drm/i915: Sanitize engine context sizes

Pre-calculate engine context size based on engine class and device
generation and store it in the engine instance.

v2:
- Squash and get rid of hw_context_size (Chris)

v3:
- Move after MMIO init for probing on Gen7 and 8 (Chris)
- Retained rounding (Tvrtko)
v4:
- Rebase for deferred legacy context allocation

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: intel-gvt-dev@lists.freedesktop.org
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 87 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 82a274b336c5..6d3d83876da9 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -26,6 +26,22 @@
 #include "intel_ringbuffer.h"
 #include "intel_lrc.h"
 
+/* Haswell does have the CXT_SIZE register however it does not appear to be
+ * valid. Now, docs explain in dwords what is in the context object. The full
+ * size is 70720 bytes, however, the power context and execlist context will
+ * never be saved (power context is stored elsewhere, and execlists don't work
+ * on HSW) - so the final size, including the extra state required for the
+ * Resource Streamer, is 66944 bytes, which rounds to 17 pages.
+ */
+#define HSW_CXT_TOTAL_SIZE              (17 * PAGE_SIZE)
+/* Same as Haswell, but 72064 bytes now. */
+#define GEN8_CXT_TOTAL_SIZE             (18 * PAGE_SIZE)
+
+#define GEN8_LR_CONTEXT_RENDER_SIZE     (20 * PAGE_SIZE)
+#define GEN9_LR_CONTEXT_RENDER_SIZE     (22 * PAGE_SIZE)
+
+#define GEN8_LR_CONTEXT_OTHER_SIZE      ( 2 * PAGE_SIZE)
+
 struct engine_class_info {
         const char *name;
         int (*init_legacy)(struct intel_engine_cs *engine);
@@ -107,6 +123,69 @@ static const struct engine_info intel_engines[] = {
         },
 };
 
+/**
+ * ___intel_engine_context_size() - return the size of the context for an engine
+ * @dev_priv: i915 device private
+ * @class: engine class
+ *
+ * Each engine class may require a different amount of space for a context
+ * image.
+ *
+ * Return: size (in bytes) of an engine class specific context image
+ *
+ * Note: this size includes the HWSP, which is part of the context image
+ * in LRC mode, but does not include the "shared data page" used with
+ * GuC submission. The caller should account for this if using the GuC.
+ */
+static u32
+__intel_engine_context_size(struct drm_i915_private *dev_priv, u8 class)
+{
+        u32 cxt_size;
+
+        BUILD_BUG_ON(I915_GTT_PAGE_SIZE != PAGE_SIZE);
+
+        switch (class) {
+        case RENDER_CLASS:
+                switch (INTEL_GEN(dev_priv)) {
+                default:
+                        MISSING_CASE(INTEL_GEN(dev_priv));
+                case 9:
+                        return GEN9_LR_CONTEXT_RENDER_SIZE;
+                case 8:
+                        return i915.enable_execlists ?
+                               GEN8_LR_CONTEXT_RENDER_SIZE :
+                               GEN8_CXT_TOTAL_SIZE;
+                case 7:
+                        if (IS_HASWELL(dev_priv))
+                                return HSW_CXT_TOTAL_SIZE;
+
+                        cxt_size = I915_READ(GEN7_CXT_SIZE);
+                        return round_up(GEN7_CXT_TOTAL_SIZE(cxt_size) * 64,
+                                        PAGE_SIZE);
+                case 6:
+                        cxt_size = I915_READ(CXT_SIZE);
+                        return round_up(GEN6_CXT_TOTAL_SIZE(cxt_size) * 64,
+                                        PAGE_SIZE);
+                case 5:
+                case 4:
+                case 3:
+                case 2:
+                /* For the special day when i810 gets merged. */
+                case 1:
+                        return 0;
+                }
+                break;
+        default:
+                MISSING_CASE(class);
+        case VIDEO_DECODE_CLASS:
+        case VIDEO_ENHANCEMENT_CLASS:
+        case COPY_ENGINE_CLASS:
+                if (INTEL_GEN(dev_priv) < 8)
+                        return 0;
+                return GEN8_LR_CONTEXT_OTHER_SIZE;
+        }
+}
+
 static int
 intel_engine_setup(struct drm_i915_private *dev_priv,
                    enum intel_engine_id id)
@@ -135,6 +214,11 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
         engine->class = info->class;
         engine->instance = info->instance;
 
+        engine->context_size = __intel_engine_context_size(dev_priv,
+                                                           engine->class);
+        if (WARN_ON(engine->context_size > BIT(20)))
+                engine->context_size = 0;
+
         /* Nothing to do here, execute in order of dependencies */
         engine->schedule = NULL;
 
@@ -145,12 +229,12 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
 }
 
 /**
- * intel_engines_init_early() - allocate the Engine Command Streamers
+ * intel_engines_init_mmio() - allocate and prepare the Engine Command Streamers
  * @dev_priv: i915 device private
  *
  * Return: non-zero if the initialization failed.
  */
-int intel_engines_init_early(struct drm_i915_private *dev_priv)
+int intel_engines_init_mmio(struct drm_i915_private *dev_priv)
 {
         struct intel_device_info *device_info = mkwrite_device_info(dev_priv);
         const unsigned int ring_mask = INTEL_INFO(dev_priv)->ring_mask;
@@ -200,7 +284,7 @@ cleanup:
 }
 
 /**
- * intel_engines_init() - allocate, populate and init the Engine Command Streamers
+ * intel_engines_init() - init the Engine Command Streamers
  * @dev_priv: i915 device private
  *
  * Return: non-zero if the initialization failed.