* watchdog: sp5100_tco support for AMD V/R/E series @ 2020-09-07 11:20 Jan Kiszka 2020-09-07 15:31 ` Guenter Roeck 0 siblings, 1 reply; 7+ messages in thread From: Jan Kiszka @ 2020-09-07 11:20 UTC (permalink / raw) To: Guenter Roeck, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade Hi all, Arsalan reported that the upstream driver for sp5100_tco does not work for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled ..and fix it: diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c index 85e9664318c9..5482154fde42 100644 --- a/drivers/watchdog/sp5100_tco.c +++ b/drivers/watchdog/sp5100_tco.c @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) /* Set the Watchdog timer resolution to 1 sec and enable */ sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, ~EFCH_PM_WATCHDOG_DISABLE, - EFCH_PM_DECODEEN_SECOND_RES); + EFCH_PM_DECODEEN_SECOND_RES | + EFCH_PM_DECODEEN_WDT_TMREN); break; } } Does anyone have an idea if such unconditional setting could be problematic on older/different efch? We probe for that bit in sp5100_tco_setupdevice but we never set it so far. I'm missing specs... Thanks, Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-07 11:20 watchdog: sp5100_tco support for AMD V/R/E series Jan Kiszka @ 2020-09-07 15:31 ` Guenter Roeck 2020-09-07 15:46 ` Jan Kiszka 0 siblings, 1 reply; 7+ messages in thread From: Guenter Roeck @ 2020-09-07 15:31 UTC (permalink / raw) To: Jan Kiszka, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 9/7/20 4:20 AM, Jan Kiszka wrote: > Hi all, > > Arsalan reported that the upstream driver for sp5100_tco does not work > for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: > > [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver > [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address > [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled > > ..and fix it: > > diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c > index 85e9664318c9..5482154fde42 100644 > --- a/drivers/watchdog/sp5100_tco.c > +++ b/drivers/watchdog/sp5100_tco.c > @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) > /* Set the Watchdog timer resolution to 1 sec and enable */ > sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, > ~EFCH_PM_WATCHDOG_DISABLE, > - EFCH_PM_DECODEEN_SECOND_RES); > + EFCH_PM_DECODEEN_SECOND_RES | > + EFCH_PM_DECODEEN_WDT_TMREN); Confusing. The register in question is a 32-bit register, but only a byte is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. This is from AMD Publication 52740. So something in the existing code is (or seems to be) wrong, but either case I don't see how setting bit 7 (or 31 ?) would enable the watchdog hardware. Hmm, I wrote that code. Guess I'll need to to spend some time figuring out what is going on. Guenter > break; > } > } > > Does anyone have an idea if such unconditional setting could be > problematic on older/different efch? We probe for that bit in > sp5100_tco_setupdevice but we never set it so far. > > I'm missing specs... > > Thanks, > Jan > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-07 15:31 ` Guenter Roeck @ 2020-09-07 15:46 ` Jan Kiszka 2020-09-07 19:18 ` Guenter Roeck 0 siblings, 1 reply; 7+ messages in thread From: Jan Kiszka @ 2020-09-07 15:46 UTC (permalink / raw) To: Guenter Roeck, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 07.09.20 17:31, Guenter Roeck wrote: > On 9/7/20 4:20 AM, Jan Kiszka wrote: >> Hi all, >> >> Arsalan reported that the upstream driver for sp5100_tco does not work >> for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: >> >> [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver >> [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address >> [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled >> >> ..and fix it: >> >> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c >> index 85e9664318c9..5482154fde42 100644 >> --- a/drivers/watchdog/sp5100_tco.c >> +++ b/drivers/watchdog/sp5100_tco.c >> @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) >> /* Set the Watchdog timer resolution to 1 sec and enable */ >> sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, >> ~EFCH_PM_WATCHDOG_DISABLE, >> - EFCH_PM_DECODEEN_SECOND_RES); >> + EFCH_PM_DECODEEN_SECOND_RES | >> + EFCH_PM_DECODEEN_WDT_TMREN); > > Confusing. The register in question is a 32-bit register, but only a byte > is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 > set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. > This is from AMD Publication 52740. So something in the existing code > is (or seems to be) wrong, but either case I don't see how setting bit 7 > (or 31 ?) would enable the watchdog hardware. > > Hmm, I wrote that code. Guess I'll need to to spend some time figuring out > what is going on. The logic came from [1] which inspired [2] - that's where I pointed out the large overlap with the existing upstream driver. I would love to see all that consolidated. BTW, the R1505G is family 0x17. Maybe something changed there, and that bit 7 was just reserved/ignored so far. ENOSPECS Jan [1] https://git.yoctoproject.org/cgit/cgit.cgi/meta-amd/commit/meta-amd-bsp/recipes-kernel/amd-wdt/files/amd_wdt.c?id=cd760c9f04d276382a0f5156dabdb766594ace56 [2] https://github.com/siemens/efibootguard/commit/3a702aa96d193f26571ea4e70db29ef01a0d4d5f -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-07 15:46 ` Jan Kiszka @ 2020-09-07 19:18 ` Guenter Roeck 2020-09-07 20:45 ` Guenter Roeck 0 siblings, 1 reply; 7+ messages in thread From: Guenter Roeck @ 2020-09-07 19:18 UTC (permalink / raw) To: Jan Kiszka, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 9/7/20 8:46 AM, Jan Kiszka wrote: > On 07.09.20 17:31, Guenter Roeck wrote: >> On 9/7/20 4:20 AM, Jan Kiszka wrote: >>> Hi all, >>> >>> Arsalan reported that the upstream driver for sp5100_tco does not work >>> for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: >>> >>> [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver >>> [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address >>> [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled >>> >>> ..and fix it: >>> >>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c >>> index 85e9664318c9..5482154fde42 100644 >>> --- a/drivers/watchdog/sp5100_tco.c >>> +++ b/drivers/watchdog/sp5100_tco.c >>> @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) >>> /* Set the Watchdog timer resolution to 1 sec and enable */ >>> sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, >>> ~EFCH_PM_WATCHDOG_DISABLE, >>> - EFCH_PM_DECODEEN_SECOND_RES); >>> + EFCH_PM_DECODEEN_SECOND_RES | >>> + EFCH_PM_DECODEEN_WDT_TMREN); >> >> Confusing. The register in question is a 32-bit register, but only a byte >> is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 >> set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. >> This is from AMD Publication 52740. So something in the existing code >> is (or seems to be) wrong, but either case I don't see how setting bit 7 >> (or 31 ?) would enable the watchdog hardware. >> >> Hmm, I wrote that code. Guess I'll need to to spend some time figuring out >> what is going on. > > The logic came from [1] which inspired [2] - that's where I pointed out > the large overlap with the existing upstream driver. I would love to see > all that consolidated. > > BTW, the R1505G is family 0x17. Maybe something changed there, and that > bit 7 was just reserved/ignored so far. ENOSPECS > Thanks for the pointers. I think you are talking about bit 31. Bit 7 is and was WatchdogTmrEn, but that supposedly only enables watchdog timer memory access at 0xfeb00000. From what I glance from the other drivers, the existing code is wrong. It should set the disable and resolution bits in register offset 3 (bit 24..27), not 0. In other words, EFCH_PM_DECODEEN3 should be defined as 0x03, not as 0x00. Which actually makes sense from the name. Playing with my hardware, turns out that setting bit 7 in EFCH_PM_DECODEEN (register offset 0) does indeed enable the watchdog. I'll need to check if it actually works. Either case, -ENOSPECS is really a problem here. Guenter > Jan > > [1] > https://git.yoctoproject.org/cgit/cgit.cgi/meta-amd/commit/meta-amd-bsp/recipes-kernel/amd-wdt/files/amd_wdt.c?id=cd760c9f04d276382a0f5156dabdb766594ace56 > [2] > https://github.com/siemens/efibootguard/commit/3a702aa96d193f26571ea4e70db29ef01a0d4d5f > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-07 19:18 ` Guenter Roeck @ 2020-09-07 20:45 ` Guenter Roeck 2020-09-09 16:04 ` Guenter Roeck 0 siblings, 1 reply; 7+ messages in thread From: Guenter Roeck @ 2020-09-07 20:45 UTC (permalink / raw) To: Jan Kiszka, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 9/7/20 12:18 PM, Guenter Roeck wrote: > On 9/7/20 8:46 AM, Jan Kiszka wrote: >> On 07.09.20 17:31, Guenter Roeck wrote: >>> On 9/7/20 4:20 AM, Jan Kiszka wrote: >>>> Hi all, >>>> >>>> Arsalan reported that the upstream driver for sp5100_tco does not work >>>> for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: >>>> >>>> [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver >>>> [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address >>>> [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled >>>> >>>> ..and fix it: >>>> >>>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c >>>> index 85e9664318c9..5482154fde42 100644 >>>> --- a/drivers/watchdog/sp5100_tco.c >>>> +++ b/drivers/watchdog/sp5100_tco.c >>>> @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) >>>> /* Set the Watchdog timer resolution to 1 sec and enable */ >>>> sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, >>>> ~EFCH_PM_WATCHDOG_DISABLE, >>>> - EFCH_PM_DECODEEN_SECOND_RES); >>>> + EFCH_PM_DECODEEN_SECOND_RES | >>>> + EFCH_PM_DECODEEN_WDT_TMREN); >>> >>> Confusing. The register in question is a 32-bit register, but only a byte >>> is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 >>> set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. >>> This is from AMD Publication 52740. So something in the existing code >>> is (or seems to be) wrong, but either case I don't see how setting bit 7 >>> (or 31 ?) would enable the watchdog hardware. >>> >>> Hmm, I wrote that code. Guess I'll need to to spend some time figuring out >>> what is going on. >> >> The logic came from [1] which inspired [2] - that's where I pointed out >> the large overlap with the existing upstream driver. I would love to see >> all that consolidated. >> >> BTW, the R1505G is family 0x17. Maybe something changed there, and that >> bit 7 was just reserved/ignored so far. ENOSPECS >> > > Thanks for the pointers. > > I think you are talking about bit 31. Bit 7 is and was WatchdogTmrEn, but that > supposedly only enables watchdog timer memory access at 0xfeb00000. From what > I glance from the other drivers, the existing code is wrong. It should set > the disable and resolution bits in register offset 3 (bit 24..27), not 0. > In other words, EFCH_PM_DECODEEN3 should be defined as 0x03, not as 0x00. > Which actually makes sense from the name. > > Playing with my hardware, turns out that setting bit 7 in EFCH_PM_DECODEEN > (register offset 0) does indeed enable the watchdog. I'll need to check > if it actually works. Either case, -ENOSPECS is really a problem here. > ... and it does work. After playing with it, it seems that on Family 17h CPUs EFCH_PM_DECODEEN_WDT_TMREN not only enables watchdog timer memory access at 0xfeb0000, but also enables the watchdog itself. Also, turns out the documentation is now public, at least for some of the Family 17h CPUs (though oddly enough not for all of them). See processor reference manuals at https://www.amd.com/en/support/tech-docs. The documents for model 18h and model 20h include a note stating that bit 7 of EFCH_PM_DECODEEN enables both memory access and the watchdog hardware. So we'll need two patches - one to fix the value of EFCH_PM_DECODEEN3, and one to enable the watchdog bit setting bit 7 of EFCH_PM_DECODEEN for Family 17h CPUs. Thanks, Guenter > Guenter > >> Jan >> >> [1] >> https://git.yoctoproject.org/cgit/cgit.cgi/meta-amd/commit/meta-amd-bsp/recipes-kernel/amd-wdt/files/amd_wdt.c?id=cd760c9f04d276382a0f5156dabdb766594ace56 >> [2] >> https://github.com/siemens/efibootguard/commit/3a702aa96d193f26571ea4e70db29ef01a0d4d5f >> > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-07 20:45 ` Guenter Roeck @ 2020-09-09 16:04 ` Guenter Roeck 2020-09-10 6:09 ` Jan Kiszka 0 siblings, 1 reply; 7+ messages in thread From: Guenter Roeck @ 2020-09-09 16:04 UTC (permalink / raw) To: Jan Kiszka, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 9/7/20 1:45 PM, Guenter Roeck wrote: > On 9/7/20 12:18 PM, Guenter Roeck wrote: >> On 9/7/20 8:46 AM, Jan Kiszka wrote: >>> On 07.09.20 