drm/i915: Slaughter the thundering i915_wait_request herd

[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / i915 / intel_ringbuffer.h

#ifndef _INTEL_RINGBUFFER_H_
#define _INTEL_RINGBUFFER_H_

#include <linux/hashtable.h>
#include "i915_gem_batch_pool.h"

#define I915_CMD_HASH_ORDER 9

/* Early gen2 devices have a cacheline of just 32 bytes, using 64 is overkill,
 * but keeps the logic simple. Indeed, the whole purpose of this macro is just
 * to give some inclination as to some of the magic values used in the various
 * workarounds!
 */
#define CACHELINE_BYTES 64
#define CACHELINE_DWORDS (CACHELINE_BYTES / sizeof(uint32_t))

/*
 * Gen2 BSpec "1. Programming Environment" / 1.4.4.6 "Ring Buffer Use"
 * Gen3 BSpec "vol1c Memory Interface Functions" / 2.3.4.5 "Ring Buffer Use"
 * Gen4+ BSpec "vol1c Memory Interface and Command Stream" / 5.3.4.5 "Ring Buffer Use"
 *
 * "If the Ring Buffer Head Pointer and the Tail Pointer are on the same
 * cacheline, the Head Pointer must not be greater than the Tail
 * Pointer."
 */
#define I915_RING_FREE_SPACE 64

struct  intel_hw_status_page {
        u32             *page_addr;
        unsigned int    gfx_addr;
        struct          drm_i915_gem_object *obj;
};

#define I915_READ_TAIL(ring) I915_READ(RING_TAIL((ring)->mmio_base))
#define I915_WRITE_TAIL(ring, val) I915_WRITE(RING_TAIL((ring)->mmio_base), val)

#define I915_READ_START(ring) I915_READ(RING_START((ring)->mmio_base))
#define I915_WRITE_START(ring, val) I915_WRITE(RING_START((ring)->mmio_base), val)

#define I915_READ_HEAD(ring)  I915_READ(RING_HEAD((ring)->mmio_base))
#define I915_WRITE_HEAD(ring, val) I915_WRITE(RING_HEAD((ring)->mmio_base), val)

#define I915_READ_CTL(ring) I915_READ(RING_CTL((ring)->mmio_base))
#define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL((ring)->mmio_base), val)

#define I915_READ_IMR(ring) I915_READ(RING_IMR((ring)->mmio_base))
#define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)

#define I915_READ_MODE(ring) I915_READ(RING_MI_MODE((ring)->mmio_base))
#define I915_WRITE_MODE(ring, val) I915_WRITE(RING_MI_MODE((ring)->mmio_base), val)

/* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
 * do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
 */
#define gen8_semaphore_seqno_size sizeof(uint64_t)
#define GEN8_SEMAPHORE_OFFSET(__from, __to)                          \
        (((__from) * I915_NUM_ENGINES  + (__to)) * gen8_semaphore_seqno_size)
#define GEN8_SIGNAL_OFFSET(__ring, to)                       \
        (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
         GEN8_SEMAPHORE_OFFSET((__ring)->id, (to)))
#define GEN8_WAIT_OFFSET(__ring, from)                       \
        (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
         GEN8_SEMAPHORE_OFFSET(from, (__ring)->id))

enum intel_ring_hangcheck_action {
        HANGCHECK_IDLE = 0,
        HANGCHECK_WAIT,
        HANGCHECK_ACTIVE,
        HANGCHECK_KICK,
        HANGCHECK_HUNG,
};

#define HANGCHECK_SCORE_RING_HUNG 31

struct intel_ring_hangcheck {
        u64 acthd;
        u32 seqno;
        unsigned user_interrupts;
        int score;
        enum intel_ring_hangcheck_action action;
        int deadlock;
        u32 instdone[I915_NUM_INSTDONE_REG];
};

struct intel_ringbuffer {
        struct drm_i915_gem_object *obj;
        void __iomem *virtual_start;
        struct i915_vma *vma;

        struct intel_engine_cs *engine;
        struct list_head link;

        u32 head;
        u32 tail;
        int space;
        int size;
        int effective_size;

        /** We track the position of the requests in the ring buffer, and
         * when each is retired we increment last_retired_head as the GPU
         * must have finished processing the request and so we know we
         * can advance the ringbuffer up to that position.
         *
         * last_retired_head is set to -1 after the value is consumed so
         * we can detect new retirements.
         */
        u32 last_retired_head;
};

struct i915_gem_context;
struct drm_i915_reg_table;

