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stm32-usart.c
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stm32-usart.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 int stm32_usart_pending_rx(struct uart_port *port, u32 *sr,
int *last_res, bool threaded)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
enum dma_status status;
struct dma_tx_state state;
*sr = readl_relaxed(port->membase + ofs->isr);
if (threaded && stm32_port->rx_ch) {
status = dmaengine_tx_status(stm32_port->rx_ch,
stm32_port->rx_ch->cookie,
&state);
if (status == DMA_IN_PROGRESS && (*last_res != state.residue))
return 1;
else
return 0;
} else if (*sr & USART_SR_RXNE) {
return 1;
}
return 0;
}
static unsigned long stm32_usart_get_char(struct uart_port *port, u32 *sr,
int *last_res)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long c;
if (stm32_port->rx_ch) {
c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
if ((*last_res) == 0)
*last_res = RX_BUF_L;
} else {
c = readl_relaxed(port->membase + ofs->rdr);
/* apply RDR data mask */
c &= stm32_port->rdr_mask;
}
return c;
}
static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
{
struct tty_port *tport = &port->state->port;
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long c;
u32 sr;
char flag;
spin_lock(&port->lock);
while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res,
threaded)) {
sr |= USART_SR_DUMMY_RX;
flag = TTY_NORMAL;
/*
* Status bits has to be cleared before reading the RDR:
* In FIFO mode, reading the RDR will pop the next data
* (if any) along with its status bits into the SR.
* Not doing so leads to misalignement between RDR and SR,
* and clear status bits of the next rx data.
*
* Clear errors flags for stm32f7 and stm32h7 compatible
* devices. On stm32f4 compatible devices, the error bit is
* cleared by the sequence [read SR - read DR].
*/
if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
writel_relaxed(sr & USART_SR_ERR_MASK,
port->membase + ofs->icr);
c = stm32_usart_get_char(port, &sr, &stm32_port->last_res);
port->icount.rx++;
if (sr & USART_SR_ERR_MASK) {
if (sr & USART_SR_ORE) {
port->icount.overrun++;
} else if (sr & USART_SR_PE) {
port->icount.parity++;
} else if (sr & USART_SR_FE) {
/* Break detection if character is null */
if (!c) {
port->icount.brk++;
if (uart_handle_break(port))
continue;
} else {
port->icount.frame++;
}
}
sr &= port->read_status_mask;
if (sr & USART_SR_PE) {
flag = TTY_PARITY;
} else if (sr & USART_SR_FE) {
if (!c)
flag = TTY_BREAK;
else
flag = TTY_FRAME;
}
}
if (uart_handle_sysrq_char(port, c))
continue;
uart_insert_char(port, sr, USART_SR_ORE, c, flag);
}
spin_unlock(&port->lock);
tty_flip_buffer_push(tport);
}
static void stm32_usart_tx_dma_complete(void *arg)
{
struct uart_port *port = arg;
struct stm32_port *stm32port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
unsigned long flags;
dmaengine_terminate_async(stm32port->tx_ch);
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
stm32port->tx_dma_busy = false;
/* Let's see if we have pending data to send */
spin_lock_irqsave(&port->lock, flags);
stm32_usart_transmit_chars(port);
spin_unlock_irqrestore(&port->lock, flags);
}
static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
/*
* Enables TX FIFO threashold irq when FIFO is enabled,
* or TX empty irq when FIFO is disabled
*/
if (stm32_port->fifoen)
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
else
stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
}
static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
if (stm32_port->fifoen)
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
else
stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
}
static void stm32_usart_transmit_chars_pio(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct circ_buf *xmit = &port->state->xmit;
if (stm32_port->tx_dma_busy) {
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
stm32_port->tx_dma_busy = false;
}
while (!uart_circ_empty(xmit)) {
/* Check that TDR is empty before filling FIFO */
if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
break;
writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
/* rely on TXE irq (mask or unmask) for sending remaining data */
if (uart_circ_empty(xmit))
stm32_usart_tx_interrupt_disable(port);
else
stm32_usart_tx_interrupt_enable(port);
}
static void stm32_usart_transmit_chars_dma(struct uart_port *port)
{
struct stm32_port *stm32port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
struct circ_buf *xmit = &port->state->xmit;
struct dma_async_tx_descriptor *desc = NULL;
unsigned int count, i;
if (stm32port->tx_dma_busy)
return;
stm32port->tx_dma_busy = true;
