Since commit 21947ba6 the 8250 driver crashes in the byt_set_termios()
function with a divide error. This is caused by the fact that a baud rate
of 0 (B0) is not handled correctly.
The attached patch fixes this by restoring the old behavior for the B0
case.
Signed-off-by: David Müller <d.mueller@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_pci.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 98862aa..610c747 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1377,17 +1377,23 @@ byt_set_termios(struct uart_port *p, struct ktermios *termios,
unsigned long m, n;
u32 reg;
- /* Get Fuart closer to Fref */
- fuart *= rounddown_pow_of_two(fref / fuart);
+ if (fuart) {
+ /* Get Fuart closer to Fref */
+ fuart *= rounddown_pow_of_two(fref / fuart);
- /*
- * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
- * dividers must be adjusted.
- *
- * uartclk = (m / n) * 100 MHz, where m <= n
- */
- rational_best_approximation(fuart, fref, w, w, &m, &n);
- p->uartclk = fuart;
+ /*
+ * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
+ * dividers must be adjusted.
+ *
+ * uartclk = (m / n) * 100 MHz, where m <= n
+ */
+ rational_best_approximation(fuart, fref, w, w, &m, &n);
+ p->uartclk = fuart;
+ } else {
+ m = 2304;
+ n = 3125;
+ p->uartclk = 73728000;
+ }
/* Reset the clock */
reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
--
2.7.4
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