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Wysocki" , Viresh Kumar , MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , Subject: [PATCH v3 1/3] cpufreq: mediatek: using global lock avoid race condition Date: Fri, 14 Feb 2025 15:43:32 +0800 Message-ID: <20250214074353.1169864-2-chun-jen.tseng@mediatek.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250214074353.1169864-1-chun-jen.tseng@mediatek.com> References: <20250214074353.1169864-1-chun-jen.tseng@mediatek.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250213_234402_143627_8EA39457 X-CRM114-Status: GOOD ( 16.48 ) X-BeenThere: linux-mediatek@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-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org In mtk_cpufreq_set_target() is re-enter function but the mutex lock decalre in mtk_cpu_dvfs_info structure for each policy. It should change to global variable for critical session avoid race condition with 2 or more policy. add mtk_cpufreq_get() replace cpufreq_generic_get() and use global lock avoid return wrong clock. Signed-off-by: Mark Tseng --- drivers/cpufreq/mediatek-cpufreq.c | 39 ++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c index 2656b88db378..07d5958e106a 100644 --- a/drivers/cpufreq/mediatek-cpufreq.c +++ b/drivers/cpufreq/mediatek-cpufreq.c @@ -49,8 +49,6 @@ struct mtk_cpu_dvfs_info { bool need_voltage_tracking; int vproc_on_boot; int pre_vproc; - /* Avoid race condition for regulators between notify and policy */ - struct mutex reg_lock; struct notifier_block opp_nb; unsigned int opp_cpu; unsigned long current_freq; @@ -59,6 +57,9 @@ struct mtk_cpu_dvfs_info { bool ccifreq_bound; }; +/* Avoid race condition for regulators between notify and policy */ +static DEFINE_MUTEX(mtk_policy_lock); + static struct platform_device *cpufreq_pdev; static LIST_HEAD(dvfs_info_list); @@ -209,12 +210,12 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy, long freq_hz, pre_freq_hz; int vproc, pre_vproc, inter_vproc, target_vproc, ret; + mutex_lock(&mtk_policy_lock); + inter_vproc = info->intermediate_voltage; pre_freq_hz = clk_get_rate(cpu_clk); - mutex_lock(&info->reg_lock); - if (unlikely(info->pre_vproc <= 0)) pre_vproc = regulator_get_voltage(info->proc_reg); else @@ -308,7 +309,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy, info->current_freq = freq_hz; out: - mutex_unlock(&info->reg_lock); + mutex_unlock(&mtk_policy_lock); return ret; } @@ -316,19 +317,20 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy, static int mtk_cpufreq_opp_notifier(struct notifier_block *nb, unsigned long event, void *data) { - struct dev_pm_opp *opp = data; + struct dev_pm_opp *opp; struct dev_pm_opp *new_opp; struct mtk_cpu_dvfs_info *info; unsigned long freq, volt; struct cpufreq_policy *policy; int ret = 0; + mutex_lock(&mtk_policy_lock); + opp = data; info = container_of(nb, struct mtk_cpu_dvfs_info, opp_nb); if (event == OPP_EVENT_ADJUST_VOLTAGE) { freq = dev_pm_opp_get_freq(opp); - mutex_lock(&info->reg_lock); if (info->current_freq == freq) { volt = dev_pm_opp_get_voltage(opp); ret = mtk_cpufreq_set_voltage(info, volt); @@ -336,7 +338,6 @@ static int mtk_cpufreq_opp_notifier(struct notifier_block *nb, dev_err(info->cpu_dev, "failed to scale voltage: %d\n", ret); } - mutex_unlock(&info->reg_lock); } else if (event == OPP_EVENT_DISABLE) { freq = dev_pm_opp_get_freq(opp); @@ -361,6 +362,7 @@ static int mtk_cpufreq_opp_notifier(struct notifier_block *nb, } } } + mutex_unlock(&mtk_policy_lock); return notifier_from_errno(ret); } @@ -495,7 +497,6 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu) info->intermediate_voltage = dev_pm_opp_get_voltage(opp); dev_pm_opp_put(opp); - mutex_init(&info->reg_lock); info->current_freq = clk_get_rate(info->cpu_clk); info->opp_cpu = cpu; @@ -607,13 +608,31 @@ static void mtk_cpufreq_exit(struct cpufreq_policy *policy) dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table); } +static unsigned int mtk_cpufreq_get(unsigned int cpu) +{ + struct mtk_cpu_dvfs_info *info; + unsigned long current_freq; + + mutex_lock(&mtk_policy_lock); + info = mtk_cpu_dvfs_info_lookup(cpu); + if (!info) { + mutex_unlock(&mtk_policy_lock); + return 0; + } + + current_freq = info->current_freq / 1000; + mutex_unlock(&mtk_policy_lock); + + return current_freq; +} + static struct cpufreq_driver mtk_cpufreq_driver = { .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | CPUFREQ_IS_COOLING_DEV, .verify = cpufreq_generic_frequency_table_verify, .target_index = mtk_cpufreq_set_target, - .get = cpufreq_generic_get, + .get = mtk_cpufreq_get, .init = mtk_cpufreq_init, .exit = mtk_cpufreq_exit, .register_em = cpufreq_register_em_with_opp,