Merge remote-tracking branch 'asoc/topic/rcar' into asoc-next

[sfrench/cifs-2.6.git] / drivers / gpu / drm / i915 / i915_guc_submission.c

/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */
#include <linux/circ_buf.h>
#include "i915_drv.h"
#include "intel_uc.h"

#include <trace/events/dma_fence.h>

/**
 * DOC: GuC-based command submission
 *
 * GuC client:
 * A i915_guc_client refers to a submission path through GuC. Currently, there
 * is only one of these (the execbuf_client) and this one is charged with all
 * submissions to the GuC. This struct is the owner of a doorbell, a process
 * descriptor and a workqueue (all of them inside a single gem object that
 * contains all required pages for these elements).
 *
 * GuC stage descriptor:
 * During initialization, the driver allocates a static pool of 1024 such
 * descriptors, and shares them with the GuC.
 * Currently, there exists a 1:1 mapping between a i915_guc_client and a
 * guc_stage_desc (via the client's stage_id), so effectively only one
 * gets used. This stage descriptor lets the GuC know about the doorbell,
 * workqueue and process descriptor. Theoretically, it also lets the GuC
 * know about our HW contexts (context ID, etc...), but we actually
 * employ a kind of submission where the GuC uses the LRCA sent via the work
 * item instead (the single guc_stage_desc associated to execbuf client
 * contains information about the default kernel context only, but this is
 * essentially unused). This is called a "proxy" submission.
 *
 * The Scratch registers:
 * There are 16 MMIO-based registers start from 0xC180. The kernel driver writes
 * a value to the action register (SOFT_SCRATCH_0) along with any data. It then
 * triggers an interrupt on the GuC via another register write (0xC4C8).
 * Firmware writes a success/fail code back to the action register after
 * processes the request. The kernel driver polls waiting for this update and
 * then proceeds.
 * See intel_guc_send()
 *
 * Doorbells:
 * Doorbells are interrupts to uKernel. A doorbell is a single cache line (QW)
 * mapped into process space.
 *
 * Work Items:
 * There are several types of work items that the host may place into a
 * workqueue, each with its own requirements and limitations. Currently only
 * WQ_TYPE_INORDER is needed to support legacy submission via GuC, which
 * represents in-order queue. The kernel driver packs ring tail pointer and an
 * ELSP context descriptor dword into Work Item.
 * See guc_wq_item_append()
 *
 * ADS:
 * The Additional Data Struct (ADS) has pointers for different buffers used by
 * the GuC. One single gem object contains the ADS struct itself (guc_ads), the
 * scheduling policies (guc_policies), a structure describing a collection of
 * register sets (guc_mmio_reg_state) and some extra pages for the GuC to save
 * its internal state for sleep.
 *
 */

static inline bool is_high_priority(struct i915_guc_client* client)
{
        return client->priority <= GUC_CLIENT_PRIORITY_HIGH;
}

static int __reserve_doorbell(struct i915_guc_client *client)
{
        unsigned long offset;
        unsigned long end;
        u16 id;

        GEM_BUG_ON(client->doorbell_id != GUC_DOORBELL_INVALID);

        /*
         * The bitmap tracks which doorbell registers are currently in use.
         * It is split into two halves; the first half is used for normal
         * priority contexts, the second half for high-priority ones.
         */
        offset = 0;
        end = GUC_NUM_DOORBELLS/2;
        if (is_high_priority(client)) {
                offset = end;
                end += offset;
        }

        id = find_next_zero_bit(client->guc->doorbell_bitmap, offset, end);
        if (id == end)
                return -ENOSPC;

        __set_bit(id, client->guc->doorbell_bitmap);
        client->doorbell_id = id;
        DRM_DEBUG_DRIVER("client %u (high prio=%s) reserved doorbell: %d\n",
                         client->stage_id, yesno(is_high_priority(client)),
                         id);
        return 0;
}

static void __unreserve_doorbell(struct i915_guc_client *client)
{
        GEM_BUG_ON(client->doorbell_id == GUC_DOORBELL_INVALID);

        __clear_bit(client->doorbell_id, client->guc->doorbell_bitmap);
        client->doorbell_id = GUC_DOORBELL_INVALID;
}

/*
 * Tell the GuC to allocate or deallocate a specific doorbell
 */

static int __guc_allocate_doorbell(struct intel_guc *guc, u32 stage_id)
{
        u32 action[] = {
                INTEL_GUC_ACTION_ALLOCATE_DOORBELL,
                stage_id
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static int __guc_deallocate_doorbell(struct intel_guc *guc, u32 stage_id)
{
        u32 action[] = {
                INTEL_GUC_ACTION_DEALLOCATE_DOORBELL,
                stage_id
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static struct guc_stage_desc *__get_stage_desc(struct i915_guc_client *client)
{
        struct guc_stage_desc *base = client->guc->stage_desc_pool_vaddr;

        return &base[client->stage_id];
}

/*
 * Initialise, update, or clear doorbell data shared with the GuC
 *
 * These functions modify shared data and so need access to the mapped
 * client object which contains the page being used for the doorbell
 */

static void __update_doorbell_desc(struct i915_guc_client *client, u16 new_id)
{
        struct guc_stage_desc *desc;

