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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/tty/serial/stm32-usart.c

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C
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// 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@foss.st.com>
* Erwan Le Ray <erwan.leray@foss.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;
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 bool stm32_usart_rx_dma_enabled(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->rx_ch)
return false;
return !!(readl_relaxed(port->membase + ofs->cr3) & USART_CR3_DMAR);
}
/* Return true when data is pending (in pio mode), and false when no data is pending. */
static bool stm32_usart_pending_rx_pio(struct uart_port *port, u32 *sr)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
*sr = readl_relaxed(port->membase + ofs->isr);
/* Get pending characters in RDR or FIFO */
if (*sr & USART_SR_RXNE) {
/* Get all pending characters from the RDR or the FIFO when using interrupts */
if (!stm32_usart_rx_dma_enabled(port))
return true;
/* Handle only RX data errors when using DMA */
if (*sr & USART_SR_ERR_MASK)
return true;
}
return false;
}
static unsigned long stm32_usart_get_char_pio(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long c;
c = readl_relaxed(port->membase + ofs->rdr);
/* Apply RDR data mask */
c &= stm32_port->rdr_mask;
return c;
}
static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long c;
unsigned int size = 0;
u32 sr;
char flag;
while (stm32_usart_pending_rx_pio(port, &sr)) {
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_pio(port);
port->icount.rx++;
size++;
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_prepare_sysrq_char(port, c))
continue;
uart_insert_char(port, sr, USART_SR_ORE, c, flag);
}
return size;
}
static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct tty_port *ttyport = &stm32_port->port.state->port;
unsigned char *dma_start;
int dma_count, i;
dma_start = stm32_port->rx_buf + (RX_BUF_L - stm32_port->last_res);
/*
* Apply rdr_mask on buffer in order to mask parity bit.
* This loop is useless in cs8 mode because DMA copies only
* 8 bits and already ignores parity bit.
*/
if (!(stm32_port->rdr_mask == (BIT(8) - 1)))
for (i = 0; i < dma_size; i++)
*(dma_start + i) &= stm32_port->rdr_mask;
dma_count = tty_insert_flip_string(ttyport, dma_start, dma_size);
port->icount.rx += dma_count;
if (dma_count != dma_size)
port->icount.buf_overrun++;
stm32_port->last_res -= dma_count;
if (stm32_port->last_res == 0)
stm32_port->last_res = RX_BUF_L;
}
static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
unsigned int dma_size, size = 0;
/* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */
if (stm32_port->rx_dma_state.residue > stm32_port->last_res) {
/* Conditional first part: from last_res to end of DMA buffer */
dma_size = stm32_port->last_res;
stm32_usart_push_buffer_dma(port, dma_size);
size = dma_size;
}
dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue;
stm32_usart_push_buffer_dma(port, dma_size);
size += dma_size;
return size;
}
static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
enum dma_status rx_dma_status;
u32 sr;
unsigned int size = 0;
if (stm32_usart_rx_dma_enabled(port) || force_dma_flush) {
rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
stm32_port->rx_ch->cookie,
&stm32_port->rx_dma_state);
if (rx_dma_status == DMA_IN_PROGRESS) {
/* Empty DMA buffer */
size = stm32_usart_receive_chars_dma(port);
sr = readl_relaxed(port->membase + ofs->isr);
if (sr & USART_SR_ERR_MASK) {
/* Disable DMA request line */
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
/* Switch to PIO mode to handle the errors */
size += stm32_usart_receive_chars_pio(port);
/* Switch back to DMA mode */
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
}
} else {
/* Disable RX DMA */
dmaengine_terminate_async(stm32_port->rx_ch);
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
/* Fall back to interrupt mode */
dev_dbg(port->dev, "DMA error, fallback to irq mode\n");
size = stm32_usart_receive_chars_pio(port);
}
} else {
size = stm32_usart_receive_chars_pio(port);
}
return size;
}
static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port)
{
dmaengine_terminate_async(stm32_port->tx_ch);
stm32_port->tx_dma_busy = false;
}
static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port)
{
/*
* We cannot use the function "dmaengine_tx_status" to know the
* status of DMA. This function does not show if the "dma complete"
* callback of the DMA transaction has been called. So we prefer
* to use "tx_dma_busy" flag to prevent dual DMA transaction at the
* same time.
