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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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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-de= vfreq.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; }; =20 +/* 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_vo= ltage) { const struct mtk_ccifreq_platform_data *soc_data =3D 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 =3D 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; =20 + mutex_lock(®_lock); + + drv =3D dev_get_drvdata(dev); if (!drv) return -EINVAL; =20 - if (drv->pre_freq =3D=3D *freq) - return 0; - - mutex_lock(&drv->reg_lock); - - inter_voltage =3D drv->inter_voltage; cci_pll =3D clk_get_parent(drv->cci_clk); + inter_voltage =3D drv->inter_voltage; =20 opp_rate =3D *freq; opp =3D devfreq_recommended_opp(dev, &opp_rate, 1); @@ -206,7 +205,7 @@ static int mtk_ccifreq_target(struct device *dev, unsig= ned long *freq, } =20 drv->pre_freq =3D *freq; - mutex_unlock(&drv->reg_lock); + mutex_unlock(®_lock); =20 return 0; =20 @@ -214,21 +213,23 @@ static int mtk_ccifreq_target(struct device *dev, uns= igned long *freq, mtk_ccifreq_set_voltage(drv, pre_voltage); =20 out_unlock: - mutex_unlock(&drv->reg_lock); + mutex_unlock(®_lock); return ret; } =20 static int mtk_ccifreq_opp_notifier(struct notifier_block *nb, unsigned long event, void *data) { - struct dev_pm_opp *opp =3D data; + struct dev_pm_opp *opp; struct mtk_ccifreq_drv *drv; unsigned long freq, volt; =20 + mutex_lock(®_lock); + + opp =3D data; drv =3D container_of(nb, struct mtk_ccifreq_drv, opp_nb); =20 if (event =3D=3D OPP_EVENT_ADJUST_VOLTAGE) { - mutex_lock(&drv->reg_lock); freq =3D dev_pm_opp_get_freq(opp); =20 /* current opp item is changed */ @@ -236,8 +237,8 @@ static int mtk_ccifreq_opp_notifier(struct notifier_blo= ck *nb, volt =3D dev_pm_opp_get_voltage(opp); mtk_ccifreq_set_voltage(drv, volt); } - mutex_unlock(&drv->reg_lock); } + mutex_unlock(®_lock); =20 return 0; } @@ -262,7 +263,6 @@ static int mtk_ccifreq_probe(struct platform_device *pd= ev) drv->dev =3D dev; drv->soc_data =3D (const struct mtk_ccifreq_platform_data *) of_device_get_match_data(&pdev->dev); - mutex_init(&drv->reg_lock); platform_set_drvdata(pdev, drv); =20 drv->cci_clk =3D devm_clk_get(dev, "cci"); --=20 2.45.2