17:31, Guenter Roeck wrote: >>>> On 9/7/20 4:20 AM, Jan Kiszka wrote: >>>>> Hi all, >>>>> >>>>> Arsalan reported that the upstream driver for sp5100_tco does not work >>>>> for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: >>>>> >>>>> [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver >>>>> [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address >>>>> [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled >>>>> >>>>> ..and fix it: >>>>> >>>>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c >>>>> index 85e9664318c9..5482154fde42 100644 >>>>> --- a/drivers/watchdog/sp5100_tco.c >>>>> +++ b/drivers/watchdog/sp5100_tco.c >>>>> @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) >>>>> /* Set the Watchdog timer resolution to 1 sec and enable */ >>>>> sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, >>>>> ~EFCH_PM_WATCHDOG_DISABLE, >>>>> - EFCH_PM_DECODEEN_SECOND_RES); >>>>> + EFCH_PM_DECODEEN_SECOND_RES | >>>>> + EFCH_PM_DECODEEN_WDT_TMREN); >>>> >>>> Confusing. The register in question is a 32-bit register, but only a byte >>>> is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 >>>> set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. >>>> This is from AMD Publication 52740. So something in the existing code >>>> is (or seems to be) wrong, but either case I don't see how setting bit 7 >>>> (or 31 ?) would enable the watchdog hardware. >>>> >>>> Hmm, I wrote that code. Guess I'll need to to spend some time figuring out >>>> what is going on. >>> >>> The logic came from [1] which inspired [2] - that's where I pointed out >>> the large overlap with the existing upstream driver. I would love to see >>> all that consolidated. >>> >>> BTW, the R1505G is family 0x17. Maybe something changed there, and that >>> bit 7 was just reserved/ignored so far. ENOSPECS >>> >> >> Thanks for the pointers. >> >> I think you are talking about bit 31. Bit 7 is and was WatchdogTmrEn, but that >> supposedly only enables watchdog timer memory access at 0xfeb00000. From what >> I glance from the other drivers, the existing code is wrong. It should set >> the disable and resolution bits in register offset 3 (bit 24..27), not 0. >> In other words, EFCH_PM_DECODEEN3 should be defined as 0x03, not as 0x00. >> Which actually makes sense from the name. >> >> Playing with my hardware, turns out that setting bit 7 in EFCH_PM_DECODEEN >> (register offset 0) does indeed enable the watchdog. I'll need to check >> if it actually works. Either case, -ENOSPECS is really a problem here. >> > > ... and it does work. After playing with it, it seems that on Family 17h > CPUs EFCH_PM_DECODEEN_WDT_TMREN not only enables watchdog timer memory > access at 0xfeb0000, but also enables the watchdog itself. > > Also, turns out the documentation is now public, at least for some of the > Family 17h CPUs (though oddly enough not for all of them). See processor > reference manuals at https://www.amd.com/en/support/tech-docs. The documents > for model 18h and model 20h include a note stating that bit 7 of > EFCH_PM_DECODEEN enables both memory access and the watchdog hardware. > > So we'll need two patches - one to fix the value of EFCH_PM_DECODEEN3, > and one to enable the watchdog bit setting bit 7 of EFCH_PM_DECODEEN > for Family 17h CPUs. > Jan - any chance you can submit those patches ? Or do you want me to do it ? Thanks, Guenter > Thanks, > Guenter > >> Guenter >> >>> Jan >>> >>> [1] >>> https://git.yoctoproject.org/cgit/cgit.cgi/meta-amd/commit/meta-amd-bsp/recipes-kernel/amd-wdt/files/amd_wdt.c?id=cd760c9f04d276382a0f5156dabdb766594ace56 >>> [2] >>> https://github.com/siemens/efibootguard/commit/3a702aa96d193f26571ea4e70db29ef01a0d4d5f >>> >> > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: watchdog: sp5100_tco support for AMD V/R/E series 2020-09-09 16:04 ` Guenter Roeck @ 2020-09-10 6:09 ` Jan Kiszka 0 siblings, 0 replies; 7+ messages in thread From: Jan Kiszka @ 2020-09-10 6:09 UTC (permalink / raw) To: Guenter Roeck, linux-watchdog Cc: Wim Van Sebroeck, linux-kernel, Awan, Arsalan, Hombourger, Cedric, Farnsworth, Wade On 09.09.20 18:04, Guenter Roeck wrote: > On 9/7/20 1:45 PM, Guenter Roeck wrote: >> On 9/7/20 12:18 PM, Guenter Roeck wrote: >>> On 9/7/20 8:46 AM, Jan