        /* Update the GuC's idea of the doorbell ID */
        desc = __get_stage_desc(client);
        desc->db_id = new_id;
}

static struct guc_doorbell_info *__get_doorbell(struct i915_guc_client *client)
{
        return client->vaddr + client->doorbell_offset;
}

static bool has_doorbell(struct i915_guc_client *client)
{
        if (client->doorbell_id == GUC_DOORBELL_INVALID)
                return false;

        return test_bit(client->doorbell_id, client->guc->doorbell_bitmap);
}

static int __create_doorbell(struct i915_guc_client *client)
{
        struct guc_doorbell_info *doorbell;
        int err;

        doorbell = __get_doorbell(client);
        doorbell->db_status = GUC_DOORBELL_ENABLED;
        doorbell->cookie = client->doorbell_cookie;

        err = __guc_allocate_doorbell(client->guc, client->stage_id);
        if (err) {
                doorbell->db_status = GUC_DOORBELL_DISABLED;
                doorbell->cookie = 0;
        }
        return err;
}

static int __destroy_doorbell(struct i915_guc_client *client)
{
        struct drm_i915_private *dev_priv = guc_to_i915(client->guc);
        struct guc_doorbell_info *doorbell;
        u16 db_id = client->doorbell_id;

        GEM_BUG_ON(db_id >= GUC_DOORBELL_INVALID);

        doorbell = __get_doorbell(client);
        doorbell->db_status = GUC_DOORBELL_DISABLED;
        doorbell->cookie = 0;

        /* Doorbell release flow requires that we wait for GEN8_DRB_VALID bit
         * to go to zero after updating db_status before we call the GuC to
         * release the doorbell */
        if (wait_for_us(!(I915_READ(GEN8_DRBREGL(db_id)) & GEN8_DRB_VALID), 10))
                WARN_ONCE(true, "Doorbell never became invalid after disable\n");

        return __guc_deallocate_doorbell(client->guc, client->stage_id);
}

static int create_doorbell(struct i915_guc_client *client)
{
        int ret;

        ret = __reserve_doorbell(client);
        if (ret)
                return ret;

        __update_doorbell_desc(client, client->doorbell_id);

        ret = __create_doorbell(client);
        if (ret)
                goto err;

        return 0;

err:
        __update_doorbell_desc(client, GUC_DOORBELL_INVALID);
        __unreserve_doorbell(client);
        return ret;
}

static int destroy_doorbell(struct i915_guc_client *client)
{
        int err;

        GEM_BUG_ON(!has_doorbell(client));

        /* XXX: wait for any interrupts */
        /* XXX: wait for workqueue to drain */

        err = __destroy_doorbell(client);
        if (err)
                return err;

        __update_doorbell_desc(client, GUC_DOORBELL_INVALID);

        __unreserve_doorbell(client);

        return 0;
}

static unsigned long __select_cacheline(struct intel_guc* guc)
{
        unsigned long offset;

        /* Doorbell uses a single cache line within a page */
        offset = offset_in_page(guc->db_cacheline);

        /* Moving to next cache line to reduce contention */
        guc->db_cacheline += cache_line_size();

        DRM_DEBUG_DRIVER("reserved cacheline 0x%lx, next 0x%x, linesize %u\n",
                        offset, guc->db_cacheline, cache_line_size());
        return offset;
}

static inline struct guc_process_desc *
__get_process_desc(struct i915_guc_client *client)
{
        return client->vaddr + client->proc_desc_offset;
}

/*
 * Initialise the process descriptor shared with the GuC firmware.
 */
static void guc_proc_desc_init(struct intel_guc *guc,
                               struct i915_guc_client *client)
{
        struct guc_process_desc *desc;

        desc = memset(__get_process_desc(client), 0, sizeof(*desc));

        /*
         * XXX: pDoorbell and WQVBaseAddress are pointers in process address
         * space for ring3 clients (set them as in mmap_ioctl) or kernel
         * space for kernel clients (map on demand instead? May make debug
         * easier to have it mapped).
         */
        desc->wq_base_addr = 0;
        desc->db_base_addr = 0;

        desc->stage_id = client->stage_id;
        desc->wq_size_bytes = client->wq_size;
        desc->wq_status = WQ_STATUS_ACTIVE;
        desc->priority = client->priority;
}

/*
 * Initialise/clear the stage descriptor shared with the GuC firmware.
 *
 * This descriptor tells the GuC where (in GGTT space) to find the important
 * data structures relating to this client (doorbell, process descriptor,
 * write queue, etc).
 */
static void guc_stage_desc_init(struct intel_guc *guc,
                                struct i915_guc_client *client)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct intel_engine_cs *engine;
        struct i915_gem_context *ctx = client->owner;
        struct guc_stage_desc *desc;
        unsigned int tmp;
        u32 gfx_addr;

        desc = __get_stage_desc(client);
        memset(desc, 0, sizeof(*desc));

        desc->attribute = GUC_STAGE_DESC_ATTR_ACTIVE | GUC_STAGE_DESC_ATTR_KERNEL;
        desc->stage_id = client->stage_id;
        desc->priority = client->priority;
        desc->db_id = client->doorbell_id;

        for_each_engine_masked(engine, dev_priv, client->engines, tmp) {
                struct intel_context *ce = &ctx->engine[engine->id];
                uint32_t guc_engine_id = engine->guc_id;
                struct guc_execlist_context *lrc = &desc->lrc[guc_engine_id];

                /* TODO: We have a design issue to be solved here. Only when we
                 * receive the first batch, we know which engine is used by the
                 * user. But here GuC expects the lrc and ring to be pinned. It
                 * is not an issue for default context, which is the only one
                 * for now who owns a GuC client. But for future owner of GuC
                 * client, need to make sure lrc is pinned prior to enter here.
                 */
                if (!ce->state)
                        break;  /* XXX: continue? */

