 device->port.private_data = &stm32h7_info;
2030 device->con->write = early_stm32_serial_write;
2034 static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options)
2036 if (!(device->port.membase || device->port.iobase))
2038 device->port.private_data = &stm32f7_info;
2039 device->con->write = early_stm32_serial_write;
2043 static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options)
2045 if (!(device->port.membase || device->port.iobase))
2047 device->port.private_data = &stm32f4_info;
2048 device->con->write = early_stm32_serial_write;
2052 OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup);
2053 OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup);
2054 OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup);
2055 #endif /* CONFIG_SERIAL_EARLYCON */
2057 static struct uart_driver stm32_usart_driver = {
2058 .driver_name = DRIVER_NAME,
2059 .dev_name = STM32_SERIAL_NAME,
2062 .nr = STM32_MAX_PORTS,
2063 .cons = STM32_SERIAL_CONSOLE,
2066 static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
2069 struct stm32_port *stm32_port = to_stm32_port(port);
2070 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
2071 struct tty_port *tport = &port->state->port;
2073 unsigned int size = 0;
2074 unsigned long flags;
2076 if (!stm32_port->wakeup_src || !tty_port_initialized(tport))
2080 * Enable low-power wake-up and wake-up irq if argument is set to
2081 * "enable", disable low-power wake-up and wake-up irq otherwise
2084 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
2085 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
2086 mctrl_gpio_enable_irq_wake(stm32_port->gpios);
2089 * When DMA is used for reception, it must be disabled before
2090 * entering low-power mode and re-enabled when exiting from
2093 if (stm32_port->rx_ch) {
2094 uart_port_lock_irqsave(port, &flags);
2095 /* Poll data from DMA RX buffer if any */
2096 if (!stm32_usart_rx_dma_pause(stm32_port))
2097 size += stm32_usart_receive_chars(port, true);
2098 stm32_usart_rx_dma_terminate(stm32_port);
2099 uart_unlock_and_check_sysrq_irqrestore(port, flags);
2101 tty_flip_buffer_push(tport);
2104 /* Poll data from RX FIFO if any */
2105 stm32_usart_receive_chars(port, false);
2107 if (stm32_port->rx_ch) {
2108 ret = stm32_usart_rx_dma_start_or_resume(port);
2112 mctrl_gpio_disable_irq_wake(stm32_port->gpios);
2113 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
2114 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
2120 static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
2122 struct uart_port *port = dev_get_drvdata(dev);
2125 uart_suspend_port(&stm32_usart_driver, port);
2127 if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2128 ret = stm32_usart_serial_en_wakeup(port, true);
2134 * When "no_console_suspend" is enabled, keep the pinctrl default state
2135 * and rely on bootloader stage to restore this state upon resume.
2136 * Otherwise, apply the idle or sleep states depending on wakeup
2139 if (console_suspend_enabled || !uart_console(port)) {
2140 if (device_may_wakeup(dev) || device_wakeup_path(dev))
2141 pinctrl_pm_select_idle_state(dev);
2143 pinctrl_pm_select_sleep_state(dev);
2149 static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
2151 struct uart_port *port = dev_get_drvdata(dev);
2154 pinctrl_pm_select_default_state(dev);
2156 if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2157 ret = stm32_usart_serial_en_wakeup(port, false);
2162 return uart_resume_port(&stm32_usart_driver, port);
2165 static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev)
2167 struct uart_port *port = dev_get_drvdata(dev);
2168 struct stm32_port *stm32port = container_of(port,
2169 struct stm32_port, port);
2171 clk_disable_unprepare(stm32port->clk);
2176 static int __maybe_unused stm32_usart_runtime_resume(struct device *dev)
2178 struct uart_port *port = dev_get_drvdata(dev);
2179 struct stm32_port *stm32port = container_of(port,
2180 struct stm32_port, port);
2182 return clk_prepare_enable(stm32port->clk);
2185 static const struct dev_pm_ops stm32_serial_pm_ops = {
2186 SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend,
2187 stm32_usart_runtime_resume, NULL)
2188 SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend,
2189 stm32_usart_serial_resume)
2192 static struct platform_driver stm32_serial_driver = {
2193 .probe = stm32_usart_serial_probe,
2194 .remove_new = stm32_usart_serial_remove,
2196 .name = DRIVER_NAME,
2197 .pm = &stm32_serial_pm_ops,
2198 .of_match_table = of_match_ptr(stm32_match),
2202 static int __init stm32_usart_init(void)
2204 static char banner[] __initdata = "STM32 USART driver initialized";
2207 pr_info("%s\n", banner);
2209 ret = uart_register_driver(&stm32_usart_driver);
2213 ret = platform_driver_register(&stm32_serial_driver);
2215 uart_unregister_driver(&stm32_usart_driver);
2220 static void __exit stm32_usart_exit(void)
2222 platform_driver_unregister(&stm32_serial_driver);
2223 uart_unregister_driver(&stm32_usart_driver);
2226 module_init(stm32_usart_init);
2227 module_exit(stm32_usart_exit);
2229 MODULE_ALIAS("platform:" DRIVER_NAME);
2230 MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
2231 MODULE_LICENSE("GPL v2");