6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shiji Yang <yangshiji66@xxxxxxxxxxx>
[ Upstream commit f07798d7bb9c46d17d80103fb772fd2c75d47919 ]
bgpio_bits must be aligned with the data bus width. For example, on a
32 bit big endian system and we only have 16 GPIOs. If we only assume
bgpio_bits=16 we can never control the GPIO because the base address
is the lowest address.
low address high address
-------------------------------------------------
| byte3 | byte2 | byte1 | byte0 |
-------------------------------------------------
| NaN | NaN | gpio8-15 | gpio0-7 |
-------------------------------------------------
Fixes: 55b2395e4e92 ("gpio: mmio: handle "ngpios" properly in bgpio_init()")
Fixes: https://github.com/openwrt/openwrt/issues/15739
Reported-by: Mark Mentovai <mark@xxxxxxxxxxxx>
Signed-off-by: Shiji Yang <yangshiji66@xxxxxxxxxxx>
Suggested-By: Mark Mentovai <mark@xxxxxxxxxxxx>
Reviewed-by: Jonas Gorski <jonas.gorski@xxxxxxxxx>
Tested-by: Lóránd Horváth <lorand.horvath82@xxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Link: https://lore.kernel.org/r/TYCP286MB089577B47D70F0AB25ABA6F5BCD52@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpio/gpio-mmio.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index 74fdf0d87b2c8..c9f9f4e36c89b 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -622,8 +622,6 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
ret = gpiochip_get_ngpios(gc, dev);
if (ret)
gc->ngpio = gc->bgpio_bits;
- else
- gc->bgpio_bits = roundup_pow_of_two(round_up(gc->ngpio, 8));
ret = bgpio_setup_io(gc, dat, set, clr, flags);
if (ret)
--
2.43.0