*/
return stm32_port->tx_dma_busy;
}
static bool stm32_usart_tx_dma_enabled(struct stm32_port *stm32_port)
{
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
return !!(readl_relaxed(stm32_port->port.membase + ofs->cr3) & USART_CR3_DMAT);
}
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;
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
stm32_usart_tx_dma_terminate(stm32port);
/* 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_port->txftcfg >= 0)
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
else
stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
}
static void stm32_usart_rx_dma_complete(void *arg)
{
struct uart_port *port = arg;
struct tty_port *tport = &port->state->port;
unsigned int size;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
size = stm32_usart_receive_chars(port, false);
uart_unlock_and_check_sysrq_irqrestore(port, flags);
if (size)
tty_flip_buffer_push(tport);
}
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_port->txftcfg >= 0)
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
else
stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
}
static void stm32_usart_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_usart_tx_dma_enabled(stm32_port))
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
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;
if (stm32_usart_tx_dma_started(stm32port)) {
if (!stm32_usart_tx_dma_enabled(stm32port))
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
return;
}
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;
/*
* Set "tx_dma_busy" flag. This flag will be released when
* dmaengine_terminate_async will be called. This flag helps
* transmit_chars_dma not to start another DMA transaction
* if the callback of the previous is not yet called.
*/
stm32port->tx_dma_busy = true;
desc->callback = stm32_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 */
stm32_usart_tx_dma_terminate(stm32port);
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:
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;
if (port->x_char) {
if (stm32_usart_tx_dma_started(stm32_port) &&
stm32_usart_tx_dma_enabled(stm32_port))
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
writel_relaxed(port->x_char, port->membase + ofs->tdr);
port->x_char = 0;
port->icount.tx++;
if (stm32_usart_tx_dma_started(stm32_port))
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;
unsigned int size;
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);
}
/*
* rx errors in dma mode has to be handled ASAP to avoid overrun as the DMA request
* line has been masked by HW and rx data are stacking in FIFO.
*/
if (!stm32_port->throttled) {
if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_enabled(port)) ||
((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_enabled(port))) {
spin_lock(&port->lock);
size = stm32_usart_receive_chars(port, false);
uart_unlock_and_check_sysrq(port);
if (size)
tty_flip_buffer_push(tport);
}
}
if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
spin_lock(&port->lock);
stm32_usart_transmit_chars(port);
spin_unlock(&port->lock);
}
if (stm32_usart_rx_dma_enabled(port))
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 tty_port *tport = &port->state->port;
struct stm32_port *stm32_port = to_stm32_port(port);
unsigned int size;
unsigned long flags;
/* Receiver timeout irq for DMA RX */
if (!stm32_port->throttled) {
spin_lock_irqsave(&port->lock, flags);
size = stm32_usart_receive_chars(port, false);
uart_unlock_and_check_sysrq_irqrestore(port, flags);
if (size)
tty_flip_buffer_push(tport);
}
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;
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
stm32_usart_tx_interrupt_disable(port);
if (stm32_usart_tx_dma_started(stm32_port) && stm32_usart_tx_dma_enabled(stm32_port))
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
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))
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);
}
/* Flush the transmit buffer. */
static void stm32_usart_flush_buffer(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->tx_ch) {
stm32_usart_tx_dma_terminate(stm32_port);
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
}
}
/* 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);
/*
* Disable DMA request line if enabled, so the RX data gets queued into the FIFO.
* Hardware flow control is triggered when RX FIFO is full.
*/
if (stm32_usart_rx_dma_enabled(port))
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
if (stm32_port->cr3_irq)
stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
stm32_port->throttled = true;
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);
/*
* Switch back to DMA mode (re-enable DMA request line).
* Hardware flow control is stopped when FIFO is not full any more.
*/
if (stm32_port->rx_ch)
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
stm32_port->throttled = false;
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;
/* Disable DMA request line. */
if (stm32_port->rx_ch)
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
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_start_rx_dma_cyclic(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct dma_async_tx_descriptor *desc;
int ret;
stm32_port->last_res = RX_BUF_L;
/* Prepare a DMA cyclic transaction */
desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch,
stm32_port->rx_dma_buf,
RX_BUF_L, RX_BUF_P,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(port->dev, "rx dma prep cyclic failed\n");
return -ENODEV;
}
desc->callback = stm32_usart_rx_dma_complete;
desc->callback_param = port;
/* Push current DMA transaction in the pending queue */
ret = dma_submit_error(dmaengine_submit(desc));
if (ret) {
dmaengine_terminate_sync(stm32_port->rx_ch);
return ret;
}
/* Issue pending DMA requests */
dma_async_issue_pending(stm32_port->rx_ch);
/*
* DMA request line not re-enabled at resume when port is throttled.
