From patchwork Wed Aug 15 10:02:43 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean Pihet X-Patchwork-Id: 1325081 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 08956DFFED for ; Wed, 15 Aug 2012 10:03:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752769Ab2HOKDP (ORCPT ); Wed, 15 Aug 2012 06:03:15 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:37506 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752091Ab2HOKDO (ORCPT ); Wed, 15 Aug 2012 06:03:14 -0400 Received: by weyx8 with SMTP id x8so884296wey.19 for ; Wed, 15 Aug 2012 03:03:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references :x-gm-message-state; bh=qXKzuPLojjJmgKsIpQfNIRvbXrqVRcuK8Ux1O5HGCj8=; b=IotkNn36mlyPkIWjln4bxOwwtlTvWYdX/xGwKaMC77LdTZcHukeT8LNWftaCiyKUzn Qqzy+3t/uLCkCjEZEOSXllfnJcqBMeABfOl56xhHgN5+PqSsbrhR+hpTW/rUGXSn9J/9 k6Y4KA4CQoYGhOVCIWcBLzlmowYfUk1qJJKsQD9X2F3adbiZ4lwsb0KNVdaWuLxdQ0i5 UUjIFRTLC+nVNaWqhkFYG26KBRfF1IGmG5ek9OXeU+PMcc1MZRM/LVGGJwKBy6x79NYS DaGjtQAhaSK8cBM3qO87hK/ZznBMXupzspm2uT2ojXGq+CdINWhAq2C1Ru8qgajTvKaH FOBA== Received: by 10.216.241.198 with SMTP id g48mr9375697wer.156.1345024993006; Wed, 15 Aug 2012 03:03:13 -0700 (PDT) Received: from localhost.localdomain (49.68-66-87.adsl-dyn.isp.belgacom.be. [87.66.68.49]) by mx.google.com with ESMTPS id q4sm27679093wix.9.2012.08.15.03.03.12 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 15 Aug 2012 03:03:12 -0700 (PDT) From: Jean Pihet To: linux-omap@vger.kernel.org, paul@pwsan.com, linux-arm-kernel@lists.infradead.org, khilman@ti.com, Rajendra Nayak , Santosh Shilimkar , Nishanth Menon Cc: Jean Pihet Subject: [PATCH 3/8] ARM: OMAP2+: PM: add a lock to protect the powerdomains next state Date: Wed, 15 Aug 2012 12:02:43 +0200 Message-Id: <1345024968-28951-4-git-send-email-j-pihet@ti.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1345024968-28951-1-git-send-email-j-pihet@ti.com> References: <1345024968-28951-1-git-send-email-j-pihet@ti.com> X-Gm-Message-State: ALoCoQnPJ7Gy/5IJCfaORtJE/RFAiurjnU+G+xneVzQ6yG8pfsIJBgs72Gi5K7TtedDPu1XdWm5b Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org pwrdm_set_next_fpwrst and pwrdm_read_next_fpwrst are intented to be the only API to program and request the next state of a power domain. This patch protects the power domain next state settings and structs from concurrent accesses by the use of a lock. A spinlock is used since pwrdm_set_next_fpwrst and pwrdm_read_next_fpwrst can be called from atomic context (.i.e) either from cpuidle path or suspend path. [ambresh@ti.com: reported the atomic context issue and suggested to replace the mutex with a spinlock] Signed-off-by: Jean Pihet Reported-by: Ambresh K --- arch/arm/mach-omap2/powerdomain.c | 36 +++++++++++++++++++++++++++++++----- arch/arm/mach-omap2/powerdomain.h | 3 +++ 2 files changed, 34 insertions(+), 5 deletions(-) diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c index 3a1f56c..a8f7a81 100644 --- a/arch/arm/mach-omap2/powerdomain.c +++ b/arch/arm/mach-omap2/powerdomain.c @@ -102,6 +102,7 @@ static int _pwrdm_register(struct powerdomain *pwrdm) INIT_LIST_HEAD(&pwrdm->voltdm_node); voltdm_add_pwrdm(voltdm, pwrdm); + spin_lock_init(&pwrdm->lock); list_add(&pwrdm->node, &pwrdm_list); /* Initialize the powerdomain's state