These changes are the raw update to linux-4.4.6-rt14. Kernel sources
[kvmfornfv.git] / kernel / drivers / gpu / drm / i915 / i915_guc_submission.c
diff --git a/kernel/drivers/gpu/drm/i915/i915_guc_submission.c b/kernel/drivers/gpu/drm/i915/i915_guc_submission.c
new file mode 100644 (file)
index 0000000..036b42b
--- /dev/null
@@ -0,0 +1,975 @@
+/*
+ * 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/firmware.h>
+#include <linux/circ_buf.h>
+#include "i915_drv.h"
+#include "intel_guc.h"
+
+/**
+ * DOC: GuC Client
+ *
+ * i915_guc_client:
+ * We use the term client to avoid confusion with contexts. A i915_guc_client is
+ * equivalent to GuC object guc_context_desc. This context descriptor is
+ * allocated from a pool of 1024 entries. Kernel driver will allocate doorbell
+ * and workqueue for it. Also the process descriptor (guc_process_desc), which
+ * is mapped to client space. So the client can write Work Item then ring the
+ * doorbell.
+ *
+ * To simplify the implementation, we allocate one gem object that contains all
+ * pages for doorbell, process descriptor and workqueue.
+ *
+ * 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 host2guc_action()
+ *
+ * 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_add_workqueue_item()
+ *
+ */
+
+/*
+ * Read GuC command/status register (SOFT_SCRATCH_0)
+ * Return true if it contains a response rather than a command
+ */
+static inline bool host2guc_action_response(struct drm_i915_private *dev_priv,
+                                           u32 *status)
+{
+       u32 val = I915_READ(SOFT_SCRATCH(0));
+       *status = val;
+       return GUC2HOST_IS_RESPONSE(val);
+}
+
+static int host2guc_action(struct intel_guc *guc, u32 *data, u32 len)
+{
+       struct drm_i915_private *dev_priv = guc_to_i915(guc);
+       u32 status;
+       int i;
+       int ret;
+
+       if (WARN_ON(len < 1 || len > 15))
+               return -EINVAL;
+
+       intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+       spin_lock(&dev_priv->guc.host2guc_lock);
+
+       dev_priv->guc.action_count += 1;
+       dev_priv->guc.action_cmd = data[0];
+
+       for (i = 0; i < len; i++)
+               I915_WRITE(SOFT_SCRATCH(i), data[i]);
+
+       POSTING_READ(SOFT_SCRATCH(i - 1));
+
+       I915_WRITE(HOST2GUC_INTERRUPT, HOST2GUC_TRIGGER);
+
+       /* No HOST2GUC command should take longer than 10ms */
+       ret = wait_for_atomic(host2guc_action_response(dev_priv, &status), 10);
+       if (status != GUC2HOST_STATUS_SUCCESS) {
+               /*
+                * Either the GuC explicitly returned an error (which
+                * we convert to -EIO here) or no response at all was
+                * received within the timeout limit (-ETIMEDOUT)
+                */
+               if (ret != -ETIMEDOUT)
+                       ret = -EIO;
+
+               DRM_ERROR("GUC: host2guc action 0x%X failed. ret=%d "
+                               "status=0x%08X response=0x%08X\n",
+                               data[0], ret, status,
+                               I915_READ(SOFT_SCRATCH(15)));
+
+               dev_priv->guc.action_fail += 1;
+               dev_priv->guc.action_err = ret;
+       }
+       dev_priv->guc.action_status = status;
+
+       spin_unlock(&dev_priv->guc.host2guc_lock);
+       intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+
+       return ret;
+}
+
+/*
+ * Tell the GuC to allocate or deallocate a specific doorbell
+ */
+
+static int host2guc_allocate_doorbell(struct intel_guc *guc,
+                                     struct i915_guc_client *client)
+{
+       u32 data[2];
+
+       data[0] = HOST2GUC_ACTION_ALLOCATE_DOORBELL;
+       data[1] = client->ctx_index;
+
+       return host2guc_action(guc, data, 2);
+}
+
+static int host2guc_release_doorbell(struct intel_guc *guc,
+                                    struct i915_guc_client *client)
+{
+       u32 data[2];
+
+       data[0] = HOST2GUC_ACTION_DEALLOCATE_DOORBELL;
+       data[1] = client->ctx_index;
+
+       return host2guc_action(guc, data, 2);
+}
+
+static int host2guc_sample_forcewake(struct intel_guc *guc,
+                                    struct i915_guc_client *client)