* It will be re-enabled by unthrottle ops.
*/
if (!stm32_port->throttled)
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
return 0;
}
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;
if (stm32_port->swap) {
val = readl_relaxed(port->membase + ofs->cr2);
val |= USART_CR2_SWAP;
writel_relaxed(val, port->membase + ofs->cr2);
}
/* RX FIFO Flush */
if (ofs->rqr != UNDEF_REG)
writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
if (stm32_port->rx_ch) {
ret = stm32_usart_start_rx_dma_cyclic(port);
if (ret) {
free_irq(port->irq, port);
return ret;
}
}
/* RX enabling */
val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
stm32_usart_set_bits(port, ofs->cr1, val);
return 0;
}
static void stm32_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;
if (stm32_usart_tx_dma_enabled(stm32_port))
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
if (stm32_usart_tx_dma_started(stm32_port))
stm32_usart_tx_dma_terminate(stm32_port);
/* 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);
/* Send the TC error message only when ISR_TC is not set */
if (ret)
dev_err(port->dev, "Transmission is not complete\n");
/* Disable RX DMA. */
if (stm32_port->rx_ch)
dmaengine_terminate_async(stm32_port->rx_ch);
/* flush RX & TX FIFO */
if (ofs->rqr != UNDEF_REG)
writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
port->membase + ofs->rqr);
stm32_usart_clr_bits(port, ofs->cr1, val);
free_irq(port->irq, port);
}
static void stm32_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 = stm32_port->swap ? USART_CR2_SWAP : 0;
/* Tx and RX FIFO configuration */
cr3 = readl_relaxed(port->membase + ofs->cr3);
cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
if (stm32_port->fifoen) {
if (stm32_port->txftcfg >= 0)
cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
if (stm32_port->rxftcfg >= 0)
cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
}
if (cflag & CSTOPB)
cr2 |= USART_CR2_STOP_2B;
bits = tty_get_char_size(cflag);
stm32_port->rdr_mask = (BIT(bits) - 1);
if (cflag & PARENB) {
bits++;
cr1 |= USART_CR1_PCE;
}
/*
* 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);
if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
(stm32_port->fifoen &&
stm32_port->rxftcfg >= 0))) {
if (cflag & CSTOPB)
bits = bits + 3; /* 1 start bit + 2 stop bits */
else
bits = bits + 2; /* 1 start bit + 1 stop bit */
/* RX timeout irq to occur after last stop bit + bits */
stm32_port->cr1_irq = USART_CR1_RTOIE;
writel_relaxed(bits, port->membase + ofs->rtor);
cr2 |= USART_CR2_RTOEN;
/*
* Enable fifo threshold irq in two cases, either when there is no DMA, or when
* wake up over usart, from low power until the DMA gets re-enabled by resume.
*/
stm32_port->cr3_irq = USART_CR3_RXFTIE;
}
cr1 |= stm32_port->cr1_irq;
cr3 |= stm32_port->cr3_irq;
if (cflag & PARODD)
cr1 |= USART_CR1_PS;
port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
if (cflag & CRTSCTS) {
port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
cr3 |= USART_CR3_CTSE | 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) {
/*
* Setup DMA to collect only valid data and enable error irqs.
* This also enables break reception when using DMA.
*/
cr1 |= USART_CR1_PEIE;
cr3 |= USART_CR3_EIE;
cr3 |= USART_CR3_DMAR;
cr3 |= USART_CR3_DDRE;
}
if (rs485conf->flags & SER_RS485_ENABLED) {
stm32_usart_config_reg_rs485(&cr1, &cr3,
rs485conf->delay_rts_before_send,
rs485conf->delay_rts_after_send,
baud);
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
cr3 &= ~USART_CR3_DEP;
rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
} else {
cr3 |= USART_CR3_DEP;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
}
} else {
cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
}
/* Configure wake up from low power on start bit detection */
if (stm32_port->wakeup_src) {
cr3 &= ~USART_CR3_WUS_MASK;
cr3 |= USART_CR3_WUS_START_BIT;
}
writel_relaxed(cr3, port->membase + ofs->cr3);
writel_relaxed(cr2, port->membase + ofs->cr2);
writel_relaxed(cr1, port->membase + ofs->cr1);
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;
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,
.flush_buffer = stm32_usart_flush_buffer,
.set_termios = stm32_usart_set_termios,
.pm = stm32_usart_pm,
.type = stm32_usart_type,
.release_port = stm32_usart_release_port,
.request_port = stm32_usart_request_port,
.config_port = stm32_usart_config_port,
.verify_port = stm32_usart_verify_port,
};
/*
* STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG)
* Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case,
* RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE.
