[PATCH] watchdog: cadence: Add expire_now method

[Michal Simek]

po 28. 6. 2021 v 15:45 odesílatel Michal Simek <michal.simek at xilinx.com> napsal:
>
> It is working in a way that only minimal timeout is setup to reach
> expiration just right after it is setup.
> Please make sure that PMUFW is compiled with ENABLE_EM flag.
>
> On U-Boot prompt you can test it like:
> ZynqMP> wdt dev watchdog at fd4d0000
> ZynqMP> wdt list
> watchdog at fd4d0000 (cdns_wdt)
> ZynqMP> wdt dev
> dev: watchdog at fd4d0000
> ZynqMP> wdt expire
> (And reset should happen here)
>
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
>
>  drivers/watchdog/cdns_wdt.c | 41 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/cdns_wdt.c b/drivers/watchdog/cdns_wdt.c
> index 966d010e40d9..6dfdd31c8b8f 100644
> --- a/drivers/watchdog/cdns_wdt.c
> +++ b/drivers/watchdog/cdns_wdt.c
> @@ -214,6 +214,45 @@ static int cdns_wdt_stop(struct udevice *dev)
>         return 0;
>  }
>
> +/**
> + * cdns_wdt_expire_now - Expire the watchdog.
> + *
> + * @dev: Watchdog device
> + * @flags: Driver flags
> + *
> + * Access WDT and configure with minimal counter value to expire ASAP.
> + * Expiration issues system reset. When DEBUG is enabled count should be
> + * bigger to at least see debug message.
> + *
> + * Return: Always 0
> + */
> +static int cdns_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> +       struct cdns_wdt_priv *priv = dev_get_priv(dev);
> +       u32 data, count = 0;
> +
> +#if defined(DEBUG)
> +       count = 0x40; /* Increase the value if you need more time */
> +       debug("%s: Expire wdt%u\n", __func__, dev_seq(dev));
> +#endif
> +
> +       cdns_wdt_writereg(&priv->regs->zmr, CDNS_WDT_ZMR_ZKEY_VAL);
> +
> +       count = (count << 2) & CDNS_WDT_CCR_CRV_MASK;
> +
> +       /* Write counter access key first to be able write to register */
> +       data = count | CDNS_WDT_REGISTER_ACCESS_KEY;
> +       cdns_wdt_writereg(&priv->regs->ccr, data);
> +
> +       data = CDNS_WDT_ZMR_WDEN_MASK |  CDNS_WDT_ZMR_RSTEN_MASK |
> +               CDNS_WDT_ZMR_ZKEY_VAL;
> +
> +       cdns_wdt_writereg(&priv->regs->zmr, data);
> +       cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY);
> +
> +       return 0;
> +}
> +
>  /**
>   * cdns_wdt_probe - Probe call for the device.
>   *
> @@ -247,7 +286,7 @@ static const struct wdt_ops cdns_wdt_ops = {
>         .start = cdns_wdt_start,
>         .reset = cdns_wdt_reset,
>         .stop = cdns_wdt_stop,
> -       /* There is no bit/reg/support in IP for expire_now functionality */
> +       .expire_now = cdns_wdt_expire_now,
>  };
>
>  static const struct udevice_id cdns_wdt_ids[] = {
> --
> 2.32.0
>

Applied.
M

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP/Versal SoCs