                /*
                 * XXX: When this is a GUC_STAGE_DESC_ATTR_KERNEL client (proxy
                 * submission or, in other words, not using a direct submission
                 * model) the KMD's LRCA is not used for any work submission.
                 * Instead, the GuC uses the LRCA of the user mode context (see
                 * guc_wq_item_append below).
                 */
                lrc->context_desc = lower_32_bits(ce->lrc_desc);

                /* The state page is after PPHWSP */
                lrc->ring_lrca =
                        guc_ggtt_offset(ce->state) + LRC_STATE_PN * PAGE_SIZE;

                /* XXX: In direct submission, the GuC wants the HW context id
                 * here. In proxy submission, it wants the stage id */
                lrc->context_id = (client->stage_id << GUC_ELC_CTXID_OFFSET) |
                                (guc_engine_id << GUC_ELC_ENGINE_OFFSET);

                lrc->ring_begin = guc_ggtt_offset(ce->ring->vma);
                lrc->ring_end = lrc->ring_begin + ce->ring->size - 1;
                lrc->ring_next_free_location = lrc->ring_begin;
                lrc->ring_current_tail_pointer_value = 0;

                desc->engines_used |= (1 << guc_engine_id);
        }

        DRM_DEBUG_DRIVER("Host engines 0x%x => GuC engines used 0x%x\n",
                        client->engines, desc->engines_used);
        WARN_ON(desc->engines_used == 0);

        /*
         * The doorbell, process descriptor, and workqueue are all parts
         * of the client object, which the GuC will reference via the GGTT
         */
        gfx_addr = guc_ggtt_offset(client->vma);
        desc->db_trigger_phy = sg_dma_address(client->vma->pages->sgl) +
                                client->doorbell_offset;
        desc->db_trigger_cpu = (uintptr_t)__get_doorbell(client);
        desc->db_trigger_uk = gfx_addr + client->doorbell_offset;
        desc->process_desc = gfx_addr + client->proc_desc_offset;
        desc->wq_addr = gfx_addr + client->wq_offset;
        desc->wq_size = client->wq_size;

        desc->desc_private = (uintptr_t)client;
}

static void guc_stage_desc_fini(struct intel_guc *guc,
                                struct i915_guc_client *client)
{
        struct guc_stage_desc *desc;

        desc = __get_stage_desc(client);
        memset(desc, 0, sizeof(*desc));
}

/**
 * i915_guc_wq_reserve() - reserve space in the GuC's workqueue
 * @request:    request associated with the commands
 *
 * Return:      0 if space is available
 *              -EAGAIN if space is not currently available
 *
 * This function must be called (and must return 0) before a request
 * is submitted to the GuC via i915_guc_submit() below. Once a result
 * of 0 has been returned, it must be balanced by a corresponding
 * call to submit().
 *
 * Reservation allows the caller to determine in advance that space
 * will be available for the next submission before committing resources
 * to it, and helps avoid late failures with complicated recovery paths.
 */
int i915_guc_wq_reserve(struct drm_i915_gem_request *request)
{
        const size_t wqi_size = sizeof(struct guc_wq_item);
        struct i915_guc_client *client = request->i915->guc.execbuf_client;
        struct guc_process_desc *desc = __get_process_desc(client);
        u32 freespace;
        int ret;

        spin_lock_irq(&client->wq_lock);
        freespace = CIRC_SPACE(client->wq_tail, desc->head, client->wq_size);
        freespace -= client->wq_rsvd;
        if (likely(freespace >= wqi_size)) {
                client->wq_rsvd += wqi_size;
                ret = 0;
        } else {
                client->no_wq_space++;
                ret = -EAGAIN;
        }
        spin_unlock_irq(&client->wq_lock);

        return ret;
}

static void guc_client_update_wq_rsvd(struct i915_guc_client *client, int size)
{
        unsigned long flags;

        spin_lock_irqsave(&client->wq_lock, flags);
        client->wq_rsvd += size;
        spin_unlock_irqrestore(&client->wq_lock, flags);
}

void i915_guc_wq_unreserve(struct drm_i915_gem_request *request)
{
        const int wqi_size = sizeof(struct guc_wq_item);
        struct i915_guc_client *client = request->i915->guc.execbuf_client;

        GEM_BUG_ON(READ_ONCE(client->wq_rsvd) < wqi_size);
        guc_client_update_wq_rsvd(client, -wqi_size);
}

/* Construct a Work Item and append it to the GuC's Work Queue */
static void guc_wq_item_append(struct i915_guc_client *client,
                               struct drm_i915_gem_request *rq)
{
        /* wqi_len is in DWords, and does not include the one-word header */
        const size_t wqi_size = sizeof(struct guc_wq_item);
        const u32 wqi_len = wqi_size/sizeof(u32) - 1;
        struct intel_engine_cs *engine = rq->engine;
        struct guc_process_desc *desc = __get_process_desc(client);
        struct guc_wq_item *wqi;
        u32 freespace, tail, wq_off;

        /* Free space is guaranteed, see i915_guc_wq_reserve() above */
        freespace = CIRC_SPACE(client->wq_tail, desc->head, client->wq_size);
        GEM_BUG_ON(freespace < wqi_size);

        /* The GuC firmware wants the tail index in QWords, not bytes */
        tail = intel_ring_set_tail(rq->ring, rq->tail) >> 3;
        GEM_BUG_ON(tail > WQ_RING_TAIL_MAX);

        /* For now workqueue item is 4 DWs; workqueue buffer is 2 pages. So we
         * should not have the case where structure wqi is across page, neither
         * wrapped to the beginning. This simplifies the implementation below.
         *
         * XXX: if not the case, we need save data to a temp wqi and copy it to
         * workqueue buffer dw by dw.
         */
        BUILD_BUG_ON(wqi_size != 16);
        GEM_BUG_ON(client->wq_rsvd < wqi_size);

