From: Ray Jui <ray.jui@broadcom.com> To: Robin Murphy <robin.murphy@arm.com>, Scott Branden <scott.branden@broadcom.com>, Guenter Roeck <linux@roeck-us.net> Cc: Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org, linux-watchdog@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>, bcm-kernel-feedback-list@broadcom.com, Wim Van Sebroeck <wim@linux-watchdog.org>, Frank Rowand <frowand.list@gmail.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate Date: Wed, 23 May 2018 09:29:23 -0700 [thread overview] Message-ID: <5a996888-d3d3-9ae6-e438-5de4d5e3ea32@broadcom.com> (raw) In-Reply-To: <76d47e02-7a5f-3fc2-3905-cd4aa03ac69c@arm.com> Hi Robin, On 5/23/2018 4:48 AM, Robin Murphy wrote: > On 23/05/18 08:52, Scott Branden wrote: >> >> >> On 18-05-22 04:24 PM, Ray Jui wrote: >>> Hi Guenter, >>> >>> On 5/22/2018 1:54 PM, Guenter Roeck wrote: >>>> On Tue, May 22, 2018 at 11:47:18AM -0700, Ray Jui wrote: >>>>> If the watchdog hardware is already enabled during the boot process, >>>>> when the Linux watchdog driver loads, it should reset the watchdog and >>>>> tell the watchdog framework. As a result, ping can be generated from >>>>> the watchdog framework, until the userspace watchdog daemon takes over >>>>> control >>>>> >>>>> Signed-off-by: Ray Jui <ray.jui@broadcom.com> >>>>> Reviewed-by: Vladimir Olovyannikov >>>>> <vladimir.olovyannikov@broadcom.com> >>>>> Reviewed-by: Scott Branden <scott.branden@broadcom.com> >>>>> --- >>>>> drivers/watchdog/sp805_wdt.c | 22 ++++++++++++++++++++++ >>>>> 1 file changed, 22 insertions(+) >>>>> >>>>> diff --git a/drivers/watchdog/sp805_wdt.c >>>>> b/drivers/watchdog/sp805_wdt.c >>>>> index 1484609..408ffbe 100644 >>>>> --- a/drivers/watchdog/sp805_wdt.c >>>>> +++ b/drivers/watchdog/sp805_wdt.c >>>>> @@ -42,6 +42,7 @@ >>>>> /* control register masks */ >>>>> #define INT_ENABLE (1 << 0) >>>>> #define RESET_ENABLE (1 << 1) >>>>> + #define ENABLE_MASK (INT_ENABLE | RESET_ENABLE) >>>>> #define WDTINTCLR 0x00C >>>>> #define WDTRIS 0x010 >>>>> #define WDTMIS 0x014 >>>>> @@ -74,6 +75,18 @@ module_param(nowayout, bool, 0); >>>>> MODULE_PARM_DESC(nowayout, >>>>> "Set to 1 to keep watchdog running after device release"); >>>>> +/* returns true if wdt is running; otherwise returns false */ >>>>> +static bool wdt_is_running(struct watchdog_device *wdd) >>>>> +{ >>>>> + struct sp805_wdt *wdt = watchdog_get_drvdata(wdd); >>>>> + >>>>> + if ((readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK) == >>>>> + ENABLE_MASK) >>>>> + return true; >>>>> + else >>>>> + return false; >>>> >>>> return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK)); >>>> >>> >>> Note ENABLE_MASK contains two bits (INT_ENABLE and RESET_ENABLE); >>> therefore, a simple !!