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Wed, 2 Dec 2020 17:12:43 +0000 Received: from DM6PR11MB4250.namprd11.prod.outlook.com ([fe80::b90d:d053:9de6:e5ef]) by DM6PR11MB4250.namprd11.prod.outlook.com ([fe80::b90d:d053:9de6:e5ef%4]) with mapi id 15.20.3611.025; Wed, 2 Dec 2020 17:12:43 +0000 From: "Ayyathurai, Vijayakannan" To: Guenter Roeck CC: "wim@linux-watchdog.org" , "robh+dt@kernel.org" , "linux-watchdog@vger.kernel.org" , "devicetree@vger.kernel.org" , "andriy.shevchenko@linux.intel.com" , "mgross@linux.intel.com" , "Wan Mohamad, Wan Ahmad Zainie" , "Raja Subramanian, Lakshmi Bai" Subject: RE: [PATCH v3 1/2] watchdog: Add watchdog driver for Intel Keembay Soc Thread-Topic: [PATCH v3 1/2] watchdog: Add watchdog driver for Intel Keembay Soc Thread-Index: AQHWx/CMDVzq6Upyk0GVGIKivB/BZanibsAAgAFtX+CAACV+AIAACNCw Date: Wed, 2 Dec 2020 17:12:43 +0000 Message-ID: References: <20201201163044.GA89174@roeck-us.net> <20201202163238.GA215023@roeck-us.net> In-Reply-To: <20201202163238.GA215023@roeck-us.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-reaction: no-action dlp-version: 11.5.1.3 authentication-results: roeck-us.net; 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x-ms-exchange-antispam-messagedata: =?us-ascii?Q?npqNjDGBwVuvEsjljzdUFw1voYWZ4uJ59Zk3+Epqy/UujRzXtOa6xnZtOrKL?= =?us-ascii?Q?ULXvsYSs/txZwWWeTphDekVBXXICJpWQlTS4hzZW3aINVSx4DajGh1JgaYYV?= =?us-ascii?Q?dgB2OSvFWvteghsCShmugPsd0VhWaM1AK0OaKQoOX5+DsxCfG2EFOS3Z54pg?= =?us-ascii?Q?kxJp9INgXerPlD2GpPdpZTkN6GbtaXgKyRoOn86PrHJ/Kj87XljNVIBeTvGf?= =?us-ascii?Q?IQxX28gpZPp1SMW/TAmjLgj8GjVyZm2XVcZqDoFRbxALgmt2OiFXes4Xxazc?= =?us-ascii?Q?nEyW07dDKdVi1jn62KJAmLLT66KZpQvYpfd3WWd09VLA14h9lY0vAzSPKVSA?= =?us-ascii?Q?0g/cUinCki2mOwAsWt14mi207hkN/Ync9xxtDr3tqinX/V3zJIKquBOkDDw0?= =?us-ascii?Q?lDjbRe0qmwE3LWm2mt2c4Ke+iaDrMRfjWxELnxkpFwljxrTuh8u0dOcHHg+g?= =?us-ascii?Q?RPC8HKYhe4s1qMYEQqJAjkUgWhZatpyIhHJtOPVSTiy8ZOjJXkNh6qH5YaZw?= =?us-ascii?Q?dvXzs241+a5je0aj3yCYS66N8RkTXdIPLEe9bn2ksJKF7BBrQNS/d3sRUYaW?= =?us-ascii?Q?x+20ckUqjlcV9et9HAUc/iKIRyN8P692kkU+7FMQ3EsJ48QwP0wjcPQUqu3Q?= =?us-ascii?Q?2zy0LVyX+wq+aY+PYPMZtwdiqFLcc64up71ME+c5S+rtvCgkKlSgNVOAaNz4?= =?us-ascii?Q?7r27SAaY9S9kB01Be8wDBpug2spZ5H87gTm6Z1IfjfU8+TQMyXqMoNSsgF1H?= =?us-ascii?Q?CoOE1oYJ7LBbDC5zFnw+DZCqD+nXu4eGvh6qFyldJILv9xX7N1cvvCgHBAIf?= =?us-ascii?Q?gOcr2G7YpRLHi87Ubt3aZqmsE3y/M6Lh8yF2TOwivbO5Rou+f5wDLF8l+F/w?= =?us-ascii?Q?jPtDkqjhqjFRp8dxlmDeBMI7GG5sNcxeOg8v22kYli8O3hf1O3M42fAJYNGu?= =?us-ascii?Q?ExJjsI8Tm3z82cvbu6Sp6uEKUgGce91YWZZvbw/92GU=3D?= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM6PR11MB4250.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: e6661c78-3aef-4468-275c-08d896e57b80 X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Dec 2020 17:12:43.5689 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: S1cZgEg9+cTAXd1vBpZ6cX4d1Zg+MxDU8sI0SJOUdmdsrooeUo2emjQ4jxOt+H56gmBRPoFEEkbx3sqaWvn+YzV/NzsvqeES9ZlGLuj1JPjpR6tZfm32fds647HFbvz/ X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR11MB3579 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Hi Guenter, > From: Guenter Roeck >=20 > On Wed, Dec 02, 2020 at 02:55:32PM +0000, Ayyathurai, Vijayakannan wrote: > > > > > From: Guenter Roeck > > > Sent: Wednesday, 2 December, 2020 12:31 AM > > > > > > On Tue, Dec 01, 2020 at 11:10:33PM +0800, > > > > From: Vijayakannan Ayyathurai > > > > > > > > > > > > +static void keembay_wdt_set_timeout_reg(struct watchdog_device > *wdog, > > > bool ping) > > > > +{ > > > > + struct keembay_wdt *wdt =3D watchdog_get_drvdata(wdog); > > > > + u32 th_val =3D 0; > > > > + > > > > + if (!ping && wdog->pretimeout) { > > > > + th_val =3D wdog->timeout - wdog->pretimeout; > > > > + keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val > > > * wdt->rate); > > > > > > Sorry for annoying you now, but I may have found another potential > problem. > > > > > > What happens if the user sets a pretimeout, then removes it ? > > > What should TIM_WATCHDOG_INT_THRES be set to in that case ? > > > Right now TIM_WATCHDOG_INT_THRES won't be updated anymore > > > > It is a good catch. Indeed, I don't have coverage like this. > > > > > in that case, which seems wrong. This might get worse with > > > the following sequence. > > > > > > - set pretimeout > > > - clear pretimeout > > > - set timeout to some other value > > > > > > > Can the below method resolve this issue? > > > > > > static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 > t) > > { > > struct keembay_wdt *wdt =3D watchdog_get_drvdata(wdog); > > > > if(!t) > > keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, 0); > > >=20 > Partially, only it makes for awkward code. After all, it is never really > necessary to set the timeout register after updating the pretimeout. > The "ping" parameter makes less and less sense with this in mind. Yes. > It might be better to split the set_timeout_reg function into > set_timeout_reg and set_pretimeout_reg and call those functions as needed > (and handle the if() above in the set_pretimeout_reg function). >=20 Ok. Thanks for your suggestion. Let me incorporate necessary changes in the next version. > Thanks, > Guenter > Thanks, Vijay