        /* postincrement WQ tail for next time */
        wq_off = client->wq_tail;
        GEM_BUG_ON(wq_off & (wqi_size - 1));
        client->wq_tail += wqi_size;
        client->wq_tail &= client->wq_size - 1;
        client->wq_rsvd -= wqi_size;

        /* WQ starts from the page after doorbell / process_desc */
        wqi = client->vaddr + wq_off + GUC_DB_SIZE;

        /* Now fill in the 4-word work queue item */
        wqi->header = WQ_TYPE_INORDER |
                        (wqi_len << WQ_LEN_SHIFT) |
                        (engine->guc_id << WQ_TARGET_SHIFT) |
                        WQ_NO_WCFLUSH_WAIT;

        /* The GuC wants only the low-order word of the context descriptor */
        wqi->context_desc = (u32)intel_lr_context_descriptor(rq->ctx, engine);

        wqi->submit_element_info = tail << WQ_RING_TAIL_SHIFT;
        wqi->fence_id = rq->global_seqno;
}

static void guc_reset_wq(struct i915_guc_client *client)
{
        struct guc_process_desc *desc = __get_process_desc(client);

        desc->head = 0;
        desc->tail = 0;

        client->wq_tail = 0;
}

static int guc_ring_doorbell(struct i915_guc_client *client)
{
        struct guc_process_desc *desc = __get_process_desc(client);
        union guc_doorbell_qw db_cmp, db_exc, db_ret;
        union guc_doorbell_qw *db;
        int attempt = 2, ret = -EAGAIN;

        /* Update the tail so it is visible to GuC */
        desc->tail = client->wq_tail;

        /* current cookie */
        db_cmp.db_status = GUC_DOORBELL_ENABLED;
        db_cmp.cookie = client->doorbell_cookie;

        /* cookie to be updated */
        db_exc.db_status = GUC_DOORBELL_ENABLED;
        db_exc.cookie = client->doorbell_cookie + 1;
        if (db_exc.cookie == 0)
                db_exc.cookie = 1;

        /* pointer of current doorbell cacheline */
        db = (union guc_doorbell_qw *)__get_doorbell(client);

        while (attempt--) {
                /* lets ring the doorbell */
                db_ret.value_qw = atomic64_cmpxchg((atomic64_t *)db,
                        db_cmp.value_qw, db_exc.value_qw);

                /* if the exchange was successfully executed */
                if (db_ret.value_qw == db_cmp.value_qw) {
                        /* db was successfully rung */
                        client->doorbell_cookie = db_exc.cookie;
                        ret = 0;
                        break;
                }

                /* XXX: doorbell was lost and need to acquire it again */
                if (db_ret.db_status == GUC_DOORBELL_DISABLED)
                        break;

                DRM_WARN("Cookie mismatch. Expected %d, found %d\n",
                         db_cmp.cookie, db_ret.cookie);

                /* update the cookie to newly read cookie from GuC */
                db_cmp.cookie = db_ret.cookie;
                db_exc.cookie = db_ret.cookie + 1;
                if (db_exc.cookie == 0)
                        db_exc.cookie = 1;
        }

        return ret;
}

/**
 * __i915_guc_submit() - Submit commands through GuC
 * @rq:         request associated with the commands
 *
 * The caller must have already called i915_guc_wq_reserve() above with
 * a result of 0 (success), guaranteeing that there is space in the work
 * queue for the new request, so enqueuing the item cannot fail.
 *
 * Bad Things Will Happen if the caller violates this protocol e.g. calls
 * submit() when _reserve() says there's no space, or calls _submit()
 * a different number of times from (successful) calls to _reserve().
 *
 * The only error here arises if the doorbell hardware isn't functioning
 * as expected, which really shouln't happen.
 */
static void __i915_guc_submit(struct drm_i915_gem_request *rq)
{
        struct drm_i915_private *dev_priv = rq->i915;
        struct intel_engine_cs *engine = rq->engine;
        unsigned int engine_id = engine->id;
        struct intel_guc *guc = &rq->i915->guc;
        struct i915_guc_client *client = guc->execbuf_client;
        unsigned long flags;
        int b_ret;

        /* WA to flush out the pending GMADR writes to ring buffer. */
        if (i915_vma_is_map_and_fenceable(rq->ring->vma))
                POSTING_READ_FW(GUC_STATUS);

        spin_lock_irqsave(&client->wq_lock, flags);

        guc_wq_item_append(client, rq);
        b_ret = guc_ring_doorbell(client);

        client->submissions[engine_id] += 1;
        client->retcode = b_ret;
        if (b_ret)
                client->b_fail += 1;

        guc->submissions[engine_id] += 1;
        guc->last_seqno[engine_id] = rq->global_seqno;

        spin_unlock_irqrestore(&client->wq_lock, flags);
}

static void i915_guc_submit(struct drm_i915_gem_request *rq)
{
        __i915_gem_request_submit(rq);
        __i915_guc_submit(rq);
}

static void nested_enable_signaling(struct drm_i915_gem_request *rq)
{
        /* If we use dma_fence_enable_sw_signaling() directly, lockdep
         * detects an ordering issue between the fence lockclass and the
         * global_timeline. This circular dependency can only occur via 2
         * different fences (but same fence lockclass), so we use the nesting
         * annotation here to prevent the warn, equivalent to the nesting
         * inside i915_gem_request_submit() for when we also enable the
         * signaler.
         */

        if (test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
                             &rq->fence.flags))
                return;

