drm: kerneldoc for drm_fops.c
Just prep work before I throw more drm_event refactorings on top. Acked-by: Daniel Stone <daniels@collabora.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Link: http://patchwork.freedesktop.org/patch/msgid/1452548477-15905-2-git-send-email-daniel.vetter@ffwll.ch Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
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Daniel Vetter
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@ -2886,52 +2886,8 @@ void (*postclose) (struct drm_device *, struct drm_file *);</synopsis>
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</sect2>
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<sect2>
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<title>File Operations</title>
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<synopsis>const struct file_operations *fops</synopsis>
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<abstract>File operations for the DRM device node.</abstract>
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<para>
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Drivers must define the file operations structure that forms the DRM
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userspace API entry point, even though most of those operations are
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implemented in the DRM core. The <methodname>open</methodname>,
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<methodname>release</methodname> and <methodname>ioctl</methodname>
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operations are handled by
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<programlisting>
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.owner = THIS_MODULE,
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.open = drm_open,
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.release = drm_release,
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.unlocked_ioctl = drm_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = drm_compat_ioctl,
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#endif
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</programlisting>
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</para>
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<para>
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Drivers that implement private ioctls that requires 32/64bit
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compatibility support must provide their own
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<methodname>compat_ioctl</methodname> handler that processes private
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ioctls and calls <function>drm_compat_ioctl</function> for core ioctls.
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</para>
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<para>
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The <methodname>read</methodname> and <methodname>poll</methodname>
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operations provide support for reading DRM events and polling them. They
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are implemented by
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<programlisting>
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.poll = drm_poll,
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.read = drm_read,
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.llseek = no_llseek,
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</programlisting>
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</para>
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<para>
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The memory mapping implementation varies depending on how the driver
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manages memory. Pre-GEM drivers will use <function>drm_mmap</function>,
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while GEM-aware drivers will use <function>drm_gem_mmap</function>. See
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<xref linkend="drm-gem"/>.
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<programlisting>
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.mmap = drm_gem_mmap,
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</programlisting>
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</para>
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<para>
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No other file operation is supported by the DRM API.
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</para>
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!Pdrivers/gpu/drm/drm_fops.c file operations
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!Edrivers/gpu/drm/drm_fops.c
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</sect2>
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<sect2>
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<title>IOCTLs</title>
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@ -1,4 +1,4 @@
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/**
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/*
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* \file drm_fops.c
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* File operations for DRM
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*
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@ -44,6 +44,46 @@
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/* from BKL pushdown */
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DEFINE_MUTEX(drm_global_mutex);
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/**
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* DOC: file operations
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*
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* Drivers must define the file operations structure that forms the DRM
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* userspace API entry point, even though most of those operations are
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* implemented in the DRM core. The mandatory functions are drm_open(),
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* drm_read(), drm_ioctl() and drm_compat_ioctl if CONFIG_COMPAT is enabled.
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* Drivers which implement private ioctls that require 32/64 bit compatibility
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* support must provided their onw .compat_ioctl() handler that processes
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* private ioctls and calls drm_compat_ioctl() for core ioctls.
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*
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* In addition drm_read() and drm_poll() provide support for DRM events. DRM
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* events are a generic and extensible means to send asynchronous events to
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* userspace through the file descriptor. They are used to send vblank event and
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* page flip completions by the KMS API. But drivers can also use it for their
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* own needs, e.g. to signal completion of rendering.
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*
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* The memory mapping implementation will vary depending on how the driver
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* manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
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* function, modern drivers should use one of the provided memory-manager
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* specific implementations. For GEM-based drivers this is drm_gem_mmap().
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*
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* No other file operations are supported by the DRM userspace API. Overall the
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* following is an example #file_operations structure:
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*
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* static const example_drm_fops = {
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* .owner = THIS_MODULE,
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* .open = drm_open,
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* .release = drm_release,
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* .unlocked_ioctl = drm_ioctl,
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* #ifdef CONFIG_COMPAT
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* .compat_ioctl = drm_compat_ioctl,
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* #endif
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* .poll = drm_poll,
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* .read = drm_read,
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* .llseek = no_llseek,
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* .mmap = drm_gem_mmap,
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* };
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*/
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static int drm_open_helper(struct file *filp, struct drm_minor *minor);
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static int drm_setup(struct drm_device * dev)
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@ -67,15 +107,17 @@ static int drm_setup(struct drm_device * dev)
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}
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/**
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* Open file.
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* drm_open - open method for DRM file
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* @inode: device inode
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* @filp: file pointer.
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*
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* \param inode device inode
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* \param filp file pointer.
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* \return zero on success or a negative number on failure.
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* This function must be used by drivers as their .open() #file_operations
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* method. It looks up the correct DRM device and instantiates all the per-file
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* resources for it.
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*
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* Searches the DRM device with the same minor number, calls open_helper(), and
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* increments the device open count. If the open count was previous at zero,
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* i.e., it's the first that the device is open, then calls setup().
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* RETURNS:
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*
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* 0 on success or negative errno value on falure.
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*/
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int drm_open(struct inode *inode, struct file *filp)
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{
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@ -112,7 +154,7 @@ err_undo:
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}
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EXPORT_SYMBOL(drm_open);
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/**
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/*
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* Check whether DRI will run on this CPU.
