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Wysocki" , Viresh Kumar , MyungJoo Ham , "Kyungmin Park" , Chanwoo Choi , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , Subject: [PATCH v1 1/2] PM / devfreq: mediatek: protect oop in critical session Date: Fri, 13 Sep 2024 18:39:32 +0800 Message-ID: <20240913103933.30895-2-chun-jen.tseng@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20240913103933.30895-1-chun-jen.tseng@mediatek.com> References: <20240913103933.30895-1-chun-jen.tseng@mediatek.com> MIME-Version: 1.0 X-TM-AS-Product-Ver: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-AS-Result: No-10--4.484100-8.000000 X-TMASE-MatchedRID: LAlCrEnopVXUzvcPSorAlFz+axQLnAVBtGonEOW5g+agaf0+XUrNk3kk h754FS8n6DB7yJ7eUTP0VyIrxg+OJcZEoJx1HltluIwLnB3Aqp25+1figft3Lg5SzgJNSArLkVq DBn//HhImL4e5hLr+f0mZgncXR4mgGAdnzrnkM48URSScn+QSXt0H8LFZNFG7doMssNsUwYVV2Y FKivUXnovjZuoPNVwq7Ouc1TlJj0nz/pMg4hZ1PL27cYXrOln+oV7D15FntQdDvz+t8eVtJ0AAL As+DNqOStqwsbgFR/qAhOcaQrQ0U1GyRcoeF18qmKP0zzpTAeGwod8xOMKmvA1Aka/KIp/p X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No X-TMASE-Result: 10--4.484100-8.000000 X-TMASE-Version: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-SNTS-SMTP: FC2A249B0FAC5904A78B645CACC39F666E4A44308525607319F5BE191941A9442000:8 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240913_034944_922413_279B7DD0 X-CRM114-Status: GOOD ( 15.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org mtk_ccifreq_target() & mtk_ccifreq_opp_notifier() is re-enter funtion when cpufreq governor is more than one. It should add global mutex to protect OPP , avoid get wrong frequency & voltage. Signed-off-by: Mark Tseng --- drivers/devfreq/mtk-cci-devfreq.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c index 7ad5225b0381..293cf81e53fe 100644 --- a/drivers/devfreq/mtk-cci-devfreq.c +++ b/drivers/devfreq/mtk-cci-devfreq.c @@ -29,13 +29,14 @@ struct mtk_ccifreq_drv { struct clk *inter_clk; int inter_voltage; unsigned long pre_freq; - /* Avoid race condition for regulators between notify and policy */ - struct mutex reg_lock; struct notifier_block opp_nb; const struct mtk_ccifreq_platform_data *soc_data; int vtrack_max; }; +/* Avoid race condition for regulators between notify and policy */ +static DEFINE_MUTEX(reg_lock); + static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, int new_voltage) { const struct mtk_ccifreq_platform_data *soc_data = drv->soc_data; @@ -125,22 +126,20 @@ static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, int new_voltage) static int mtk_ccifreq_target(struct device *dev, unsigned long *freq, u32 flags) { - struct mtk_ccifreq_drv *drv = dev_get_drvdata(dev); + struct mtk_ccifreq_drv *drv; struct clk *cci_pll; struct dev_pm_opp *opp; unsigned long opp_rate; int voltage, pre_voltage, inter_voltage, target_voltage, ret; + mutex_lock(®_lock); + + drv = dev_get_drvdata(dev); if (!drv) return -EINVAL; - if (drv->pre_freq == *freq) - return 0; - - mutex_lock(&drv->reg_lock); - - inter_voltage = drv->inter_voltage; cci_pll = clk_get_parent(drv->cci_clk); + inter_voltage = drv->inter_voltage; opp_rate = *freq; opp = devfreq_recommended_opp(dev, &opp_rate, 1); @@ -206,7 +205,7 @@ static int mtk_ccifreq_target(struct device *dev, unsigned long *freq, } drv->pre_freq = *freq; - mutex_unlock(&drv->reg_lock); + mutex_unlock(®_lock); return 0; @@ -214,21 +213,23 @@ static int mtk_ccifreq_target(struct device *dev, unsigned long *freq, mtk_ccifreq_set_voltage(drv, pre_voltage); out_unlock: - mutex_unlock(&drv->reg_lock); + mutex_unlock(®_lock); return ret; } static int mtk_ccifreq_opp_notifier(struct notifier_block *nb, unsigned long event, void *data) { - struct dev_pm_opp *opp = data; + struct dev_pm_opp *opp; struct mtk_ccifreq_drv *drv; unsigned long freq, volt; + mutex_lock(®_lock); + + opp = data; drv = container_of(nb, struct mtk_ccifreq_drv, opp_nb); if (event == OPP_EVENT_ADJUST_VOLTAGE) { - mutex_lock(&drv->reg_lock); freq = dev_pm_opp_get_freq(opp); /* current opp item is changed */ @@ -236,8 +237,8 @@ static int mtk_ccifreq_opp_notifier(struct notifier_block *nb, volt = dev_pm_opp_get_voltage(opp); mtk_ccifreq_set_voltage(drv, volt); } - mutex_unlock(&drv->reg_lock); } + mutex_unlock(®_lock); return 0; } @@ -262,7 +263,6 @@ static int mtk_ccifreq_probe(struct platform_device *pdev) drv->dev = dev; drv->soc_data = (const struct mtk_ccifreq_platform_data *) of_device_get_match_data(&pdev->dev); - mutex_init(&drv->reg_lock); platform_set_drvdata(pdev, drv); drv->cci_clk = devm_clk_get(dev, "cci");