        GEM_BUG_ON(test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags));
        trace_dma_fence_enable_signal(&rq->fence);

        spin_lock_nested(&rq->lock, SINGLE_DEPTH_NESTING);
        intel_engine_enable_signaling(rq);
        spin_unlock(&rq->lock);
}

static bool i915_guc_dequeue(struct intel_engine_cs *engine)
{
        struct execlist_port *port = engine->execlist_port;
        struct drm_i915_gem_request *last = port[0].request;
        struct rb_node *rb;
        bool submit = false;

        spin_lock_irq(&engine->timeline->lock);
        rb = engine->execlist_first;
        while (rb) {
                struct drm_i915_gem_request *rq =
                        rb_entry(rb, typeof(*rq), priotree.node);

                if (last && rq->ctx != last->ctx) {
                        if (port != engine->execlist_port)
                                break;

                        i915_gem_request_assign(&port->request, last);
                        nested_enable_signaling(last);
                        port++;
                }

                rb = rb_next(rb);
                rb_erase(&rq->priotree.node, &engine->execlist_queue);
                RB_CLEAR_NODE(&rq->priotree.node);
                rq->priotree.priority = INT_MAX;

                i915_guc_submit(rq);
                trace_i915_gem_request_in(rq, port - engine->execlist_port);
                last = rq;
                submit = true;
        }
        if (submit) {
                i915_gem_request_assign(&port->request, last);
                nested_enable_signaling(last);
                engine->execlist_first = rb;
        }
        spin_unlock_irq(&engine->timeline->lock);

        return submit;
}

static void i915_guc_irq_handler(unsigned long data)
{
        struct intel_engine_cs *engine = (struct intel_engine_cs *)data;
        struct execlist_port *port = engine->execlist_port;
        struct drm_i915_gem_request *rq;
        bool submit;

        do {
                rq = port[0].request;
                while (rq && i915_gem_request_completed(rq)) {
                        trace_i915_gem_request_out(rq);
                        i915_gem_request_put(rq);
                        port[0].request = port[1].request;
                        port[1].request = NULL;
                        rq = port[0].request;
                }

                submit = false;
                if (!port[1].request)
                        submit = i915_guc_dequeue(engine);
        } while (submit);
}

/*
 * Everything below here is concerned with setup & teardown, and is
 * therefore not part of the somewhat time-critical batch-submission
 * path of i915_guc_submit() above.
 */

/**
 * intel_guc_allocate_vma() - Allocate a GGTT VMA for GuC usage
 * @guc:        the guc
 * @size:       size of area to allocate (both virtual space and memory)
 *
 * This is a wrapper to create an object for use with the GuC. In order to
 * use it inside the GuC, an object needs to be pinned lifetime, so we allocate
 * both some backing storage and a range inside the Global GTT. We must pin
 * it in the GGTT somewhere other than than [0, GUC_WOPCM_TOP) because that
 * range is reserved inside GuC.
 *
 * Return:      A i915_vma if successful, otherwise an ERR_PTR.
 */
struct i915_vma *intel_guc_allocate_vma(struct intel_guc *guc, u32 size)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct drm_i915_gem_object *obj;
        struct i915_vma *vma;
        int ret;

        obj = i915_gem_object_create(dev_priv, size);
        if (IS_ERR(obj))
                return ERR_CAST(obj);

        vma = i915_vma_instance(obj, &dev_priv->ggtt.base, NULL);
        if (IS_ERR(vma))
                goto err;

        ret = i915_vma_pin(vma, 0, PAGE_SIZE,
                           PIN_GLOBAL | PIN_OFFSET_BIAS | GUC_WOPCM_TOP);
        if (ret) {
                vma = ERR_PTR(ret);
                goto err;
        }

        return vma;

err:
        i915_gem_object_put(obj);
        return vma;
}

/* Check that a doorbell register is in the expected state */
static bool doorbell_ok(struct intel_guc *guc, u16 db_id)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        u32 drbregl;
        bool valid;

        GEM_BUG_ON(db_id >= GUC_DOORBELL_INVALID);

        drbregl = I915_READ(GEN8_DRBREGL(db_id));
        valid = drbregl & GEN8_DRB_VALID;

        if (test_bit(db_id, guc->doorbell_bitmap) == valid)
                return true;

        DRM_DEBUG_DRIVER("Doorbell %d has unexpected state (0x%x): valid=%s\n",
                         db_id, drbregl, yesno(valid));

        return false;
}

/*
 * If the GuC thinks that the doorbell is unassigned (e.g. because we reset and
 * reloaded the GuC FW) we can use this function to tell the GuC to reassign the
 * doorbell to the rightful owner.
 */
static int __reset_doorbell(struct i915_guc_client* client, u16 db_id)
{
        int err;

        __update_doorbell_desc(client, db_id);
        err = __create_doorbell(client);
        if (!err)
                err = __destroy_doorbell(client);

        return err;
}

/*
 * Set up & tear down each unused doorbell in turn, to ensure that all doorbell
 * HW is (re)initialised. For that end, we might have to borrow the first
 * client. Also, tell GuC about all the doorbells in use by all clients.
 * We do this because the KMD, the GuC and the doorbell HW can easily go out of
 * sync (e.g. we can reset the GuC, but not the doorbel HW).
 */
static int guc_init_doorbell_hw(struct intel_guc *guc)
{
        struct i915_guc_client *client = guc->execbuf_client;
        bool recreate_first_client = false;
        u16 db_id;
        int ret;

