| Message ID | 20200504181616.175477-2-srinivas.pandruvada@linux.intel.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | thermal: Add new mechanism to get thermal notification | expand |
On Mon, May 4, 2020 at 11:47 PM Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> wrote: > > This change adds an optional feature to add a new device entry > /dev/thermal_notify. > > When config CONFIG_THERMAL_USER_EVENT_INTERFACE is selected, this new > device entry is created. > > Thermal core or any thermal driver can use thermal_dev_send_event() interface Do you have any particular use case in mind where a platform driver will use this interface to send platform-specific events? IMO, we should probably try to keep this restricted to messages from thermal core if we are to have any hope of having a standard library in userspace capable of parsing these thermal events. > to send events. Each user events follows a standard format: > - zone_id > - event_id > - event_data > - reserved for future, currently 0s > > User space can basically: > fd = open ("/dev/thermal_notify") > In a loop > read (fd) > read and process event > > or > fd = open ("/dev/thermal_notify") > Set the fs as non blocking > In a loop > Use poll() and wait > read and process event > > There are predefined events added to thermal.h. Based on need they can > be extended. > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > --- > drivers/thermal/Kconfig | 9 ++ > drivers/thermal/Makefile | 3 + > drivers/thermal/thermal_dev_if.c | 195 +++++++++++++++++++++++++++++++ > include/linux/thermal.h | 24 ++++ > 4 files changed, 231 insertions(+) > create mode 100644 drivers/thermal/thermal_dev_if.c > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > index 91af271e9bb0..27d05d62458e 100644 > --- a/drivers/thermal/Kconfig > +++ b/drivers/thermal/Kconfig > @@ -78,6 +78,15 @@ config THERMAL_WRITABLE_TRIPS > Say 'Y' here if you would like to allow userspace tools to > change trip temperatures. > > +config THERMAL_USER_EVENT_INTERFACE > + bool "Allow user space to read thermal events from a dev file" > + help > + This option allows a user space program to read thermal events > + via /dev/thermal_notify file. > + > + Say 'Y' here if you would like to allow userspace programs to > + read thermal events. > + > choice > prompt "Default Thermal governor" > default THERMAL_DEFAULT_GOV_STEP_WISE > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > index 8c8ed7b79915..8f65832d755a 100644 > --- a/drivers/thermal/Makefile > +++ b/drivers/thermal/Makefile > @@ -11,6 +11,9 @@ thermal_sys-y += thermal_core.o thermal_sysfs.o \ > thermal_sys-$(CONFIG_THERMAL_HWMON) += thermal_hwmon.o > thermal_sys-$(CONFIG_THERMAL_OF) += of-thermal.o > > +# Thermal user space events > +obj-$(CONFIG_THERMAL_USER_EVENT_INTERFACE) += thermal_dev_if.o > + > # governors > thermal_sys-$(CONFIG_THERMAL_GOV_FAIR_SHARE) += fair_share.o > thermal_sys-$(CONFIG_THERMAL_GOV_BANG_BANG) += gov_bang_bang.o > diff --git a/drivers/thermal/thermal_dev_if.c b/drivers/thermal/thermal_dev_if.c > new file mode 100644 > index 000000000000..763bfe9eef9d > --- /dev/null > +++ b/drivers/thermal/thermal_dev_if.c > @@ -0,0 +1,195 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Thermal device file interface > + * Copyright (c) 2020, Intel Corporation. > + * All rights reserved. > + * > + * Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > + */ > + > +#include <linux/init.h> > +#include <linux/kfifo.h> > +#include <linux/miscdevice.h> > +#include <linux/poll.h> > +#include <linux/slab.h> > +#include <linux/thermal.h> > +#include <linux/wait.h> > + > +#define THERMAL_DEV_FIFO_SIZE 1024 > + > +struct thermal_chdev_sample { > + int zone_id; > + int event; > + u64 event_data; > + u64 reserved; > +}; > + > +struct thermal_chdev { > + struct miscdevice therm_dev; > + struct kfifo data_fifo; > + unsigned long misc_opened; > + wait_queue_head_t wait; > +}; > + > +static DEFINE_MUTEX(thermal_chdev_mutex); > +static struct thermal_chdev *thermal_chdev; > + > +static int thermal_chdev_open(struct inode *inode, struct file *file) > +{ > + struct thermal_chdev *chdev; > + > + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); > + > + /* We essentially have single reader and writer */ > + if (test_and_set_bit(0, &chdev->misc_opened)) > + return -EBUSY; > + > + return stream_open(inode, file); > +} > + > +static int thermal_chdev_release(struct inode *inode, struct file *file) > +{ > + struct thermal_chdev *chdev; > + > + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); > + > + clear_bit(0, &chdev->misc_opened); > + > + return 0; > +} > + > +static __poll_t thermal_chdev_poll(struct file *file, struct poll_table_struct *wait) > +{ > + struct thermal_chdev *chdev; > + __poll_t mask = 0; > + > + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); > + > + poll_wait(file, &chdev->wait, wait); > + > + if (!kfifo_is_empty(&chdev->data_fifo)) > + mask = EPOLLIN | EPOLLRDNORM; > + > + return mask; > +} > + > +static ssize_t thermal_chdev_read(struct file *file, char __user *buf, size_t count, loff_t *f_ps) > +{ > + struct thermal_chdev *chdev; > + unsigned int copied; > + int ret; > + > + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); > + > + if (count < sizeof(struct thermal_chdev_sample)) > + return -EINVAL; > + > + do { > + if (kfifo_is_empty(&chdev->data_fifo)) { > + if (file->f_flags & O_NONBLOCK) > + return -EAGAIN; > + > + ret = wait_event_interruptible(chdev->wait, !kfifo_is_empty(&chdev->data_fifo)); > + if (ret) > + return ret; > + } > + ret = kfifo_to_user(&chdev->data_fifo, buf, count, &copied); > + if (ret) > + return ret; > + > + } while (copied == 0); > + > + return copied; > +} > + > +static int thermal_chdev_capture_sample(struct thermal_chdev *chdev, struct thermal_chdev_sample *sample) > +{ > + int ret = 0; > + > + if (!test_bit(0, &chdev->misc_opened)) > + return 0; > + > + mutex_lock(&thermal_chdev_mutex); > + if (kfifo_avail(&chdev->data_fifo) >= sizeof(*sample)) { > + kfifo_in(&chdev->data_fifo, (unsigned char *)sample, sizeof(*sample)); > + wake_up(&chdev->wait); > + } else { > + ret = -ENOMEM; > + } > + mutex_unlock(&thermal_chdev_mutex); > + > + return ret; > +} > + > +static const struct file_operations thermal_chdev_fops = { > + .open = thermal_chdev_open, > + .read = thermal_chdev_read, > + .release = thermal_chdev_release, > + .poll = thermal_chdev_poll, > + .llseek = noop_llseek, > +}; > + > +static int thermal_dev_if_add(void) > +{ > + int ret; > + > + if (thermal_chdev) > + return 0; > + > + thermal_chdev = kzalloc(sizeof(*thermal_chdev), GFP_KERNEL); > + if (!thermal_chdev) > + return -ENOMEM; > + > + ret = kfifo_alloc(&thermal_chdev->data_fifo, THERMAL_DEV_FIFO_SIZE, GFP_KERNEL); > + if (ret) > + goto free_mem; > + > + init_waitqueue_head(&thermal_chdev->wait); > + > + thermal_chdev->therm_dev.minor = MISC_DYNAMIC_MINOR; > + thermal_chdev->therm_dev.name = "thermal_notify"; > + thermal_chdev->therm_dev.fops = &thermal_chdev_fops; > + ret = misc_register(&thermal_chdev->therm_dev); > + if (ret) { > + kfifo_free(&thermal_chdev->data_fifo); > + goto free_mem; > + } > + > + return 0; > + > +free_mem: > + kfree(thermal_chdev); > + thermal_chdev = NULL; > + return ret; > +} > + > +/** > + * thermal_dev_send_event() - Send thermal event to user space > + * @zone_id: Zone id of the caller > + * @event: A predefined thermal event > + * @event_data: Event specific data > + * > + * An interface to send event to user space with an optional associated > + * data. > + * > + * Return: 0 on success, other values on error. > + */ > +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data) > +{ > + struct thermal_chdev_sample sample; > + > + if (!thermal_chdev) { > + int ret; > + > + ret = thermal_dev_if_add(); > + if (ret) > + return ret; > + } > + > + sample.zone_id = zone_id; > + sample.event = event; > + sample.event_data = event_data; > + sample.reserved = 0; > + return thermal_chdev_capture_sample(thermal_chdev, &sample); > +} > +EXPORT_SYMBOL_GPL(thermal_dev_send_event); > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index c91b1e344d56..f5e1e7c6a9a2 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -543,4 +543,28 @@ static inline void thermal_notify_framework(struct thermal_zone_device *tz, > { } > #endif /* CONFIG_THERMAL */ > > +enum thermal_device_events { > + THERMAL_TEMP_SAMPLE = 0, > + THERMAL_ZONE_CREATE, > + THERMAL_ZONE_DELETE, > + THERMAL_ZONE_DISABLED, > + THERMAL_ZONE_ENABLED, > + THERMAL_TEMP_LOW_THRES, > + THERMAL_TEMP_HIGH_THRES, > + THERMAL_TRIP_ADD, > + THERMAL_TRIP_DELETE, > + THERMAL_TRIP_UPDATE, > + THERMAL_TRIP_REACHED, > + THERMAL_PERF_CHANGED, > +}; > + > +#ifdef CONFIG_THERMAL_USER_EVENT_INTERFACE > +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data); > +#else > +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data) > +{ > + return 0; > +} > +#endif > + > #endif /* __THERMAL_H__ */ > -- > 2.25.4 >