count = uart_circ_chars_pending(xmit);
if (count > TX_BUF_L)
count = TX_BUF_L;
if (xmit->tail < xmit->head) {
memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
} else {
size_t one = UART_XMIT_SIZE - xmit->tail;
size_t two;
if (one > count)
one = count;
two = count - one;
memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
if (two)
memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
}
desc = dmaengine_prep_slave_single(stm32port->tx_ch,
stm32port->tx_dma_buf,
count,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT);
if (!desc)
goto fallback_err;
desc->callback = stm32_usart_tx_dma_complete;
desc->callback_param = port;
/* Push current DMA TX transaction in the pending queue */
if (dma_submit_error(dmaengine_submit(desc))) {
/* dma no yet started, safe to free resources */
dmaengine_terminate_async(stm32port->tx_ch);
goto fallback_err;
}
/* Issue pending DMA TX requests */
dma_async_issue_pending(stm32port->tx_ch);
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
port->icount.tx += count;
return;
fallback_err:
for (i = count; i > 0; i--)
stm32_usart_transmit_chars_pio(port);
}
static void stm32_usart_transmit_chars(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct circ_buf *xmit = &port->state->xmit;
if (port->x_char) {
if (stm32_port->tx_dma_busy)
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_port->tx_dma_busy)
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
stm32_usart_tx_interrupt_disable(port);
return;
}
if (ofs->icr == UNDEF_REG)
stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC);
else
writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
if (stm32_port->tx_ch)
stm32_usart_transmit_chars_dma(port);
else
stm32_usart_transmit_chars_pio(port);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
stm32_usart_tx_interrupt_disable(port);
}
static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
{
struct uart_port *port = ptr;
struct tty_port *tport = &port->state->port;
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
u32 sr;
sr = readl_relaxed(port->membase + ofs->isr);
if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
writel_relaxed(USART_ICR_RTOCF,
port->membase + ofs->icr);
if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
/* Clear wake up flag and disable wake up interrupt */
writel_relaxed(USART_ICR_WUCF,
port->membase + ofs->icr);
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
pm_wakeup_event(tport->tty->dev, 0);
}
if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
stm32_usart_receive_chars(port, false);
if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
spin_lock(&port->lock);
stm32_usart_transmit_chars(port);
spin_unlock(&port->lock);
}
if (stm32_port->rx_ch)
return IRQ_WAKE_THREAD;
else
return IRQ_HANDLED;
}
static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
{
struct uart_port *port = ptr;
struct stm32_port *stm32_port = to_stm32_port(port);
if (stm32_port->rx_ch)
stm32_usart_receive_chars(port, true);
return IRQ_HANDLED;
}
static unsigned int stm32_usart_tx_empty(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
return TIOCSER_TEMT;
return 0;
}
static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE);
else
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
mctrl_gpio_set(stm32_port->gpios, mctrl);
}
static unsigned int stm32_usart_get_mctrl(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
unsigned int ret;
/* This routine is used to get signals of: DCD, DSR, RI, and CTS */
ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
return mctrl_gpio_get(stm32_port->gpios, &ret);
}
static void stm32_usart_enable_ms(struct uart_port *port)
{
mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
}
static void stm32_usart_disable_ms(struct uart_port *port)
{
mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
}
/* Transmit stop */
static void stm32_usart_stop_tx(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct serial_rs485 *rs485conf = &port->rs485;
stm32_usart_tx_interrupt_disable(port);
if (rs485conf->flags & SER_RS485_ENABLED) {
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
mctrl_gpio_set(stm32_port->gpios,
stm32_port->port.mctrl & ~TIOCM_RTS);
} else {
mctrl_gpio_set(stm32_port->gpios,
stm32_port->port.mctrl | TIOCM_RTS);
}
}
}
/* There are probably characters waiting to be transmitted. */
static void stm32_usart_start_tx(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct serial_rs485 *rs485conf = &port->rs485;
struct circ_buf *xmit = &port->state->xmit;
if (uart_circ_empty(xmit))
return;
if (rs485conf->flags & SER_RS485_ENABLED) {
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