        /* For unused doorbells, make sure they are disabled */
        for_each_clear_bit(db_id, guc->doorbell_bitmap, GUC_NUM_DOORBELLS) {
                if (doorbell_ok(guc, db_id))
                        continue;

                if (has_doorbell(client)) {
                        /* Borrow execbuf_client (we will recreate it later) */
                        destroy_doorbell(client);
                        recreate_first_client = true;
                }

                ret = __reset_doorbell(client, db_id);
                WARN(ret, "Doorbell %u reset failed, err %d\n", db_id, ret);
        }

        if (recreate_first_client) {
                ret = __reserve_doorbell(client);
                if (unlikely(ret)) {
                        DRM_ERROR("Couldn't re-reserve first client db: %d\n", ret);
                        return ret;
                }

                __update_doorbell_desc(client, client->doorbell_id);
        }

        /* Now for every client (and not only execbuf_client) make sure their
         * doorbells are known by the GuC */
        //for (client = client_list; client != NULL; client = client->next)
        {
                ret = __create_doorbell(client);
                if (ret) {
                        DRM_ERROR("Couldn't recreate client %u doorbell: %d\n",
                                client->stage_id, ret);
                        return ret;
                }
        }

        /* Read back & verify all (used & unused) doorbell registers */
        for (db_id = 0; db_id < GUC_NUM_DOORBELLS; ++db_id)
                WARN_ON(!doorbell_ok(guc, db_id));

        return 0;
}

/**
 * guc_client_alloc() - Allocate an i915_guc_client
 * @dev_priv:   driver private data structure
 * @engines:    The set of engines to enable for this client
 * @priority:   four levels priority _CRITICAL, _HIGH, _NORMAL and _LOW
 *              The kernel client to replace ExecList submission is created with
 *              NORMAL priority. Priority of a client for scheduler can be HIGH,
 *              while a preemption context can use CRITICAL.
 * @ctx:        the context that owns the client (we use the default render
 *              context)
 *
 * Return:      An i915_guc_client object if success, else NULL.
 */
static struct i915_guc_client *
guc_client_alloc(struct drm_i915_private *dev_priv,
                 uint32_t engines,
                 uint32_t priority,
                 struct i915_gem_context *ctx)
{
        struct i915_guc_client *client;
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_vma *vma;
        void *vaddr;
        int ret;

        client = kzalloc(sizeof(*client), GFP_KERNEL);
        if (!client)
                return ERR_PTR(-ENOMEM);

        client->guc = guc;
        client->owner = ctx;
        client->engines = engines;
        client->priority = priority;
        client->doorbell_id = GUC_DOORBELL_INVALID;
        client->wq_offset = GUC_DB_SIZE;
        client->wq_size = GUC_WQ_SIZE;
        spin_lock_init(&client->wq_lock);

        ret = ida_simple_get(&guc->stage_ids, 0, GUC_MAX_STAGE_DESCRIPTORS,
                                GFP_KERNEL);
        if (ret < 0)
                goto err_client;

        client->stage_id = ret;

        /* The first page is doorbell/proc_desc. Two followed pages are wq. */
        vma = intel_guc_allocate_vma(guc, GUC_DB_SIZE + GUC_WQ_SIZE);
        if (IS_ERR(vma)) {
                ret = PTR_ERR(vma);
                goto err_id;
        }

        /* We'll keep just the first (doorbell/proc) page permanently kmap'd. */
        client->vma = vma;

        vaddr = i915_gem_object_pin_map(vma->obj, I915_MAP_WB);
        if (IS_ERR(vaddr)) {
                ret = PTR_ERR(vaddr);
                goto err_vma;
        }
        client->vaddr = vaddr;

        client->doorbell_offset = __select_cacheline(guc);

        /*
         * Since the doorbell only requires a single cacheline, we can save
         * space by putting the application process descriptor in the same
         * page. Use the half of the page that doesn't include the doorbell.
         */
        if (client->doorbell_offset >= (GUC_DB_SIZE / 2))
                client->proc_desc_offset = 0;
        else
                client->proc_desc_offset = (GUC_DB_SIZE / 2);

        guc_proc_desc_init(guc, client);
        guc_stage_desc_init(guc, client);

        ret = create_doorbell(client);
        if (ret)
                goto err_vaddr;

        DRM_DEBUG_DRIVER("new priority %u client %p for engine(s) 0x%x: stage_id %u\n",
                         priority, client, client->engines, client->stage_id);
        DRM_DEBUG_DRIVER("doorbell id %u, cacheline offset 0x%lx\n",
                         client->doorbell_id, client->doorbell_offset);

        return client;

err_vaddr:
        i915_gem_object_unpin_map(client->vma->obj);
err_vma:
        i915_vma_unpin_and_release(&client->vma);
err_id:
        ida_simple_remove(&guc->stage_ids, client->stage_id);
err_client:
        kfree(client);
        return ERR_PTR(ret);
}

static void guc_client_free(struct i915_guc_client *client)
{
        /*
         * XXX: wait for any outstanding submissions before freeing memory.
         * Be sure to drop any locks
         */

        /* FIXME: in many cases, by the time we get here the GuC has been
         * reset, so we cannot destroy the doorbell properly. Ignore the
         * error message for now */
        destroy_doorbell(client);
        guc_stage_desc_fini(client->guc, client);
        i915_gem_object_unpin_map(client->vma->obj);
        i915_vma_unpin_and_release(&client->vma);
        ida_simple_remove(&client->guc->stage_ids, client->stage_id);
        kfree(client);
}

static void guc_policies_init(struct guc_policies *policies)
{
        struct guc_policy *policy;
        u32 p, i;

        policies->dpc_promote_time = 500000;
        policies->max_num_work_items = POLICY_MAX_NUM_WI;

        for (p = 0; p < GUC_CLIENT_PRIORITY_NUM; p++) {
                for (i = GUC_RENDER_ENGINE; i < GUC_MAX_ENGINES_NUM; i++) {
                        policy = &policies->policy[p][i];

