From patchwork Wed Sep 9 00:12:31 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Dannenberg X-Patchwork-Id: 7143871 Return-Path: X-Original-To: patchwork-linux-pm@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 779D19F1BF for ; Wed, 9 Sep 2015 00:13:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 850E220650 for ; Wed, 9 Sep 2015 00:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDB702087F for ; Wed, 9 Sep 2015 00:13:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754204AbbIIANy (ORCPT ); Tue, 8 Sep 2015 20:13:54 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:58606 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753945AbbIIANx (ORCPT ); Tue, 8 Sep 2015 20:13:53 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id t890DRg2026387; Tue, 8 Sep 2015 19:13:27 -0500 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id t890DRdW021973; Tue, 8 Sep 2015 19:13:27 -0500 Received: from dlep32.itg.ti.com (157.170.170.100) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.3.224.2; Tue, 8 Sep 2015 19:13:20 -0500 Received: from beast.tx.rr.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id t890D0S6019642; Tue, 8 Sep 2015 19:13:25 -0500 From: Andreas Dannenberg To: Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse , Laurentiu Palcu , Krzysztof Kozlowski CC: , , Andreas Dannenberg Subject: [PATCH v2 07/13] power: bq24257: Extend scope of mutex protection Date: Tue, 8 Sep 2015 19:12:31 -0500 Message-ID: <1441757557-7266-8-git-send-email-dannenberg@ti.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1441757557-7266-1-git-send-email-dannenberg@ti.com> References: <1441757557-7266-1-git-send-email-dannenberg@ti.com> MIME-Version: 1.0 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, T_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 This commit extends the use of the existing mutex to pave the way for using direct device access inside sysfs getter/setter routines in a way that the access during interrupts and timer routines does not interfere with device access by the CPU or between multiple cores. This also addresses a potential race condition that could be caused by bq24257_irq_handler_thread() and bq24257_iilimit_autoset() accessing the device simultaneously. Signed-off-by: Andreas Dannenberg --- drivers/power/bq24257_charger.c | 60 ++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 25 deletions(-) diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c index c160fde..f0d4307 100644 --- a/drivers/power/bq24257_charger.c +++ b/drivers/power/bq24257_charger.c @@ -102,7 +102,7 @@ struct bq24257_device { struct bq24257_init_data init_data; struct bq24257_state state; - struct mutex lock; /* protect state data */ + struct mutex lock; /* protect device access and state data */ bool in_ilimit_autoset_disable; bool pg_gpio_disable; @@ -271,10 +271,10 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, { struct bq24257_device *bq = power_supply_get_drvdata(psy); struct bq24257_state state; + int ret = 0; mutex_lock(&bq->lock); state = bq->state; - mutex_unlock(&bq->lock); switch (psp) { case POWER_SUPPLY_PROP_STATUS: @@ -350,10 +350,12 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, break; default: - return -EINVAL; + ret = -EINVAL; } - return 0; + mutex_unlock(&bq->lock); + + return ret; } static int bq24257_get_chip_state(struct bq24257_device *bq, @@ -400,15 +402,9 @@ static int bq24257_get_chip_state(struct bq24257_device *bq, static bool bq24257_state_changed(struct bq24257_device *bq, struct bq24257_state *new_state) { - int ret; - - mutex_lock(&bq->lock); - ret = (bq->state.status != new_state->status || - bq->state.fault != new_state->fault || - bq->state.power_good != new_state->power_good); - mutex_unlock(&bq->lock); - - return ret; + return bq->state.status != new_state->status || + bq->state.fault != new_state->fault || + bq->state.power_good != new_state->power_good; } enum bq24257_loop_status { @@ -531,7 +527,9 @@ static void bq24257_iilimit_setup_work(struct work_struct *work) struct bq24257_device *bq = container_of(work, struct bq24257_device, iilimit_setup_work.work); + mutex_lock(&bq->lock); bq24257_iilimit_autoset(bq); + mutex_unlock(&bq->lock); } static void bq24257_handle_state_change(struct bq24257_device *bq, @@ -542,9 +540,7 @@ static void bq24257_handle_state_change(struct bq24257_device *bq, bool reset_iilimit = false; bool config_iilimit = false; - mutex_lock(&bq->lock); old_state = bq->state; - mutex_unlock(&bq->lock); /* * Handle BQ2425x state changes observing whether the D+/D- based input @@ -599,25 +595,30 @@ static irqreturn_t bq24257_irq_handler_thread(int irq, void *private) struct bq24257_device *bq = private; struct bq24257_state state; + mutex_lock(&bq->lock); + ret = bq24257_get_chip_state(bq, &state); if (ret < 0) - return IRQ_HANDLED; + goto out; if (!bq24257_state_changed(bq, &state)) - return IRQ_HANDLED; + goto out; dev_dbg(bq->dev, "irq(state changed): status/fault/pg = %d/%d/%d\n", state.status, state.fault, state.power_good); bq24257_handle_state_change(bq, &state); - - mutex_lock(&bq->lock); bq->state = state; + mutex_unlock(&bq->lock); power_supply_changed(bq->charger); return IRQ_HANDLED; + +out: + mutex_unlock(&bq->lock); + return IRQ_HANDLED; } static int bq24257_hw_init(struct bq24257_device *bq) @@ -657,9 +658,7 @@ static int bq24257_hw_init(struct bq24257_device *bq) if (ret < 0) return ret; - mutex_lock(&bq->lock); bq->state = state; - mutex_unlock(&bq->lock); if (bq->in_ilimit_autoset_disable) { dev_dbg(bq->dev, "manually setting iilimit = %d\n", @@ -1018,11 +1017,15 @@ static int bq24257_suspend(struct device *dev) if (!bq->in_ilimit_autoset_disable) cancel_delayed_work_sync(&bq->iilimit_setup_work); + mutex_lock(&bq->lock); + /* reset all registers to default (and activate standalone mode) */ ret = bq24257_field_write(bq, F_RESET, 1); if (ret < 0) dev_err(bq->dev, "Cannot reset chip to standalone mode.\n"); + mutex_unlock(&bq->lock); + return ret; } @@ -1031,24 +1034,31 @@ static int bq24257_resume(struct device *dev) int ret; struct bq24257_device *bq = dev_get_drvdata(dev); + mutex_lock(&bq->lock); + ret = regcache_drop_region(bq->rmap, BQ24257_REG_1, BQ24257_REG_7); if (ret < 0) - return ret; + goto err; ret = bq24257_field_write(bq, F_RESET, 0); if (ret < 0) - return ret; + goto err; ret = bq24257_hw_init(bq); if (ret < 0) { dev_err(bq->dev, "Cannot init chip after resume.\n"); - return ret; + goto err; } + mutex_unlock(&bq->lock); + /* signal userspace, maybe state changed while suspended */ power_supply_changed(bq->charger); - return 0; + +err: + mutex_unlock(&bq->lock); + return ret; } #endif