/*
 * we use a single page to load ctx workarounds so all of these
 * values are referred in terms of dwords
 *
 * struct i915_wa_ctx_bb:
 *  offset: specifies batch starting position, also helpful in case
 *    if we want to have multiple batches at different offsets based on
 *    some criteria. It is not a requirement at the moment but provides
 *    an option for future use.
 *  size: size of the batch in DWORDS
 */
struct  i915_ctx_workarounds {
        struct i915_wa_ctx_bb {
                u32 offset;
                u32 size;
        } indirect_ctx, per_ctx;
        struct drm_i915_gem_object *obj;
};

struct intel_engine_cs {
        struct drm_i915_private *i915;
        const char      *name;
        enum intel_engine_id {
                RCS = 0,
                BCS,
                VCS,
                VCS2,   /* Keep instances of the same type engine together. */
                VECS
        } id;
#define I915_NUM_ENGINES 5
#define _VCS(n) (VCS + (n))
        unsigned int exec_id;
        unsigned int hw_id;
        unsigned int guc_id; /* XXX same as hw_id? */
        u32             mmio_base;
        struct intel_ringbuffer *buffer;
        struct list_head buffers;

        /* Rather than have every client wait upon all user interrupts,
         * with the herd waking after every interrupt and each doing the
         * heavyweight seqno dance, we delegate the task (of being the
         * bottom-half of the user interrupt) to the first client. After
         * every interrupt, we wake up one client, who does the heavyweight
         * coherent seqno read and either goes back to sleep (if incomplete),
         * or wakes up all the completed clients in parallel, before then
         * transferring the bottom-half status to the next client in the queue.
         *
         * Compared to walking the entire list of waiters in a single dedicated
         * bottom-half, we reduce the latency of the first waiter by avoiding
         * a context switch, but incur additional coherent seqno reads when
         * following the chain of request breadcrumbs. Since it is most likely
         * that we have a single client waiting on each seqno, then reducing
         * the overhead of waking that client is much preferred.
         */
        struct intel_breadcrumbs {
                spinlock_t lock; /* protects the lists of requests */
                struct rb_root waiters; /* sorted by retirement, priority */
                struct intel_wait *first_wait; /* oldest waiter by retirement */
                struct task_struct *tasklet; /* bh for user interrupts */
                struct timer_list fake_irq; /* used after a missed interrupt */
                bool irq_enabled;
                bool rpm_wakelock;
        } breadcrumbs;

        /*
         * A pool of objects to use as shadow copies of client batch buffers
         * when the command parser is enabled. Prevents the client from
         * modifying the batch contents after software parsing.
         */
        struct i915_gem_batch_pool batch_pool;

        struct intel_hw_status_page status_page;
        struct i915_ctx_workarounds wa_ctx;

        unsigned irq_refcount; /* protected by dev_priv->irq_lock */
        u32             irq_enable_mask;        /* bitmask to enable ring interrupt */
        struct drm_i915_gem_request *trace_irq_req;
        bool __must_check (*irq_get)(struct intel_engine_cs *ring);
        void            (*irq_put)(struct intel_engine_cs *ring);

        int             (*init_hw)(struct intel_engine_cs *ring);

        int             (*init_context)(struct drm_i915_gem_request *req);

        void            (*write_tail)(struct intel_engine_cs *ring,
                                      u32 value);
        int __must_check (*flush)(struct drm_i915_gem_request *req,
                                  u32   invalidate_domains,
                                  u32   flush_domains);
        int             (*add_request)(struct drm_i915_gem_request *req);
        /* Some chipsets are not quite as coherent as advertised and need
         * an expensive kick to force a true read of the up-to-date seqno.
         * However, the up-to-date seqno is not always required and the last
         * seen value is good enough. Note that the seqno will always be
         * monotonic, even if not coherent.
         */
        void            (*irq_seqno_barrier)(struct intel_engine_cs *ring);
        u32             (*get_seqno)(struct intel_engine_cs *ring);
        void            (*set_seqno)(struct intel_engine_cs *ring,
                                     u32 seqno);
        int             (*dispatch_execbuffer)(struct drm_i915_gem_request *req,
                                               u64 offset, u32 length,
                                               unsigned dispatch_flags);
#define I915_DISPATCH_SECURE 0x1
#define I915_DISPATCH_PINNED 0x2
#define I915_DISPATCH_RS     0x4
        void            (*cleanup)(struct intel_engine_cs *ring);

