On 10.09.20 18:31, Guenter Roeck wrote:
> On Family 17h (Ryzen) devices, the WatchdogTmrEn bit of PmDecodeEn not only
> enables watchdog memory decoding at 0xfeb00000, it also enables the
> watchdog hardware itself. Use this information to enable the watchdog if
> it is not already enabled.
> 
> Cc: Jan Kiszka <jan.kis...@siemens.com>
> Signed-off-by: Guenter Roeck <li...@roeck-us.net>
> ---
>  drivers/watchdog/sp5100_tco.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index 85e9664318c9..a730ecbf78cd 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -17,6 +17,12 @@
>   *       AMD Publication 51192 "AMD Bolton FCH Register Reference Guide"
>   *       AMD Publication 52740 "BIOS and Kernel Developer’s Guide (BKDG)
>   *                           for AMD Family 16h Models 30h-3Fh Processors"
> + *       AMD Publication 55570-B1-PUB "Processor Programming Reference (PPR)
> + *                           for AMD Family 17h Model 18h, Revision B1
> + *                           Processors (PUB)
> + *       AMD Publication 55772-A1-PUB "Processor Programming Reference (PPR)
> + *                           for AMD Family 17h Model 20h, Revision A1
> + *                           Processors (PUB)
>   */
>  
>  /*
> @@ -241,6 +247,18 @@ static int sp5100_tco_setupdevice(struct device *dev,
>               break;
>       case efch:
>               dev_name = SB800_DEVNAME;
> +             /*
> +              * On Family 17h devices, the EFCH_PM_DECODEEN_WDT_TMREN bit of
> +              * EFCH_PM_DECODEEN not only enables the EFCH_PM_WDT_ADDR memory
> +              * region, it also enables the watchdog itself.
> +              */
> +             if (boot_cpu_data.x86 == 0x17) {
> +                     val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
> +                     if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
> +                             sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN, 
> 0xff,
> +                                                       
> EFCH_PM_DECODEEN_WDT_TMREN);
> +                     }
> +             }
>               val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
>               if (val & EFCH_PM_DECODEEN_WDT_TMREN)
>                       mmio_addr = EFCH_PM_WDT_ADDR;
> 

Won't that bring us EFCH_PM_WDT_ADDR as address, rather than
EFCH_PM_ACPI_MMIO_ADDR which worked in my case? Or is one an alias of
the other.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

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