gpu: host1x: Flesh out kerneldoc

Improve kerneldoc for the public parts of the host1x infrastructure in
preparation for adding driver-specific part to the GPU documentation.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>

3 files changed, 170 insertions, 11 deletions

diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index 561831e1ae2c..a048e3ac523d 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -40,6 +40,9 @@ struct host1x_subdev {
 
 /**
  * host1x_subdev_add() - add a new subdevice with an associated device node
+ * @device: host1x device to add the subdevice to
+ * @driver: host1x driver
+ * @np: device node
  */
 static int host1x_subdev_add(struct host1x_device *device,
                              struct device_node *np)
@@ -62,6 +65,7 @@ static int host1x_subdev_add(struct host1x_device *device,
 
 /**
  * host1x_subdev_del() - remove subdevice
+ * @subdev: subdevice to remove
  */
 static void host1x_subdev_del(struct host1x_subdev *subdev)
 {
@@ -72,6 +76,8 @@ static void host1x_subdev_del(struct host1x_subdev *subdev)
 
 /**
  * host1x_device_parse_dt() - scan device tree and add matching subdevices
+ * @device: host1x logical device
+ * @driver: host1x driver
  */
 static int host1x_device_parse_dt(struct host1x_device *device,
                                   struct host1x_driver *driver)
@@ -166,6 +172,16 @@ static void host1x_subdev_unregister(struct host1x_device *device,
         mutex_unlock(&device->subdevs_lock);
 }
 
+/**
+ * host1x_device_init() - initialize a host1x logical device
+ * @device: host1x logical device
+ *
+ * The driver for the host1x logical device can call this during execution of
+ * its &host1x_driver.probe implementation to initialize each of its clients.
+ * The client drivers access the subsystem specific driver data using the
+ * &host1x_client.parent field and driver data associated with it (usually by
+ * calling dev_get_drvdata()).
+ */
 int host1x_device_init(struct host1x_device *device)
 {
         struct host1x_client *client;
@@ -192,6 +208,15 @@ int host1x_device_init(struct host1x_device *device)
 }
 EXPORT_SYMBOL(host1x_device_init);
 
+/**
+ * host1x_device_exit() - uninitialize host1x logical device
+ * @device: host1x logical device
+ *
+ * When the driver for a host1x logical device is unloaded, it can call this
+ * function to tear down each of its clients. Typically this is done after a
+ * subsystem-specific data structure is removed and the functionality can no
+ * longer be used.
+ */
 int host1x_device_exit(struct host1x_device *device)
 {
         struct host1x_client *client;
@@ -446,6 +471,14 @@ static void host1x_detach_driver(struct host1x *host1x,
         mutex_unlock(&host1x->devices_lock);
 }
 
+/**
+ * host1x_register() - register a host1x controller
+ * @host1x: host1x controller
+ *
+ * The host1x controller driver uses this to register a host1x controller with
+ * the infrastructure. Note that all Tegra SoC generations have only ever come
+ * with a single host1x instance, so this function is somewhat academic.
+ */
 int host1x_register(struct host1x *host1x)
 {
         struct host1x_driver *driver;
@@ -464,6 +497,13 @@ int host1x_register(struct host1x *host1x)
         return 0;
 }
 
+/**
+ * host1x_unregister() - unregister a host1x controller
+ * @host1x: host1x controller
+ *
+ * The host1x controller driver uses this to remove a host1x controller from
+ * the infrastructure.
+ */
 int host1x_unregister(struct host1x *host1x)
 {
         struct host1x_driver *driver;
@@ -513,6 +553,16 @@ static void host1x_device_shutdown(struct device *dev)
                 driver->shutdown(device);
 }
 
+/**
+ * host1x_driver_register_full() - register a host1x driver
+ * @driver: host1x driver
+ * @owner: owner module
+ *
+ * Drivers for host1x logical devices call this function to register a driver
+ * with the infrastructure. Note that since these drive logical devices, the
+ * registration of the driver actually triggers tho logical device creation.
+ * A logical device will be created for each host1x instance.
+ */
 int host1x_driver_register_full(struct host1x_driver *driver,
                                 struct module *owner)
 {
@@ -541,6 +591,13 @@ int host1x_driver_register_full(struct host1x_driver *driver,
 }
 EXPORT_SYMBOL(host1x_driver_register_full);
 