mctrl_gpio_set(stm32_port->gpios,
stm32_port->port.mctrl | TIOCM_RTS);
} else {
mctrl_gpio_set(stm32_port->gpios,
stm32_port->port.mctrl & ~TIOCM_RTS);
}
}
stm32_usart_transmit_chars(port);
}
/* Throttle the remote when input buffer is about to overflow. */
static void stm32_usart_throttle(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
if (stm32_port->cr3_irq)
stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
spin_unlock_irqrestore(&port->lock, flags);
}
/* Unthrottle the remote, the input buffer can now accept data. */
static void stm32_usart_unthrottle(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
if (stm32_port->cr3_irq)
stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
spin_unlock_irqrestore(&port->lock, flags);
}
/* Receive stop */
static void stm32_usart_stop_rx(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
if (stm32_port->cr3_irq)
stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
}
/* Handle breaks - ignored by us */
static void stm32_usart_break_ctl(struct uart_port *port, int break_state)
{
}
static int stm32_usart_startup(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
const char *name = to_platform_device(port->dev)->name;
u32 val;
int ret;
ret = request_threaded_irq(port->irq, stm32_usart_interrupt,
stm32_usart_threaded_interrupt,
IRQF_ONESHOT | IRQF_NO_SUSPEND,
name, port);
if (ret)
return ret;
/* RX FIFO Flush */
if (ofs->rqr != UNDEF_REG)
writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
/* RX enabling */
val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
stm32_usart_set_bits(port, ofs->cr1, val);
return 0;
}
static void stm32_usart_shutdown(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
u32 val, isr;
int ret;
/* Disable modem control interrupts */
stm32_usart_disable_ms(port);
val = USART_CR1_TXEIE | USART_CR1_TE;
val |= stm32_port->cr1_irq | USART_CR1_RE;
val |= BIT(cfg->uart_enable_bit);
if (stm32_port->fifoen)
val |= USART_CR1_FIFOEN;
ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
isr, (isr & USART_SR_TC),
10, 100000);
/* Send the TC error message only when ISR_TC is not set */
if (ret)
dev_err(port->dev, "Transmission is not complete\n");
/* flush RX & TX FIFO */
if (ofs->rqr != UNDEF_REG)
writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
port->membase + ofs->rqr);
stm32_usart_clr_bits(port, ofs->cr1, val);
free_irq(port->irq, port);
}
static unsigned int stm32_usart_get_databits(struct ktermios *termios)
{
unsigned int bits;
tcflag_t cflag = termios->c_cflag;
switch (cflag & CSIZE) {
/*
* CSIZE settings are not necessarily supported in hardware.
* CSIZE unsupported configurations are handled here to set word length
* to 8 bits word as default configuration and to print debug message.
*/
case CS5:
bits = 5;
break;
case CS6:
bits = 6;
break;
case CS7:
bits = 7;
break;
/* default including CS8 */
default:
bits = 8;
break;
}
return bits;
}
static void stm32_usart_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
struct serial_rs485 *rs485conf = &port->rs485;
unsigned int baud, bits;
u32 usartdiv, mantissa, fraction, oversampling;
tcflag_t cflag = termios->c_cflag;
u32 cr1, cr2, cr3, isr;
unsigned long flags;
int ret;
if (!stm32_port->hw_flow_control)
cflag &= ~CRTSCTS;
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
spin_lock_irqsave(&port->lock, flags);
ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
isr,
(isr & USART_SR_TC),
10, 100000);
/* Send the TC error message only when ISR_TC is not set. */
if (ret)
dev_err(port->dev, "Transmission is not complete\n");
/* Stop serial port and reset value */
writel_relaxed(0, port->membase + ofs->cr1);
/* flush RX & TX FIFO */
if (ofs->rqr != UNDEF_REG)
writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
port->membase + ofs->rqr);
cr1 = USART_CR1_TE | USART_CR1_RE;
if (stm32_port->fifoen)
cr1 |= USART_CR1_FIFOEN;
cr2 = 0;
/* Tx and RX FIFO configuration */
cr3 = readl_relaxed(port->membase + ofs->cr3);
cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
if (stm32_port->fifoen) {
cr3 &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
cr3 |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
cr3 |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
}
if (cflag & CSTOPB)
cr2 |= USART_CR2_STOP_2B;
bits = stm32_usart_get_databits(termios);
stm32_port->rdr_mask = (BIT(bits) - 1);
if (cflag & PARENB) {
bits++;
cr1 |= USART_CR1_PCE;
}
/*
* Word length configuration:
* CS8 + parity, 9 bits word aka [M1:M0] = 0b01
* CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
* CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
* M0 and M1 already cleared by cr1 initialization.
