[v2] tty: serial: msm_serial: Fix XON/XOFF

Message ID 20190520183848.27719-1-jorge.ramirez-ortiz@linaro.org
State Accepted
Commit 61c0e37950b88bad590056286c1d766b1f167f4e
Headers show
Series
  • [v2] tty: serial: msm_serial: Fix XON/XOFF
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Commit Message

Jorge Ramirez-Ortiz May 20, 2019, 6:38 p.m.
When the tty layer requests the uart to throttle, the current code
executing in msm_serial will trigger "Bad mode in Error Handler" and
generate an invalid stack frame in pstore before rebooting (that is if
pstore is indeed configured: otherwise the user shall just notice a
reboot with no further information dumped to the console).

This patch replaces the PIO byte accessor with the word accessor
already used in PIO mode.

Fixes: 68252424a7c7 ("tty: serial: msm: Support big-endian CPUs")
Cc: stable@vger.kernel.org
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

---
 drivers/tty/serial/msm_serial.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
2.21.0

Comments

Vinod Koul May 21, 2019, 10:31 a.m. | #1
On 20-05-19, 20:38, Jorge Ramirez-Ortiz wrote:
> When the tty layer requests the uart to throttle, the current code

> executing in msm_serial will trigger "Bad mode in Error Handler" and

> generate an invalid stack frame in pstore before rebooting (that is if

> pstore is indeed configured: otherwise the user shall just notice a

> reboot with no further information dumped to the console).

> 

> This patch replaces the PIO byte accessor with the word accessor

> already used in PIO mode.

> 

> Fixes: 68252424a7c7 ("tty: serial: msm: Support big-endian CPUs")

> Cc: stable@vger.kernel.org

> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>

> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>


Reviewed-by: Vinod Koul <vkoul@kernel.org>


-- 
~Vinod

Patch

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index 109096033bb1..23833ad952ba 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -860,6 +860,7 @@  static void msm_handle_tx(struct uart_port *port)
 	struct circ_buf *xmit = &msm_port->uart.state->xmit;
 	struct msm_dma *dma = &msm_port->tx_dma;
 	unsigned int pio_count, dma_count, dma_min;
+	char buf[4] = { 0 };
 	void __iomem *tf;
 	int err = 0;
 
@@ -869,10 +870,12 @@  static void msm_handle_tx(struct uart_port *port)
 		else
 			tf = port->membase + UART_TF;
 
+		buf[0] = port->x_char;
+
 		if (msm_port->is_uartdm)
 			msm_reset_dm_count(port, 1);
 
-		iowrite8_rep(tf, &port->x_char, 1);
+		iowrite32_rep(tf, buf, 1);
 		port->icount.tx++;
 		port->x_char = 0;
 		return;