From: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
imx_put_poll_char() has been simplified to remove the code to disable
interrupts. The present code can corrupt register state when re-entered
from FIQ handler.
Switch to _relaxed() MMIO functions (which are safe for polled I/O and
needed to avoid taking spin locks).
Signed-off-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Signed-off-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Huang Shijie <b32955@xxxxxxxxxxxxx>
Cc: linux-serial@xxxxxxxxxxxxxxx
---
drivers/tty/serial/imx.c | 24 +++++-------------------
1 file changed, 5 insertions(+), 19 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 8f62a3c..0b6f14b 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1509,42 +1509,28 @@ imx_verify_port(struct uart_port *port, struct serial_struct *ser)
#if defined(CONFIG_CONSOLE_POLL)
static int imx_poll_get_char(struct uart_port *port)
{
- if (!(readl(port->membase + USR2) & USR2_RDR))
+ if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))
return NO_POLL_CHAR;
- return readl(port->membase + URXD0) & URXD_RX_DATA;
+ return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA;
}
static void imx_poll_put_char(struct uart_port *port, unsigned char c)
{
- struct imx_port_ucrs old_ucr;
unsigned int status;
- /* save control registers */
- imx_port_ucrs_save(port, &old_ucr);
-
- /* disable interrupts */
- writel(UCR1_UARTEN, port->membase + UCR1);
- writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),
- port->membase + UCR2);
- writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),
- port->membase + UCR3);
-
/* drain */
do {
- status = readl(port->membase + USR1);
+ status = readl_relaxed(port->membase + USR1);
} while (~status & USR1_TRDY);
/* write */
- writel(c, port->membase + URTX0);
+ writel_relaxed(c, port->membase + URTX0);
/* flush */
do {
- status = readl(port->membase + USR2);
+ status = readl_relaxed(port->membase + USR2);
} while (~status & USR2_TXDC);
-
- /* restore control registers */
- imx_port_ucrs_restore(port, &old_ucr);
}
#endif
--
1.8.2
--
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