+{
+       struct drm_i915_private *dev_priv = guc_to_i915(guc);
+       struct drm_device *dev = dev_priv->dev;
+       u32 data[2];
+
+       data[0] = HOST2GUC_ACTION_SAMPLE_FORCEWAKE;
+       /* WaRsDisableCoarsePowerGating:skl,bxt */
+       if (!intel_enable_rc6(dev_priv->dev) ||
+           (IS_BROXTON(dev) && (INTEL_REVID(dev) < BXT_REVID_B0)) ||
+           (IS_SKL_GT3(dev) && (INTEL_REVID(dev) <= SKL_REVID_E0)) ||
+           (IS_SKL_GT4(dev) && (INTEL_REVID(dev) <= SKL_REVID_E0)))
+               data[1] = 0;
+       else
+               /* bit 0 and 1 are for Render and Media domain separately */
+               data[1] = GUC_FORCEWAKE_RENDER | GUC_FORCEWAKE_MEDIA;
+
+       return host2guc_action(guc, data, ARRAY_SIZE(data));
+}
+
+/*
+ * 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 guc_init_doorbell(struct intel_guc *guc,
+                             struct i915_guc_client *client)
+{
+       struct guc_doorbell_info *doorbell;
+       void *base;
+
+       base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+       doorbell = base + client->doorbell_offset;
+
+       doorbell->db_status = 1;
+       doorbell->cookie = 0;
+
+       kunmap_atomic(base);
+}
+
+static int guc_ring_doorbell(struct i915_guc_client *gc)
+{
+       struct guc_process_desc *desc;
+       union guc_doorbell_qw db_cmp, db_exc, db_ret;
+       union guc_doorbell_qw *db;
+       void *base;
+       int attempt = 2, ret = -EAGAIN;
+
+       base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
+       desc = base + gc->proc_desc_offset;
+
+       /* Update the tail so it is visible to GuC */
+       desc->tail = gc->wq_tail;
+
+       /* current cookie */
+       db_cmp.db_status = GUC_DOORBELL_ENABLED;
+       db_cmp.cookie = gc->cookie;
+
+       /* cookie to be updated */
+       db_exc.db_status = GUC_DOORBELL_ENABLED;
+       db_exc.cookie = gc->cookie + 1;
+       if (db_exc.cookie == 0)
+               db_exc.cookie = 1;
+
+       /* pointer of current doorbell cacheline */
+       db = base + gc->doorbell_offset;
+
+       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 */
+                       gc->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_ERROR("Cookie mismatch. Expected %d, returned %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;
+       }
+
+       kunmap_atomic(base);
+       return ret;
+}
+
+static void guc_disable_doorbell(struct intel_guc *guc,
+                                struct i915_guc_client *client)
+{
+       struct drm_i915_private *dev_priv = guc_to_i915(guc);
+       struct guc_doorbell_info *doorbell;
+       void *base;
+       int drbreg = GEN8_DRBREGL(client->doorbell_id);
+       int value;
+
+       base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+       doorbell = base + client->doorbell_offset;
+
+       doorbell->db_status = 0;
+
+       kunmap_atomic(base);
+
+       I915_WRITE(drbreg, I915_READ(drbreg) & ~GEN8_DRB_VALID);
+
+       value = I915_READ(drbreg);
+       WARN_ON((value & GEN8_DRB_VALID) != 0);
+
+       I915_WRITE(GEN8_DRBREGU(client->doorbell_id), 0);
+       I915_WRITE(drbreg, 0);
+
+       /* XXX: wait for any interrupts */
+       /* XXX: wait for workqueue to drain */
+}
+
+/*
+ * Select, assign and relase doorbell cachelines
+ *
+ * These functions track which doorbell cachelines are in use.
+ * The data they manipulate is protected by the host2guc lock.
+ */
+
+static uint32_t select_doorbell_cacheline(struct intel_guc *guc)
+{
+       const uint32_t cacheline_size = cache_line_size();
+       uint32_t offset;
+
+       spin_lock(&guc->host2guc_lock);
+
+       /* 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 += cacheline_size;
+
+       spin_unlock(&guc->host2guc_lock);
+
+       DRM_DEBUG_DRIVER("selected doorbell cacheline 0x%x, next 0x%x, linesize %u\n",
+                       offset, guc->db_cacheline, cacheline_size);
+
+       return offset;
+}
+
+static uint16_t assign_doorbell(struct intel_guc *guc, uint32_t priority)
+{
+       /*
+        * The bitmap is split into two halves; the first half is used for
+        * normal priority contexts, the second half for high-priority ones.
