From patchwork Wed Aug 28 10:23:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Mikhaylov X-Patchwork-Id: 11118473 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9E948112C for ; Wed, 28 Aug 2019 10:24:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74DD423403 for ; Wed, 28 Aug 2019 10:24:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="kKOabCZV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726623AbfH1KYV (ORCPT ); Wed, 28 Aug 2019 06:24:21 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:60490 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726391AbfH1KYU (ORCPT ); Wed, 28 Aug 2019 06:24:20 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id B2AF442ECC; Wed, 28 Aug 2019 10:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-type:content-type:content-transfer-encoding:mime-version :references:in-reply-to:x-mailer:message-id:date:date:subject :subject:from:from:received:received:received; s=mta-01; t= 1566987857; x=1568802258; bh=mEhEh6gAJzPJESzZ96RxoI02+oLNMejWhrw LDGL5SN0=; b=kKOabCZVeDyfKrSCli9AkXX2Agt3eD3zzw2mcblcZTYGiS1H9Wn HTxaSHs0GO5StyQtHNTvtzOjH8GVPxf2ojsZeGerV4OWL9qDH/ZFNa6+N54WEvvP xHv1cEw2wCjtefWPgQu1iATdxLHQhC5IiewfNk0YpLIn9Qw0gSnu2VBk= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id g55r3vv1PqKs; Wed, 28 Aug 2019 13:24:17 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id C344742E7D; Wed, 28 Aug 2019 13:24:16 +0300 (MSK) Received: from localhost.dev.yadro.com (172.17.15.69) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Wed, 28 Aug 2019 13:24:16 +0300 From: Ivan Mikhaylov To: Guenter Roeck , Wim Van Sebroeck CC: Joel Stanley , Andrew Jeffery , , , , , Alexander Amelkin , , Rob Herring , Mark Rutland , , Ivan Mikhaylov Subject: [PATCH v4 1/4] vesnin: add wdt2 section with alt-boot option Date: Wed, 28 Aug 2019 13:23:59 +0300 Message-ID: <20190828102402.13155-2-i.mikhaylov@yadro.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190828102402.13155-1-i.mikhaylov@yadro.com> References: <20190828102402.13155-1-i.mikhaylov@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.69] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Adds wdt2 section with 'alt-boot' option into dts for vesnin. Signed-off-by: Ivan Mikhaylov --- arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts b/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts index 0b9e29c3212e..2ee26c86a32e 100644 --- a/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts +++ b/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts @@ -222,3 +222,7 @@ &vuart { status = "okay"; }; + +&wdt2 { + aspeed,alt-boot; +}; From patchwork Wed Aug 28 10:24:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Mikhaylov X-Patchwork-Id: 11118467 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AF356112C for ; Wed, 28 Aug 2019 10:24:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DE5422CF5 for ; Wed, 28 Aug 2019 10:24:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="UkIIgnlG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726719AbfH1KYV (ORCPT ); Wed, 28 Aug 2019 06:24:21 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:60512 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726246AbfH1KYU (ORCPT ); Wed, 28 Aug 2019 06:24:20 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 1498A42E7D; Wed, 28 Aug 2019 10:24:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-type:content-type:content-transfer-encoding:mime-version :references:in-reply-to:x-mailer:message-id:date:date:subject :subject:from:from:received:received:received; s=mta-01; t= 1566987858; x=1568802259; bh=GCxrgga2ACU49JHMFa9Qm+9SSWX1i4ngDP9 HAa9kUNA=; b=UkIIgnlGPKh9mkuPPvxNFzZpN4Iw1iHEkn+9dyLAmXfN2MdiO3p Cx7N9xgoJzBmiVWmCe5CBzo/GffHtif/sDvP5beoRm2Jq+fDMWkgG38z3uWi+ofR CU+baYQhzTKT+qlSEPvSc1Fu9IOeny5K3FycdLy/tbvRGgKHwlh2cvKs= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7U2d1OXvcQTD; Wed, 28 Aug 2019 13:24:18 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id 12F8A404CB; Wed, 28 Aug 2019 13:24:18 +0300 (MSK) Received: from localhost.dev.yadro.com (172.17.15.69) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Wed, 28 Aug 2019 13:24:17 +0300 From: Ivan Mikhaylov To: Guenter Roeck , Wim Van Sebroeck CC: Joel Stanley , Andrew Jeffery , , , , , Alexander Amelkin , , Rob Herring , Mark Rutland , , Ivan Mikhaylov Subject: [PATCH v4 2/4] vesnin: add secondary SPI flash chip Date: Wed, 28 Aug 2019 13:24:00 +0300 Message-ID: <20190828102402.13155-3-i.mikhaylov@yadro.