linux/include/drm/drm_device.h
Chris Wilson 7e13ad8964 drm: Avoid drm_global_mutex for simple inc/dec of dev->open_count
Since drm_global_mutex is a true global mutex across devices, we don't
want to acquire it unless absolutely necessary. For maintaining the
device local open_count, we can use atomic operations on the counter
itself, except when making the transition to/from 0. Here, we tackle the
easy portion of delaying acquiring the drm_global_mutex for the final
release by using atomic_dec_and_mutex_lock(), leaving the global
serialisation across the device opens.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Thomas Hellström (VMware) <thomas_os@shipmail.org>
Reviewed-by: Thomas Hellström <thellstrom@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200124130107.125404-1-chris@chris-wilson.co.uk
2020-01-24 17:41:34 +00:00

364 lines
8.4 KiB
C

#ifndef _DRM_DEVICE_H_
#define _DRM_DEVICE_H_
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include <drm/drm_hashtab.h>
#include <drm/drm_mode_config.h>
struct drm_driver;
struct drm_minor;
struct drm_master;
struct drm_device_dma;
struct drm_vblank_crtc;
struct drm_sg_mem;
struct drm_local_map;
struct drm_vma_offset_manager;
struct drm_vram_mm;
struct drm_fb_helper;
struct inode;
struct pci_dev;
struct pci_controller;
/**
* enum drm_switch_power - power state of drm device
*/
enum switch_power_state {
/** @DRM_SWITCH_POWER_ON: Power state is ON */
DRM_SWITCH_POWER_ON = 0,
/** @DRM_SWITCH_POWER_OFF: Power state is OFF */
DRM_SWITCH_POWER_OFF = 1,
/** @DRM_SWITCH_POWER_CHANGING: Power state is changing */
DRM_SWITCH_POWER_CHANGING = 2,
/** @DRM_SWITCH_POWER_DYNAMIC_OFF: Suspended */
DRM_SWITCH_POWER_DYNAMIC_OFF = 3,
};
/**
* struct drm_device - DRM device structure
*
* This structure represent a complete card that
* may contain multiple heads.
*/
struct drm_device {
/**
* @legacy_dev_list:
*
* List of devices per driver for stealth attach cleanup
*/
struct list_head legacy_dev_list;
/** @if_version: Highest interface version set */
int if_version;
/** @ref: Object ref-count */
struct kref ref;
/** @dev: Device structure of bus-device */
struct device *dev;
/** @driver: DRM driver managing the device */
struct drm_driver *driver;
/**
* @dev_private:
*
* DRM driver private data. Instead of using this pointer it is
* recommended that drivers use drm_dev_init() and embed struct
* &drm_device in their larger per-device structure.
*/
void *dev_private;
/** @primary: Primary node */
struct drm_minor *primary;
/** @render: Render node */
struct drm_minor *render;
/**
* @registered:
*
* Internally used by drm_dev_register() and drm_connector_register().
*/
bool registered;
/**
* @master:
*
* Currently active master for this device.
* Protected by &master_mutex
*/
struct drm_master *master;
/**
* @driver_features: per-device driver features
*
* Drivers can clear specific flags here to disallow
* certain features on a per-device basis while still
* sharing a single &struct drm_driver instance across
* all devices.
*/
u32 driver_features;
/**
* @unplugged:
*
* Flag to tell if the device has been unplugged.
* See drm_dev_enter() and drm_dev_is_unplugged().
*/
bool unplugged;
/** @anon_inode: inode for private address-space */
struct inode *anon_inode;
/** @unique: Unique name of the device */
char *unique;
/**
* @struct_mutex:
*
* Lock for others (not &drm_minor.master and &drm_file.is_master)
*/
struct mutex struct_mutex;
/**
* @master_mutex:
*
* Lock for &drm_minor.master and &drm_file.is_master
*/
struct mutex master_mutex;
/**
* @open_count:
*
* Usage counter for outstanding files open,
* protected by drm_global_mutex
*/
atomic_t open_count;
/** @filelist_mutex: Protects @filelist. */
struct mutex filelist_mutex;
/**
* @filelist:
*
* List of userspace clients, linked through &drm_file.lhead.
*/
struct list_head filelist;
/**
* @filelist_internal:
*
* List of open DRM files for in-kernel clients.
* Protected by &filelist_mutex.
*/
struct list_head filelist_internal;
/**
* @clientlist_mutex:
*
* Protects &clientlist access.
*/
struct mutex clientlist_mutex;
/**
* @clientlist:
*
* List of in-kernel clients. Protected by &clientlist_mutex.
*/
struct list_head clientlist;
/**
* @irq_enabled:
*
* Indicates that interrupt handling is enabled, specifically vblank
* handling. Drivers which don't use drm_irq_install() need to set this
* to true manually.