+        * Note that logically higher priorities are numerically less than
+        * normal ones, so the test below means "is it high-priority?"
+        */
+       const bool hi_pri = (priority <= GUC_CTX_PRIORITY_HIGH);
+       const uint16_t half = GUC_MAX_DOORBELLS / 2;
+       const uint16_t start = hi_pri ? half : 0;
+       const uint16_t end = start + half;
+       uint16_t id;
+
+       spin_lock(&guc->host2guc_lock);
+       id = find_next_zero_bit(guc->doorbell_bitmap, end, start);
+       if (id == end)
+               id = GUC_INVALID_DOORBELL_ID;
+       else
+               bitmap_set(guc->doorbell_bitmap, id, 1);
+       spin_unlock(&guc->host2guc_lock);
+
+       DRM_DEBUG_DRIVER("assigned %s priority doorbell id 0x%x\n",
+                       hi_pri ? "high" : "normal", id);
+
+       return id;
+}
+
+static void release_doorbell(struct intel_guc *guc, uint16_t id)
+{
+       spin_lock(&guc->host2guc_lock);
+       bitmap_clear(guc->doorbell_bitmap, id, 1);
+       spin_unlock(&guc->host2guc_lock);
+}
+
+/*
+ * Initialise the process descriptor shared with the GuC firmware.
+ */
+static void guc_init_proc_desc(struct intel_guc *guc,
+                              struct i915_guc_client *client)
+{
+       struct guc_process_desc *desc;
+       void *base;
+
+       base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+       desc = base + client->proc_desc_offset;
+
+       memset(desc, 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->context_id = client->ctx_index;
+       desc->wq_size_bytes = client->wq_size;
+       desc->wq_status = WQ_STATUS_ACTIVE;
+       desc->priority = client->priority;
+
+       kunmap_atomic(base);
+}
+
+/*
+ * Initialise/clear the context 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_init_ctx_desc(struct intel_guc *guc,
+                             struct i915_guc_client *client)
+{
+       struct intel_context *ctx = client->owner;
+       struct guc_context_desc desc;
+       struct sg_table *sg;
+       int i;
+
+       memset(&desc, 0, sizeof(desc));
+
+       desc.attribute = GUC_CTX_DESC_ATTR_ACTIVE | GUC_CTX_DESC_ATTR_KERNEL;
+       desc.context_id = client->ctx_index;
+       desc.priority = client->priority;
+       desc.db_id = client->doorbell_id;
+
+       for (i = 0; i < I915_NUM_RINGS; i++) {
+               struct guc_execlist_context *lrc = &desc.lrc[i];
+               struct intel_ringbuffer *ringbuf = ctx->engine[i].ringbuf;
+               struct intel_engine_cs *ring;
+               struct drm_i915_gem_object *obj;
+               uint64_t ctx_desc;
+
+               /* 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.
+                */
+               obj = ctx->engine[i].state;
+               if (!obj)
+                       break;  /* XXX: continue? */
+
+               ring = ringbuf->ring;
+               ctx_desc = intel_lr_context_descriptor(ctx, ring);
+               lrc->context_desc = (u32)ctx_desc;
+
+               /* The state page is after PPHWSP */
+               lrc->ring_lcra = i915_gem_obj_ggtt_offset(obj) +
+                               LRC_STATE_PN * PAGE_SIZE;
+               lrc->context_id = (client->ctx_index << GUC_ELC_CTXID_OFFSET) |
+                               (ring->id << GUC_ELC_ENGINE_OFFSET);
+
+               obj = ringbuf->obj;
+
+               lrc->ring_begin = i915_gem_obj_ggtt_offset(obj);
+               lrc->ring_end = lrc->ring_begin + obj->base.size - 1;
+               lrc->ring_next_free_location = lrc->ring_begin;
+               lrc->ring_current_tail_pointer_value = 0;
+
+               desc.engines_used |= (1 << ring->id);
+       }
+
+       WARN_ON(desc.engines_used == 0);
+
+       /*
+        * The CPU address is only needed at certain points, so kmap_atomic on
+        * demand instead of storing it in the ctx descriptor.