                        policy->execution_quantum = 1000000;
                        policy->preemption_time = 500000;
                        policy->fault_time = 250000;
                        policy->policy_flags = 0;
                }
        }

        policies->is_valid = 1;
}

static int guc_ads_create(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct i915_vma *vma;
        struct page *page;
        /* The ads obj includes the struct itself and buffers passed to GuC */
        struct {
                struct guc_ads ads;
                struct guc_policies policies;
                struct guc_mmio_reg_state reg_state;
                u8 reg_state_buffer[GUC_S3_SAVE_SPACE_PAGES * PAGE_SIZE];
        } __packed *blob;
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        u32 base;

        GEM_BUG_ON(guc->ads_vma);

        vma = intel_guc_allocate_vma(guc, PAGE_ALIGN(sizeof(*blob)));
        if (IS_ERR(vma))
                return PTR_ERR(vma);

        guc->ads_vma = vma;

        page = i915_vma_first_page(vma);
        blob = kmap(page);

        /* GuC scheduling policies */
        guc_policies_init(&blob->policies);

        /* MMIO reg state */
        for_each_engine(engine, dev_priv, id) {
                blob->reg_state.white_list[engine->guc_id].mmio_start =
                        engine->mmio_base + GUC_MMIO_WHITE_LIST_START;

                /* Nothing to be saved or restored for now. */
                blob->reg_state.white_list[engine->guc_id].count = 0;
        }

        /*
         * The GuC requires a "Golden Context" when it reinitialises
         * engines after a reset. Here we use the Render ring default
         * context, which must already exist and be pinned in the GGTT,
         * so its address won't change after we've told the GuC where
         * to find it.
         */
        blob->ads.golden_context_lrca =
                dev_priv->engine[RCS]->status_page.ggtt_offset;

        for_each_engine(engine, dev_priv, id)
                blob->ads.eng_state_size[engine->guc_id] =
                        intel_lr_context_size(engine);

        base = guc_ggtt_offset(vma);
        blob->ads.scheduler_policies = base + ptr_offset(blob, policies);
        blob->ads.reg_state_buffer = base + ptr_offset(blob, reg_state_buffer);
        blob->ads.reg_state_addr = base + ptr_offset(blob, reg_state);

        kunmap(page);

        return 0;
}

static void guc_ads_destroy(struct intel_guc *guc)
{
        i915_vma_unpin_and_release(&guc->ads_vma);
}

/*
 * Set up the memory resources to be shared with the GuC (via the GGTT)
 * at firmware loading time.
 */
int i915_guc_submission_init(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_vma *vma;
        void *vaddr;
        int ret;

        if (guc->stage_desc_pool)
                return 0;

        vma = intel_guc_allocate_vma(guc,
                                PAGE_ALIGN(sizeof(struct guc_stage_desc) *
                                        GUC_MAX_STAGE_DESCRIPTORS));
        if (IS_ERR(vma))
                return PTR_ERR(vma);

        guc->stage_desc_pool = vma;

        vaddr = i915_gem_object_pin_map(guc->stage_desc_pool->obj, I915_MAP_WB);
        if (IS_ERR(vaddr)) {
                ret = PTR_ERR(vaddr);
                goto err_vma;
        }

        guc->stage_desc_pool_vaddr = vaddr;

        ret = intel_guc_log_create(guc);
        if (ret < 0)
                goto err_vaddr;

        ret = guc_ads_create(guc);
        if (ret < 0)
                goto err_log;

        ida_init(&guc->stage_ids);

        return 0;

err_log:
        intel_guc_log_destroy(guc);
err_vaddr:
        i915_gem_object_unpin_map(guc->stage_desc_pool->obj);
err_vma:
        i915_vma_unpin_and_release(&guc->stage_desc_pool);
        return ret;
}

void i915_guc_submission_fini(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;

        ida_destroy(&guc->stage_ids);
        guc_ads_destroy(guc);
        intel_guc_log_destroy(guc);
        i915_gem_object_unpin_map(guc->stage_desc_pool->obj);
        i915_vma_unpin_and_release(&guc->stage_desc_pool);
}

static void guc_interrupts_capture(struct drm_i915_private *dev_priv)
{
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        int irqs;

        /* tell all command streamers to forward interrupts (but not vblank) to GuC */
        irqs = _MASKED_BIT_ENABLE(GFX_INTERRUPT_STEERING);
        for_each_engine(engine, dev_priv, id)
                I915_WRITE(RING_MODE_GEN7(engine), irqs);

        /* route USER_INTERRUPT to Host, all others are sent to GuC. */
        irqs = GT_RENDER_USER_INTERRUPT << GEN8_RCS_IRQ_SHIFT |
               GT_RENDER_USER_INTERRUPT << GEN8_BCS_IRQ_SHIFT;
        /* These three registers have the same bit definitions */
        I915_WRITE(GUC_BCS_RCS_IER, ~irqs);
        I915_WRITE(GUC_VCS2_VCS1_IER, ~irqs);
        I915_WRITE(GUC_WD_VECS_IER, ~irqs);

