drm: document drm_ioctl.[hc]
Also unify/merge with the existing stuff. I was a bit torn where to put this, but in the end I decided to put all the ioctl/sysfs/debugfs stuff into drm-uapi.rst. That means we have a bit a split with the other uapi related stuff used internally, like drm_file.[hc], but I think overall this makes more sense. If it's too confusing we can always add more cross-links to make it more discoverable. But the auto-sprinkling of links kernel-doc already does seems sufficient. Also for prettier docs and more cross-links, switch the internal defines over to an enum, as usual. v2: Update kerneldoc fro drm_compat_ioctl too (caught by 0day), plus a bit more drive-by polish. v3: Fix typo, spotted by xerpi on irc (Sergi). v4: Add missing space in comment (Neil). Cc: Sergi Granell <xerpi.g.12@gmail.com> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170404095304.17599-4-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter
parent
e22717046a
commit
2640981f36
5 changed files with 203 additions and 103 deletions
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@ -255,56 +255,6 @@ File Operations
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.. kernel-doc:: drivers/gpu/drm/drm_file.c
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:export:
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IOCTLs
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------
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struct drm_ioctl_desc \*ioctls; int num_ioctls;
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Driver-specific ioctls descriptors table.
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Driver-specific ioctls numbers start at DRM_COMMAND_BASE. The ioctls
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descriptors table is indexed by the ioctl number offset from the base
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value. Drivers can use the DRM_IOCTL_DEF_DRV() macro to initialize
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the table entries.
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::
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DRM_IOCTL_DEF_DRV(ioctl, func, flags)
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``ioctl`` is the ioctl name. Drivers must define the DRM_##ioctl and
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DRM_IOCTL_##ioctl macros to the ioctl number offset from
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DRM_COMMAND_BASE and the ioctl number respectively. The first macro is
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private to the device while the second must be exposed to userspace in a
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public header.
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``func`` is a pointer to the ioctl handler function compatible with the
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``drm_ioctl_t`` type.
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::
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typedef int drm_ioctl_t(struct drm_device *dev, void *data,
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struct drm_file *file_priv);
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``flags`` is a bitmask combination of the following values. It restricts
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how the ioctl is allowed to be called.
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- DRM_AUTH - Only authenticated callers allowed
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- DRM_MASTER - The ioctl can only be called on the master file handle
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- DRM_ROOT_ONLY - Only callers with the SYSADMIN capability allowed
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- DRM_CONTROL_ALLOW - The ioctl can only be called on a control
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device
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- DRM_UNLOCKED - The ioctl handler will be called without locking the
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DRM global mutex. This is the enforced default for kms drivers (i.e.
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using the DRIVER_MODESET flag) and hence shouldn't be used any more
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for new drivers.
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.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
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:export:
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Misc Utilities
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==============
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@ -160,6 +160,20 @@ other hand, a driver requires shared state between clients which is
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visible to user-space and accessible beyond open-file boundaries, they
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cannot support render nodes.
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IOCTL Support on Device Nodes
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=============================
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.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
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:doc: driver specific ioctls
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.. kernel-doc:: include/drm/drm_ioctl.h
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:internal:
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.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
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:export:
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.. kernel-doc:: drivers/gpu/drm/drm_ioc32.c
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:export:
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Testing and validation
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======================
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@ -1,4 +1,4 @@
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/**
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/*
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* \file drm_ioc32.c
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*
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* 32-bit ioctl compatibility routines for the DRM.