* So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1.
*/
static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 };
static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p,
int *ftcfg)
{
u32 bytes, i;
/* DT option to get RX & TX FIFO threshold (default to 8 bytes) */
if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
bytes = 8;
for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++)
if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes)
break;
if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
dev_dbg(&pdev->dev, "%s set to %d bytes\n", p,
stm32h7_usart_fifo_thresh_cfg[i]);
/* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */
if (i)
*ftcfg = i - 1;
else
*ftcfg = -EINVAL;
}
static void stm32_usart_deinit_port(struct stm32_port *stm32port)
{
clk_disable_unprepare(stm32port->clk);
}
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, irq;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &stm32_uart_ops;
port->dev = &pdev->dev;
port->fifosize = stm32port->info->cfg.fifosize;
port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
port->irq = irq;
port->rs485_config = stm32_usart_config_rs485;
ret = stm32_usart_init_rs485(port, pdev);
if (ret)
return ret;
stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
of_property_read_bool(pdev->dev.of_node, "wakeup-source");
stm32port->swap = stm32port->info->cfg.has_swap &&
of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
stm32port->fifoen = stm32port->info->cfg.has_fifo;
if (stm32port->fifoen) {
stm32_usart_get_ftcfg(pdev, "rx-threshold",
&stm32port->rxftcfg);
stm32_usart_get_ftcfg(pdev, "tx-threshold",
&stm32port->txftcfg);
}
port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(port->membase))
return PTR_ERR(port->membase);
port->mapbase = res->start;
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" (deprecated) or "uart-has-rtscts"
* properties should not be specified.
*/
if (stm32port->hw_flow_control) {
if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
ret = -EINVAL;
goto err_clk;
}
}
return ret;
err_clk:
clk_disable_unprepare(stm32port->clk);
return ret;
}
static struct stm32_port *stm32_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 void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
struct platform_device *pdev)
{
if (stm32port->rx_buf)
dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
stm32port->rx_dma_buf);
}
static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
struct platform_device *pdev)
{
const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
struct uart_port *port = &stm32port->port;
struct device *dev = &pdev->dev;
struct dma_slave_config config;
int ret;
/*
* Using DMA and threaded handler for the console could lead to
* deadlocks.
*/
if (uart_console(port))
return -ENODEV;
stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
&stm32port->rx_dma_buf,
GFP_KERNEL);
if (!stm32port->rx_buf)
return -ENOMEM;
/* Configure DMA channel */
memset(&config, 0, sizeof(config));
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");
stm32_usart_of_dma_rx_remove(stm32port, pdev);
return ret;
}
return 0;
}
static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
struct platform_device *pdev)
{
if (stm32port->tx_buf)
dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
stm32port->tx_dma_buf);
}
static int stm32_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_buf = dma_alloc_coherent(dev, TX_BUF_L,
&stm32port->tx_dma_buf,
GFP_KERNEL);
if (!stm32port->tx_buf)
return -ENOMEM;
/* Configure DMA channel */
memset(&config, 0, sizeof(config));
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");
stm32_usart_of_dma_tx_remove(stm32port, pdev);
return ret;
}
return 0;
}
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->wakeup_src) {
device_set_wakeup_capable(&pdev->dev, true);
ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
if (ret)
goto err_deinit_port;
}
stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) {
ret = -EPROBE_DEFER;
goto err_wakeirq;
}
/* Fall back in interrupt mode for any non-deferral error */
if (IS_ERR(stm32port->rx_ch))
stm32port->rx_ch = NULL;
stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
ret = -EPROBE_DEFER;
goto err_dma_rx;
}
/* Fall back in interrupt mode for any non-deferral error */
if (IS_ERR(stm32port->tx_ch))
stm32port->tx_ch = NULL;
if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
/* Fall back in interrupt mode */
dma_release_channel(stm32port->rx_ch);
stm32port->rx_ch = NULL;
}
if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
/* Fall back in interrupt mode */
dma_release_channel(stm32port->tx_ch);
stm32port->tx_ch = NULL;
}
if (!stm32port->rx_ch)
dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
if (!stm32port->tx_ch)
dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
