Re: [PATCHv7 1/3] hw: gpio: implement gpio-pwr driver for qemu reset/poweroff

[Peter Maydell]

On Fri, 15 Jan 2021 at 10:11, Maxim Uvarov <maxim.uvarov@linaro.org> wrote:
>
> Implement gpio-pwr driver to allow reboot and poweroff machine.
> This is simple driver with just 2 gpios lines. Current use case
> is to reboot and poweroff virt machine in secure mode. Secure
> pl066 gpio chip is needed for that.
>
> Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> Reviewed-by: Hao Wu <wuhaotsh@google.com>
> ---
>  hw/gpio/Kconfig     |  3 ++
>  hw/gpio/gpio_pwr.c  | 70 +++++++++++++++++++++++++++++++++++++++++++++
>  hw/gpio/meson.build |  1 +
>  3 files changed, 74 insertions(+)
>  create mode 100644 hw/gpio/gpio_pwr.c

> +/*
> + * QEMU interface:
> + * two named input GPIO lines:
> + *   'reset' : when asserted, trigger system reset
> + *   'shutdown' : when asserted, trigger system shutdown
> + */

The comment says we perform the actions when the lines are
asserted...

> +static void gpio_pwr_reset(void *opaque, int n, int level)
> +{
> +    if (!level) {
> +        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
> +    }
> +}
> +
> +static void gpio_pwr_shutdown(void *opaque, int n, int level)
> +{
> +    if (!level) {
> +        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> +    }
> +}

...but the code performs the actions when the lines
are de-asserted, ie when they go to 0. I think the code
should be "if (level)".

thanks
-- PMM