*/
if (bits == 9)
cr1 |= USART_CR1_M0;
else if ((bits == 7) && cfg->has_7bits_data)
cr1 |= USART_CR1_M1;
else if (bits != 8)
dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
, bits);
if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
stm32_port->fifoen)) {
if (cflag & CSTOPB)
bits = bits + 3; /* 1 start bit + 2 stop bits */
else
bits = bits + 2; /* 1 start bit + 1 stop bit */
/* RX timeout irq to occur after last stop bit + bits */
stm32_port->cr1_irq = USART_CR1_RTOIE;
writel_relaxed(bits, port->membase + ofs->rtor);
cr2 |= USART_CR2_RTOEN;
/* Not using dma, enable fifo threshold irq */
if (!stm32_port->rx_ch)
stm32_port->cr3_irq = USART_CR3_RXFTIE;
}
cr1 |= stm32_port->cr1_irq;
cr3 |= stm32_port->cr3_irq;
if (cflag & PARODD)
cr1 |= USART_CR1_PS;
port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
if (cflag & CRTSCTS) {
port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
}
usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
/*
* The USART supports 16 or 8 times oversampling.
* By default we prefer 16 times oversampling, so that the receiver
* has a better tolerance to clock deviations.
* 8 times oversampling is only used to achieve higher speeds.
*/
if (usartdiv < 16) {
oversampling = 8;
cr1 |= USART_CR1_OVER8;
stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8);
} else {
oversampling = 16;
cr1 &= ~USART_CR1_OVER8;
stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
}
mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
fraction = usartdiv % oversampling;
writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
uart_update_timeout(port, cflag, baud);
port->read_status_mask = USART_SR_ORE;
if (termios->c_iflag & INPCK)
port->read_status_mask |= USART_SR_PE | USART_SR_FE;
if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
port->read_status_mask |= USART_SR_FE;
/* Characters to ignore */
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= USART_SR_FE;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= USART_SR_ORE;
}
/* Ignore all characters if CREAD is not set */
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= USART_SR_DUMMY_RX;
if (stm32_port->rx_ch)
cr3 |= USART_CR3_DMAR;
if (rs485conf->flags & SER_RS485_ENABLED) {
stm32_usart_config_reg_rs485(&cr1, &cr3,
rs485conf->delay_rts_before_send,
rs485conf->delay_rts_after_send,
baud);
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
cr3 &= ~USART_CR3_DEP;
rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
} else {
cr3 |= USART_CR3_DEP;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
}
} else {
cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
}
/* Configure wake up from low power on start bit detection */
if (stm32_port->wakeirq > 0) {
cr3 &= ~USART_CR3_WUS_MASK;
cr3 |= USART_CR3_WUS_START_BIT;
}
writel_relaxed(cr3, port->membase + ofs->cr3);
writel_relaxed(cr2, port->membase + ofs->cr2);
writel_relaxed(cr1, port->membase + ofs->cr1);
stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
spin_unlock_irqrestore(&port->lock, flags);
/* Handle modem control interrupts */
if (UART_ENABLE_MS(port, termios->c_cflag))
stm32_usart_enable_ms(port);
else
stm32_usart_disable_ms(port);
}
static const char *stm32_usart_type(struct uart_port *port)
{
return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
}
static void stm32_usart_release_port(struct uart_port *port)
{
}
static int stm32_usart_request_port(struct uart_port *port)
{
return 0;
}
static void stm32_usart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_STM32;
}
static int
stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
/* No user changeable parameters */
return -EINVAL;
}
static void stm32_usart_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
struct stm32_port *stm32port = container_of(port,
struct stm32_port, port);
const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
const struct stm32_usart_config *cfg = &stm32port->info->cfg;
unsigned long flags = 0;
switch (state) {
case UART_PM_STATE_ON:
pm_runtime_get_sync(port->dev);
break;
case UART_PM_STATE_OFF:
spin_lock_irqsave(&port->lock, flags);
stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
spin_unlock_irqrestore(&port->lock, flags);
pm_runtime_put_sync(port->dev);
break;
}
}
static const struct uart_ops stm32_uart_ops = {
.tx_empty = stm32_usart_tx_empty,
.set_mctrl = stm32_usart_set_mctrl,
.get_mctrl = stm32_usart_get_mctrl,
.stop_tx = stm32_usart_stop_tx,
.start_tx = stm32_usart_start_tx,
.throttle = stm32_usart_throttle,
.unthrottle = stm32_usart_unthrottle,
.stop_rx = stm32_usart_stop_rx,
.enable_ms = stm32_usart_enable_ms,
.break_ctl = stm32_usart_break_ctl,
.startup = stm32_usart_startup,
.shutdown = stm32_usart_shutdown,
.set_termios = stm32_usart_set_termios,
.pm = stm32_usart_pm,
.type = stm32_usart_type,
.release_port = stm32_usart_release_port,
.request_port = stm32_usart_request_port,
.config_port = stm32_usart_config_port,
.verify_port = stm32_usart_verify_port,
};
static void stm32_usart_deinit_port(struct stm32_port *stm32port)
{