Kiszka wrote: >>>> On 07.09.20 17:31, Guenter Roeck wrote: >>>>> On 9/7/20 4:20 AM, Jan Kiszka wrote: >>>>>> Hi all, >>>>>> >>>>>> Arsalan reported that the upstream driver for sp5100_tco does not work >>>>>> for embedded Ryzen. Meanwhile, I was able to confirm that on an R1505G: >>>>>> >>>>>> [ 11.607251] sp5100_tco: SP5100/SB800 TCO WatchDog Timer Driver >>>>>> [ 11.607337] sp5100-tco sp5100-tco: Using 0xfed80b00 for watchdog MMIO address >>>>>> [ 11.607344] sp5100-tco sp5100-tco: Watchdog hardware is disabled >>>>>> >>>>>> ..and fix it: >>>>>> >>>>>> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c >>>>>> index 85e9664318c9..5482154fde42 100644 >>>>>> --- a/drivers/watchdog/sp5100_tco.c >>>>>> +++ b/drivers/watchdog/sp5100_tco.c >>>>>> @@ -193,7 +193,8 @@ static void tco_timer_enable(struct sp5100_tco *tco) >>>>>> /* Set the Watchdog timer resolution to 1 sec and enable */ >>>>>> sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3, >>>>>> ~EFCH_PM_WATCHDOG_DISABLE, >>>>>> - EFCH_PM_DECODEEN_SECOND_RES); >>>>>> + EFCH_PM_DECODEEN_SECOND_RES | >>>>>> + EFCH_PM_DECODEEN_WDT_TMREN); >>>>> >>>>> Confusing. The register in question is a 32-bit register, but only a byte >>>>> is written into it. Bit 24-25 are supposed to be the resolution, bit 25-26 >>>>> set to 0 enable the watchdog. Bit 7 is supposed to enable MMIO decoding. >>>>> This is from AMD Publication 52740. So something in the existing code >>>>> is (or seems to be) wrong, but either case I don't see how setting bit 7 >>>>> (or 31 ?) would enable the watchdog hardware. >>>>> >>>>> Hmm, I wrote that code. Guess I'll need to to spend some time figuring out >>>>> what is going on. >>>> >>>> The logic came from [1] which inspired [2] - that's where I pointed out >>>> the large overlap with the existing upstream driver. I would love to see >>>> all that consolidated. >>>> >>>> BTW, the R1505G is family 0x17. Maybe something changed there, and that >>>> bit 7 was just reserved/ignored so far. ENOSPECS >>>> >>> >>> Thanks for the pointers. >>> >>> I think you are talking about bit 31. Bit 7 is and was WatchdogTmrEn, but that >>> supposedly only enables watchdog timer memory access at 0xfeb00000. From what >>> I glance from the other drivers, the existing code is wrong. It should set >>> the disable and resolution bits in register offset 3 (bit 24..27), not 0. >>> In other words, EFCH_PM_DECODEEN3 should be defined as 0x03, not as 0x00. >>> Which actually makes sense from the name. >>> >>> Playing with my hardware, turns out that setting bit 7 in EFCH_PM_DECODEEN >>> (register offset 0) does indeed enable the watchdog. I'll need to check >>> if it actually works. Either case, -ENOSPECS is really a problem here. >>> >> >> ... and it does work. After playing with it, it seems that on Family 17h >> CPUs EFCH_PM_DECODEEN_WDT_TMREN not only enables watchdog timer memory >> access at 0xfeb0000, but also enables the watchdog itself. >> >> Also, turns out the documentation is now public, at least for some of the >> Family 17h CPUs (though oddly enough not for all of them). See processor >> reference manuals at https://www.amd.com/en/support/tech-docs. The documents >> for model 18h and model 20h include a note stating that bit 7 of >> EFCH_PM_DECODEEN enables both memory access and the watchdog hardware. >> >> So we'll need two patches - one to fix the value of EFCH_PM_DECODEEN3, >> and one to enable the watchdog bit setting bit 7 of EFCH_PM_DECODEEN >> for Family 17h CPUs. >> > Jan - any chance you can submit those patches ? Or do you want me to do it ? Oh, I was reading your reply as if you were writing the patches. The first one is definitely your finding, and while I can also see now what is wrong and needed on 17h, I'm unsure about the rest. If you have a better picture, please go ahead. Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-09-10 6:09 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-09-07 11:20 watchdog: sp5100_tco support for AMD V/R/E series Jan Kiszka 2020-09-07 15:31 ` Guenter Roeck 2020-09-07 15:46 ` Jan Kiszka 2020-09-07 19:18 ` Guenter Roeck 2020-09-07 20:45 ` Guenter Roeck 2020-09-09 16:04 ` Guenter Roeck 2020-09-10 6:09 ` Jan Kiszka
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