From 6f2a35d65b3c4bbc579a115589edcc7ed6239dce Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Tue, 5 Nov 2019 00:56:06 +0300 Subject: [PATCH] PM / devfreq: tegra30: Move clk-notifier's registration to governor's start There is no point in receiving of the notifications while governor is stopped, let's keep them disabled like we do for the CPU freq-change notifications. This also fixes a potential use-after-free bug if notification happens after device's removal. Reviewed-by: Chanwoo Choi Tested-by: Peter Geis Signed-off-by: Dmitry Osipenko Signed-off-by: Chanwoo Choi --- drivers/devfreq/tegra30-devfreq.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c index 2d720e7..6960d8b 100644 --- a/drivers/devfreq/tegra30-devfreq.c +++ b/drivers/devfreq/tegra30-devfreq.c @@ -514,6 +514,21 @@ static int tegra_actmon_start(struct tegra_devfreq *tegra) actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1, ACTMON_GLB_PERIOD_CTRL); + /* + * CLK notifications are needed in order to reconfigure the upper + * consecutive watermark in accordance to the actual clock rate + * to avoid unnecessary upper interrupts. + */ + err = clk_notifier_register(tegra->emc_clock, + &tegra->clk_rate_change_nb); + if (err) { + dev_err(tegra->devfreq->dev.parent, + "Failed to register rate change notifier\n"); + return err; + } + + tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ; + for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) tegra_actmon_configure_device(tegra, &tegra->devices[i]); @@ -539,6 +554,8 @@ static int tegra_actmon_start(struct tegra_devfreq *tegra) err_stop: tegra_actmon_stop_devices(tegra); + clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb); + return err; } @@ -552,6 +569,8 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra) cancel_delayed_work_sync(&tegra->cpufreq_update_work); tegra_actmon_stop_devices(tegra); + + clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb); } static int tegra_devfreq_target(struct device *dev, unsigned long *freq, @@ -768,7 +787,6 @@ static int tegra_devfreq_probe(struct platform_device *pdev) return rate; } - tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ; tegra->max_freq = rate / KHZ; for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) { @@ -796,27 +814,20 @@ static int tegra_devfreq_probe(struct platform_device *pdev) platform_set_drvdata(pdev, tegra); + tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb; tegra->cpu_rate_change_nb.notifier_call = tegra_actmon_cpu_notify_cb; INIT_DELAYED_WORK(&tegra->cpufreq_update_work, tegra_actmon_delayed_update); - tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb; - err = clk_notifier_register(tegra->emc_clock, - &tegra->clk_rate_change_nb); - if (err) { - dev_err(&pdev->dev, - "Failed to register rate change notifier\n"); - goto remove_opps; - } - err = devfreq_add_governor(&tegra_devfreq_governor); if (err) { dev_err(&pdev->dev, "Failed to add governor: %d\n", err); - goto unreg_notifier; + goto remove_opps; } - tegra_devfreq_profile.initial_freq = tegra->cur_freq; + tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock); + tegra_devfreq_profile.initial_freq /= KHZ; devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile, "tegra_actmon", NULL); @@ -830,9 +841,6 @@ static int tegra_devfreq_probe(struct platform_device *pdev) remove_governor: devfreq_remove_governor(&tegra_devfreq_governor); -unreg_notifier: - clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb); - remove_opps: dev_pm_opp_remove_all_dynamic(&pdev->dev); @@ -849,7 +857,6 @@ static int tegra_devfreq_remove(struct platform_device *pdev) devfreq_remove_device(tegra->devfreq); devfreq_remove_governor(&tegra_devfreq_governor); - clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb); dev_pm_opp_remove_all_dynamic(&pdev->dev); reset_control_reset(tegra->reset); -- 2.7.4