(expression) would not work? That is, the >>> masked result needs to be compared against the mask again to ensure >>> both bits are set, right? >> Ray - your original code looks correct to me. Easier to read and less >> prone to errors as shown in the attempted translation to a single >> statement. > > if (<boolean condition>) > return true; > else > return false; > > still looks really dumb, though, and IMO is actually harder to read than > just "return <boolean condition>;" because it forces you to stop and > double-check that the logic is, in fact, only doing the obvious thing. If you can propose a way to modify my original code above to make it more readable, I'm fine to make the change. As I mentioned, I don't think the following change proposed by Guenter will work due to the reason I pointed out: return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK)); > > Robin. > > > > p.s. No thanks for making me remember the mind-boggling horror of > briefly maintaining part of this legacy codebase... :P > > $ grep -r '? true : false' --include=*.cpp . | wc -l > 951
WARNING: multiple messages have this Message-ID (diff)
From: ray.jui@broadcom.com (Ray Jui) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate Date: Wed, 23 May 2018 09:29:23 -0700 [thread overview] Message-ID: <5a996888-d3d3-9ae6-e438-5de4d5e3ea32@broadcom.com> (raw) In-Reply-To: <76d47e02-7a5f-3fc2-3905-cd4aa03ac69c@arm.com> Hi Robin, On 5/23/2018 4:48 AM, Robin Murphy wrote: > On 23/05/18 08:52, Scott Branden wrote: >> >> >> On 18-05-22 04:24 PM, Ray Jui wrote: >>> Hi Guenter, >>> >>> On 5/22/2018 1:54 PM, Guenter Roeck wrote: >>>> On Tue, May 22, 2018 at 11:47:18AM -0700, Ray Jui wrote: >>>>> If the watchdog hardware is already enabled during the boot process, >>>>> when the Linux watchdog driver loads, it should reset the watchdog and >>>>> tell the watchdog framework. As a result, ping can be generated from >>>>> the watchdog framework, until the userspace watchdog daemon takes over >>>>> control >>>>> >>>>> Signed-off-by: Ray Jui <ray.jui@broadcom.com> >>>>> Reviewed-by: Vladimir Olovyannikov >>>>> <vladimir.olovyannikov@broadcom.com> >>>>> Reviewed-by: Scott Branden <scott.branden@broadcom.com> >>>>> --- >>>>> ? drivers/watchdog/sp805_wdt.c | 22 ++++++++++++++++++++++ >>>>> ? 1 file changed, 22 insertions(+) >>>>> >>>>> diff --git a/drivers/watchdog/sp805_wdt.c >>>>> b/drivers/watchdog/sp805_wdt.c >>>>> index 1484609..408ffbe 100644 >>>>> --- a/drivers/watchdog/sp805_wdt.c >>>>> +++ b/drivers/watchdog/sp805_wdt.c >>>>> @@ -42,6 +42,7 @@ >>>>> ????? /* control register masks */ >>>>> ????? #define??? INT_ENABLE??? (1 << 0) >>>>> ????? #define??? RESET_ENABLE??? (1 << 1) >>>>> +??? #define??? ENABLE_MASK??? (INT_ENABLE | RESET_ENABLE) >>>>> ? #define WDTINTCLR??????? 0x00C >>>>> ? #define WDTRIS??????????? 0x010 >>>>> ? #define WDTMIS??????????? 0x014 >>>>> @@ -74,6 +75,18 @@ module_param(nowayout, bool, 0); >>>>> ? MODULE_PARM_DESC(nowayout, >>>>> ????????? "Set to 1 to keep watchdog running after device release"); >>>>> ? +/* returns true if wdt is running; otherwise returns false */ >>>>> +static bool wdt_is_running(struct watchdog_device *wdd) >>>>> +{ >>>>> +??? struct sp805_wdt *wdt = watchdog_get_drvdata(wdd); >>>>> + >>>>> +??? if ((readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK) == >>>>> +??????? ENABLE_MASK) >>>>> +??????? return true; >>>>> +??? else >>>>> +??????? return false; >>>> >>>> ????return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK)); >>>> >>> >>> Note ENABLE_MASK contains two bits (INT_ENABLE and RESET_ENABLE); >>> therefore, a simple !!