Re: [RFC PATCH 1/5] thermal: cpu_cooling: Support passing driver private data.

From: Eduardo Valentin
Date: Thu May 15 2014 - 14:28:10 EST


Hello Amit,


On Thu, May 08, 2014 at 08:07:56PM +0530, Amit Daniel Kachhap wrote:
> This patch is in preparation to add notfication support for cpufrequency
> cooling changes. This change also removes the unnecessary exposing of
> internal housekeeping structure via thermal_cooling_device->devdata to the
> users of cpufreq cooling APIs.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> ---
> drivers/thermal/cpu_cooling.c | 79 +++++++++++++++----
> drivers/thermal/db8500_cpufreq_cooling.c | 2 +-
> drivers/thermal/samsung/exynos_thermal_common.c | 2 +-
> drivers/thermal/ti-soc-thermal/ti-thermal-common.c | 2 +-
> include/linux/cpu_cooling.h | 5 +-
> 5 files changed, 68 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index 4246262..21f44d4 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -50,16 +50,18 @@ struct cpufreq_cooling_device {
> unsigned int cpufreq_state;
> unsigned int cpufreq_val;
> struct cpumask allowed_cpus;
> + struct list_head node;
> };
> static DEFINE_IDR(cpufreq_idr);
> static DEFINE_MUTEX(cooling_cpufreq_lock);
>
> -static unsigned int cpufreq_dev_count;
> -
> /* notify_table passes value to the CPUFREQ_ADJUST callback function. */
> #define NOTIFY_INVALID NULL
> static struct cpufreq_cooling_device *notify_device;
>
> +/* A list to hold all the cpufreq cooling devices registered */
> +static LIST_HEAD(cpufreq_cooling_list);
> +
> /**
> * get_idr - function to get a unique id.
> * @idr: struct idr * handle used to create a id.
> @@ -357,12 +359,23 @@ static int cpufreq_thermal_notifier(struct notifier_block *nb,
> static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
> unsigned long *state)
> {
> - struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
> - struct cpumask *mask = &cpufreq_device->allowed_cpus;
> + struct cpufreq_cooling_device *cpufreq_device = NULL;
> + struct cpumask *mask = NULL;
> unsigned int cpu;
> unsigned int count = 0;
> int ret;
>
> + mutex_lock(&cooling_cpufreq_lock);
> + list_for_each_entry(cpufreq_device, &cpufreq_cooling_list, node)
> + if (cpufreq_device->cool_dev == cdev)
> + break;
> + mutex_unlock(&cooling_cpufreq_lock);
> + if (!cpufreq_device) {
> + /* Cooling device pointer not found */
> + return -EINVAL;
> + }
> +
> + mask = &cpufreq_device->allowed_cpus;
> cpu = cpumask_any(mask);
>
> ret = get_property(cpu, 0, &count, GET_MAXL);
> @@ -386,7 +399,17 @@ static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
> static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
> unsigned long *state)
> {
> - struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
> + struct cpufreq_cooling_device *cpufreq_device = NULL;
> +
> + mutex_lock(&cooling_cpufreq_lock);
> + list_for_each_entry(cpufreq_device, &cpufreq_cooling_list, node)
> + if (cpufreq_device->cool_dev == cdev)
> + break;
> + mutex_unlock(&cooling_cpufreq_lock);
> + if (!cpufreq_device) {
> + /* Cooling device pointer not found */
> + return -EINVAL;
> + }
>
> *state = cpufreq_device->cpufreq_state;
>
> @@ -406,7 +429,17 @@ static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
> static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
> unsigned long state)
> {
> - struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
> + struct cpufreq_cooling_device *cpufreq_device = NULL;
> +
> + mutex_lock(&cooling_cpufreq_lock);
> + list_for_each_entry(cpufreq_device, &cpufreq_cooling_list, node)