+        * XXX: May make debug easier to have it mapped
+        */
+       desc.db_trigger_cpu = 0;
+       desc.db_trigger_uk = client->doorbell_offset +
+               i915_gem_obj_ggtt_offset(client->client_obj);
+       desc.db_trigger_phy = client->doorbell_offset +
+               sg_dma_address(client->client_obj->pages->sgl);
+
+       desc.process_desc = client->proc_desc_offset +
+               i915_gem_obj_ggtt_offset(client->client_obj);
+
+       desc.wq_addr = client->wq_offset +
+               i915_gem_obj_ggtt_offset(client->client_obj);
+
+       desc.wq_size = client->wq_size;
+
+       /*
+        * XXX: Take LRCs from an existing intel_context if this is not an
+        * IsKMDCreatedContext client
+        */
+       desc.desc_private = (uintptr_t)client;
+
+       /* Pool context is pinned already */
+       sg = guc->ctx_pool_obj->pages;
+       sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
+                            sizeof(desc) * client->ctx_index);
+}
+
+static void guc_fini_ctx_desc(struct intel_guc *guc,
+                             struct i915_guc_client *client)
+{
+       struct guc_context_desc desc;
+       struct sg_table *sg;
+
+       memset(&desc, 0, sizeof(desc));
+
+       sg = guc->ctx_pool_obj->pages;
+       sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
+                            sizeof(desc) * client->ctx_index);
+}
+
+/* Get valid workqueue item and return it back to offset */
+static int guc_get_workqueue_space(struct i915_guc_client *gc, u32 *offset)
+{
+       struct guc_process_desc *desc;
+       void *base;
+       u32 size = sizeof(struct guc_wq_item);
+       int ret = 0, timeout_counter = 200;
+
+       base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
+       desc = base + gc->proc_desc_offset;
+
+       while (timeout_counter-- > 0) {
+               ret = wait_for_atomic(CIRC_SPACE(gc->wq_tail, desc->head,
+                               gc->wq_size) >= size, 1);
+
+               if (!ret) {
+                       *offset = gc->wq_tail;
+
+                       /* advance the tail for next workqueue item */
+                       gc->wq_tail += size;
+                       gc->wq_tail &= gc->wq_size - 1;
+
+                       /* this will break the loop */
+                       timeout_counter = 0;
+               }
+       };
+
+       kunmap_atomic(base);
+
+       return ret;
+}
+
+static int guc_add_workqueue_item(struct i915_guc_client *gc,
+                                 struct drm_i915_gem_request *rq)
+{
+       enum intel_ring_id ring_id = rq->ring->id;
+       struct guc_wq_item *wqi;
+       void *base;
+       u32 tail, wq_len, wq_off = 0;
+       int ret;
+
+       ret = guc_get_workqueue_space(gc, &wq_off);
+       if (ret)
+               return ret;
+
+       /* 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.
+        */
+       WARN_ON(sizeof(struct guc_wq_item) != 16);
+       WARN_ON(wq_off & 3);
+
+       /* wq starts from the page after doorbell / process_desc */
+       base = kmap_atomic(i915_gem_object_get_page(gc->client_obj,
+                       (wq_off + GUC_DB_SIZE) >> PAGE_SHIFT));
+       wq_off &= PAGE_SIZE - 1;
+       wqi = (struct guc_wq_item *)((char *)base + wq_off);
+
+       /* len does not include the header */
+       wq_len = sizeof(struct guc_wq_item) / sizeof(u32) - 1;
+       wqi->header = WQ_TYPE_INORDER |
+                       (wq_len << WQ_LEN_SHIFT) |
+                       (ring_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, rq->ring);
+
+       /* The GuC firmware wants the tail index in QWords, not bytes */
+       tail = rq->ringbuf->tail >> 3;
+       wqi->ring_tail = tail << WQ_RING_TAIL_SHIFT;
+       wqi->fence_id = 0; /*XXX: what fence to be here */
+
+       kunmap_atomic(base);
+
+       return 0;
+}
+
+#define CTX_RING_BUFFER_START          0x08
+
+/* Update the ringbuffer pointer in a saved context image */
+static void lr_context_update(struct drm_i915_gem_request *rq)
+{
+       enum intel_ring_id ring_id = rq->ring->id;
+       struct drm_i915_gem_object *ctx_obj = rq->ctx->engine[ring_id].state;
+       struct drm_i915_gem_object *rb_obj = rq->ringbuf->obj;
+       struct page *page;