*/
bool irq_enabled;
/**
* @irq: Used by the drm_irq_install() and drm_irq_unistall() helpers.
*/
int irq;
/**
* @vblank_disable_immediate:
*
* If true, vblank interrupt will be disabled immediately when the
* refcount drops to zero, as opposed to via the vblank disable
* timer.
*
* This can be set to true it the hardware has a working vblank counter
* with high-precision timestamping (otherwise there are races) and the
* driver uses drm_crtc_vblank_on() and drm_crtc_vblank_off()
* appropriately. See also @max_vblank_count and
* &drm_crtc_funcs.get_vblank_counter.
*/
bool vblank_disable_immediate;
/**
* @vblank:
*
* Array of vblank tracking structures, one per &struct drm_crtc. For
* historical reasons (vblank support predates kernel modesetting) this
* is free-standing and not part of &struct drm_crtc itself. It must be
* initialized explicitly by calling drm_vblank_init().
*/
struct drm_vblank_crtc *vblank;
/**
* @vblank_time_lock:
*
* Protects vblank count and time updates during vblank enable/disable
*/
spinlock_t vblank_time_lock;
/**
* @vbl_lock: Top-level vblank references lock, wraps the low-level
* @vblank_time_lock.
*/
spinlock_t vbl_lock;
/**
* @max_vblank_count:
*
* Maximum value of the vblank registers. This value +1 will result in a
* wrap-around of the vblank register. It is used by the vblank core to
* handle wrap-arounds.
*
* If set to zero the vblank core will try to guess the elapsed vblanks
* between times when the vblank interrupt is disabled through
* high-precision timestamps. That approach is suffering from small
* races and imprecision over longer time periods, hence exposing a
* hardware vblank counter is always recommended.
*
* This is the statically configured device wide maximum. The driver
* can instead choose to use a runtime configurable per-crtc value
* &drm_vblank_crtc.max_vblank_count, in which case @max_vblank_count
* must be left at zero. See drm_crtc_set_max_vblank_count() on how
* to use the per-crtc value.
*
* If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
*/
u32 max_vblank_count;
/** @vblank_event_list: List of vblank events */
struct list_head vblank_event_list;
/**
* @event_lock:
*
* Protects @vblank_event_list and event delivery in
* general. See drm_send_event() and drm_send_event_locked().
*/
spinlock_t event_lock;
/** @agp: AGP data */
struct drm_agp_head *agp;
/** @pdev: PCI device structure */
struct pci_dev *pdev;
#ifdef __alpha__
/** @hose: PCI hose, only used on ALPHA platforms. */
struct pci_controller *hose;
#endif
/** @num_crtcs: Number of CRTCs on this device */
unsigned int num_crtcs;
/** @mode_config: Current mode config */
struct drm_mode_config mode_config;
/** @object_name_lock: GEM information */
struct mutex object_name_lock;
/** @object_name_idr: GEM information */
struct idr object_name_idr;
/** @vma_offset_manager: GEM information */
struct drm_vma_offset_manager *vma_offset_manager;
/** @vram_mm: VRAM MM memory manager */
struct drm_vram_mm *vram_mm;
/**
* @switch_power_state:
*
* Power state of the client.
* Used by drivers supporting the switcheroo driver.
* The state is maintained in the
* &vga_switcheroo_client_ops.set_gpu_state callback
*/
enum switch_power_state switch_power_state;
/**
* @fb_helper:
*
* Pointer to the fbdev emulation structure.
* Set by drm_fb_helper_init() and cleared by drm_fb_helper_fini().
*/
struct drm_fb_helper *fb_helper;
/* Everything below here is for legacy driver, never use! */
/* private: */
#if IS_ENABLED(CONFIG_DRM_LEGACY)
/* Context handle management - linked list of context handles */
struct list_head ctxlist;
/* Context handle management - mutex for &ctxlist */
struct mutex ctxlist_mutex;
/* Context handle management */
struct idr ctx_idr;
/* Memory management - linked list of regions */
struct list_head maplist;
/* Memory management - user token hash table for maps */
struct drm_open_hash map_hash;
/* Context handle management - list of vmas (for debugging) */
struct list_head vmalist;
/* Optional pointer for DMA support */
struct drm_device_dma *dma;
/* Context swapping flag */
__volatile__ long context_flag;
/* Last current context */
int last_context;
/* Lock for &buf_use and a few other things. */
spinlock_t buf_lock;
/* Usage counter for buffers in use -- cannot alloc */
int buf_use;
/* Buffer allocation in progress */
atomic_t buf_alloc;
struct {
int context;
struct drm_hw_lock *lock;
} sigdata;
struct drm_local_map *agp_buffer_map;
unsigned int agp_buffer_token;
/* Scatter gather memory */
struct drm_sg_mem *sg;
#endif
};
#endif