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@ -72,15 +72,15 @@
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#define DRM_IOCTL_MODE_ADDFB232 DRM_IOWR(0xb8, drm_mode_fb_cmd232_t)
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typedef struct drm_version_32 {
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int version_major; /**< Major version */
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int version_minor; /**< Minor version */
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int version_patchlevel; /**< Patch level */
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u32 name_len; /**< Length of name buffer */
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u32 name; /**< Name of driver */
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u32 date_len; /**< Length of date buffer */
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u32 date; /**< User-space buffer to hold date */
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u32 desc_len; /**< Length of desc buffer */
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u32 desc; /**< User-space buffer to hold desc */
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int version_major; /* Major version */
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int version_minor; /* Minor version */
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int version_patchlevel; /* Patch level */
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u32 name_len; /* Length of name buffer */
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u32 name; /* Name of driver */
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u32 date_len; /* Length of date buffer */
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u32 date; /* User-space buffer to hold date */
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u32 desc_len; /* Length of desc buffer */
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u32 desc; /* User-space buffer to hold desc */
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} drm_version32_t;
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static int compat_drm_version(struct file *file, unsigned int cmd,
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@ -126,8 +126,8 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
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}
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typedef struct drm_unique32 {
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u32 unique_len; /**< Length of unique */
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u32 unique; /**< Unique name for driver instantiation */
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u32 unique_len; /* Length of unique */
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u32 unique; /* Unique name for driver instantiation */
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} drm_unique32_t;
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static int compat_drm_getunique(struct file *file, unsigned int cmd,
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@ -180,12 +180,12 @@ static int compat_drm_setunique(struct file *file, unsigned int cmd,
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}
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typedef struct drm_map32 {
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u32 offset; /**< Requested physical address (0 for SAREA)*/
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u32 size; /**< Requested physical size (bytes) */
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enum drm_map_type type; /**< Type of memory to map */
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enum drm_map_flags flags; /**< Flags */
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u32 handle; /**< User-space: "Handle" to pass to mmap() */
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int mtrr; /**< MTRR slot used */
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u32 offset; /* Requested physical address (0 for SAREA) */
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u32 size; /* Requested physical size (bytes) */
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enum drm_map_type type; /* Type of memory to map */
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enum drm_map_flags flags; /* Flags */
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u32 handle; /* User-space: "Handle" to pass to mmap() */
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int mtrr; /* MTRR slot used */
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} drm_map32_t;
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static int compat_drm_getmap(struct file *file, unsigned int cmd,
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@ -286,12 +286,12 @@ static int compat_drm_rmmap(struct file *file, unsigned int cmd,
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}
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typedef struct drm_client32 {
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int idx; /**< Which client desired? */
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int auth; /**< Is client authenticated? */
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u32 pid; /**< Process ID */
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u32 uid; /**< User ID */
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u32 magic; /**< Magic */
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u32 iocs; /**< Ioctl count */
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int idx; /* Which client desired? */
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int auth; /* Is client authenticated? */
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u32 pid; /* Process ID */
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u32 uid; /* User ID */
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u32 magic; /* Magic */
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u32 iocs; /* Ioctl count */
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} drm_client32_t;
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static int compat_drm_getclient(struct file *file, unsigned int cmd,
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@ -366,12 +366,12 @@ static int compat_drm_getstats(struct file *file, unsigned int cmd,
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}
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typedef struct drm_buf_desc32 {
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int count; /**< Number of buffers of this size */
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int size; /**< Size in bytes */
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int low_mark; /**< Low water mark */
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int high_mark; /**< High water mark */
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int count; /* Number of buffers of this size */
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int size; /* Size in bytes */
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int low_mark; /* Low water mark */
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int high_mark; /* High water mark */
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int flags;
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u32 agp_start; /**< Start address in the AGP aperture */
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u32 agp_start; /* Start address in the AGP aperture */
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} drm_buf_desc32_t;
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static int compat_drm_addbufs(struct file *file, unsigned int cmd,
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@ -1111,13 +1111,18 @@ static drm_ioctl_compat_t *drm_compat_ioctls[] = {
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};
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/**
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* Called whenever a 32-bit process running under a 64-bit kernel
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* performs an ioctl on /dev/drm.
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* drm_compat_ioctl - 32bit IOCTL compatibility handler for DRM drivers
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* @filp: file this ioctl is called on
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* @cmd: ioctl cmd number
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* @arg: user argument
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*
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* \param file_priv DRM file private.
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* \param cmd command.
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* \param arg user argument.
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* \return zero on success or negative number on failure.
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* Compatibility handler for 32 bit userspace running on 64 kernels. All actual
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* IOCTL handling is forwarded to drm_ioctl(), while marshalling structures as
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* appropriate. Note that this only handles DRM core IOCTLs, if the driver has
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* botched IOCTL itself, it must handle those by wrapping this function.
