clk_round_rate returns a signed long and may possibly return errors
in it, for example if there is no possible rate.
Till now dw8250_set_termios ignored any error, the signednes and would
just use the value as input to clk_set_rate. This of course falls apart
if there is an actual error, so check for errors and only try to set
a rate if the value is actually valid.
This turned up on some Rockchip platforms after commit
6a171b299379 ("serial: 8250_dw: Allow hardware flow control to be used")
enabled set_termios callback in all cases, not only ACPI.
Fixes: 6a171b299379 ("serial: 8250_dw: Allow hardware flow control to be used")
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
There is also another patch floating around, fixing a separate issue
on top of this one: "serial: 8250_dw: Fix breakage when HAVE_CLK=n"
changes in v2:
- adapt commit message to make it more explicit, that this is a
somewhat critical fix
- add Andy's Reviewed-by
drivers/tty/serial/8250/8250_dw.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 6ee55a2d47bb..223ac234ddb2 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -257,7 +257,7 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
{
unsigned int baud = tty_termios_baud_rate(termios);
struct dw8250_data *d = p->private_data;
- unsigned int rate;
+ long rate;
int ret;
if (IS_ERR(d->clk) || !old)
@@ -265,7 +265,10 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
clk_disable_unprepare(d->clk);
rate = clk_round_rate(d->clk, baud * 16);
- ret = clk_set_rate(d->clk, rate);
+ if (rate < 0)
+ ret = rate;
+ else
+ ret = clk_set_rate(d->clk, rate);
clk_prepare_enable(d->clk);
if (!ret)
--
2.11.0
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
