Commit bcb877e4 authored by Daniel Vetter's avatar Daniel Vetter

drm: kerneldoc for drm_fops.c

Just prep work before I throw more drm_event refactorings on top.
Acked-by: default avatarDaniel Stone <daniels@collabora.com>
Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452548477-15905-2-git-send-email-daniel.vetter@ffwll.chSigned-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
parent 40f8cf4b
......@@ -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>
......
/**
/*
* \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 @@ int drm_open(struct inode *inode, struct file *filp)
}
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 @@ int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
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 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
}
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;
......
......@@ -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,
......
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