diff --git a/target/linux/generic/backport-6.6/801-v6.11-gpio-mmio-do-not-calculate-bgpio_bits-via-ngpios.patch b/target/linux/generic/backport-6.6/801-v6.11-gpio-mmio-do-not-calculate-bgpio_bits-via-ngpios.patch new file mode 100644 index 00000000000..117c879e48e --- /dev/null +++ b/target/linux/generic/backport-6.6/801-v6.11-gpio-mmio-do-not-calculate-bgpio_bits-via-ngpios.patch @@ -0,0 +1,42 @@ +From f07798d7bb9c46d17d80103fb772fd2c75d47919 Mon Sep 17 00:00:00 2001 +From: Shiji Yang +Date: Tue, 25 Jun 2024 09:19:49 +0800 +Subject: [PATCH] gpio: mmio: do not calculate bgpio_bits via "ngpios" + +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 +Signed-off-by: Shiji Yang +Suggested-By: Mark Mentovai +Reviewed-by: Jonas Gorski +Tested-by: Lóránd Horváth +Reviewed-by: Linus Walleij +Link: https://lore.kernel.org/r/TYCP286MB089577B47D70F0AB25ABA6F5BCD52@TYCP286MB0895.JPNP286.PROD.OUTLOOK.COM +Signed-off-by: Bartosz Golaszewski +--- + drivers/gpio/gpio-mmio.c | 2 -- + 1 file changed, 2 deletions(-) + +--- a/drivers/gpio/gpio-mmio.c ++++ b/drivers/gpio/gpio-mmio.c +@@ -622,8 +622,6 @@ int bgpio_init(struct gpio_chip *gc, str + 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)