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