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*
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* \return non-zero if the DRI will run on this CPU, or zero otherwise.
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@ -125,7 +167,7 @@ static int drm_cpu_valid(void)
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return 1;
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}
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/**
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/*
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* drm_new_set_master - Allocate a new master object and become master for the
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* associated master realm.
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*
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@ -179,7 +221,7 @@ out_err:
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return ret;
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}
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/**
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/*
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* Called whenever a process opens /dev/drm.
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*
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* \param filp file pointer.
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@ -333,7 +375,7 @@ static void drm_events_release(struct drm_file *file_priv)
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spin_unlock_irqrestore(&dev->event_lock, flags);
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}
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/**
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/*
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* drm_legacy_dev_reinit
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*
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* Reinitializes a legacy/ums drm device in it's lastclose function.
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@ -350,7 +392,7 @@ static void drm_legacy_dev_reinit(struct drm_device *dev)
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dev->if_version = 0;
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}
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/**
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/*
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* Take down the DRM device.
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*
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* \param dev DRM device structure.
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@ -387,16 +429,17 @@ int drm_lastclose(struct drm_device * dev)
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}
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/**
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* Release file.
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* drm_release - release method for DRM file
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* @inode: device inode
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* @filp: file pointer.
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*
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* \param inode device inode
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* \param file_priv DRM file private.
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* \return zero on success or a negative number on failure.
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* This function must be used by drivers as their .release() #file_operations
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* method. It frees any resources associated with the open file, and if this is
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* the last open file for the DRM device also proceeds to call drm_lastclose().
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*
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* If the hardware lock is held then free it, and take it again for the kernel
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* context since it's necessary to reclaim buffers. Unlink the file private
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* data from its list and free it. Decreases the open count and if it reaches
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* zero calls drm_lastclose().
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* RETURNS:
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*
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* Always succeeds and returns 0.
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*/
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int drm_release(struct inode *inode, struct file *filp)
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{
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@ -451,7 +494,7 @@ int drm_release(struct inode *inode, struct file *filp)
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if (file_priv->is_master) {
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struct drm_master *master = file_priv->master;
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/**
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/*
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* Since the master is disappearing, so is the
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* possibility to lock.
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*/
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@ -508,6 +551,32 @@ int drm_release(struct inode *inode, struct file *filp)
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}
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EXPORT_SYMBOL(drm_release);
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/**
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* drm_read - read method for DRM file
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* @filp: file pointer
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* @buffer: userspace destination pointer for the read
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* @count: count in bytes to read
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* @offset: offset to read
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*
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* This function must be used by drivers as their .read() #file_operations
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* method iff they use DRM events for asynchronous signalling to userspace.
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* Since events are used by the KMS API for vblank and page flip completion this
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* means all modern display drivers must use it.
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*
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* @offset is ignore, DRM events are read like a pipe. Therefore drivers also
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* must set the .llseek() #file_operation to no_llseek(). Polling support is
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* provided by drm_poll().
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*
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* This function will only ever read a full event. Therefore userspace must
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* supply a big enough buffer to fit any event to ensure forward progress. Since
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* the maximum event space is currently 4K it's recommended to just use that for
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* safety.
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*
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* RETURNS:
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*
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* Number of bytes read (always aligned to full events, and can be 0) or a
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* negative error code on failure.
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*/
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ssize_t drm_read(struct file *filp, char __user *buffer,
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size_t count, loff_t *offset)
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{
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@ -578,6 +647,22 @@ put_back_event:
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}
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EXPORT_SYMBOL(drm_read);
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/**
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* drm_poll - poll method for DRM file
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* @filp: file pointer
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* @wait: poll waiter table
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*
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* This function must be used by drivers as their .read() #file_operations
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* method iff they use DRM events for asynchronous signalling to userspace.
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* Since events are used by the KMS API for vblank and page flip completion this
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* means all modern display drivers must use it.
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*
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* See also drm_read().
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*
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* RETURNS:
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*
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* Mask of POLL flags indicating the current status of the file.
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*/
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unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
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{
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struct drm_file *file_priv = filp->private_data;
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@ -919,15 +919,14 @@ extern long drm_compat_ioctl(struct file *filp,
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unsigned int cmd, unsigned long arg);
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extern bool drm_ioctl_flags(unsigned int nr, unsigned int *flags);
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/* Device support (drm_fops.h) */
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extern int drm_open(struct inode *inode, struct file *filp);
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extern ssize_t drm_read(struct file *filp, char __user *buffer,
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size_t count, loff_t *offset);
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extern int drm_release(struct inode *inode, struct file *filp);
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extern int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv);
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/* File Operations (drm_fops.c) */
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int drm_open(struct inode *inode, struct file *filp);
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ssize_t drm_read(struct file *filp, char __user *buffer,
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size_t count, loff_t *offset);
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int drm_release(struct inode *inode, struct file *filp);
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int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv);
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/* Mapping support (drm_vm.h) */
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extern unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait);
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unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait);
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/* Misc. IOCTL support (drm_ioctl.c) */
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int drm_noop(struct drm_device *dev, void *data,
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