counter */ @@ -601,6 +602,22 @@ int pwrdm_pwrst_to_fpwrst(struct powerdomain *pwrdm, u8 pwrst, u8 logic) } /** + * _pwrdm_read_next_fpwrst - get next powerdomain functional power state + * @pwrdm: struct powerdomain * to get power state + * + * Return the powerdomain @pwrdm's next functional power state. + * Returns -EINVAL if the powerdomain pointer is null or returns + * the next power state upon success. + */ +int _pwrdm_read_next_fpwrst(struct powerdomain *pwrdm) +{ + int next_pwrst = pwrdm_read_next_pwrst(pwrdm); + int next_logic = pwrdm_read_logic_retst(pwrdm); + + return pwrdm_pwrst_to_fpwrst(pwrdm, next_pwrst, next_logic); +} + +/** * pwrdm_get_achievable_fpwrst() - Provide achievable functional state * @pwrdm: struct powerdomain * to set * @fpwrst: minimum functional state we would like to hit @@ -670,6 +687,7 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, int sleep_switch = -1, ret = 0, hwsup = 0; int new_fpwrst, next_fpwrst, pwrst, logic; u8 curr_pwrst; + unsigned long flags; if (!pwrdm || IS_ERR(pwrdm)) { pr_debug("%s: invalid params: pwrdm=%p\n", __func__, pwrdm); @@ -678,13 +696,15 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, pr_debug("%s(%s, fpwrst=%0x)\n", __func__, pwrdm->name, fpwrst); + spin_lock_irqsave(&pwrdm->lock, flags); + new_fpwrst = pwrdm_get_achievable_fpwrst(pwrdm, fpwrst); pwrst = pwrdm_fpwrst_to_pwrst(pwrdm, new_fpwrst); logic = pwrdm_fpwrst_to_logic_pwrst(pwrdm, new_fpwrst); - next_fpwrst = pwrdm_read_next_fpwrst(pwrdm); + next_fpwrst = _pwrdm_read_next_fpwrst(pwrdm); if (new_fpwrst == next_fpwrst) - return ret; + goto out; curr_pwrst = pwrdm_read_pwrst(pwrdm); if (curr_pwrst < PWRDM_POWER_ON) { @@ -732,6 +752,8 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, break; } +out: + spin_unlock_irqrestore(&pwrdm->lock, flags); return ret; } @@ -801,10 +823,14 @@ int pwrdm_read_next_pwrst(struct powerdomain *pwrdm) */ int pwrdm_read_next_fpwrst(struct powerdomain *pwrdm) { - int next_pwrst = pwrdm_read_next_pwrst(pwrdm); - int next_logic = pwrdm_read_logic_retst(pwrdm); + int ret; + unsigned long flags; - return pwrdm_pwrst_to_fpwrst(pwrdm, next_pwrst, next_logic); + spin_lock_irqsave(&pwrdm->lock, flags); + ret = _pwrdm_read_next_fpwrst(pwrdm); + spin_unlock_irqrestore(&pwrdm->lock, flags); + + return ret; } /** diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h index 45c449d..23b9da9 100644 --- a/arch/arm/mach-omap2/powerdomain.h +++ b/arch/arm/mach-omap2/powerdomain.h @@ -17,6 +17,7 @@ #include #include +#include #include #include @@ -109,6 +110,7 @@ struct powerdomain; * @pwrdm_clkdms: Clockdomains in this powerdomain * @node: list_head linking all powerdomains * @voltdm_node: list_head linking all powerdomains in a voltagedomain + * @lock: powerdomain next state registers protection lock * @pwrstctrl_offs: (AM33XX only) XXX_PWRSTCTRL reg offset from prcm_offs * @pwrstst_offs: (AM33XX only) XXX_PWRSTST reg offset from prcm_offs * @logicretstate_mask: (AM33XX only) mask for logic retention bitfield @@ -142,6 +144,7 @@ struct powerdomain { struct clockdomain *pwrdm_clkdms[PWRDM_MAX_CLKDMS]; struct list_head node; struct list_head voltdm_node; + spinlock_t lock; int state; unsigned state_counter[PWRDM_MAX_PWRSTS]; unsigned ret_logic_off_counter;