Lukasz, Thanks for the keeping this up. And apologize for late answer. On Thu, Nov 13, 2014 at 06:02:37PM +0100, Lukasz Majewski wrote: > Presented fixes are a response for problem described below: > http://thread.gmane.org/gmane.linux.kernel/1793821/match=thermal+core+fix+initialize+max_state+variable+0 > > In short - it turned out that two trivial fixes (included in this patch set) > require support for deferred probe in thermal drivers. > > This situation shows up when CPU frequency reduction is used as a thermal cooling > device for a thermal zone. > It happens that during initialization, the call to thermal probe will be executed > before cpufreq probe (it can be observed at ./drivers/Makefile). > In such a situation thermal will not be properly configured until cpufreq policy > is setup. > > In the current code (without included fixes) there is a time window in which thermal > can try to use not configured cpufreq and possibly crash the system. > > > Proposed solution was based on the code already available in the imx_thermal.c file. > > /db8500_thermal.c: -> NOT NEEDED > /intel_powerclamp.c: -> NOT NEEDED - INTEL (x86) > /intel_powerclamp.c: -> NOT NEEDED - INTEL (x86) > /ti-soc-thermal/ti-bandgap.c: -> FIXED [omap2plus_defconfig] > /dove_thermal.c: -> NOT NEEDED - CPU_COOLING NOT AVAILABLE > [dove_defconfig] > /spear_thermal.c: -> FIXED [spear3xx_defconfig] > /samsung/exynos_tmu.c: -> NOT NEEDED (nasty hack - will be reworked in later patches) > /imx_thermal.c: -> OK (deferred probe already in place) > /int340x_thermal/int3402_thermal.c: -> NOT NEEDED - ACPI x86 - Intel specific > /int340x_thermal/int3400_thermal.c: -> NOT NEEDED - ACPI x86 - Intel specific > /tegra_soctherm.c: -> FIXED [tegra_defconfig] > /kirkwood_thermal.c: -> FIXED [multi_v5_defconfig] > /armada_thermal.c: -> FIXED [multi_v7_defconfig] > /rcar_thermal.c: -> FIXED [shmobile_defconfig] > /db8500_cpufreq_cooling.c: -> OK (deferred probe already in place) [multi_v7_defconfig] > /st/st_thermal_syscfg.c: -> NOT NEEDED (Those two are enabled by e.g. ARMADA) > /st/st_thermal_memmap.c: > > Instead of doing the same check on all drivers in the need for cpu cooling looks like a promiscuous solution. What if we do this check in cpu cooling itself and we propagate the error in callers code? From what I see, only exynos does not propagate the error. And we would need a tweak in the cpufreq-dt code. Something like the following (not tested): diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c index f657c57..f139247 100644 --- a/drivers/cpufreq/cpufreq-dt.c +++ b/drivers/cpufreq/cpufreq-dt.c @@ -181,7 +181,6 @@ static int cpufreq_init(struct cpufreq_policy *policy) { struct cpufreq_dt_platform_data *pd; struct cpufreq_frequency_table *freq_table; - struct thermal_cooling_device *cdev; struct device_node *np; struct private_data *priv; struct device *cpu_dev; @@ -264,20 +263,6 @@ static int cpufreq_init(struct cpufreq_policy *policy) goto out_free_priv; } - /* - * For now, just loading the cooling device; - * thermal DT code takes care of matching them. - */ - if (of_find_property(np, "#cooling-cells", NULL)) { - cdev = of_cpufreq_cooling_register(np, cpu_present_mask); - if (IS_ERR(cdev)) - dev_err(cpu_dev, - "running cpufreq without cooling device: %ld\n", - PTR_ERR(cdev)); - else - priv->cdev = cdev; - } - priv->cpu_dev = cpu_dev; priv->cpu_reg = cpu_reg; policy->driver_data = priv; @@ -287,7 +272,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) if (ret) { dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__, ret); - goto out_cooling_unregister; + goto free_table; } policy->cpuinfo.transition_latency = transition_latency; @@ -300,8 +285,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) return 0; -out_cooling_unregister: - cpufreq_cooling_unregister(priv->cdev); +free_table: dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); out_free_priv: kfree(priv); @@ -342,11 +326,14 @@ static struct cpufreq_driver dt_cpufreq_driver = { static int dt_cpufreq_probe(struct platform_device *pdev) { + struct device_node *np; struct device *cpu_dev; struct regulator *cpu_reg; struct clk *cpu_clk; int ret; + /* at this point we checked the pointer already right? */ + np = of_node_get(pdev->dev.of_node); /* * All per-cluster (CPUs sharing clock/voltages) initialization is done * from ->init(). In probe(), we just need to make sure that clk and @@ -368,6 +355,28 @@ static int dt_cpufreq_probe(struct platform_device *pdev) if (ret) dev_err(cpu_dev, "failed register driver: %d\n", ret); + /* + * For now, just loading the cooling device; + * thermal DT code takes care of matching them. + */ + if (of_find_property(np, "#cooling-cells", NULL)) { + struct cpufreq_policy policy; + struct private_data *priv; + struct thermal_cooling_device *cdev; + + /* TODO: can cpu0 be always used ? */ + cpufreq_get_policy(&policy, 0); + priv = policy.driver_data; + cdev = of_cpufreq_cooling_register(np, cpu_present_mask); + if (IS_ERR(cdev)) + dev_err(cpu_dev, + "running cpufreq without cooling device: %ld\n", + PTR_ERR(cdev)); + else + priv->cdev = cdev; + } + of_node_put(np); + return ret; } diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c index 1ab0018..342eb9e 100644 --- a/drivers/thermal/cpu_cooling.c +++ b/drivers/thermal/cpu_cooling.c @@ -440,6 +440,11 @@ __cpufreq_cooling_register(struct device_node *np, int ret = 0, i; struct cpufreq_policy policy; + if (!cpufreq_get_current_driver()) { + dev_warn(&pdev->dev, "no cpufreq driver, deferring."); + return -EPROBE_DEFER; + } + /* Verify that all the clip cpus have same freq_min, freq_max limit */ for_each_cpu(i, clip_cpus) { /* continue if cpufreq policy not found and not return error */ diff --git a/drivers/thermal/samsung/exynos_thermal_common.c b/drivers/thermal/samsung/exynos_thermal_common.c index 3f5ad25..f84975e 100644 --- a/drivers/thermal/samsung/exynos_thermal_common.c +++ b/drivers/thermal/samsung/exynos_thermal_common.c @@ -373,7 +373,7 @@ int exynos_register_thermal(struct thermal_sensor_conf *sensor_conf) if (IS_ERR(th_zone->cool_dev[th_zone->cool_dev_size])) { dev_err(sensor_conf->dev, "Failed to register cpufreq cooling device\n"); - ret = -EINVAL; + ret = PTR_ERR(th_zone->cool_dev[th_zone->cool_dev_size]); goto err_unregister; } th_zone->cool_dev_size++; The above way, we avoid having same test in every driver that needs it. Besides, it makes sense the cpu_cooling code takes care of this check, as it is the very first part that has direct dependency with cpufreq. > I only possess Exynos boards and Beagle Bone Black, so I'd be grateful for > testing proposed solution on other boards. The posted code is compile tested. > > This code applies on Eduardo's ti-soc-thermal-next tree: > SHA1: 208a97042d66d9bfbcfab0d4a00c9fe317bb73d3 > > Lukasz Majewski (8): > thermal:cpu cooling:armada: Provide deferred probing for armada driver > thermal:cpu cooling:kirkwood: Provide deferred probing for kirkwood > driver > thermal:cpu cooling:rcar: Provide deferred probing for rcar driver > thermal:cpu cooling:spear: Provide deferred probing for spear driver > thermal:cpu cooling:tegra: Provide deferred probing for tegra driver > thermal:cpu cooling:ti: Provide deferred probing for ti drivers > thermal:core:fix: Initialize the max_state variable to 0 > thermal:core:fix: Check return code of the ->get_max_state() callback > > drivers/thermal/armada_thermal.c | 7 +++++++ > drivers/thermal/kirkwood_thermal.c | 7 +++++++ > drivers/thermal/rcar_thermal.c | 7 +++++++ > drivers/thermal/spear_thermal.c | 7 +++++++ > drivers/thermal/tegra_soctherm.c | 7 +++++++ > drivers/thermal/thermal_core.c | 8 +++++--- > drivers/thermal/ti-soc-thermal/ti-bandgap.c | 7 +++++++ > 7 files changed, 47 insertions(+), 3 deletions(-) > > -- > 2.0.0.rc2 >
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