From patchwork Mon Jul 21 16:06:21 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenzo Pieralisi X-Patchwork-Id: 4597241 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DD92BC0514 for ; Mon, 21 Jul 2014 16:06:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CE086200FE for ; Mon, 21 Jul 2014 16:06:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACC4D2013D for ; Mon, 21 Jul 2014 16:06:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932667AbaGUQGr (ORCPT ); Mon, 21 Jul 2014 12:06:47 -0400 Received: from service87.mimecast.com ([91.220.42.44]:41598 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932793AbaGUQGl (ORCPT ); Mon, 21 Jul 2014 12:06:41 -0400 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Mon, 21 Jul 2014 17:06:39 +0100 Received: from red-moon.cambridge.arm.com ([10.1.255.212]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Mon, 21 Jul 2014 17:06:36 +0100 From: Lorenzo Pieralisi To: linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org Cc: devicetree@vger.kernel.org, Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Catalin Marinas , Charles Garcia Tobin , Nicolas Pitre , Rob Herring , Grant Likely , Peter De Schrijver , Santosh Shilimkar , Daniel Lezcano , Amit Kucheria , Vincent Guittot , Antti Miettinen , Stephen Boyd , Kevin Hilman , Sebastian Capella , Tomasz Figa , Mark Brown , Paul Walmsley , Chander Kashyap , Geoff Levand , Bartlomiej Zolnierkiewicz Subject: [PATCH v6 2/7] drivers: cpuidle: implement DT based idle states infrastructure Date: Mon, 21 Jul 2014 17:06:21 +0100 Message-Id: <1405958786-17243-3-git-send-email-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1405958786-17243-1-git-send-email-lorenzo.pieralisi@arm.com> References: <1405958786-17243-1-git-send-email-lorenzo.pieralisi@arm.com> X-OriginalArrivalTime: 21 Jul 2014 16:06:36.0477 (UTC) FILETIME=[BF9296D0:01CFA4FD] X-MC-Unique: 114072117063912501 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On most common ARM systems, the low-power states a CPU can be put into are not discoverable in HW and require device tree bindings to describe power down suspend operations and idle states parameters. In order to enable DT based idle states and configure idle drivers, this patch implements the bulk infrastructure required to parse the device tree idle states bindings and initialize the corresponding CPUidle driver states data. The parsing API accepts a start index that defines the first idle state that should be initialized by the parsing code in order to give new and legacy driver flexibility over which states should be parsed using the new DT mechanism. The idle states list is obtained from the first cpu in the driver cpumask, which implicitly means the parsing code expects idle states (and related list of phandles) to be the same for all CPUs in the CPUidle driver mask. The kernel does not check this assumption, it must be enforced by the bootloader to ensure correct system behaviour. Signed-off-by: Lorenzo Pieralisi --- drivers/cpuidle/Kconfig | 8 +++ drivers/cpuidle/Makefile | 1 + drivers/cpuidle/dt_idle_states.c | 138 +++++++++++++++++++++++++++++++++++++++ drivers/cpuidle/dt_idle_states.h | 5 ++ 4 files changed, 152 insertions(+) create mode 100644 drivers/cpuidle/dt_idle_states.c create mode 100644 drivers/cpuidle/dt_idle_states.h diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index 1b96fb9..414e7a96 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -30,6 +30,14 @@ config CPU_IDLE_GOV_MENU bool "Menu governor (for tickless system)" default y +config DT_IDLE_STATES + bool "Idle states DT support" + depends on ARM || ARM64 + help + Allows the CPU idle framework to initialize CPU idle drivers + state data by using DT provided nodes compliant with idle states + device tree bindings. + menu "ARM CPU Idle Drivers" depends on ARM source "drivers/cpuidle/Kconfig.arm" diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index d8bb1ff..b27a062 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -4,6 +4,7 @@ obj-y += cpuidle.o driver.o governor.o sysfs.o governors/ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o +obj-$(CONFIG_DT_IDLE_STATES) += dt_idle_states.o ################################################################################## # ARM SoC drivers diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c new file mode 100644 index 0000000..5413132 --- /dev/null +++ b/drivers/cpuidle/dt_idle_states.c @@ -0,0 +1,138 @@ +/* + * DT idle states parsing code. + * + * Copyright (C) 2014 ARM Ltd. + * Author: Lorenzo Pieralisi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#define pr_fmt(fmt) "DT idle-states: " fmt + +#include +#include +#include +#include +#include +#include +#include + +#include "dt_idle_states.h" + +static int init_state_node(struct cpuidle_state *idle_state, + struct device_node *state_node) +{ + int err; + + err = of_property_read_u32(state_node, "wakeup-latency-us", + &idle_state->exit_latency); + if (err) { + u32 entry_latency, exit_latency; + + err = of_property_read_u32(state_node, "entry-latency-us", + &entry_latency); + if (err) { + pr_debug(" * %s missing entry-latency-us property\n", + state_node->full_name); + return -EINVAL; + } + + err = of_property_read_u32(state_node, "exit-latency-us", + &exit_latency); + if (err) { + pr_debug(" * %s missing exit-latency-us property\n", + state_node->full_name); + return -EINVAL; + } + /* + * If wakeup-latency-us is missing, default to entry+exit + * latencies as defined in idle states bindings + */ + idle_state->exit_latency = entry_latency + exit_latency; + } + + err = of_property_read_u32(state_node, "min-residency-us", + &idle_state->target_residency); + if (err) { + pr_debug(" * %s missing min-residency-us property\n", + state_node->full_name); + return -EINVAL; + } + + idle_state->flags = CPUIDLE_FLAG_TIME_VALID; + if (of_property_read_bool(state_node, "local-timer-stop")) + idle_state->flags |= CPUIDLE_FLAG_TIMER_STOP; + /* + * TODO: + * replace with kstrdup and pointer assignment when name + * and desc become string pointers + */ + strncpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN - 1); + strncpy(idle_state->desc, state_node->name, CPUIDLE_DESC_LEN - 1); + return 0; +} + +/** + * dt_init_idle_driver() - Parse the DT idle states and initialize the + * idle driver states array + * + * @drv: Pointer to CPU idle driver to be initialized + * @start_idx: First idle state index to be initialized + * + * On success the states array in the cpuidle driver contains + * initialized entries in the states array, starting from index start_idx. + * + * Return: + * 0 on success + * <0 on failure + */ +int dt_init_idle_driver(struct cpuidle_driver *drv, unsigned int start_idx) +{ + unsigned int i, state_idx = start_idx; + struct cpuidle_state *idle_state; + struct device_node *state_node, *cpu_node; + + + if (state_idx >= CPUIDLE_STATE_MAX) + return -EINVAL; + /* + * We get the idle states for the first logical cpu in the + * driver mask. The kernel does not check idle states on all + * cpus in the driver mask, they are assumed to be the same + * by default. + */ + cpu_node = of_cpu_device_node_get(cpumask_first(drv->cpumask)); + + for (i = 0; ; i++) { + int err; + + state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); + if (!state_node) + break; + + if (state_idx == CPUIDLE_STATE_MAX) { + pr_warn("State index reached static CPU idle driver states array size\n"); + break; + } + + idle_state = &drv->states[state_idx++]; + err = init_state_node(idle_state, state_node); + if (err) + return err; + } + + /* + * If no idle states are detected, return an error and let the idle + * driver initialization fail accordingly since initializing a driver + * with simple WFI as an idle state is equivalent to letting the + * kernel run the default idle loop. + */ + if (!i) + return -ENODATA; + + drv->state_count = state_idx; + return 0; +} +EXPORT_SYMBOL_GPL(dt_init_idle_driver); diff --git a/drivers/cpuidle/dt_idle_states.h b/drivers/cpuidle/dt_idle_states.h new file mode 100644 index 0000000..728c37c --- /dev/null +++ b/drivers/cpuidle/dt_idle_states.h @@ -0,0 +1,5 @@ +#ifndef __DT_IDLE_STATES +#define __DT_IDLE_STATES + +int dt_init_idle_driver(struct cpuidle_driver *drv, unsigned int start_idx); +#endif