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190828102402.13155-1-i.mikhaylov@yadro.com> References: <20190828102402.13155-1-i.mikhaylov@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.69] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Adds secondary SPI flash chip into dts for vesnin. Signed-off-by: Ivan Mikhaylov --- arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts b/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts index 2ee26c86a32e..db4cc3df61ce 100644 --- a/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts +++ b/arch/arm/boot/dts/aspeed-bmc-opp-vesnin.dts @@ -81,6 +81,14 @@ label = "bmc"; #include "openbmc-flash-layout.dtsi" }; + + flash@1 { + status = "okay"; + reg = < 1 >; + compatible = "jedec,spi-nor"; + m25p,fast-read; + label = "alt"; + }; }; &spi { From patchwork Wed Aug 28 10:24:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Mikhaylov X-Patchwork-Id: 11118471 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 159E71800 for ; Wed, 28 Aug 2019 10:24:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8B55217F5 for ; Wed, 28 Aug 2019 10:24:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="BOdFlclP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726775AbfH1KYW (ORCPT ); Wed, 28 Aug 2019 06:24:22 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:60538 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726616AbfH1KYW (ORCPT ); Wed, 28 Aug 2019 06:24:22 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 7F8A742ECD; Wed, 28 Aug 2019 10:24:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-type:content-type:content-transfer-encoding:mime-version :references:in-reply-to:x-mailer:message-id:date:date:subject :subject:from:from:received:received:received; s=mta-01; t= 1566987859; x=1568802260; bh=HJZyEVApdw1Mju6dqt61w539MuWoTZM60B1 9nvgkkt8=; b=BOdFlclPmsB0fpH2LPSCgTuBa3meuJWyDi8eOFKQ0jvchmZAK5p exW4ZNo6XlaX7exdgEc6Vg85UXQQtX9LAQdIqCqE1Qzivkt8lqOG+T6HWcjTdWCT F0bMYRHCayX4PGAsKaCT9mJwXtACUd2vtdz6H0/lMNK13vL3BLpv5LwA= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id N_qy3AKWzIFk; Wed, 28 Aug 2019 13:24:19 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id 54A31404CB; Wed, 28 Aug 2019 13:24:19 +0300 (MSK) Received: from localhost.dev.yadro.com (172.17.15.69) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Wed, 28 Aug 2019 13:24:18 +0300 From: Ivan Mikhaylov To: Guenter Roeck , Wim Van Sebroeck CC: Joel Stanley , Andrew Jeffery , , , , , Alexander Amelkin , , Rob Herring , Mark Rutland , , Ivan Mikhaylov Subject: [PATCH v4 3/4] watchdog/aspeed: add support for dual boot Date: Wed, 28 Aug 2019 13:24:01 +0300 Message-ID: <20190828102402.13155-4-i.mikhaylov@yadro.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190828102402.13155-1-i.mikhaylov@yadro.com> References: <20190828102402.13155-1-i.mikhaylov@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.69] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Set WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION into WDT_CLEAR_TIMEOUT_STATUS to clear out boot code source and re-enable access to the primary SPI flash chip while booted via wdt2 from the alternate chip. AST2400 datasheet says: "In the 2nd flash booting mode, all the address mapping to CS0# would be re-directed to CS1#. And CS0# is not accessible under this mode. To access CS0#, firmware should clear the 2nd boot mode register in the WDT2 status register WDT30.bit[1]." Signed-off-by: Ivan Mikhaylov Reviewed-by: Guenter Roeck --- drivers/watchdog/aspeed_wdt.c | 65 ++++++++++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c index cc71861e033a..125dbd349b00 100644 --- a/drivers/watchdog/aspeed_wdt.c +++ b/drivers/watchdog/aspeed_wdt.c @@ -53,6 +53,8 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table); #define WDT_CTRL_ENABLE BIT(0) #define WDT_TIMEOUT_STATUS 0x10 #define WDT_TIMEOUT_STATUS_BOOT_SECONDARY BIT(1) +#define WDT_CLEAR_TIMEOUT_STATUS 0x14 +#define WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0) /* * WDT_RESET_WIDTH controls the characteristics of the external pulse (if @@ -165,6 +167,60 @@ static int aspeed_wdt_restart(struct watchdog_device *wdd, return 0; } +/* access_cs0 shows if cs0 is accessible, hence the reverted bit */ +static ssize_t access_cs0_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct aspeed_wdt *wdt = dev_get_drvdata(dev); + u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS); + + return sprintf(buf, "%u\n", + !(status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY)); +} + +static ssize_t access_cs0_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t size) +{ + struct aspeed_wdt *wdt = dev_get_drvdata(dev); + unsigned long val; + + if (kstrtoul(buf, 10, &val)) + return -EINVAL; + + if (val) + writel(WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION, + wdt->base + WDT_CLEAR_TIMEOUT_STATUS); + + return size; +} + +/* + * This attribute exists only if the system has booted from the alternate + * flash with 'alt-boot' option. + * + * At alternate flash the 'access_cs0' sysfs node provides: + * ast2400: a way to get access to the primary SPI flash chip at CS0 + * after booting from the alternate chip at CS1. + * ast2500: a way to restore the normal address mapping from + * (CS0->CS1, CS1->CS0) to (CS0->CS0, CS1->CS1). + * + * Clearing the boot code selection and timeout counter also resets to the + * initial state the chip select line mapping. When the SoC is in normal + * mapping state (i.e. booted from CS0), clearing those bits does nothing for + * both versions of the SoC. For alternate boot