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 91af271e9bb0..27d05d62458e 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -78,6 +78,15 @@ config THERMAL_WRITABLE_TRIPS Say 'Y' here if you would like to allow userspace tools to change trip temperatures. +config THERMAL_USER_EVENT_INTERFACE + bool "Allow user space to read thermal events from a dev file" + help + This option allows a user space program to read thermal events + via /dev/thermal_notify file. + + Say 'Y' here if you would like to allow userspace programs to + read thermal events. + choice prompt "Default Thermal governor" default THERMAL_DEFAULT_GOV_STEP_WISE diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 8c8ed7b79915..8f65832d755a 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -11,6 +11,9 @@ thermal_sys-y += thermal_core.o thermal_sysfs.o \ thermal_sys-$(CONFIG_THERMAL_HWMON) += thermal_hwmon.o thermal_sys-$(CONFIG_THERMAL_OF) += of-thermal.o +# Thermal user space events +obj-$(CONFIG_THERMAL_USER_EVENT_INTERFACE) += thermal_dev_if.o + # governors thermal_sys-$(CONFIG_THERMAL_GOV_FAIR_SHARE) += fair_share.o thermal_sys-$(CONFIG_THERMAL_GOV_BANG_BANG) += gov_bang_bang.o diff --git a/drivers/thermal/thermal_dev_if.c b/drivers/thermal/thermal_dev_if.c new file mode 100644 index 000000000000..763bfe9eef9d --- /dev/null +++ b/drivers/thermal/thermal_dev_if.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Thermal device file interface + * Copyright (c) 2020, Intel Corporation. + * All rights reserved. + * + * Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> + */ + +#include <linux/init.h> +#include <linux/kfifo.h> +#include <linux/miscdevice.h> +#include <linux/poll.h> +#include <linux/slab.h> +#include <linux/thermal.h> +#include <linux/wait.h> + +#define THERMAL_DEV_FIFO_SIZE 1024 + +struct thermal_chdev_sample { + int zone_id; + int event; + u64 event_data; + u64 reserved; +}; + +struct thermal_chdev { + struct miscdevice therm_dev; + struct kfifo data_fifo; + unsigned long misc_opened; + wait_queue_head_t wait; +}; + +static DEFINE_MUTEX(thermal_chdev_mutex); +static struct thermal_chdev *thermal_chdev; + +static int thermal_chdev_open(struct inode *inode, struct file *file) +{ + struct thermal_chdev *chdev; + + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); + + /* We essentially have single reader and writer */ + if (test_and_set_bit(0, &chdev->misc_opened)) + return -EBUSY; + + return stream_open(inode, file); +} + +static int thermal_chdev_release(struct inode *inode, struct file *file) +{ + struct thermal_chdev *chdev; + + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); + + clear_bit(0, &chdev->misc_opened); + + return 0; +} + +static __poll_t thermal_chdev_poll(struct file *file, struct poll_table_struct *wait) +{ + struct thermal_chdev *chdev; + __poll_t mask = 0; + + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); + + poll_wait(file, &chdev->wait, wait); + + if (!kfifo_is_empty(&chdev->data_fifo)) + mask = EPOLLIN | EPOLLRDNORM; + + return mask; +} + +static ssize_t thermal_chdev_read(struct file *file, char __user *buf, size_t count, loff_t *f_ps) +{ + struct thermal_chdev *chdev; + unsigned int copied; + int ret; + + chdev = container_of(file->private_data, struct thermal_chdev, therm_dev); + + if (count < sizeof(struct thermal_chdev_sample)) + return -EINVAL; + + do { + if (kfifo_is_empty(&chdev->data_fifo)) { + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible(chdev->wait, !kfifo_is_empty(&chdev->data_fifo)); + if (ret) + return ret; + } + ret = kfifo_to_user(&chdev->data_fifo, buf, count, &copied); + if (ret) + return ret; + + } while (copied == 0); + + return copied; +} + +static int thermal_chdev_capture_sample(struct thermal_chdev *chdev, struct thermal_chdev_sample *sample) +{ + int ret = 0; + + if (!test_bit(0, &chdev->misc_opened)) + return 0; + + mutex_lock(&thermal_chdev_mutex); + if (kfifo_avail(&chdev->data_fifo) >= sizeof(*sample)) { + kfifo_in(&chdev->data_fifo, (unsigned char *)sample, sizeof(*sample)); + wake_up(&chdev->wait); + } else { + ret = -ENOMEM; + } + mutex_unlock(&thermal_chdev_mutex); + + return ret; +} + +static const struct file_operations thermal_chdev_fops = { + .open = thermal_chdev_open, + .read = thermal_chdev_read, + .release = thermal_chdev_release, + .poll = thermal_chdev_poll, + .llseek = noop_llseek, +}; + +static int thermal_dev_if_add(void) +{ + int ret; + + if (thermal_chdev) + return 0; + + thermal_chdev = kzalloc(sizeof(*thermal_chdev), GFP_KERNEL); + if (!thermal_chdev) + return -ENOMEM; + + ret = kfifo_alloc(&thermal_chdev->data_fifo, THERMAL_DEV_FIFO_SIZE, GFP_KERNEL); + if (ret) + goto free_mem; + + init_waitqueue_head(&thermal_chdev->wait); + + thermal_chdev->therm_dev.minor = MISC_DYNAMIC_MINOR; + thermal_chdev->therm_dev.name = "thermal_notify"; + thermal_chdev->therm_dev.fops = &thermal_chdev_fops; + ret = misc_register(&thermal_chdev->therm_dev); + if (ret) { + kfifo_free(&thermal_chdev->data_fifo); + goto free_mem; + } + + return 0; + +free_mem: + kfree(thermal_chdev); + thermal_chdev = NULL; + return ret; +} + +/** + * thermal_dev_send_event() - Send thermal event to user space + * @zone_id: Zone id of the caller + * @event: A predefined thermal event + * @event_data: Event specific data + * + * An interface to send event to user space with an optional associated + * data. + * + * Return: 0 on success, other values on error. + */ +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data) +{ + struct thermal_chdev_sample sample; + + if (!thermal_chdev) { + int ret; + + ret = thermal_dev_if_add(); + if (ret) + return ret; + } + + sample.zone_id = zone_id; + sample.event = event; + sample.event_data = event_data; + sample.reserved = 0; + return thermal_chdev_capture_sample(thermal_chdev, &sample); +} +EXPORT_SYMBOL_GPL(thermal_dev_send_event); diff --git a/include/linux/thermal.h b/include/linux/thermal.h index c91b1e344d56..f5e1e7c6a9a2 100644 --- a/include/linux/thermal.h +++ b/include/linux/thermal.h @@ -543,4 +543,28 @@ static inline void thermal_notify_framework(struct thermal_zone_device *tz, { } #endif /* CONFIG_THERMAL */ +enum thermal_device_events { + THERMAL_TEMP_SAMPLE = 0, + THERMAL_ZONE_CREATE, + THERMAL_ZONE_DELETE, + THERMAL_ZONE_DISABLED, + THERMAL_ZONE_ENABLED, + THERMAL_TEMP_LOW_THRES, + THERMAL_TEMP_HIGH_THRES, + THERMAL_TRIP_ADD, + THERMAL_TRIP_DELETE, + THERMAL_TRIP_UPDATE, + THERMAL_TRIP_REACHED, + THERMAL_PERF_CHANGED, +}; + +#ifdef CONFIG_THERMAL_USER_EVENT_INTERFACE +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data); +#else +int thermal_dev_send_event(int zone_id, enum thermal_device_events event, u64 event_data) +{ + return 0; +} +#endif + #endif /* __THERMAL_H__ */
This change adds an optional feature to add a new device entry /dev/thermal_notify. When config CONFIG_THERMAL_USER_EVENT_INTERFACE is selected, this new device entry is created. Thermal core or any thermal driver can use thermal_dev_send_event() interface to send events. Each user events follows a standard format: - zone_id - event_id - event_data - reserved for future, currently 0s User space can basically: fd = open ("/dev/thermal_notify") In a loop read (fd) read and process event or fd = open ("/dev/thermal_notify") Set the fs as non blocking In a loop Use poll() and wait read and process event There are predefined events added to thermal.h. Based on need they can be extended. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> --- drivers/thermal/Kconfig | 9 ++ drivers/thermal/Makefile | 3 + drivers/thermal/thermal_dev_if.c | 195 +++++++++++++++++++++++++++++++ include/linux/thermal.h | 24 ++++ 4 files changed, 231 insertions(+) create mode 100644 drivers/thermal/thermal_dev_if.c