From patchwork Thu Mar 2 17:31:11 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Belloni X-Patchwork-Id: 9601199 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 81F5360429 for ; Thu, 2 Mar 2017 17:33:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 74A7528599 for ; Thu, 2 Mar 2017 17:33:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 69790285A1; Thu, 2 Mar 2017 17:33:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 14F9528599 for ; Thu, 2 Mar 2017 17:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=4D0+7TBqFkOG3N4v3Qsv/mypNI4GbAb+PhI+vAZBUn0=; b=EWlvFHM1X5B86MWRReBzjbfBpx hUoJ6BxobykRCyhHMWLsrzbAaE/osLKaqLVCUZPOv9lmApdFUEgTC0eT4mhh+4bbevu8xcaUl3zxk 4JZAKaLESfcfiHQup1vWJSg++c/W+HSGFK6A6a1LX4yLERMbhuTqDOCwxKIrfX0bhK/dHVX1lMIVa REqXx0g7mGc4VNkLnCsMx3vf7qWJNM6J6Vc0qQRrHgp3PDcbqE+VkOUfEo4ZWbj2x2dIJnNn0YHg/ k1w04qK4dwsU4Zgk0D+UUqnbmbwqUTS3lTIQvr3bqaCERRtALadcXU83bZebGU5sRYi3EldbLz0Zi 2kfxljQw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cjUba-00069p-QK; Thu, 02 Mar 2017 17:33:30 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cjUZs-00058U-AD for linux-arm-kernel@lists.infradead.org; Thu, 02 Mar 2017 17:31:48 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id 519C8207EE; Thu, 2 Mar 2017 18:31:19 +0100 (CET) Received: from localhost (unknown [88.191.26.124]) by mail.free-electrons.com (Postfix) with ESMTPSA id 2C952206E1; Thu, 2 Mar 2017 18:31:19 +0100 (CET) From: Alexandre Belloni To: Guenter Roeck Subject: [PATCH 1/4] watchdog: sama5d4: fix WDDIS handling Date: Thu, 2 Mar 2017 18:31:11 +0100 Message-Id: <20170302173114.28508-2-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170302173114.28508-1-alexandre.belloni@free-electrons.com> References: <20170302173114.28508-1-alexandre.belloni@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170302_093144_717006_700D2C47 X-CRM114-Status: GOOD ( 17.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-watchdog@vger.kernel.org, Wenyou.Yang@microchip.com, linux-kernel@vger.kernel.org, Nicolas Ferre , Wim Van Sebroeck , Alexandre Belloni , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The datasheet states: "When setting the WDDIS bit, and while it is set, the fields WDV and WDD must not be modified." Because the whole configuration is already cached inside .mr, wait for the user to enable the watchdog to configure it so it is enabled and configured at the same time (what the IP is actually expecting). When the watchdog is already enabled, it is not an issue to reconfigure it. Signed-off-by: Alexandre Belloni Reviewed-by: Guenter Roeck Acked-by: Wenyou.Yang --- drivers/watchdog/sama5d4_wdt.c | 48 ++++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 18 deletions(-) diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c index f709962018ac..5cee20caca78 100644 --- a/drivers/watchdog/sama5d4_wdt.c +++ b/drivers/watchdog/sama5d4_wdt.c @@ -44,6 +44,8 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); +#define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS)) + #define wdt_read(wdt, field) \ readl_relaxed((wdt)->reg_base + (field)) @@ -89,7 +91,16 @@ static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd, wdt->mr &= ~AT91_WDT_WDD; wdt->mr |= AT91_WDT_SET_WDV(value); wdt->mr |= AT91_WDT_SET_WDD(value); - wdt_write(wdt, AT91_WDT_MR, wdt->mr); + + /* + * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When + * setting the WDDIS bit, and while it is set, the fields WDV and WDD + * must not be modified. + * If the watchdog is enabled, then the timeout can be updated. Else, + * wait that the user enables it. + */ + if (wdt_enabled) + wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); wdd->timeout = timeout; @@ -145,23 +156,20 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt) static int sama5d4_wdt_init(struct sama5d4_wdt *wdt) { - struct watchdog_device *wdd = &wdt->wdd; - u32 value = WDT_SEC2TICKS(wdd->timeout); u32 reg; - /* - * Because the fields WDV and WDD must not be modified when the WDDIS - * bit is set, so clear the WDDIS bit before writing the WDT_MR. + * When booting and resuming, the bootloader may have changed the + * watchdog configuration. + * If the watchdog is already running, we can safely update it. + * Else, we have to disable it properly. */ - reg = wdt_read(wdt, AT91_WDT_MR); - reg &= ~AT91_WDT_WDDIS; - wdt_write(wdt, AT91_WDT_MR, reg); - - wdt->mr |= AT91_WDT_SET_WDD(value); - wdt->mr |= AT91_WDT_SET_WDV(value); - - wdt_write(wdt, AT91_WDT_MR, wdt->mr); - + if (wdt_enabled) { + wdt_write(wdt, AT91_WDT_MR, wdt->mr); + } else { + reg = wdt_read(wdt, AT91_WDT_MR); + if (!(reg & AT91_WDT_WDDIS)) + wdt_write(wdt, AT91_WDT_MR, reg | AT91_WDT_WDDIS); + } return 0; } @@ -172,6 +180,7 @@ static int sama5d4_wdt_probe(struct platform_device *pdev) struct resource *res; void __iomem *regs; u32 irq = 0; + u32 timeout; int ret; wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); @@ -221,6 +230,11 @@ static int sama5d4_wdt_probe(struct platform_device *pdev) return ret; } + timeout = WDT_SEC2TICKS(wdd->timeout); + + wdt->mr |= AT91_WDT_SET_WDD(timeout); + wdt->mr |= AT91_WDT_SET_WDV(timeout); + ret = sama5d4_wdt_init(wdt); if (ret) return ret; @@ -263,9 +277,7 @@ static int sama5d4_wdt_resume(struct device *dev) { struct sama5d4_wdt *wdt = dev_get_drvdata(dev); - wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); - if (wdt->mr & AT91_WDT_WDDIS) - wdt_write(wdt, AT91_WDT_MR, wdt->mr); + sama5d4_wdt_init(wdt); return 0; }