[PATCH v5] serial: 8250_dw: fix wrong logic in dw8250_check_lcr()

From: Kefeng Wang
Date: Mon May 02 2016 - 05:14:46 EST

Commit cdcea058e510 ("serial: 8250_dw: Avoid serial_outx code duplicate
with new dw8250_check_lcr()") introduce a wrong logic when write val to
LCR reg. When CONFIG_64BIT enabled, __raw_writeq is used unconditionally.

The __raw_readq/__raw_writeq is introduced by commit bca2092d7897 ("serial:
8250_dw: Use 64-bit access for OCTEON.") for OCTEON.

So for 64BIT && !PORT_OCTEON, we better to use coincident write function.

Fixes: cdcea058e510("serial: 8250_dw: Avoid serial_outx code duplicate with new dw8250_check_lcr()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>

Changes since v4:
- Update change log, suggested by Andy Shevchenko.
Changes since v3:
- Add patch change log, suggested by Greg Kroah-Hartman.
Changes since v2:
- Add #ifdef CONFIG_64BIT back, ensure it can be built under configuration lacking readq/writeq.
Changes since v1:
- Repace '#ifdef CONFIG_64BIT' with IS_ENABLED(CONFIG_64BIT).
- Enrich patch log, and add Fixes tag.

drivers/tty/serial/8250/8250_dw.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index a3fb95d..47d1f3e 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -104,15 +104,16 @@ static void dw8250_check_lcr(struct uart_port *p, int value)

#ifdef CONFIG_64BIT
- __raw_writeq(value & 0xff, offset);
+ if (p->type == PORT_OCTEON)
+ __raw_writeq(value & 0xff, offset);
+ else
if (p->iotype == UPIO_MEM32)
writel(value, offset);
else if (p->iotype == UPIO_MEM32BE)
iowrite32be(value, offset);
writeb(value, offset);
* FIXME: this deadlocks if port->lock is already held