> + if (cpufreq_device->cool_dev == cdev)
> + break;
> + mutex_unlock(&cooling_cpufreq_lock);
> + if (!cpufreq_device) {
> + /* Cooling device pointer not found */
> + return -EINVAL;
> + }
>
> return cpufreq_apply_cooling(cpufreq_device, state);
> }
> @@ -427,6 +460,7 @@ static struct notifier_block thermal_cpufreq_notifier_block = {
> * __cpufreq_cooling_register - helper function to create cpufreq cooling device
> * @np: a valid struct device_node to the cooling device device tree node
> * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
> + * @devdata: driver data pointer
> *
> * This interface function registers the cpufreq cooling device with the name
> * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
> @@ -438,7 +472,7 @@ static struct notifier_block thermal_cpufreq_notifier_block = {
> */
> static struct thermal_cooling_device *
> __cpufreq_cooling_register(struct device_node *np,
> - const struct cpumask *clip_cpus)
> + const struct cpumask *clip_cpus, void *devdata)
> {
> struct thermal_cooling_device *cool_dev;
> struct cpufreq_cooling_device *cpufreq_dev = NULL;
> @@ -477,7 +511,7 @@ __cpufreq_cooling_register(struct device_node *np,
> snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
> cpufreq_dev->id);
>
> - cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,
> + cool_dev = thermal_of_cooling_device_register(np, dev_name, devdata,
> &cpufreq_cooling_ops);
> if (IS_ERR(cool_dev)) {
> release_idr(&cpufreq_idr, cpufreq_dev->id);
> @@ -489,10 +523,11 @@ __cpufreq_cooling_register(struct device_node *np,
> mutex_lock(&cooling_cpufreq_lock);
>
> /* Register the notifier for first cpufreq cooling device */
> - if (cpufreq_dev_count == 0)
> + if (list_empty(&cpufreq_cooling_list))
> cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
> CPUFREQ_POLICY_NOTIFIER);
> - cpufreq_dev_count++;
> +
> + list_add(&cpufreq_dev->node, &cpufreq_cooling_list);
>
> mutex_unlock(&cooling_cpufreq_lock);
>
> @@ -502,6 +537,7 @@ __cpufreq_cooling_register(struct device_node *np,
> /**
> * cpufreq_cooling_register - function to create cpufreq cooling device.
> * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
> + * @devdata: driver data pointer
> *
> * This interface function registers the cpufreq cooling device with the name
> * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
> @@ -511,9 +547,9 @@ __cpufreq_cooling_register(struct device_node *np,
> * on failure, it returns a corresponding ERR_PTR().
> */
> struct thermal_cooling_device *
> -cpufreq_cooling_register(const struct cpumask *clip_cpus)
> +cpufreq_cooling_register(const struct cpumask *clip_cpus, void *devdata)
> {
> - return __cpufreq_cooling_register(NULL, clip_cpus);
> + return __cpufreq_cooling_register(NULL, clip_cpus, devdata);
> }
> EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
>
> @@ -537,7 +573,7 @@ of_cpufreq_cooling_register(struct device_node *np,
> if (!np)
> return ERR_PTR(-EINVAL);
>
> - return __cpufreq_cooling_register(np, clip_cpus);
> + return __cpufreq_cooling_register(np, clip_cpus, NULL);
> }
> EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
>
> @@ -554,17 +590,26 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
> if (!cdev)
> return;
>
> - cpufreq_dev = cdev->devdata;
> mutex_lock(&cooling_cpufreq_lock);
> - cpufreq_dev_count--;
> +
> + list_for_each_entry(cpufreq_dev, &cpufreq_cooling_list, node)
> + if (cpufreq_dev->cool_dev == cdev)
> + break;
> +
> + if (!cpufreq_dev) {
> + /* Cooling device pointer not found */
> + mutex_unlock(&cooling_cpufreq_lock);
> + return;
> + }