+       uint32_t *reg_state;
+
+       BUG_ON(!ctx_obj);
+       WARN_ON(!i915_gem_obj_is_pinned(ctx_obj));
+       WARN_ON(!i915_gem_obj_is_pinned(rb_obj));
+
+       page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
+       reg_state = kmap_atomic(page);
+
+       reg_state[CTX_RING_BUFFER_START+1] = i915_gem_obj_ggtt_offset(rb_obj);
+
+       kunmap_atomic(reg_state);
+}
+
+/**
+ * i915_guc_submit() - Submit commands through GuC
+ * @client:    the guc client where commands will go through
+ * @ctx:       LRC where commands come from
+ * @ring:      HW engine that will excute the commands
+ *
+ * Return:     0 if succeed
+ */
+int i915_guc_submit(struct i915_guc_client *client,
+                   struct drm_i915_gem_request *rq)
+{
+       struct intel_guc *guc = client->guc;
+       enum intel_ring_id ring_id = rq->ring->id;
+       unsigned long flags;
+       int q_ret, b_ret;
+
+       /* Need this because of the deferred pin ctx and ring */
+       /* Shall we move this right after ring is pinned? */
+       lr_context_update(rq);
+
+       spin_lock_irqsave(&client->wq_lock, flags);
+
+       q_ret = guc_add_workqueue_item(client, rq);
+       if (q_ret == 0)
+               b_ret = guc_ring_doorbell(client);
+
+       client->submissions[ring_id] += 1;
+       if (q_ret) {
+               client->q_fail += 1;
+               client->retcode = q_ret;
+       } else if (b_ret) {
+               client->b_fail += 1;
+               client->retcode = q_ret = b_ret;
+       } else {
+               client->retcode = 0;
+       }
+       spin_unlock_irqrestore(&client->wq_lock, flags);
+
+       spin_lock(&guc->host2guc_lock);
+       guc->submissions[ring_id] += 1;
+       guc->last_seqno[ring_id] = rq->seqno;
+       spin_unlock(&guc->host2guc_lock);
+
+       return q_ret;
+}
+
+/*
+ * 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.
+ */
+
+/**
+ * gem_allocate_guc_obj() - Allocate gem object for GuC usage
+ * @dev:       drm device
+ * @size:      size of object
+ *
+ * This is a wrapper to create a gem obj. In order to use it inside GuC, the
+ * object needs to be pinned lifetime. Also we must pin it to gtt space other
+ * than [0, GUC_WOPCM_TOP) because this range is reserved inside GuC.
+ *
+ * Return:     A drm_i915_gem_object if successful, otherwise NULL.
+ */
+static struct drm_i915_gem_object *gem_allocate_guc_obj(struct drm_device *dev,
+                                                       u32 size)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct drm_i915_gem_object *obj;
+
+       obj = i915_gem_alloc_object(dev, size);
+       if (!obj)
+               return NULL;
+
+       if (i915_gem_object_get_pages(obj)) {
+               drm_gem_object_unreference(&obj->base);
+               return NULL;
+       }
+
+       if (i915_gem_obj_ggtt_pin(obj, PAGE_SIZE,
+                       PIN_OFFSET_BIAS | GUC_WOPCM_TOP)) {
+               drm_gem_object_unreference(&obj->base);
+               return NULL;
+       }
+
+       /* Invalidate GuC TLB to let GuC take the latest updates to GTT. */
+       I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
+
+       return obj;
+}
+
+/**
+ * gem_release_guc_obj() - Release gem object allocated for GuC usage
+ * @obj:       gem obj to be released
+  */
+static void gem_release_guc_obj(struct drm_i915_gem_object *obj)
+{
+       if (!obj)
+               return;
+
+       if (i915_gem_obj_is_pinned(obj))
+               i915_gem_object_ggtt_unpin(obj);
+
+       drm_gem_object_unreference(&obj->base);
+}
+
+static void guc_client_free(struct drm_device *dev,
+                           struct i915_guc_client *client)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+
+       if (!client)
+               return;
+
+       if (client->doorbell_id != GUC_INVALID_DOORBELL_ID) {
+               /*
+                * First disable the doorbell, then tell the GuC we've
+                * finished with it, finally deallocate it in our bitmap
+                */
+               guc_disable_doorbell(guc, client);
+               host2guc_release_doorbell(guc, client);
+               release_doorbell(guc, client->doorbell_id);
+       }
+
+       /*
+        * XXX: wait for any outstanding submissions before freeing memory.