mode (booted from CS1 due to + * wdt2 expiration) the behavior differs as described above. + * + * This option can be used with wdt2 (watchdog1) only. + */ +static DEVICE_ATTR_RW(access_cs0); + +static struct attribute *bswitch_attrs[] = { + &dev_attr_access_cs0.attr, + NULL +}; +ATTRIBUTE_GROUPS(bswitch); + static const struct watchdog_ops aspeed_wdt_ops = { .start = aspeed_wdt_start, .stop = aspeed_wdt_stop, @@ -306,9 +362,16 @@ static int aspeed_wdt_probe(struct platform_device *pdev) } status = readl(wdt->base + WDT_TIMEOUT_STATUS); - if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) + if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) { wdt->wdd.bootstatus = WDIOF_CARDRESET; + if (of_device_is_compatible(np, "aspeed,ast2400-wdt") || + of_device_is_compatible(np, "aspeed,ast2500-wdt")) + wdt->wdd.groups = bswitch_groups; + } + + dev_set_drvdata(dev, wdt); + return devm_watchdog_register_device(dev, &wdt->wdd); } From patchwork Wed Aug 28 10:24:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Mikhaylov X-Patchwork-Id: 11118469 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DD1B4112C for ; Wed, 28 Aug 2019 10:24:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD7CE217F5 for ; Wed, 28 Aug 2019 10:24:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="ftjErji2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726836AbfH1KYZ (ORCPT ); Wed, 28 Aug 2019 06:24:25 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:60554 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726738AbfH1KYY (ORCPT ); Wed, 28 Aug 2019 06:24:24 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 07E1F42ECE; Wed, 28 Aug 2019 10:24:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-type:content-type:content-transfer-encoding:mime-version :references:in-reply-to:x-mailer:message-id:date:date:subject :subject:from:from:received:received:received; s=mta-01; t= 1566987860; x=1568802261; bh=87VA5h5waSDTUF2CVQN/4Wwh9JYi5VNM4bl aFGLhSMY=; b=ftjErji2haH19AzZFUWJf73ObDZba5bpxrSSs758XIdfDgACCZk jPlBP+oacojsvpJcH/Aq0ofG5bq36R++M4CPVB+RcmRQYJxUXVx26Iyk/bGeYABI 10uOLFbik5rkwD2UUHG7HkcmPXm+H/zjYStNE9UUWOOxCX8ZpzlFMMas= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id maoMV8-Mbqiy; Wed, 28 Aug 2019 13:24:20 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id D90F3404CB; Wed, 28 Aug 2019 13:24:20 +0300 (MSK) Received: from localhost.dev.yadro.com (172.17.15.69) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Wed, 28 Aug 2019 13:24:20 +0300 From: Ivan Mikhaylov To: Guenter Roeck , Wim Van Sebroeck CC: Joel Stanley , Andrew Jeffery , , , , , Alexander Amelkin , , Rob Herring , Mark Rutland , , Ivan Mikhaylov Subject: [PATCH v4 4/4] aspeed/watchdog: Add access_cs0 option for alt-boot Date: Wed, 28 Aug 2019 13:24:02 +0300 Message-ID: <20190828102402.13155-5-i.mikhaylov@yadro.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190828102402.13155-1-i.mikhaylov@yadro.com> References: <20190828102402.13155-1-i.mikhaylov@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.69] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org The option for the ast2400/2500 to get access to CS0 at runtime. Signed-off-by: Ivan Mikhaylov Reviewed-by: Guenter Roeck --- .../ABI/testing/sysfs-class-watchdog | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog index 6317ade5ad19..675f9b537661 100644 --- a/Documentation/ABI/testing/sysfs-class-watchdog +++ b/Documentation/ABI/testing/sysfs-class-watchdog @@ -72,3 +72,37 @@ Description: It is a read/write file. When read, the currently assigned pretimeout governor is returned. When written, it sets the pretimeout governor. + +What: /sys/class/watchdog/watchdog1/access_cs0 +Date: August 2019 +Contact: Ivan Mikhaylov , + Alexander Amelkin +Description: + It is a read/write file. This attribute exists only if the + system has booted from the alternate flash chip due to + expiration of a watchdog timer of AST2400/AST2500 when + alternate boot function was enabled with 'aspeed,alt-boot' + devicetree option for that watchdog or with an appropriate + h/w strapping (for WDT2 only). + + At alternate flash the 'access_cs0' sysfs node provides: + ast2400: a way to get access to the primary SPI flash + chip at CS0 after booting from the alternate + chip at CS1. + ast2500: a way to restore the normal address mapping + from (CS0->CS1, CS1->CS0) to (CS0->CS0, + CS1->CS1). + + Clearing the boot code selection and timeout counter also + resets to the initial state the chip select line mapping. When + the SoC is in normal mapping state (i.e. booted from CS0), + clearing those bits does nothing for both versions of the SoC. + For alternate boot mode (booted from CS1 due to wdt2 + expiration) the behavior differs as described above. + + This option can be used with wdt2 (watchdog1) only. + + When read, the current status of the boot code selection is + shown. When written with any non-zero value, it clears + the boot code selection and the timeout counter, which results + in chipselect reset for AST2400/AST2500.