(expression) would not work? That is, the >>> masked result needs to be compared against the mask again to ensure >>> both bits are set, right? >> Ray - your original code looks correct to me.? Easier to read and less >> prone to errors as shown in the attempted translation to a single >> statement. > > ????if (<boolean condition>) > ??????? return true; > ????else > ??????? return false; > > still looks really dumb, though, and IMO is actually harder to read than > just "return <boolean condition>;" because it forces you to stop and > double-check that the logic is, in fact, only doing the obvious thing. If you can propose a way to modify my original code above to make it more readable, I'm fine to make the change. As I mentioned, I don't think the following change proposed by Guenter will work due to the reason I pointed out: return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK)); > > Robin. > > > > p.s. No thanks for making me remember the mind-boggling horror of > briefly maintaining part of this legacy codebase... :P > > $ grep -r '? true : false' --include=*.cpp . | wc -l > 951
next prev parent reply other threads:[~2018-05-23 16:29 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-22 18:47 [PATCH 0/5] Enhance support for the SP805 WDT Ray Jui 2018-05-22 18:47 ` Ray Jui 2018-05-22 18:47 ` [PATCH 1/5] Documentation: DT: Add optional 'timeout-sec' property for sp805 Ray Jui 2018-05-22 18:47 ` Ray Jui 2018-05-22 20:56 ` Guenter Roeck 2018-05-22 20:56 ` Guenter Roeck 2018-05-23 10:57 ` Robin Murphy 2018-05-23 10:57 ` Robin Murphy 2018-05-23 16:25 ` Ray Jui 2018-05-23 16:25 ` Ray Jui 2018-05-23 18:59 ` Rob Herring 2018-05-23 18:59 ` Rob Herring 2018-05-23 19:29 ` Ray Jui 2018-05-23 19:29 ` Ray Jui 2018-05-24 13:52 ` Robin Murphy 2018-05-24 13:52 ` Robin Murphy 2018-05-23 18:10 ` Guenter Roeck 2018-05-23 18:10 ` Guenter Roeck 2018-05-24 13:25 ` Robin Murphy 2018-05-24 13:25 ` Robin Murphy 2018-05-24 16:07 ` Guenter Roeck 2018-05-24 16:07 ` Guenter Roeck 2018-05-22 18:47 ` [PATCH 2/5] watchdog: sp805: add 'timeout-sec' DT property support Ray Jui 2018-05-22 18:47 ` Ray Jui 2018-05-22 20:57 ` Guenter Roeck 2018-05-22 20:57 ` Guenter Roeck 2018-05-22 18:47 ` [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate Ray Jui 2018-05-22 18:47 ` Ray Jui 2018-05-22 20:54 ` Guenter Roeck 2018-05-22 20:54 ` Guenter Roeck 2018-05-22 23:24 ` Ray Jui 2018-05-22 23:24 ` Ray Jui 2018-05-23 7:52 ` Scott Branden 2018-05-23 7:52 ` Scott Branden 2018-05-23 11:48 ` Robin Murphy 2018-05-23 11:48 ` Robin Murphy 2018-05-23 16:29 ` Ray Jui [this message] 2018-05-23 16:29 ` Ray Jui 2018-05-23 17:15 ` Robin Murphy 2018-05-23 17:15 ` Robin Murphy 2018-05-23 18:09 ` Guenter Roeck 2018-05-23 18:09 ` Guenter Roeck 2018-05-23 19:35 ` Ray Jui 2018-05-23 19:35 ` Ray Jui 2018-05-23 17:15 ` Scott Branden 2018-05-23 17:15 ` Scott Branden 2018-05-23 18:06 ` Guenter Roeck 2018-05-23 18:06 ` Guenter Roeck 2018-05-22 18:47 ` [PATCH 4/5] arm64: dt: set initial SR watchdog timeout to 60 seconds Ray Jui 2018-05-22 18:47 ` Ray Jui 2018-05-22 18:47 ` [PATCH 5/5] arm64: defconfig: add CONFIG_ARM_SP805_WATCHDOG Ray Jui 2018-05-22 18:47 ` Ray Jui
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