Hi Geert,
[add Phil]
> Geert Uytterhoeven <ge...@linux-m68k.org> hat am 8. April 2018 um 11:05
> geschrieben:
>
>
> If CONFIG_RASPBERRYPI_FIRMWARE=n:
>
> drivers/gpio/gpio-raspberrypi-exp.c: In function
> ‘rpi_exp_gpio_get_polarity’:
> drivers/gpio/gpio-raspberrypi-exp.c:71: warning: ‘get.polarity’ is used
> uninitialized in this function
> drivers/gpio/gpio-raspberrypi-exp.c: In function
> ‘rpi_exp_gpio_get_direction’:
> drivers/gpio/gpio-raspberrypi-exp.c:150: warning: ‘get.direction’ is used
> uninitialized in this function
>
> The dummy firmware interface functions return 0, which means success,
> causing subsequent code to make use of the never initialized output
> parameter.
i think this is more theoritical, because we need to get rpi_firmware first and
in this case it's NULL.
>
> Fix this by making the dummy functions return an error code (-ENOSYS)
> instead.
Anyway i'm okay with the change.
>
> Note that this assumes the firmware always fills in the requested data
> in the CONFIG_RASPBERRYPI_FIRMWARE=y case.
Unfortunately i don't know.
>
> Fixes: d45f1a563b92dac7 ("staging: vc04_services: fix up rpi firmware
> functions")
> Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org>
> ---
> Should get.polarity resp. get.direction be preinitialized instead,
> like is done for get.state?
>
> static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
> {
> ...
> get.state = 0; /* storage for returned value */
>
> ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,
> &get, sizeof(get));
> ...
> }
>
> This would avoid returning uninitialized data if the firmware did not
> fill in the requested data.
> ---
> include/soc/bcm2835/raspberrypi-firmware.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/soc/bcm2835/raspberrypi-firmware.h
> b/include/soc/bcm2835/raspberrypi-firmware.h
> index 50df5b28d2c9df6e..8ee8991aa099af3a 100644
> --- a/include/soc/bcm2835/raspberrypi-firmware.h
> +++ b/include/soc/bcm2835/raspberrypi-firmware.h
> @@ -143,13 +143,13 @@ struct rpi_firmware *rpi_firmware_get(struct
> device_node *firmware_node);
> static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
> void *data, size_t len)
> {
> - return 0;
> + return -ENOSYS;
> }
>
> static inline int rpi_firmware_property_list(struct rpi_firmware *fw,
> void *data, size_t tag_size)
> {
> - return 0;
> + return -ENOSYS;
> }
>
> static inline struct rpi_firmware *rpi_firmware_get(struct device_node
> *firmware_node)
> --
> 2.7.4
>
>
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