[U-Boot] [PATCH 1/2] rockchip: rk3399-puma: add code to allow forcing a power-on reset

[Simon Glass]

Hi Philipp,

On 26 November 2017 at 16:22, Philipp Tomsich
<philipp.tomsich at theobroma-systems.com> wrote:
> The reset circuitry in the RK3399 only resets 'almost all logic' when
> a software reset is performed.  To make our software maintenance
> easier in the future, we want to have the option (controlled by a DTS
> property) to force all reset causes other than a power-on reset to
> trigger a power-on reset via a GPIO trigger.
>
> This adds the necessary support to the rk3399-puma (i.e. RK3399-Q7)
> board-support and the documentation for the new property
> (sysreset-gpio) within the /config-node.
>
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Tested-by: Klaus Goger <klaus.goger at theobroma-systems.com>
> ---
>
>  board/theobroma-systems/puma_rk3399/puma-rk3399.c | 46 +++++++++++++++++++++++
>  doc/device-tree-bindings/config.txt               |  6 +++
>  2 files changed, 52 insertions(+)

Reviewed-by: Simon Glass <sjg at chromium.org>

>
> diff --git a/board/theobroma-systems/puma_rk3399/puma-rk3399.c b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
> index 2b4988e..79dbdf4 100644
> --- a/board/theobroma-systems/puma_rk3399/puma-rk3399.c
> +++ b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
> @@ -9,7 +9,10 @@
>  #include <misc.h>
>  #include <dm/pinctrl.h>
>  #include <dm/uclass-internal.h>
> +#include <asm/gpio.h>
>  #include <asm/setup.h>
> +#include <asm/arch/clock.h>
> +#include <asm/arch/cru_rk3399.h>
>  #include <asm/arch/periph.h>
>  #include <power/regulator.h>
>  #include <spl.h>
> @@ -32,9 +35,52 @@ int board_init(void)
>         return 0;
>  }
>
> +static void rk3399_force_power_on_reset(void)
> +{
> +       ofnode node;
> +       struct gpio_desc sysreset_gpio;
> +
> +       debug("%s: trying to force a power-on reset\n", __func__);
> +
> +       node = ofnode_path("/config");
> +       if (!ofnode_valid(node)) {
> +               debug("%s: no /config node?\n", __func__);
> +               return;
> +       }
> +
> +       gpio_request_by_name_nodev(node, "sysreset-gpio", 0,
> +                                  &sysreset_gpio, GPIOD_IS_OUT);
> +
> +       if (!dm_gpio_is_valid(&sysreset_gpio)) {

If you don't support this GPIO being option, you should check the
return value of gpio_request_by_name_nodev() instead. If it is < 0
then it did not find a GPIO.

> +               debug("%s: could not find a /config/sysreset-gpio\n", __func__);
> +               return;
> +       }
> +
> +       dm_gpio_set_value(&sysreset_gpio, 1);
> +}
> +
>  void spl_board_init(void)
>  {
>         int  ret;
> +       struct rk3399_cru *cru = rockchip_get_cru();
> +
> +       /*
> +        * The RK3399 resets only 'almost all logic' (see also in the TRM
> +        * "3.9.4 Global software reset"), when issuing a software reset.
> +        * This may cause issues during boot-up for some configurations of
> +        * the application software stack.
> +        *
> +        * To work around this, we test whether the last reset reason was
> +        * a power-on reset and (if not) issue an overtemp-reset to reset
> +        * the entire module.
> +        *
> +        * While this was previously fixed by modifying the various places
> +        * that could generate a software reset (e.g. U-Boot's sysreset
> +        * driver, the ATF or Linux), we now have it here to ensure that
> +        * we no longer have to track this through the various components.
> +        */
> +       if (cru->glb_rst_st != 0)
> +               rk3399_force_power_on_reset();
>
>         /*
>          * Turning the eMMC and SPI back on (if disabled via the Qseven
> diff --git a/doc/device-tree-bindings/config.txt b/doc/device-tree-bindings/config.txt
> index 15e4349..6cdc16d 100644
> --- a/doc/device-tree-bindings/config.txt
> +++ b/doc/device-tree-bindings/config.txt
> @@ -46,3 +46,9 @@ u-boot,spl-payload-offset
>         If present (and SPL is controlled by the device-tree), this allows
>         to override the CONFIG_SYS_SPI_U_BOOT_OFFS setting using a value
>         from the device-tree.
> +
> +sysreset-gpio
> +       If present (and supported by the specific board), indicates a
> +       GPIO that can be set to trigger a system reset.  It is assumed
> +       that such a system reset will effect a complete platform reset,
> +       being roughly equivalent to a power-on reset.

Is there no kernel binding for this sort of thing?

Regards,
Simon