+        * Be sure to drop any locks
+        */
+
+       gem_release_guc_obj(client->client_obj);
+
+       if (client->ctx_index != GUC_INVALID_CTX_ID) {
+               guc_fini_ctx_desc(guc, client);
+               ida_simple_remove(&guc->ctx_ids, client->ctx_index);
+       }
+
+       kfree(client);
+}
+
+/**
+ * guc_client_alloc() - Allocate an i915_guc_client
+ * @dev:       drm device
+ * @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 to own the client (we use the default render context)
+ *
+ * Return:     An i915_guc_client object if success.
+ */
+static struct i915_guc_client *guc_client_alloc(struct drm_device *dev,
+                                               uint32_t priority,
+                                               struct intel_context *ctx)
+{
+       struct i915_guc_client *client;
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+       struct drm_i915_gem_object *obj;
+
+       client = kzalloc(sizeof(*client), GFP_KERNEL);
+       if (!client)
+               return NULL;
+
+       client->doorbell_id = GUC_INVALID_DOORBELL_ID;
+       client->priority = priority;
+       client->owner = ctx;
+       client->guc = guc;
+
+       client->ctx_index = (uint32_t)ida_simple_get(&guc->ctx_ids, 0,
+                       GUC_MAX_GPU_CONTEXTS, GFP_KERNEL);
+       if (client->ctx_index >= GUC_MAX_GPU_CONTEXTS) {
+               client->ctx_index = GUC_INVALID_CTX_ID;
+               goto err;
+       }
+
+       /* The first page is doorbell/proc_desc. Two followed pages are wq. */
+       obj = gem_allocate_guc_obj(dev, GUC_DB_SIZE + GUC_WQ_SIZE);
+       if (!obj)
+               goto err;
+
+       client->client_obj = obj;
+       client->wq_offset = GUC_DB_SIZE;
+       client->wq_size = GUC_WQ_SIZE;
+       spin_lock_init(&client->wq_lock);
+
+       client->doorbell_offset = select_doorbell_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);
+
+       client->doorbell_id = assign_doorbell(guc, client->priority);
+       if (client->doorbell_id == GUC_INVALID_DOORBELL_ID)
+               /* XXX: evict a doorbell instead */
+               goto err;
+
+       guc_init_proc_desc(guc, client);
+       guc_init_ctx_desc(guc, client);
+       guc_init_doorbell(guc, client);
+
+       /* XXX: Any cache flushes needed? General domain mgmt calls? */
+
+       if (host2guc_allocate_doorbell(guc, client))
+               goto err;
+
+       DRM_DEBUG_DRIVER("new priority %u client %p: ctx_index %u db_id %u\n",
+               priority, client, client->ctx_index, client->doorbell_id);
+
+       return client;
+
+err:
+       DRM_ERROR("FAILED to create priority %u GuC client!\n", priority);
+
+       guc_client_free(dev, client);
+       return NULL;
+}
+
+static void guc_create_log(struct intel_guc *guc)
+{
+       struct drm_i915_private *dev_priv = guc_to_i915(guc);
+       struct drm_i915_gem_object *obj;
+       unsigned long offset;
+       uint32_t size, flags;
+
+       if (i915.guc_log_level < GUC_LOG_VERBOSITY_MIN)
+               return;
+
+       if (i915.guc_log_level > GUC_LOG_VERBOSITY_MAX)
+               i915.guc_log_level = GUC_LOG_VERBOSITY_MAX;
+
+       /* The first page is to save log buffer state. Allocate one
+        * extra page for others in case for overlap */
+       size = (1 + GUC_LOG_DPC_PAGES + 1 +
+               GUC_LOG_ISR_PAGES + 1 +
+               GUC_LOG_CRASH_PAGES + 1) << PAGE_SHIFT;
+
+       obj = guc->log_obj;
+       if (!obj) {
+               obj = gem_allocate_guc_obj(dev_priv->dev, size);
+               if (!obj) {
+                       /* logging will be off */
+                       i915.guc_log_level = -1;
+                       return;
+               }
+
+               guc->log_obj = obj;
+       }
+
+       /* each allocated unit is a page */
+       flags = GUC_LOG_VALID | GUC_LOG_NOTIFY_ON_HALF_FULL |
+               (GUC_LOG_DPC_PAGES << GUC_LOG_DPC_SHIFT) |
+               (GUC_LOG_ISR_PAGES << GUC_LOG_ISR_SHIFT) |
+               (GUC_LOG_CRASH_PAGES << GUC_LOG_CRASH_SHIFT);
+
+       offset = i915_gem_obj_ggtt_offset(obj) >> PAGE_SHIFT; /* in pages */
+       guc->log_flags = (offset << GUC_LOG_BUF_ADDR_SHIFT) | flags;
+}
+
+/*
+ * Set up the memory resources to be shared with the GuC.  At this point,
+ * we require just one object that can be mapped through the GGTT.
