linux-kernel - Re: [PATCH 2/2] watchdog: sp5100_tco: Enable watchdog on Family 17h devices if disabled

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Message-ID: <b17232b2-5246-d2fe-bdf9-85abb9cc78f3@siemens.com>
Date:   Fri, 11 Sep 2020 07:32:18 +0200
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] watchdog: sp5100_tco: Enable watchdog on Family 17h
 devices if disabled

On 10.09.20 18:55, Jan Kiszka wrote:
> On 10.09.20 18:53, Guenter Roeck wrote:
>> Hi Jan,
>>
>> On 9/10/20 9:34 AM, Jan Kiszka wrote:
>>> 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.kiszka@...mens.com>
>>>> Signed-off-by: Guenter Roeck <linux@...ck-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.
>>>
>>
>> Yes, it does use EFCH_PM_WDT_ADDR. EFCH_PM_ACPI_MMIO_ADDR works as well,
>> but is meant to be a fallback. Both point to the watchdog memory space.
>>
> 
> OK, will test, possibly only on the weekend, and confirm this also on my
> board.
> 
> Jan
> 

Both patches now

Tested-by: Jan Kiszka <jan.kiszka@...mens.com>

Thanks,
Jan

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