diff options
| -rw-r--r-- | Documentation/DocBook/gpu.tmpl | 48 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_fops.c | 129 | ||||
| -rw-r--r-- | include/drm/drmP.h | 17 |
3 files changed, 117 insertions, 77 deletions
diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl index a8669330b456..12731c296ff1 100644 --- a/Documentation/DocBook/gpu.tmpl +++ b/Documentation/DocBook/gpu.tmpl @@ -2886,52 +2886,8 @@ void (*postclose) (struct drm_device *, struct drm_file *);</synopsis> </sect2> <sect2> <title>File Operations</title> - <synopsis>const struct file_operations *fops</synopsis> - <abstract>File operations for the DRM device node.</abstract> - <para> - Drivers must define the file operations structure that forms the DRM - userspace API entry point, even though most of those operations are - implemented in the DRM core. The <methodname>open</methodname>, - <methodname>release</methodname> and <methodname>ioctl</methodname> - operations are handled by - <programlisting> - .owner = THIS_MODULE, - .open = drm_open, - .release = drm_release, - .unlocked_ioctl = drm_ioctl, - #ifdef CONFIG_COMPAT - .compat_ioctl = drm_compat_ioctl, - #endif - </programlisting> - </para> - <para> - Drivers that implement private ioctls that requires 32/64bit - compatibility support must provide their own - <methodname>compat_ioctl</methodname> handler that processes private - ioctls and calls <function>drm_compat_ioctl</function> for core ioctls. - </para> - <para> - The <methodname>read</methodname> and <methodname>poll</methodname> - operations provide support for reading DRM events and polling them. They - are implemented by - <programlisting> - .poll = drm_poll, - .read = drm_read, - .llseek = no_llseek, - </programlisting> - </para> - <para> - The memory mapping implementation varies depending on how the driver - manages memory. Pre-GEM drivers will use <function>drm_mmap</function>, - while GEM-aware drivers will use <function>drm_gem_mmap</function>. See - <xref linkend="drm-gem"/>. - <programlisting> - .mmap = drm_gem_mmap, - </programlisting> - </para> - <para> - No other file operation is supported by the DRM API. - </para> +!Pdrivers/gpu/drm/drm_fops.c file operations +!Edrivers/gpu/drm/drm_fops.c </sect2> <sect2> <title>IOCTLs</title> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 1ea8790e5090..1551d65db24e 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -1,4 +1,4 @@ -/** +/* * \file drm_fops.c * File operations for DRM * @@ -44,6 +44,46 @@ /* from BKL pushdown */ DEFINE_MUTEX(drm_global_mutex); +/** + * DOC: file operations + * + * Drivers must define the file operations structure that forms the DRM + * userspace API entry point, even though most of those operations are + * implemented in the DRM core. The mandatory functions are drm_open(), + * drm_read(), drm_ioctl() and drm_compat_ioctl if CONFIG_COMPAT is enabled. + * Drivers which implement private ioctls that require 32/64 bit compatibility + * support must provided their onw .compat_ioctl() handler that processes + * private ioctls and calls drm_compat_ioctl() for core ioctls. + * + * In addition drm_read() and drm_poll() provide support for DRM events. DRM + * events are a generic and extensible means to send asynchronous events to + * userspace through the file descriptor. They are used to send vblank event and + * page flip completions by the KMS API. But drivers can also use it for their + * own needs, e.g. to signal completion of rendering. + * + * The memory mapping implementation will vary depending on how the driver + * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap() + * function, modern drivers should use one of the provided memory-manager + * specific implementations. For GEM-based drivers this is drm_gem_mmap(). + * + * No other file operations are supported by the DRM userspace API. Overall the + * following is an example #file_operations structure: + * + * static const example_drm_fops = { + * .owner = THIS_MODULE, + * .open = drm_open, + * .release = drm_release, + * .unlocked_ioctl = drm_ioctl, + * #ifdef CONFIG_COMPAT + * .compat_ioctl = drm_compat_ioctl, + * #endif + * .poll = drm_poll, + * .read = drm_read, + * .llseek = no_llseek, + * .mmap = drm_gem_mmap, + * }; + */ + static int drm_open_helper(struct file *filp, struct drm_minor *minor); static int drm_setup(struct drm_device * dev) @@ -67,15 +107,17 @@ static int drm_setup(struct drm_device * dev) } /** - * Open file. + * drm_open - open method for DRM file + * @inode: device inode + * @filp: file pointer. * - * \param inode device inode - * \param filp file pointer. - * \return zero on success or a negative number on failure. + * This function must be used by drivers as their .open() #file_operations + * method. It looks up the correct DRM device and instantiates all the per-file + * resources for it. + * + * RETURNS: * - * Searches the DRM device with the same minor number, calls open_helper(), and - * increments the device open count. If the open count was previous at zero, - * i.e., it's the first that the device is open, then calls setup(). + * 0 on success or negative errno value on falure. */ int drm_open(struct inode *inode, struct file *filp) { @@ -112,7 +154,7 @@ err_undo: } EXPORT_SYMBOL(drm_open); -/** +/* * Check whether DRI will run on this CPU. * * \return non-zero if the DRI will run on this CPU, or zero otherwise. @@ -125,7 +167,7 @@ static int drm_cpu_valid(void) return 1; } -/** +/* * drm_new_set_master - Allocate a new master object and become master for the * associated master realm. * @@ -179,7 +221,7 @@ out_err: return ret; } -/** +/* * Called whenever a process opens /dev/drm. * * \param filp file pointer. @@ -333,7 +375,7 @@ static void drm_events_release(struct drm_file *file_priv) spin_unlock_irqrestore(&dev->event_lock, flags); } -/** +/* * drm_legacy_dev_reinit * * Reinitializes a legacy/ums drm device in it's lastclose function. @@ -350,7 +392,7 @@ static void drm_legacy_dev_reinit(struct drm_device *dev) dev->if_version = 0; } -/** +/* * Take down the DRM device. * * \param dev DRM device structure. @@ -387,16 +429,17 @@ int drm_lastclose(struct drm_device * dev) } /** - * Release file. + * drm_release - release method for DRM file + * @inode: device inode + * @filp: file pointer. * - * \param inode device inode - * \param file_priv DRM file private. - * \return zero on success or a negative number on failure. + * This function must be used by drivers as their .release() #file_operations + * method. It frees any resources associated with the open file, and if this is + * the last open file for the DRM device also proceeds to call drm_lastclose(). * - * If the hardware lock is held then free it, and take it again for the kernel - * context since it's necessary to reclaim buffers. Unlink the file private - * data from its list and free it. Decreases the open count and if it reaches - * zero calls drm_lastclose(). + * RETURNS: + * + * Always succeeds and returns 0. */ int drm_release(struct inode *inode, struct file *filp) { @@ -451,7 +494,7 @@ int drm_release(struct inode *inode, struct file *filp) if (file_priv->is_master) { struct drm_master *master = file_priv->master; - /** + /* * Since the master is disappearing, so is the * possibility to lock. */ @@ -508,6 +551,32 @@ int drm_release(struct inode *inode, struct file *filp) } EXPORT_SYMBOL(drm_release); +/** + * drm_read - read method for DRM file + * @filp: file pointer + * @buffer: userspace destination pointer for the read + * @count: count in bytes to read + * @offset: offset to read + * + * This function must be used by drivers as their .read() #file_operations + * method iff they use DRM events for asynchronous signalling to userspace. + * Since events are used by the KMS API for vblank and page flip completion this + * means all modern display drivers must use it. + * + * @offset is ignore, DRM events are read like a pipe. Therefore drivers also + * must set the .llseek() #file_operation to no_llseek(). Polling support is + * provided by drm_poll(). + * + * This function will only ever read a full event. Therefore userspace must + * supply a big enough buffer to fit any event to ensure forward progress. Since + * the maximum event space is currently 4K it's recommended to just use that for + * safety. + * + * RETURNS: + * + * Number of bytes read (always aligned to full events, and can be 0) or a + * negative error code on failure. + */ ssize_t drm_read(struct file *filp, char __user *buffer, size_t count, loff_t *offset) { @@ -578,6 +647,22 @@ put_back_event: } EXPORT_SYMBOL(drm_read); +/** + * drm_poll - poll method for DRM file + * @filp: file pointer + * @wait: poll waiter table + * + * This function must be used by drivers as their .read() #file_operations + * method iff they use DRM events for asynchronous signalling to userspace. + * Since events are used by the KMS API for vblank and page flip completion this + * means all modern display drivers must use it. + * + * See also drm_read(). + * + * RETURNS: + * + * Mask of POLL flags indicating the current status of the file. + */ unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait) { struct drm_file *file_priv = filp->private_data; diff --git a/include/drm/drmP.h b/include/drm/drmP.h index d7162cf1c3e1..a46a34fc67b3 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -919,15 +919,14 @@ extern long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg); extern bool drm_ioctl_flags(unsigned int nr, unsigned int *flags); - /* Device support (drm_fops.h) */ -extern int drm_open(struct inode *inode, struct file *filp); -extern ssize_t drm_read(struct file *filp, char __user *buffer, - size_t count, loff_t *offset); -extern int drm_release(struct inode *inode, struct file *filp); -extern int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv); - - /* Mapping support (drm_vm.h) */ -extern unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait); +/* File Operations (drm_fops.c) */ +int drm_open(struct inode *inode, struct file *filp); +ssize_t drm_read(struct file *filp, char __user *buffer, + size_t count, loff_t *offset); +int drm_release(struct inode *inode, struct file *filp); +int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv); + +unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait); /* Misc. IOCTL support (drm_ioctl.c) */ int drm_noop(struct drm_device *dev, void *data, |