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*
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* Returns:
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* Zero on success, negative error code on failure.
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*/
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long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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@ -1141,5 +1146,4 @@ long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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return ret;
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}
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EXPORT_SYMBOL(drm_compat_ioctl);
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@ -646,14 +646,60 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
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#define DRM_CORE_IOCTL_COUNT ARRAY_SIZE( drm_ioctls )
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/**
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* DOC: driver specific ioctls
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*
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* First things first, driver private IOCTLs should only be needed for drivers
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* supporting rendering. Kernel modesetting is all standardized, and extended
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* through properties. There are a few exceptions in some existing drivers,
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* which define IOCTL for use by the display DRM master, but they all predate
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* properties.
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*
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* Now if you do have a render driver you always have to support it through
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* driver private properties. There's a few steps needed to wire all the things
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* up.
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*
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* First you need to define the structure for your IOCTL in your driver private
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* UAPI header in ``include/uapi/drm/my_driver_drm.h``::
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*
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* struct my_driver_operation {
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* u32 some_thing;
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* u32 another_thing;
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* };
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*
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* Please make sure that you follow all the best practices from
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* ``Documentation/ioctl/botching-up-ioctls.txt``. Note that drm_ioctl()
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* automatically zero-extends structures, hence make sure you can add more stuff
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* at the end, i.e. don't put a variable sized array there.
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*
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* Then you need to define your IOCTL number, using one of DRM_IO(), DRM_IOR(),
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* DRM_IOW() or DRM_IOWR(). It must start with the DRM_IOCTL\_ prefix::
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*
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* ##define DRM_IOCTL_MY_DRIVER_OPERATION \
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* DRM_IOW(DRM_COMMAND_BASE, struct my_driver_operation)
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*
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* DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
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* DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
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* up the handlers and set the access rights:
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*
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* static const struct drm_ioctl_desc my_driver_ioctls[] = {
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* DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
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* DRM_AUTH|DRM_RENDER_ALLOW),
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* };
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*
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* And then assign this to the &drm_driver.ioctls field in your driver
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* structure.
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*/
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/**
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* drm_ioctl - ioctl callback implementation for DRM drivers
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* @filp: file this ioctl is called on
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* @cmd: ioctl cmd number
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* @arg: user argument
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*
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* Looks up the ioctl function in the ::ioctls table, checking for root
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* previleges if so required, and dispatches to the respective function.
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* Looks up the ioctl function in the DRM core and the driver dispatch table,
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* stored in &drm_driver.ioctls. It checks for necessary permission by calling
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* drm_ioctl_permit(), and dispatches to the respective function.
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*
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* Returns:
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* Zero on success, negative error code on failure.
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@ -33,6 +33,7 @@
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#define _DRM_IOCTL_H_
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#include <linux/types.h>
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#include <linux/bitops.h>
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#include <asm/ioctl.h>
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@ -41,41 +42,126 @@ struct drm_file;
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struct file;
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/**
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* Ioctl function type.
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* drm_ioctl_t - DRM ioctl function type.
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* @dev: DRM device inode
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* @data: private pointer of the ioctl call
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* @file_priv: DRM file this ioctl was made on
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*
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* \param inode device inode.
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* \param file_priv DRM file private pointer.
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* \param cmd command.
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* \param arg argument.
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* This is the DRM ioctl typedef. Note that drm_ioctl() has alrady copied @data
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* into kernel-space, and will also copy it back, depending upon the read/write
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* settings in the ioctl command code.
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*/
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typedef int drm_ioctl_t(struct drm_device *dev, void *data,
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struct drm_file *file_priv);
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/**
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* drm_ioctl_compat_t - compatibility DRM ioctl function type.
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* @filp: file pointer
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* @cmd: ioctl command code
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* @arg: DRM file this ioctl was made on
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*
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* Just a typedef to make declaring an array of compatibility handlers easier.
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* New drivers shouldn't screw up the structure layout for their ioctl
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* structures and hence never need this.