        /* GEN8 signal/wait table - never trust comments!
         *        signal to     signal to    signal to   signal to      signal to
         *          RCS            VCS          BCS        VECS          VCS2
         *      --------------------------------------------------------------------
         *  RCS | NOP (0x00) | VCS (0x08) | BCS (0x10) | VECS (0x18) | VCS2 (0x20) |
         *      |-------------------------------------------------------------------
         *  VCS | RCS (0x28) | NOP (0x30) | BCS (0x38) | VECS (0x40) | VCS2 (0x48) |
         *      |-------------------------------------------------------------------
         *  BCS | RCS (0x50) | VCS (0x58) | NOP (0x60) | VECS (0x68) | VCS2 (0x70) |
         *      |-------------------------------------------------------------------
         * VECS | RCS (0x78) | VCS (0x80) | BCS (0x88) |  NOP (0x90) | VCS2 (0x98) |
         *      |-------------------------------------------------------------------
         * VCS2 | RCS (0xa0) | VCS (0xa8) | BCS (0xb0) | VECS (0xb8) | NOP  (0xc0) |
         *      |-------------------------------------------------------------------
         *
         * Generalization:
         *  f(x, y) := (x->id * NUM_RINGS * seqno_size) + (seqno_size * y->id)
         *  ie. transpose of g(x, y)
         *
         *       sync from      sync from    sync from    sync from     sync from
         *          RCS            VCS          BCS        VECS          VCS2
         *      --------------------------------------------------------------------
         *  RCS | NOP (0x00) | VCS (0x28) | BCS (0x50) | VECS (0x78) | VCS2 (0xa0) |
         *      |-------------------------------------------------------------------
         *  VCS | RCS (0x08) | NOP (0x30) | BCS (0x58) | VECS (0x80) | VCS2 (0xa8) |
         *      |-------------------------------------------------------------------
         *  BCS | RCS (0x10) | VCS (0x38) | NOP (0x60) | VECS (0x88) | VCS2 (0xb0) |
         *      |-------------------------------------------------------------------
         * VECS | RCS (0x18) | VCS (0x40) | BCS (0x68) |  NOP (0x90) | VCS2 (0xb8) |
         *      |-------------------------------------------------------------------
         * VCS2 | RCS (0x20) | VCS (0x48) | BCS (0x70) | VECS (0x98) |  NOP (0xc0) |
         *      |-------------------------------------------------------------------
         *
         * Generalization:
         *  g(x, y) := (y->id * NUM_RINGS * seqno_size) + (seqno_size * x->id)
         *  ie. transpose of f(x, y)
         */
        struct {
                u32     sync_seqno[I915_NUM_ENGINES-1];

                union {
                        struct {
                                /* our mbox written by others */
                                u32             wait[I915_NUM_ENGINES];
                                /* mboxes this ring signals to */
                                i915_reg_t      signal[I915_NUM_ENGINES];
                        } mbox;
                        u64             signal_ggtt[I915_NUM_ENGINES];
                };

                /* AKA wait() */
                int     (*sync_to)(struct drm_i915_gem_request *to_req,
                                   struct intel_engine_cs *from,
                                   u32 seqno);
                int     (*signal)(struct drm_i915_gem_request *signaller_req,
                                  /* num_dwords needed by caller */
                                  unsigned int num_dwords);
        } semaphore;

        /* Execlists */
        struct tasklet_struct irq_tasklet;
        spinlock_t execlist_lock; /* used inside tasklet, use spin_lock_bh */
        struct list_head execlist_queue;
        unsigned int fw_domains;
        unsigned int next_context_status_buffer;
        unsigned int idle_lite_restore_wa;
        bool disable_lite_restore_wa;
        u32 ctx_desc_template;
        u32             irq_keep_mask; /* bitmask for interrupts that should not be masked */
        int             (*emit_request)(struct drm_i915_gem_request *request);
        int             (*emit_flush)(struct drm_i915_gem_request *request,
                                      u32 invalidate_domains,
                                      u32 flush_domains);
        int             (*emit_bb_start)(struct drm_i915_gem_request *req,
                                         u64 offset, unsigned dispatch_flags);

        /**
         * List of objects currently involved in rendering from the
         * ringbuffer.
         *
         * Includes buffers having the contents of their GPU caches
         * flushed, not necessarily primitives.  last_read_req
         * represents when the rendering involved will be completed.
         *
         * A reference is held on the buffer while on this list.
         */
        struct list_head active_list;

        /**
         * List of breadcrumbs associated with GPU requests currently
         * outstanding.
         */
        struct list_head request_list;