platform_set_drvdata(pdev, &stm32port->port);
pm_runtime_get_noresume(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
if (ret)
goto err_port;
pm_runtime_put_sync(&pdev->dev);
return 0;
err_port:
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_put_noidle(&pdev->dev);
if (stm32port->tx_ch) {
stm32_usart_of_dma_tx_remove(stm32port, pdev);
dma_release_channel(stm32port->tx_ch);
}
if (stm32port->rx_ch)
stm32_usart_of_dma_rx_remove(stm32port, pdev);
err_dma_rx:
if (stm32port->rx_ch)
dma_release_channel(stm32port->rx_ch);
err_wakeirq:
if (stm32port->wakeup_src)
dev_pm_clear_wake_irq(&pdev->dev);
err_deinit_port:
if (stm32port->wakeup_src)
device_set_wakeup_capable(&pdev->dev, false);
stm32_usart_deinit_port(stm32port);
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;
u32 cr3;
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->cr1, USART_CR1_PEIE);
cr3 = readl_relaxed(port->membase + ofs->cr3);
cr3 &= ~USART_CR3_EIE;
cr3 &= ~USART_CR3_DMAR;
cr3 &= ~USART_CR3_DDRE;
writel_relaxed(cr3, port->membase + ofs->cr3);
if (stm32_port->tx_ch) {
stm32_usart_of_dma_tx_remove(stm32_port, pdev);
dma_release_channel(stm32_port->tx_ch);
}
if (stm32_port->rx_ch) {
stm32_usart_of_dma_rx_remove(stm32_port, pdev);
dma_release_channel(stm32_port->rx_ch);
}
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
if (stm32_port->wakeup_src) {
dev_pm_clear_wake_irq(&pdev->dev);
device_init_wakeup(&pdev->dev, false);
}
stm32_usart_deinit_port(stm32_port);
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;
if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
/* 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_irqrestore(&port->lock, 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 int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
bool enable)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct tty_port *tport = &port->state->port;
int ret;
unsigned int size;
unsigned long flags;
if (!stm32_port->wakeup_src || !tty_port_initialized(tport))
return 0;
/*
* Enable low-power wake-up and wake-up irq if argument is set to
* "enable", disable low-power wake-up and wake-up irq otherwise
*/
if (enable) {
stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
/*
* When DMA is used for reception, it must be disabled before
* entering low-power mode and re-enabled when exiting from
* low-power mode.
*/
if (stm32_port->rx_ch) {
spin_lock_irqsave(&port->lock, flags);
/* Avoid race with RX IRQ when DMAR is cleared */
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
/* Poll data from DMA RX buffer if any */
size = stm32_usart_receive_chars(port, true);
dmaengine_terminate_async(stm32_port->rx_ch);
uart_unlock_and_check_sysrq_irqrestore(port, flags);
if (size)
tty_flip_buffer_push(tport);
}
/* Poll data from RX FIFO if any */
stm32_usart_receive_chars(port, false);
} else {
if (stm32_port->rx_ch) {
ret = stm32_usart_start_rx_dma_cyclic(port);
if (ret)
return ret;
}
stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
}
return 0;
}
static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);
int ret;
uart_suspend_port(&stm32_usart_driver, port);
if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
ret = stm32_usart_serial_en_wakeup(port, true);
if (ret)
return ret;
}
/*
* When "no_console_suspend" is enabled, keep the pinctrl default state
* and rely on bootloader stage to restore this state upon resume.
* Otherwise, apply the idle or sleep states depending on wakeup
* capabilities.
*/
if (console_suspend_enabled || !uart_console(port)) {
if (device_may_wakeup(dev) || device_wakeup_path(dev))
pinctrl_pm_select_idle_state(dev);
else
pinctrl_pm_select_sleep_state(dev);
}
return 0;
}
static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);
int ret;
pinctrl_pm_select_default_state(dev);
if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
ret = stm32_usart_serial_en_wakeup(port, false);
if (ret)
return ret;
}
return uart_resume_port(&stm32_usart_driver, port);
}
static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);
struct stm32_port *stm32port = container_of(port,
struct stm32_port, port);
clk_disable_unprepare(stm32port->clk);
return 0;
}
static int __maybe_unused stm32_usart_runtime_resume(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);
struct stm32_port *stm32port = container_of(port,
struct stm32_port, port);
return clk_prepare_enable(stm32port->clk);
}
static const struct dev_pm_ops stm32_serial_pm_ops = {
SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend,
stm32_usart_runtime_resume, NULL)
SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend,
stm32_usart_serial_resume)
};
static struct platform_driver stm32_serial_driver = {
.probe = stm32_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");
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