From patchwork Sat Sep 19 00:52:06 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 7221511 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1CDBC9F372 for ; Sat, 19 Sep 2015 00:55:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 16693209A9 for ; Sat, 19 Sep 2015 00:55:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 17C6A209A5 for ; Sat, 19 Sep 2015 00:55:05 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zd6OX-00026T-5Y; Sat, 19 Sep 2015 00:52:49 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zd6OG-00020Y-IJ for linux-arm-kernel@lists.infradead.org; Sat, 19 Sep 2015 00:52:34 +0000 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 1031713FB4F; Sat, 19 Sep 2015 00:52:13 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id E805513FB51; Sat, 19 Sep 2015 00:52:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from sboyd-linux.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: sboyd@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 813B013FB48; Sat, 19 Sep 2015 00:52:11 +0000 (UTC) From: Stephen Boyd To: linux-arm-msm@vger.kernel.org Subject: [PATCH v2 2/5] PM / OPP: Support adjusting OPP voltages at runtime Date: Fri, 18 Sep 2015 17:52:06 -0700 Message-Id: <1442623929-4507-3-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 2.6.0.rc2.11.g3da0120 In-Reply-To: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org> References: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150918_175232_721844_7B144330 X-CRM114-Status: GOOD ( 20.12 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nishanth Menon , David Collins , linux-pm@vger.kernel.org, Viresh Kumar , linux-kernel@vger.kernel.org, Mark Brown , Srinivas Kandagatla , Andy Gross , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On some SoCs the Adaptive Voltage Scaling (AVS) technique is employed to optimize the operating voltage of a device. At a given frequency, the hardware monitors dynamic factors and either makes a suggestion for how much to adjust a voltage for the current frequency, or it automatically adjusts the voltage without software intervention. Add an API to the OPP library for the former case, so that AVS type devices can update the voltages for an OPP when the hardware determines the voltage should change. The assumption is that drivers like CPUfreq or devfreq will register for the OPP notifiers and adjust the voltage according to suggestions that AVS makes. Cc: Nishanth Menon Acked-by: Viresh Kumar Signed-off-by: Stephen Boyd Acked-by: Viresh Kumar --- drivers/base/power/opp.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/pm_opp.h | 11 +++++++ 2 files changed, 88 insertions(+) diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index 28cd75c535b0..35b66c46dcb7 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -1136,6 +1136,83 @@ unlock: } /** + * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP + * @dev: device for which we do this operation + * @freq: OPP frequency to adjust voltage of + * @u_volt: new OPP voltage + * + * Change the voltage of an OPP with an RCU operation. + * + * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the + * copy operation, returns 0 if no modifcation was done OR modification was + * successful. + * + * Locking: The internal device_opp and opp structures are RCU protected. + * Hence this function internally uses RCU updater strategy with mutex locks to + * keep the integrity of the internal data structures. Callers should ensure + * that this function is *NOT* called under RCU protection or in contexts where + * mutex locking or synchronize_rcu() blocking calls cannot be used. + */ +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, + unsigned long u_volt) +{ + struct device_opp *dev_opp; + struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV); + int r = 0; + + /* keep the node allocated */ + new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL); + if (!new_opp) + return -ENOMEM; + + mutex_lock(&dev_opp_list_lock); + + /* Find the device_opp */ + dev_opp = _find_device_opp(dev); + if (IS_ERR(dev_opp)) { + r = PTR_ERR(dev_opp); + dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); + goto unlock; + } + + /* Do we have the frequency? */ + list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) { + if (tmp_opp->rate == freq) { + opp = tmp_opp; + break; + } + } + if (IS_ERR(opp)) { + r = PTR_ERR(opp); + goto unlock; + } + + /* Is update really needed? */ + if (opp->u_volt == u_volt) + goto unlock; + /* copy the old data over */ + *new_opp = *opp; + + /* plug in new node */ + new_opp->u_volt = u_volt; + + list_replace_rcu(&opp->node, &new_opp->node); + mutex_unlock(&dev_opp_list_lock); + call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu); + + /* Notify the change of the OPP */ + srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADJUST_VOLTAGE, + new_opp); + + return 0; + +unlock: + mutex_unlock(&dev_opp_list_lock); + kfree(new_opp); + return r; +} + +/** * dev_pm_opp_enable() - Enable a specific OPP * @dev: device for which we do this operation * @freq: OPP frequency to enable diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h index e817722ee3f0..f7a4a2245f53 100644 --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -22,6 +22,7 @@ struct device; enum dev_pm_opp_event { OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE, + OPP_EVENT_ADJUST_VOLTAGE, }; #if defined(CONFIG_PM_OPP) @@ -50,6 +51,9 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt); void dev_pm_opp_remove(struct device *dev, unsigned long freq); +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, + unsigned long u_volt); + int dev_pm_opp_enable(struct device *dev, unsigned long freq); int dev_pm_opp_disable(struct device *dev, unsigned long freq); @@ -114,6 +118,13 @@ static inline void dev_pm_opp_remove(struct device *dev, unsigned long freq) { } +static inline int +dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, + unsigned long u_volt) +{ + return 0; +} + static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq) { return 0;