+/**
+ * host1x_driver_unregister() - unregister a host1x driver
+ * @driver: host1x driver
+ *
+ * Unbinds the driver from each of the host1x logical devices that it is
+ * bound to, effectively removing the subsystem devices that they represent.
+ */
 void host1x_driver_unregister(struct host1x_driver *driver)
 {
         driver_unregister(&driver->driver);
@@ -551,6 +608,17 @@ void host1x_driver_unregister(struct host1x_driver *driver)
 }
 EXPORT_SYMBOL(host1x_driver_unregister);
 
+/**
+ * host1x_client_register() - register a host1x client
+ * @client: host1x client
+ *
+ * Registers a host1x client with each host1x controller instance. Note that
+ * each client will only match their parent host1x controller and will only be
+ * associated with that instance. Once all clients have been registered with
+ * their parent host1x controller, the infrastructure will set up the logical
+ * device and call host1x_device_init(), which will in turn call each client's
+ * &host1x_client_ops.init implementation.
+ */
 int host1x_client_register(struct host1x_client *client)
 {
         struct host1x *host1x;
@@ -576,6 +644,13 @@ int host1x_client_register(struct host1x_client *client)
 }
 EXPORT_SYMBOL(host1x_client_register);
 
+/**
+ * host1x_client_unregister() - unregister a host1x client
+ * @client: host1x client
+ *
+ * Removes a host1x client from its host1x controller instance. If a logical
+ * device has already been initialized, it will be torn down.
+ */
 int host1x_client_unregister(struct host1x_client *client)
 {
         struct host1x_client *c;
diff --git a/drivers/gpu/host1x/syncpt.c b/drivers/gpu/host1x/syncpt.c
index 0ac026cdc30c..048ac9e344ce 100644
--- a/drivers/gpu/host1x/syncpt.c
+++ b/drivers/gpu/host1x/syncpt.c
@@ -99,14 +99,24 @@ unlock:
         return NULL;
 }
 
+/**
+ * host1x_syncpt_id() - retrieve syncpoint ID
+ * @sp: host1x syncpoint
+ *
+ * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
+ * often used as a value to program into registers that control how hardware
+ * blocks interact with syncpoints.
+ */
 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 {
         return sp->id;
 }
 EXPORT_SYMBOL(host1x_syncpt_id);
 
-/*
- * Updates the value sent to hardware.
+/**
+ * host1x_syncpt_incr_max() - update the value sent to hardware
+ * @sp: host1x syncpoint
+ * @incrs: number of increments
  */
 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 {
@@ -175,8 +185,9 @@ u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
         return sp->base_val;
 }
 
-/*
- * Increment syncpoint value from cpu, updating cache
+/**
+ * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
+ * @sp: host1x syncpoint
  */
 int host1x_syncpt_incr(struct host1x_syncpt *sp)
 {
@@ -195,8 +206,12 @@ static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
         return host1x_syncpt_is_expired(sp, thresh);
 }
 
-/*
- * Main entrypoint for syncpoint value waits.
+/**
+ * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
+ * @sp: host1x syncpoint
+ * @thresh: threshold
+ * @timeout: maximum time to wait for the syncpoint to reach the given value
+ * @value: return location for the syncpoint value
  */
 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
                        u32 *value)
@@ -402,6 +417,16 @@ int host1x_syncpt_init(struct host1x *host)
         return 0;
 }
 
+/**
+ * host1x_syncpt_request() - request a syncpoint
+ * @dev: device requesting the syncpoint
+ * @flags: flags
+ *
+ * host1x client drivers can use this function to allocate a syncpoint for
+ * subsequent use. A syncpoint returned by this function will be reserved for
+ * use by the client exclusively. When no longer using a syncpoint, a host1x
+ * client driver needs to release it using host1x_syncpt_free().
+ */
 struct host1x_syncpt *host1x_syncpt_request(struct device *dev,
                                             unsigned long flags)
 {
@@ -411,6 +436,16 @@ struct host1x_syncpt *host1x_syncpt_request(struct device *dev,
 }
 EXPORT_SYMBOL(host1x_syncpt_request);
 
