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-rw-r--r--drivers/tty/serial/stm32-usart.c80
1 files changed, 53 insertions, 27 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 4b5b0748790c..3244e7f6818c 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -210,11 +210,12 @@ static unsigned long stm32_usart_get_char_pio(struct uart_port *port)
return c;
}
-static void stm32_usart_receive_chars_pio(struct uart_port *port)
+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;
@@ -239,6 +240,7 @@ static void stm32_usart_receive_chars_pio(struct uart_port *port)
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++;
@@ -271,6 +273,8 @@ static void stm32_usart_receive_chars_pio(struct uart_port *port)
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)
@@ -300,50 +304,48 @@ static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma
stm32_port->last_res = RX_BUF_L;
}
-static void stm32_usart_receive_chars_dma(struct uart_port *port)
+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;
+ 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 void stm32_usart_receive_chars(struct uart_port *port, bool irqflag)
+static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush)
{
- 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;
enum dma_status rx_dma_status;
- unsigned long flags;
u32 sr;
+ unsigned int size = 0;
- if (irqflag)
- spin_lock_irqsave(&port->lock, flags);
- else
- spin_lock(&port->lock);
-
- if (stm32_usart_rx_dma_enabled(port)) {
+ 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 */
- stm32_usart_receive_chars_dma(port);
+ 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 */
- stm32_usart_receive_chars_pio(port);
+ size += stm32_usart_receive_chars_pio(port);
/* Switch back to DMA mode */
stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
@@ -354,18 +356,13 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool irqflag)
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");
- stm32_usart_receive_chars_pio(port);
+ size = stm32_usart_receive_chars_pio(port);
}
} else {
- stm32_usart_receive_chars_pio(port);
+ size = stm32_usart_receive_chars_pio(port);
}
- if (irqflag)
- uart_unlock_and_check_sysrq_irqrestore(port, irqflag);
- else
- uart_unlock_and_check_sysrq(port);
-
- tty_flip_buffer_push(tport);
+ return size;
}
static void stm32_usart_tx_dma_complete(void *arg)
@@ -403,8 +400,15 @@ static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
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;
- stm32_usart_receive_chars(port, true);
+ 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)
@@ -557,6 +561,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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);
@@ -580,7 +585,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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))) {
- stm32_usart_receive_chars(port, false);
+ spin_lock(&port->lock);
+ size = stm32_usart_receive_chars(port, false);
+ uart_unlock_and_check_sysrq(port);
+ if (size)
+ tty_flip_buffer_push(tport);
}
}
@@ -599,11 +608,19 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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)
- stm32_usart_receive_chars(port, false);
+ 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;
}
@@ -1678,6 +1695,8 @@ static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_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;
@@ -1696,8 +1715,15 @@ static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
* 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);
- dmaengine_terminate_sync(stm32_port->rx_ch);
+ /* 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 */
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-26 18:06:11 +0300