From patchwork Mon May 9 17:43:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Scott Cheloha X-Patchwork-Id: 572044 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67B98C433F5 for ; Mon, 9 May 2022 17:45:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239767AbiEIRtD (ORCPT ); Mon, 9 May 2022 13:49:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239768AbiEIRtC (ORCPT ); Mon, 9 May 2022 13:49:02 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E763286FD4 for ; Mon, 9 May 2022 10:45:07 -0700 (PDT) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 249Gph8C008667; Mon, 9 May 2022 17:44:52 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=YJxjIg1FgYUMn/BysGr3B5xpD5ssCfgI/VGjDQ9drmU=; b=J3yDz88zmE3/bibY1SnSyw2uZbeo82sfq07a4etUEKu3G+fmMYicheKgOCyhdla1nI5M /L1zVpAgAExXonI8nHgUn97IU+VJd7HDIi+3c43KLQskh06bL8D8E84mjT/Ct11G/mJ3 Wq4PNfiDFNPO6HKiJS4ctKFcJAyNtfLAdbkyWJev22Vn/srV+NN/x7jRE/Qzaxs03GEA xcQ22oRdULjUvI9jWUtrj8swClDrrMH0PDHbVdw1XoPz3LpZZXIlTUY6QTLwrYSWDVIi rrGBU4PfI8Krq3wLE8NU4lViE9aFZTVPaw3QHYxlmpXPF3b5RHAyOj68rahZOON8E067 nA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3fy6ud8wnq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 May 2022 17:44:51 +0000 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 249H8Ws4011177; Mon, 9 May 2022 17:44:50 GMT Received: from ppma03wdc.us.ibm.com (ba.79.3fa9.ip4.static.sl-reverse.com [169.63.121.186]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3fy6ud8wnf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 May 2022 17:44:50 +0000 Received: from pps.filterd (ppma03wdc.us.ibm.com [127.0.0.1]) by ppma03wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 249Hgv23020655; Mon, 9 May 2022 17:44:49 GMT Received: from b03cxnp07028.gho.boulder.ibm.com (b03cxnp07028.gho.boulder.ibm.com [9.17.130.15]) by ppma03wdc.us.ibm.com with ESMTP id 3fwgd97rhe-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 May 2022 17:44:49 +0000 Received: from b03ledav001.gho.boulder.ibm.com (b03ledav001.gho.boulder.ibm.com [9.17.130.232]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 249HiloR31261134 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 May 2022 17:44:47 GMT Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 786156E052; Mon, 9 May 2022 17:44:47 +0000 (GMT) Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 56B5C6E050; Mon, 9 May 2022 17:44:47 +0000 (GMT) Received: from localhost (unknown [9.41.178.126]) by b03ledav001.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 9 May 2022 17:44:47 +0000 (GMT) From: Scott Cheloha To: linux-watchdog@vger.kernel.org Cc: linux@roeck-us.net, tzungbi@kernel.org, brking@linux.ibm.com, nathanl@linux.ibm.com, aik@ozlabs.ru, npiggin@gmail.com, vaishnavi@linux.ibm.com, wvoigt@us.ibm.com Subject: [RFC v2 0/2] Add driver for PAPR watchdog timers Date: Mon, 9 May 2022 12:43:55 -0500 Message-Id: <20220509174357.5448-1-cheloha@linux.ibm.com> X-Mailer: git-send-email 2.27.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: oMeLZEZjtktG0yMM7OdBodu1hXRf67NT X-Proofpoint-ORIG-GUID: wD_yg6UE4KxQlkbgZaIP1WbrZgS9kuAj X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-09_05,2022-05-09_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 bulkscore=0 priorityscore=1501 malwarescore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 impostorscore=0 spamscore=0 clxscore=1011 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205090092 Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org This second RFC incorporates feedback from the previous RFC: https://lore.kernel.org/linux-watchdog/20220413165104.179144-1-cheloha@linux.ibm.com/ v2 changes of note: - Add a firmware feature flag for the H_WATCHDOG feature, FW_FEATURE_WATCHDOG. - Register a platform_device for the first watchdog timer during a pseries initcall if we have FW_FEATURE_WATCHDOG. Use id zero, as there could be more than one timer in the future. - Alphabetize Makefile changes. - Add missing copyright information to pseries-wdt.c. - Add an 'action' module parameter that configures how the guest is terminated on watchdog expiration. - Use dev_*() for logging critical errors instead of pr_*(). - Handle the H_NOOP case when trying to stop the watchdog. If the given watchdog is not actually running, H_WATCHDOG returns H_NOOP. This is harmless, so we should treat it as a success. - We don't need pseries_wdt_remove() at all. - Check watchdog_active() before stopping/starting the timer across suspend/resume. - Consolidate all code from pseries_wdt_module_init() into pseries_wdt_probe(). We can then use module_platform_driver(). I have one lingering question: - The pseries-wdt module is not "automatically" loaded during boot. When I do # modprobe pseries-wdt the driver attaches to the platform bus as expected and the /dev/watchdog* devices for the pseries-wdt.0 platform device are created. I was under the impression that driver/device matching for the platform bus was simple string comparison. ... what am I doing wrong? Is this expected behavior? Do I need to do additional configuration to get the module to load automatically at boot time?