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*/
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typedef int drm_ioctl_compat_t(struct file *filp, unsigned int cmd,
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unsigned long arg);
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#define DRM_IOCTL_NR(n) _IOC_NR(n)
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#define DRM_MAJOR 226
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#define DRM_AUTH 0x1
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#define DRM_MASTER 0x2
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#define DRM_ROOT_ONLY 0x4
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#define DRM_CONTROL_ALLOW 0x8
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#define DRM_UNLOCKED 0x10
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#define DRM_RENDER_ALLOW 0x20
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/**
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* enum drm_ioctl_flags - DRM ioctl flags
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*
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* Various flags that can be set in &drm_ioctl_desc.flags to control how
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* userspace can use a given ioctl.
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*/
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enum drm_ioctl_flags {
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/**
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* @DRM_AUTH:
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*
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* This is for ioctl which are used for rendering, and require that the
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* file descriptor is either for a render node, or if it's a
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* legacy/primary node, then it must be authenticated.
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*/
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DRM_AUTH = BIT(0),
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/**
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* @DRM_MASTER:
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*
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* This must be set for any ioctl which can change the modeset or
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* display state. Userspace must call the ioctl through a primary node,
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* while it is the active master.
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*
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* Note that read-only modeset ioctl can also be called by
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* unauthenticated clients, or when a master is not the currently active
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* one.
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*/
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DRM_MASTER = BIT(1),
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/**
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* @DRM_ROOT_ONLY:
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*
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* Anything that could potentially wreak a master file descriptor needs
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* to have this flag set. Current that's only for the SETMASTER and
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* DROPMASTER ioctl, which e.g. logind can call to force a non-behaving
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* master (display compositor) into compliance.
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*
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* This is equivalent to callers with the SYSADMIN capability.
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*/
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DRM_ROOT_ONLY = BIT(2),
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/**
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* @DRM_CONTROL_ALLOW:
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*
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* Deprecated, do not use. Control nodes are in the process of getting
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* removed.
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*/
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DRM_CONTROL_ALLOW = BIT(3),
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/**
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* @DRM_UNLOCKED:
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*
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* Whether &drm_ioctl_desc.func should be called with the DRM BKL held
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* or not. Enforced as the default for all modern drivers, hence there
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* should never be a need to set this flag.
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*/
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DRM_UNLOCKED = BIT(4),
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/**
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* @DRM_RENDER_ALLOW:
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*
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* This is used for all ioctl needed for rendering only, for drivers
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* which support render nodes. This should be all new render drivers,
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* and hence it should be always set for any ioctl with DRM_AUTH set.
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* Note though that read-only query ioctl might have this set, but have
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* not set DRM_AUTH because they do not require authentication.
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*/
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DRM_RENDER_ALLOW = BIT(5),
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};
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/**
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* struct drm_ioctl_desc - DRM driver ioctl entry
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* @cmd: ioctl command number, without flags
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* @flags: a bitmask of &enum drm_ioctl_flags
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* @func: handler for this ioctl
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* @name: user-readable name for debug output
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*
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* For convenience it's easier to create these using the DRM_IOCTL_DEF_DRV()
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* macro.
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*/
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struct drm_ioctl_desc {
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unsigned int cmd;
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int flags;
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enum drm_ioctl_flags flags;
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drm_ioctl_t *func;
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const char *name;
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};
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/**
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* Creates a driver or general drm_ioctl_desc array entry for the given
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* ioctl, for use by drm_ioctl().
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* DRM_IOCTL_DEF_DRV() - helper macro to fill out a &struct drm_ioctl_desc
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* @ioctl: ioctl command suffix
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* @_func: handler for the ioctl
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* @_flags: a bitmask of &enum drm_ioctl_flags
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*
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* Small helper macro to create a &struct drm_ioctl_desc entry. The ioctl
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* command number is constructed by prepending ``DRM_IOCTL\_`` and passing that
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* to DRM_IOCTL_NR().
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*/
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#define DRM_IOCTL_DEF_DRV(ioctl, _func, _flags) \
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[DRM_IOCTL_NR(DRM_IOCTL_##ioctl) - DRM_COMMAND_BASE] = { \
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.cmd = DRM_IOCTL_##ioctl, \
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