+/**
+ * host1x_syncpt_free() - free a requested syncpoint
+ * @sp: host1x syncpoint
+ *
+ * Release a syncpoint previously allocated using host1x_syncpt_request(). A
+ * host1x client driver should call this when the syncpoint is no longer in
+ * use. Note that client drivers must ensure that the syncpoint doesn't remain
+ * under the control of hardware after calling this function, otherwise two
+ * clients may end up trying to access the same syncpoint concurrently.
+ */
 void host1x_syncpt_free(struct host1x_syncpt *sp)
 {
         if (!sp)
@@ -438,9 +473,12 @@ void host1x_syncpt_deinit(struct host1x *host)
                 kfree(sp->name);
 }
 
-/*
- * Read max. It indicates how many operations there are in queue, either in
- * channel or in a software thread.
+/**
+ * host1x_syncpt_read_max() - read maximum syncpoint value
+ * @sp: host1x syncpoint
+ *
+ * The maximum syncpoint value indicates how many operations there are in
+ * queue, either in channel or in a software thread.
  */
 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 {
@@ -450,8 +488,12 @@ u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 }
 EXPORT_SYMBOL(host1x_syncpt_read_max);
 
-/*
- * Read min, which is a shadow of the current sync point value in hardware.
+/**
+ * host1x_syncpt_read_min() - read minimum syncpoint value
+ * @sp: host1x syncpoint
+ *
+ * The minimum syncpoint value is a shadow of the current sync point value in
+ * hardware.
  */
 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 {
@@ -461,6 +503,10 @@ u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 }
 EXPORT_SYMBOL(host1x_syncpt_read_min);
 
+/**
+ * host1x_syncpt_read() - read the current syncpoint value
+ * @sp: host1x syncpoint
+ */
 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 {
         return host1x_syncpt_load(sp);
@@ -482,6 +528,11 @@ unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
         return host->info->nb_mlocks;
 }
 
+/**
+ * host1x_syncpt_get() - obtain a syncpoint by ID
+ * @host: host1x controller
+ * @id: syncpoint ID
+ */
 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 {
         if (id >= host->info->nb_pts)
@@ -491,12 +542,20 @@ struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 }
 EXPORT_SYMBOL(host1x_syncpt_get);
 
+/**
+ * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
+ * @sp: host1x syncpoint
+ */
 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 {
         return sp ? sp->base : NULL;
 }
 EXPORT_SYMBOL(host1x_syncpt_get_base);
 
+/**
+ * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
+ * @base: host1x syncpoint wait base
+ */
 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 {
         return base->id;
diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index 3d04aa1dc83e..840a8ad627b2 100644
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -32,11 +32,27 @@ enum host1x_class {
 
 struct host1x_client;
 
+/**
+ * struct host1x_client_ops - host1x client operations
+ * @init: host1x client initialization code
+ * @exit: host1x client tear down code
+ */
 struct host1x_client_ops {
         int (*init)(struct host1x_client *client);
         int (*exit)(struct host1x_client *client);
 };
 
+/**
+ * struct host1x_client - host1x client structure
+ * @list: list node for the host1x client
+ * @parent: pointer to struct device representing the host1x controller
+ * @dev: pointer to struct device backing this host1x client
+ * @ops: host1x client operations
+ * @class: host1x class represented by this client
+ * @channel: host1x channel associated with this client
+ * @syncpts: array of syncpoints requested for this client
+ * @num_syncpts: number of syncpoints requested for this client
+ */
 struct host1x_client {
         struct list_head list;
         struct device *parent;
@@ -251,6 +267,15 @@ void host1x_job_unpin(struct host1x_job *job);
 
 struct host1x_device;
 
+/**
+ * struct host1x_driver - host1x logical device driver
+ * @driver: core driver
+ * @subdevs: table of OF device IDs matching subdevices for this driver
+ * @list: list node for the driver
+ * @probe: called when the host1x logical device is probed
+ * @remove: called when the host1x logical device is removed
+ * @shutdown: called when the host1x logical device is shut down
+ */
 struct host1x_driver {
         struct device_driver driver;