Because you are adding several times the same code to search through
your list of cdevs, I recommend adding at least a helper function to
perform this recurring operation.

Besides, are you sure you cannot keep both pointers, the cpufreq_dev and
the driver devdata? One way is to embedded the driver devdata inside the
cpufreq_dev and register cpufreq_dev. Then you would adapt the code to
fetch each pointer accordingly. What do you think?

> + thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
> + list_del(&cpufreq_dev->node);
>
> /* Unregister the notifier for the last cpufreq cooling device */
> - if (cpufreq_dev_count == 0)
> + if (list_empty(&cpufreq_cooling_list))
> cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
> CPUFREQ_POLICY_NOTIFIER);
> mutex_unlock(&cooling_cpufreq_lock);
>
> - thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
> release_idr(&cpufreq_idr, cpufreq_dev->id);
> kfree(cpufreq_dev);
> }
> diff --git a/drivers/thermal/db8500_cpufreq_cooling.c b/drivers/thermal/db8500_cpufreq_cooling.c
> index 786d192..abb9bdd 100644
> --- a/drivers/thermal/db8500_cpufreq_cooling.c
> +++ b/drivers/thermal/db8500_cpufreq_cooling.c
> @@ -35,7 +35,7 @@ static int db8500_cpufreq_cooling_probe(struct platform_device *pdev)
> return -EPROBE_DEFER;
>
> cpumask_set_cpu(0, &mask_val);
> - cdev = cpufreq_cooling_register(&mask_val);
> + cdev = cpufreq_cooling_register(&mask_val, NULL);
>
> if (IS_ERR(cdev)) {
> dev_err(&pdev->dev, "Failed to register cooling device\n");
> diff --git a/drivers/thermal/samsung/exynos_thermal_common.c b/drivers/thermal/samsung/exynos_thermal_common.c
> index 3f5ad25..a7306fa 100644
> --- a/drivers/thermal/samsung/exynos_thermal_common.c
> +++ b/drivers/thermal/samsung/exynos_thermal_common.c
> @@ -369,7 +369,7 @@ int exynos_register_thermal(struct thermal_sensor_conf *sensor_conf)
> if (sensor_conf->cooling_data.freq_clip_count > 0) {
> cpumask_set_cpu(0, &mask_val);
> th_zone->cool_dev[th_zone->cool_dev_size] =
> - cpufreq_cooling_register(&mask_val);
> + cpufreq_cooling_register(&mask_val, NULL);
> if (IS_ERR(th_zone->cool_dev[th_zone->cool_dev_size])) {
> dev_err(sensor_conf->dev,
> "Failed to register cpufreq cooling device\n");
> diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> index 9eec26d..7809db6 100644
> --- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> +++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> @@ -409,7 +409,7 @@ int ti_thermal_register_cpu_cooling(struct ti_bandgap *bgp, int id)
> }
>
> /* Register cooling device */
> - data->cool_dev = cpufreq_cooling_register(cpu_present_mask);
> + data->cool_dev = cpufreq_cooling_register(cpu_present_mask, NULL);
> if (IS_ERR(data->cool_dev)) {
> dev_err(bgp->dev,
> "Failed to register cpufreq cooling device\n");
> diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
> index c303d38..aaef7d8 100644
> --- a/include/linux/cpu_cooling.h
> +++ b/include/linux/cpu_cooling.h
> @@ -32,9 +32,10 @@
> /**
> * cpufreq_cooling_register - function to create cpufreq cooling device.
> * @clip_cpus: cpumask of cpus where the frequency constraints will happen
> + * @devdata: driver data pointer
> */
> struct thermal_cooling_device *
> -cpufreq_cooling_register(const struct cpumask *clip_cpus);
> +cpufreq_cooling_register(const struct cpumask *clip_cpus, void *devdata);
>
> /**
> * of_cpufreq_cooling_register - create cpufreq cooling device based on DT.
> @@ -63,7 +64,7 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
> unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq);
> #else /* !CONFIG_CPU_THERMAL */
> static inline struct thermal_cooling_device *
> -cpufreq_cooling_register(const struct cpumask *clip_cpus)
> +cpufreq_cooling_register(const struct cpumask *clip_cpus, void *devdata)
> {
> return NULL;
> }
> --
> 1.7.1
>
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