        /**
         * Seqno of request most recently submitted to request_list.
         * Used exclusively by hang checker to avoid grabbing lock while
         * inspecting request list.
         */
        u32 last_submitted_seqno;
        unsigned user_interrupts;

        bool gpu_caches_dirty;

        struct i915_gem_context *last_context;

        struct intel_ring_hangcheck hangcheck;

        struct {
                struct drm_i915_gem_object *obj;
                u32 gtt_offset;
                volatile u32 *cpu_page;
        } scratch;

        bool needs_cmd_parser;

        /*
         * Table of commands the command parser needs to know about
         * for this ring.
         */
        DECLARE_HASHTABLE(cmd_hash, I915_CMD_HASH_ORDER);

        /*
         * Table of registers allowed in commands that read/write registers.
         */
        const struct drm_i915_reg_table *reg_tables;
        int reg_table_count;

        /*
         * Returns the bitmask for the length field of the specified command.
         * Return 0 for an unrecognized/invalid command.
         *
         * If the command parser finds an entry for a command in the ring's
         * cmd_tables, it gets the command's length based on the table entry.
         * If not, it calls this function to determine the per-ring length field
         * encoding for the command (i.e. certain opcode ranges use certain bits
         * to encode the command length in the header).
         */
        u32 (*get_cmd_length_mask)(u32 cmd_header);
};

static inline bool
intel_engine_initialized(struct intel_engine_cs *engine)
{
        return engine->i915 != NULL;
}

static inline unsigned
intel_engine_flag(struct intel_engine_cs *engine)
{
        return 1 << engine->id;
}

static inline u32
intel_ring_sync_index(struct intel_engine_cs *engine,
                      struct intel_engine_cs *other)
{
        int idx;

        /*
         * rcs -> 0 = vcs, 1 = bcs, 2 = vecs, 3 = vcs2;
         * vcs -> 0 = bcs, 1 = vecs, 2 = vcs2, 3 = rcs;
         * bcs -> 0 = vecs, 1 = vcs2. 2 = rcs, 3 = vcs;
         * vecs -> 0 = vcs2, 1 = rcs, 2 = vcs, 3 = bcs;
         * vcs2 -> 0 = rcs, 1 = vcs, 2 = bcs, 3 = vecs;
         */

        idx = (other - engine) - 1;
        if (idx < 0)
                idx += I915_NUM_ENGINES;

        return idx;
}

static inline void
intel_flush_status_page(struct intel_engine_cs *engine, int reg)
{
        mb();
        clflush(&engine->status_page.page_addr[reg]);
        mb();
}

static inline u32
intel_read_status_page(struct intel_engine_cs *engine, int reg)
{
        /* Ensure that the compiler doesn't optimize away the load. */
        return READ_ONCE(engine->status_page.page_addr[reg]);
}

static inline void
intel_write_status_page(struct intel_engine_cs *engine,
                        int reg, u32 value)
{
        engine->status_page.page_addr[reg] = value;
}

/*
 * Reads a dword out of the status page, which is written to from the command
 * queue by automatic updates, MI_REPORT_HEAD, MI_STORE_DATA_INDEX, or
 * MI_STORE_DATA_IMM.
 *
 * The following dwords have a reserved meaning:
 * 0x00: ISR copy, updated when an ISR bit not set in the HWSTAM changes.
 * 0x04: ring 0 head pointer
 * 0x05: ring 1 head pointer (915-class)
 * 0x06: ring 2 head pointer (915-class)
 * 0x10-0x1b: Context status DWords (GM45)
 * 0x1f: Last written status offset. (GM45)
 * 0x20-0x2f: Reserved (Gen6+)
 *
 * The area from dword 0x30 to 0x3ff is available for driver usage.
 */
#define I915_GEM_HWS_INDEX              0x30
#define I915_GEM_HWS_INDEX_ADDR (I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT)
#define I915_GEM_HWS_SCRATCH_INDEX      0x40
#define I915_GEM_HWS_SCRATCH_ADDR (I915_GEM_HWS_SCRATCH_INDEX << MI_STORE_DWORD_INDEX_SHIFT)

struct intel_ringbuffer *
intel_engine_create_ringbuffer(struct intel_engine_cs *engine, int size);
int intel_pin_and_map_ringbuffer_obj(struct drm_i915_private *dev_priv,
                                     struct intel_ringbuffer *ringbuf);
void intel_unpin_ringbuffer_obj(struct intel_ringbuffer *ringbuf);
void intel_ringbuffer_free(struct intel_ringbuffer *ring);

void intel_stop_engine(struct intel_engine_cs *engine);
void intel_cleanup_engine(struct intel_engine_cs *engine);

int intel_ring_alloc_request_extras(struct drm_i915_gem_request *request);