        /*
         * The REDIRECT_TO_GUC bit of the PMINTRMSK register directs all
         * (unmasked) PM interrupts to the GuC. All other bits of this
         * register *disable* generation of a specific interrupt.
         *
         * 'pm_intrmsk_mbz' indicates bits that are NOT to be set when
         * writing to the PM interrupt mask register, i.e. interrupts
         * that must not be disabled.
         *
         * If the GuC is handling these interrupts, then we must not let
         * the PM code disable ANY interrupt that the GuC is expecting.
         * So for each ENABLED (0) bit in this register, we must SET the
         * bit in pm_intrmsk_mbz so that it's left enabled for the GuC.
         * GuC needs ARAT expired interrupt unmasked hence it is set in
         * pm_intrmsk_mbz.
         *
         * Here we CLEAR REDIRECT_TO_GUC bit in pm_intrmsk_mbz, which will
         * result in the register bit being left SET!
         */
        dev_priv->rps.pm_intrmsk_mbz |= ARAT_EXPIRED_INTRMSK;
        dev_priv->rps.pm_intrmsk_mbz &= ~GEN8_PMINTR_DISABLE_REDIRECT_TO_GUC;
}

static void guc_interrupts_release(struct drm_i915_private *dev_priv)
{
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        int irqs;

        /*
         * tell all command streamers NOT to forward interrupts or vblank
         * to GuC.
         */
        irqs = _MASKED_FIELD(GFX_FORWARD_VBLANK_MASK, GFX_FORWARD_VBLANK_NEVER);
        irqs |= _MASKED_BIT_DISABLE(GFX_INTERRUPT_STEERING);
        for_each_engine(engine, dev_priv, id)
                I915_WRITE(RING_MODE_GEN7(engine), irqs);

        /* route all GT interrupts to the host */
        I915_WRITE(GUC_BCS_RCS_IER, 0);
        I915_WRITE(GUC_VCS2_VCS1_IER, 0);
        I915_WRITE(GUC_WD_VECS_IER, 0);

        dev_priv->rps.pm_intrmsk_mbz |= GEN8_PMINTR_DISABLE_REDIRECT_TO_GUC;
        dev_priv->rps.pm_intrmsk_mbz &= ~ARAT_EXPIRED_INTRMSK;
}

int i915_guc_submission_enable(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_guc_client *client = guc->execbuf_client;
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        int err;

        if (!client) {
                client = guc_client_alloc(dev_priv,
                                          INTEL_INFO(dev_priv)->ring_mask,
                                          GUC_CLIENT_PRIORITY_KMD_NORMAL,
                                          dev_priv->kernel_context);
                if (IS_ERR(client)) {
                        DRM_ERROR("Failed to create GuC client for execbuf!\n");
                        return PTR_ERR(client);
                }

                guc->execbuf_client = client;
        }

        err = intel_guc_sample_forcewake(guc);
        if (err)
                goto err_execbuf_client;

        guc_reset_wq(client);

        err = guc_init_doorbell_hw(guc);
        if (err)
                goto err_execbuf_client;

        /* Take over from manual control of ELSP (execlists) */
        guc_interrupts_capture(dev_priv);

        for_each_engine(engine, dev_priv, id) {
                const int wqi_size = sizeof(struct guc_wq_item);
                struct drm_i915_gem_request *rq;

                /* The tasklet was initialised by execlists, and may be in
                 * a state of flux (across a reset) and so we just want to
                 * take over the callback without changing any other state
                 * in the tasklet.
                 */
                engine->irq_tasklet.func = i915_guc_irq_handler;
                clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);

                /* Replay the current set of previously submitted requests */
                spin_lock_irq(&engine->timeline->lock);
                list_for_each_entry(rq, &engine->timeline->requests, link) {
                        guc_client_update_wq_rsvd(client, wqi_size);
                        __i915_guc_submit(rq);
                }
                spin_unlock_irq(&engine->timeline->lock);
        }

        return 0;

err_execbuf_client:
        guc_client_free(guc->execbuf_client);
        guc->execbuf_client = NULL;
        return err;
}

void i915_guc_submission_disable(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;

        guc_interrupts_release(dev_priv);

        /* Revert back to manual ELSP submission */
        intel_engines_reset_default_submission(dev_priv);

        guc_client_free(guc->execbuf_client);
        guc->execbuf_client = NULL;
}

/**
 * intel_guc_suspend() - notify GuC entering suspend state
 * @dev_priv:   i915 device private
 */
int intel_guc_suspend(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_gem_context *ctx;
        u32 data[3];

        if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS)
                return 0;

        gen9_disable_guc_interrupts(dev_priv);

        ctx = dev_priv->kernel_context;

        data[0] = INTEL_GUC_ACTION_ENTER_S_STATE;
        /* any value greater than GUC_POWER_D0 */
        data[1] = GUC_POWER_D1;
        /* first page is shared data with GuC */
        data[2] = guc_ggtt_offset(ctx->engine[RCS].state);

        return intel_guc_send(guc, data, ARRAY_SIZE(data));
}

/**
 * intel_guc_resume() - notify GuC resuming from suspend state
 * @dev_priv:   i915 device private
 */
int intel_guc_resume(struct drm_i915_private *dev_priv)
{
        struct intel_guc *guc = &dev_priv->guc;
        struct i915_gem_context *ctx;
        u32 data[3];

        if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS)
                return 0;

        if (i915.guc_log_level >= 0)
                gen9_enable_guc_interrupts(dev_priv);

        ctx = dev_priv->kernel_context;

        data[0] = INTEL_GUC_ACTION_EXIT_S_STATE;
        data[1] = GUC_POWER_D0;
        /* first page is shared data with GuC */
        data[2] = guc_ggtt_offset(ctx->engine[RCS].state);

        return intel_guc_send(guc, data, ARRAY_SIZE(data));
}