releases/4.14.124/tty-serial-msm_serial-fix-xon-xoff.patch

   1 From 61c0e37950b88bad590056286c1d766b1f167f4e Mon Sep 17 00:00:00 2001
   2 From: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
   3 Date: Mon, 20 May 2019 20:38:48 +0200
   4 Subject: tty: serial: msm_serial: Fix XON/XOFF
   5
   6 From: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
   7
   8 commit 61c0e37950b88bad590056286c1d766b1f167f4e upstream.
   9
  10 When the tty layer requests the uart to throttle, the current code
  11 executing in msm_serial will trigger "Bad mode in Error Handler" and
  12 generate an invalid stack frame in pstore before rebooting (that is if
  13 pstore is indeed configured: otherwise the user shall just notice a
  14 reboot with no further information dumped to the console).
  15
  16 This patch replaces the PIO byte accessor with the word accessor
  17 already used in PIO mode.
  18
  19 Fixes: 68252424a7c7 ("tty: serial: msm: Support big-endian CPUs")
  20 Cc: stable@vger.kernel.org
  21 Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
  22 Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
  23 Reviewed-by: Stephen Boyd <swboyd@chromium.org>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  drivers/tty/serial/msm_serial.c |    5 ++++-
  28  1 file changed, 4 insertions(+), 1 deletion(-)
  29
  30 --- a/drivers/tty/serial/msm_serial.c
  31 +++ b/drivers/tty/serial/msm_serial.c
  32 @@ -868,6 +868,7 @@ static void msm_handle_tx(struct uart_po
  33         struct circ_buf *xmit = &msm_port->uart.state->xmit;
  34         struct msm_dma *dma = &msm_port->tx_dma;
  35         unsigned int pio_count, dma_count, dma_min;
  36 +       char buf[4] = { 0 };
  37         void __iomem *tf;
  38         int err = 0;
  39
  40 @@ -877,10 +878,12 @@ static void msm_handle_tx(struct uart_po
  41                 else
  42                         tf = port->membase + UART_TF;
  43
  44 +               buf[0] = port->x_char;
  45 +
  46                 if (msm_port->is_uartdm)
  47                         msm_reset_dm_count(port, 1);
  48
  49 -               iowrite8_rep(tf, &port->x_char, 1);
  50 +               iowrite32_rep(tf, buf, 1);
  51                 port->icount.tx++;
  52                 port->x_char = 0;
  53                 return;