+ */
+int i915_guc_submission_init(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       const size_t ctxsize = sizeof(struct guc_context_desc);
+       const size_t poolsize = GUC_MAX_GPU_CONTEXTS * ctxsize;
+       const size_t gemsize = round_up(poolsize, PAGE_SIZE);
+       struct intel_guc *guc = &dev_priv->guc;
+
+       if (!i915.enable_guc_submission)
+               return 0; /* not enabled  */
+
+       if (guc->ctx_pool_obj)
+               return 0; /* already allocated */
+
+       guc->ctx_pool_obj = gem_allocate_guc_obj(dev_priv->dev, gemsize);
+       if (!guc->ctx_pool_obj)
+               return -ENOMEM;
+
+       spin_lock_init(&dev_priv->guc.host2guc_lock);
+
+       ida_init(&guc->ctx_ids);
+
+       guc_create_log(guc);
+
+       return 0;
+}
+
+int i915_guc_submission_enable(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+       struct intel_context *ctx = dev_priv->ring[RCS].default_context;
+       struct i915_guc_client *client;
+
+       /* client for execbuf submission */
+       client = guc_client_alloc(dev, GUC_CTX_PRIORITY_KMD_NORMAL, ctx);
+       if (!client) {
+               DRM_ERROR("Failed to create execbuf guc_client\n");
+               return -ENOMEM;
+       }
+
+       guc->execbuf_client = client;
+
+       host2guc_sample_forcewake(guc, client);
+
+       return 0;
+}
+
+void i915_guc_submission_disable(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+
+       guc_client_free(dev, guc->execbuf_client);
+       guc->execbuf_client = NULL;
+}
+
+void i915_guc_submission_fini(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+
+       gem_release_guc_obj(dev_priv->guc.log_obj);
+       guc->log_obj = NULL;
+
+       if (guc->ctx_pool_obj)
+               ida_destroy(&guc->ctx_ids);
+       gem_release_guc_obj(guc->ctx_pool_obj);
+       guc->ctx_pool_obj = NULL;
+}
+
+/**
+ * intel_guc_suspend() - notify GuC entering suspend state
+ * @dev:       drm device
+ */
+int intel_guc_suspend(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+       struct intel_context *ctx;
+       u32 data[3];
+
+       if (!i915.enable_guc_submission)
+               return 0;
+
+       ctx = dev_priv->ring[RCS].default_context;
+
+       data[0] = HOST2GUC_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] = i915_gem_obj_ggtt_offset(ctx->engine[RCS].state);
+
+       return host2guc_action(guc, data, ARRAY_SIZE(data));
+}
+
+
+/**
+ * intel_guc_resume() - notify GuC resuming from suspend state
+ * @dev:       drm device
+ */
+int intel_guc_resume(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       struct intel_guc *guc = &dev_priv->guc;
+       struct intel_context *ctx;
+       u32 data[3];
+
+       if (!i915.enable_guc_submission)
+               return 0;
+
+       ctx = dev_priv->ring[RCS].default_context;
+
+       data[0] = HOST2GUC_ACTION_EXIT_S_STATE;
+       data[1] = GUC_POWER_D0;
+       /* first page is shared data with GuC */
+       data[2] = i915_gem_obj_ggtt_offset(ctx->engine[RCS].state);
+
+       return host2guc_action(guc, data, ARRAY_SIZE(data));
+}