From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751557AbdBSRFV (ORCPT ); Sun, 19 Feb 2017 12:05:21 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:34503 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978AbdBSRFS (ORCPT ); Sun, 19 Feb 2017 12:05:18 -0500 Subject: Re: [PATCH v2 3/3] watchdog: sama5d4: Implement resume hook To: Alexandre Belloni References: <20170216193053.5546-1-alexandre.belloni@free-electrons.com> <20170216193053.5546-3-alexandre.belloni@free-electrons.com> <0fe51486-2de0-eda6-2310-823fc4fd7c82@roeck-us.net> <20170217152201.ue5ujd5ia3iqcduh@piout.net> Cc: Wim Van Sebroeck , Nicolas Ferre , linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Guenter Roeck Message-ID: <4016d976-cb6f-c303-eebe-c0bede771725@roeck-us.net> Date: Sun, 19 Feb 2017 09:05:15 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170217152201.ue5ujd5ia3iqcduh@piout.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/17/2017 07:22 AM, Alexandre Belloni wrote: > On 17/02/2017 at 06:47:03 -0800, Guenter Roeck wrote: >> On 02/16/2017 11:30 AM, Alexandre Belloni wrote: >>> When resuming for the deepest state on sama5d2, it is necessary to restore >>> MR as the registers are lost. >>> >>> Signed-off-by: Alexandre Belloni >>> --- >>> Changes in v2: >>> - cache mr beofre suspending >>> >>> drivers/watchdog/sama5d4_wdt.c | 32 ++++++++++++++++++++++++++++++++ >>> 1 file changed, 32 insertions(+) >>> >>> diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c >>> index 2a60251806d2..5ddeb4803dc3 100644 >>> --- a/drivers/watchdog/sama5d4_wdt.c >>> +++ b/drivers/watchdog/sama5d4_wdt.c >>> @@ -28,6 +28,7 @@ >>> struct sama5d4_wdt { >>> struct watchdog_device wdd; >>> void __iomem *reg_base; >>> + u32 mr; >> >> Makes me wonder if we shouldn't just retain the original 'config' >> (and maybe rename it to 'mr). After all, it _is_ used now. >> >>> }; >>> >>> static int wdt_timeout = WDT_DEFAULT_TIMEOUT; >>> @@ -248,11 +249,42 @@ static const struct of_device_id sama5d4_wdt_of_match[] = { >>> }; >>> MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match); >>> >>> +#ifdef CONFIG_PM_SLEEP >>> +static int sama5d4_wdt_suspend(struct device *dev) >>> +{ >>> + struct sama5d4_wdt *wdt = dev_get_drvdata(dev); >>> + >>> + wdt->mr = wdt_read(wdt, AT91_WDT_MR); >>> + >> >> Wouldn't you want to stop the watchdog here if it is running, >> ie set AT91_WDT_WDDIS ? >> > > Some existing customers want the watchdog to continue to run while the > system is suspended. > >>> + return 0; >>> +} >>> + >>> +static int sama5d4_wdt_resume(struct device *dev) >>> +{ >>> + struct sama5d4_wdt *wdt = dev_get_drvdata(dev); >>> + u32 reg; >>> + >>> + reg = wdt_read(wdt, AT91_WDT_MR); >>> + if (reg & AT91_WDT_WDDIS) >>> + wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS); >>> + >>> + wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); >> >> Is that necessary ? Why not just write wdt->mr unconditionally ? >> > > Because you can change WDV and WDD *OR* WDDIS but not both at the same > time. > Odd hardware ;-). Please add a comment explaining why the watchdog isn't stopped on suspend, and why the AT91_WDT_MR has to be reprogrammed on resume. Thanks, Guenter From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@roeck-us.net (Guenter Roeck) Date: Sun, 19 Feb 2017 09:05:15 -0800 Subject: [PATCH v2 3/3] watchdog: sama5d4: Implement resume hook In-Reply-To: <20170217152201.ue5ujd5ia3iqcduh@piout.net> References: <20170216193053.5546-1-alexandre.belloni@free-electrons.com> <20170216193053.5546-3-alexandre.belloni@free-electrons.com> <0fe51486-2de0-eda6-2310-823fc4fd7c82@roeck-us.net> <20170217152201.ue5ujd5ia3iqcduh@piout.net> Message-ID: <4016d976-cb6f-c303-eebe-c0bede771725@roeck-us.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 02/17/2017 07:22 AM, Alexandre Belloni wrote: > On 17/02/2017 at 06:47:03 -0800, Guenter Roeck wrote: >> On 02/16/2017 11:30 AM, Alexandre Belloni wrote: >>> When resuming for the deepest state on sama5d2, it is necessary to restore >>> MR as the registers are lost. >>> >>> Signed-off-by: Alexandre Belloni >>> --- >>> Changes in v2: >>> - cache mr beofre suspending >>> >>> drivers/watchdog/sama5d4_wdt.c | 32 ++++++++++++++++++++++++++++++++ >>> 1 file changed, 32 insertions(+) >>> >>> diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c >>> index 2a60251806d2..5ddeb4803dc3 100644 >>> --- a/drivers/watchdog/sama5d4_wdt.c >>> +++ b/drivers/watchdog/sama5d4_wdt.c >>> @@ -28,6 +28,7 @@ >>> struct sama5d4_wdt { >>> struct watchdog_device wdd; >>> void __iomem *reg_base; >>> + u32 mr; >> >> Makes me wonder if we shouldn't just retain the original 'config' >> (and maybe rename it to 'mr). After all, it _is_ used now. >> >>> }; >>> >>> static int wdt_timeout = WDT_DEFAULT_TIMEOUT; >>> @@ -248,11 +249,42 @@ static const struct of_device_id sama5d4_wdt_of_match[] = { >>> }; >>> MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match); >>> >>> +#ifdef CONFIG_PM_SLEEP >>> +static int sama5d4_wdt_suspend(struct device *dev) >>> +{ >>> + struct sama5d4_wdt *wdt = dev_get_drvdata(dev); >>> + >>> + wdt->mr = wdt_read(wdt, AT91_WDT_MR); >>> + >> >> Wouldn't you want to stop the watchdog here if it is running, >> ie set AT91_WDT_WDDIS ? >> > > Some existing customers want the watchdog to continue to run while the > system is suspended. > >>> + return 0; >>> +} >>> + >>> +static int sama5d4_wdt_resume(struct device *dev) >>> +{ >>> + struct sama5d4_wdt *wdt = dev_get_drvdata(dev); >>> + u32 reg; >>> + >>> + reg = wdt_read(wdt, AT91_WDT_MR); >>> + if (reg & AT91_WDT_WDDIS) >>> + wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS); >>> + >>> + wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); >> >> Is that necessary ? Why not just write wdt->mr unconditionally ? >> > > Because you can change WDV and WDD *OR* WDDIS but not both at the same > time. > Odd hardware ;-). Please add a comment explaining why the watchdog isn't stopped on suspend, and why the AT91_WDT_MR has to be reprogrammed on resume. Thanks, Guenter