This is a note to let you know that I've just added the patch titled
serial: stm32: re-introduce an irq flag condition in usart_receive_chars
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-stm32-re-introduce-an-irq-flag-condition-in-u.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8661fb04fedaa722480ba4fb0410ea9801db0c65
Author: Erwan Le Ray <erwan.leray@xxxxxxxxxxx>
Date: Wed Oct 20 17:03:30 2021 +0200
serial: stm32: re-introduce an irq flag condition in usart_receive_chars
[ Upstream commit cc58d0a3f0a4755b9c808e065d9227c6e984e7db ]
Re-introduce an irq flag condition in usart_receive_chars.
This condition has been deleted by commit 75f4e830fa9c ("serial: do not
restore interrupt state in sysrq helper").
This code was present to handle threaded case, and has been removed
because it is no more needed in this case. Nevertheless an irq safe lock
is still needed in some cases, when DMA should be stopped to receive errors
or breaks in PIO mode.
This patch is a precursor to the complete rework or stm32 serial driver
DMA implementation.
Signed-off-by: Erwan Le Ray <erwan.leray@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211020150332.10214-2-erwan.leray@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Stable-dep-of: adafbbf6895e ("serial: stm32: Deassert Transmit Enable on ->rs485_config()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index fc166cc2c856..bba4facf7425 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -211,19 +211,22 @@ static unsigned long stm32_usart_get_char(struct uart_port *port, u32 *sr,
return c;
}
-static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
+static void stm32_usart_receive_chars(struct uart_port *port, bool irqflag)
{
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;
+ unsigned long c, flags;
u32 sr;
char flag;
- spin_lock(&port->lock);
+ if (irqflag)
+ spin_lock_irqsave(&port->lock, flags);
+ else
+ spin_lock(&port->lock);
while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res,
- threaded)) {
+ irqflag)) {
sr |= USART_SR_DUMMY_RX;
flag = TTY_NORMAL;
@@ -277,7 +280,10 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
uart_insert_char(port, sr, USART_SR_ORE, c, flag);
}
- uart_unlock_and_check_sysrq(port);
+ if (irqflag)
+ uart_unlock_and_check_sysrq_irqrestore(port, irqflag);
+ else
+ uart_unlock_and_check_sysrq(port);
tty_flip_buffer_push(tport);
}
@@ -510,10 +516,9 @@ 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 stm32_port *stm32_port = to_stm32_port(port);
- if (stm32_port->rx_ch)
- stm32_usart_receive_chars(port, true);
+ /* Receiver timeout irq for DMA RX */
+ stm32_usart_receive_chars(port, false);
return IRQ_HANDLED;
}
