From patchwork Thu Oct 10 11:58:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Pratik R. Sampat" X-Patchwork-Id: 1174497 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46pqt014Ntz9sQy for ; Thu, 10 Oct 2019 23:20:24 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46pqsz51nNzDr4r for ; Thu, 10 Oct 2019 23:20:23 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46pqPG3FgpzDr4N for ; Thu, 10 Oct 2019 22:58:58 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) by bilbo.ozlabs.org (Postfix) with ESMTP id 46pqPF3RYkz8tL0 for ; Thu, 10 Oct 2019 22:58:57 +1100 (AEDT) Received: by ozlabs.org (Postfix) id 46pqPF2Y89z9sPd; Thu, 10 Oct 2019 22:58:57 +1100 (AEDT) Delivered-To: linuxppc-dev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=psampat@linux.ibm.com; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46pqPD5syJz9sPc for ; Thu, 10 Oct 2019 22:58:56 +1100 (AEDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x9A9cqqd049599 for ; Thu, 10 Oct 2019 07:58:53 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vj26km305-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 10 Oct 2019 07:58:53 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 10 Oct 2019 12:58:48 +0100 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x9ABwlak60293172 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 10 Oct 2019 11:58:47 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EA9BE42042; Thu, 10 Oct 2019 11:58:46 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0143742049; Thu, 10 Oct 2019 11:58:45 +0000 (GMT) Received: from pratiks-thinkpad.ibmuc.com (unknown [9.199.37.96]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 10 Oct 2019 11:58:44 +0000 (GMT) From: Pratik Rajesh Sampat To: linuxppc-dev@ozlabs.org, linux-next@vger.kernel.org, mpe@ellerman.id.au, svaidy@linux.ibm.com, ego@linux.vnet.ibm.com, premjha2@in.ibm.com, akshay.adiga@linux.vnet.ibm.com Subject: [PATCH v1 0/3] Integrate support for Self save, determine support and preference for self save or restore Date: Thu, 10 Oct 2019 17:28:40 +0530 X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19101011-0020-0000-0000-00000377D896 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19101011-0021-0000-0000-000021CDE4A8 Message-Id: <20191010115843.22283-1-psampat@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-10-10_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=657 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910100084 X-Mailman-Approved-At: Thu, 10 Oct 2019 23:17:34 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Currently the stop-api supports a mechanism called as self-restore which allows us to restore the values of certain SPRs on wakeup from a deep-stop state to a desired value. To use this, the Kernel makes an OPAL call passing the PIR of the CPU, the SPR number and the value to which the SPR should be restored when that CPU wakes up from a deep stop state. Recently, a new feature, named self-save has been enabled in the stop-api, which is an alternative mechanism to do the same, except that self-save will save the current content of the SPR before entering a deep stop state and also restore the content back on waking up from a deep stop state. This patch series aims at introducing and leveraging the self-save feature in the kernel. Now, as the kernel has a choice to prefer one mode over the other and there can be registers in both the save/restore SPR list which are sent from the device tree, a new interface has been defined for the seamless handing of the modes for each SPR. A list of preferred SPRs are maintained in the kernel which contains two properties: 1. supported_mode: Helps in identifying if it strictly supports self save or restore or both. 2. preferred_mode: Calls out what mode is preferred for each SPR. It could be strictly self save or restore, or it can also determine the preference of mode over the other if both are present by encapsulating the other in bitmask from LSB to MSB. Below is a table to show the Scenario::Consequence when the self save and self restore modes are available or disabled in different combinations as perceived from the device tree. SR = Self restore; SS = Self save .-----------------------------------.----------------------------------------. | Scenario | Consequence | :-----------------------------------+----------------------------------------: | Legacy Firmware. No SS or SR node | Self restore is called for all | | | supported SPRs | :-----------------------------------+----------------------------------------: | SR: !active SS: !active | Deep stop states disabled | :-----------------------------------+----------------------------------------: | SR: active SS: !active | Self restore is called for all | | | supported SPRs | :-----------------------------------+----------------------------------------: | SR: active SS: active | Goes through the preferences for each | | | SPR and executes of the modes | | | accordingly. Currently, Self restore is| | | called for all the SPRs except PSSCR | | | which is self saved | :-----------------------------------+----------------------------------------: | SR: active(only HID0) SS: active | Self save called for all supported | | | registers expect HID0 (as HID0 cannot | | | be self saved currently) | :-----------------------------------+----------------------------------------: | SR: !active SS: active | currently will disable deep states as | | | HID0 is needed to be self restored and | | | cannot be self saved | '-----------------------------------'----------------------------------------' Pratik Rajesh Sampat (3): powerpc/powernv: Interface to define support and preference for a SPR powerpc/powernv: Introduce Self save support powerpc/powernv: Parse device tree, population of SPR support arch/powerpc/include/asm/opal-api.h | 3 +- arch/powerpc/include/asm/opal.h | 1 + arch/powerpc/platforms/powernv/idle.c | 404 ++++++++++++++++++--- arch/powerpc/platforms/powernv/opal-call.c | 1 + 4 files changed, 357 insertions(+), 52 deletions(-)