From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7754FC43461 for ; Mon, 7 Sep 2020 15:50:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48631206B8 for ; Mon, 7 Sep 2020 15:50:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730223AbgIGPrR (ORCPT ); Mon, 7 Sep 2020 11:47:17 -0400 Received: from david.siemens.de ([192.35.17.14]:33625 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730222AbgIGPrB (ORCPT ); Mon, 7 Sep 2020 11:47:01 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by david.siemens.de (8.15.2/8.15.2) with ESMTPS id 087Fkc26025246 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 7 Sep 2020 17:46:38 +0200 Received: from [139.22.116.238] ([139.22.116.238]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 087FkbFU013301; Mon, 7 Sep 2020 17:46:37 +0200 Subject: Re: watchdog: sp5100_tco support for AMD V/R/E series To: Guenter Roeck , linux-watchdog@vger.kernel.org Cc: Wim Van Sebroeck , linux-kernel@vger.kernel.org, "Awan, Arsalan" , "Hombourger, Cedric" , "Farnsworth, Wade" References: <15c8913e-9026-2649-9911-71d6f1c79519@siemens.com> From: Jan Kiszka Message-ID: <9e270546-7962-932b-2e4c-3c833b7d4b30@siemens.com> Date: Mon, 7 Sep 2020 17:46:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org 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