int __must_check intel_ring_begin(struct drm_i915_gem_request *req, int n);
int __must_check intel_ring_cacheline_align(struct drm_i915_gem_request *req);
static inline void intel_ring_emit(struct intel_engine_cs *engine,
                                   u32 data)
{
        struct intel_ringbuffer *ringbuf = engine->buffer;
        iowrite32(data, ringbuf->virtual_start + ringbuf->tail);
        ringbuf->tail += 4;
}
static inline void intel_ring_emit_reg(struct intel_engine_cs *engine,
                                       i915_reg_t reg)
{
        intel_ring_emit(engine, i915_mmio_reg_offset(reg));
}
static inline void intel_ring_advance(struct intel_engine_cs *engine)
{
        struct intel_ringbuffer *ringbuf = engine->buffer;
        ringbuf->tail &= ringbuf->size - 1;
}
int __intel_ring_space(int head, int tail, int size);
void intel_ring_update_space(struct intel_ringbuffer *ringbuf);
bool intel_engine_stopped(struct intel_engine_cs *engine);

int __must_check intel_engine_idle(struct intel_engine_cs *engine);
void intel_ring_init_seqno(struct intel_engine_cs *engine, u32 seqno);
int intel_ring_flush_all_caches(struct drm_i915_gem_request *req);
int intel_ring_invalidate_all_caches(struct drm_i915_gem_request *req);

void intel_fini_pipe_control(struct intel_engine_cs *engine);
int intel_init_pipe_control(struct intel_engine_cs *engine);

int intel_init_render_ring_buffer(struct drm_device *dev);
int intel_init_bsd_ring_buffer(struct drm_device *dev);
int intel_init_bsd2_ring_buffer(struct drm_device *dev);
int intel_init_blt_ring_buffer(struct drm_device *dev);
int intel_init_vebox_ring_buffer(struct drm_device *dev);

u64 intel_ring_get_active_head(struct intel_engine_cs *engine);

int init_workarounds_ring(struct intel_engine_cs *engine);

static inline u32 intel_ring_get_tail(struct intel_ringbuffer *ringbuf)
{
        return ringbuf->tail;
}

/*
 * Arbitrary size for largest possible 'add request' sequence. The code paths
 * are complex and variable. Empirical measurement shows that the worst case
 * is BDW at 192 bytes (6 + 6 + 36 dwords), then ILK at 136 bytes. However,
 * we need to allocate double the largest single packet within that emission
 * to account for tail wraparound (so 6 + 6 + 72 dwords for BDW).
 */
#define MIN_SPACE_FOR_ADD_REQUEST 336

static inline u32 intel_hws_seqno_address(struct intel_engine_cs *engine)
{
        return engine->status_page.gfx_addr + I915_GEM_HWS_INDEX_ADDR;
}

/* intel_breadcrumbs.c -- user interrupt bottom-half for waiters */
struct intel_wait {
        struct rb_node node;
        struct task_struct *tsk;
        u32 seqno;
};

int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);

static inline void intel_wait_init(struct intel_wait *wait, u32 seqno)
{
        wait->tsk = current;
        wait->seqno = seqno;
}

static inline bool intel_wait_complete(const struct intel_wait *wait)
{
        return RB_EMPTY_NODE(&wait->node);
}

bool intel_engine_add_wait(struct intel_engine_cs *engine,
                           struct intel_wait *wait);
void intel_engine_remove_wait(struct intel_engine_cs *engine,
                              struct intel_wait *wait);

static inline bool intel_engine_has_waiter(struct intel_engine_cs *engine)
{
        return READ_ONCE(engine->breadcrumbs.tasklet);
}

static inline bool intel_engine_wakeup(struct intel_engine_cs *engine)
{
        bool wakeup = false;
        struct task_struct *tsk = READ_ONCE(engine->breadcrumbs.tasklet);
        /* Note that for this not to dangerously chase a dangling pointer,
         * the caller is responsible for ensure that the task remain valid for
         * wake_up_process() i.e. that the RCU grace period cannot expire.
         *
         * Also note that tsk is likely to be in !TASK_RUNNING state so an
         * early test for tsk->state != TASK_RUNNING before wake_up_process()
         * is unlikely to be beneficial.
         */
        if (tsk)
                wakeup = wake_up_process(tsk);
        return wakeup;
}

void intel_engine_enable_fake_irq(struct intel_engine_cs *engine);
void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
unsigned int intel_kick_waiters(struct drm_i915_private *i915);

#endif /* _INTEL_RINGBUFFER_H_ */