When target_rate is big enough and not permitted in hardware,
then i is looped to UART_DIV_MAX (0xFFFF), and i * max_rate will overflow
(32b signed).
A fix is to quit the loop early enough, as soon as rate < i * min_rate as it
means the rate is not permitted.
This avoids arbitraty rates to be applied. Still in my hardware the max
allowed rate (1500000) is aplied when a higher is requested. This seems a
artifact of clk_round_rate which is not understood by me and independent of
this fix. Might or might not be another bug.
Signed-off-by: Nuno Goncalves <nunojpg@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_dw.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 5bb0c42c88dd..a27ea916abbf 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -267,7 +267,13 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
for (i = 1; i <= UART_DIV_MAX; i++) {
rate = clk_round_rate(d->clk, i * target_rate);
- if (rate >= i * min_rate && rate <= i * max_rate)
+
+ if (rate < i * min_rate) {
+ i = UART_DIV_MAX + 1;
+ break;
+ }
+
+ if (rate <= i * max_rate)
break;
}
if (i <= UART_DIV_MAX) {
--
2.11.0
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