drm/i915/wopcm: Check WOPCM layout separately from calculations

We can do WOPCM partitioning using rough estimates and limits
and perform detailed check as separate step.

v2: oops! s/max/min
v3: consolidate overflow checks (Daniele)

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190816105501.31020-3-michal.wajdeczko@intel.com

diff --git a/drivers/gpu/drm/i915/intel_wopcm.c b/drivers/gpu/drm/i915/intel_wopcm.c
index 2975e00..f5cf11e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_wopcm.c
+++ b/drivers/gpu/drm/i915/intel_wopcm.c
@@ -87,7 +87,7 @@ void intel_wopcm_init_early(struct intel_wopcm *wopcm)
        else
                wopcm->size = GEN9_WOPCM_SIZE;
 
-       DRM_DEBUG_DRIVER("WOPCM size: %uKiB\n", wopcm->size / 1024);
+       DRM_DEV_DEBUG_DRIVER(i915->drm.dev, "WOPCM: %uK\n", wopcm->size / 1024);
 }
 
 static inline u32 context_reserved_size(struct drm_i915_private *i915)
@@ -138,9 +138,9 @@ static inline int gen9_check_huc_fw_fits(u32 guc_wopcm_size, u32 huc_fw_size)
        return 0;
 }
 
-static inline int check_hw_restriction(struct drm_i915_private *i915,
-                                      u32 guc_wopcm_base, u32 guc_wopcm_size,
-                                      u32 huc_fw_size)
+static inline bool check_hw_restrictions(struct drm_i915_private *i915,
+                                        u32 guc_wopcm_base, u32 guc_wopcm_size,
+                                        u32 huc_fw_size)
 {
        int err = 0;
 
@@ -151,7 +151,43 @@ static inline int check_hw_restriction(struct drm_i915_private *i915,
            (IS_GEN(i915, 9) || IS_CNL_REVID(i915, CNL_REVID_A0, CNL_REVID_A0)))
                err = gen9_check_huc_fw_fits(guc_wopcm_size, huc_fw_size);
 
-       return err;
+       return !err;
+}
+
+static inline bool __check_layout(struct drm_i915_private *i915, u32 wopcm_size,
+                                 u32 guc_wopcm_base, u32 guc_wopcm_size,
+                                 u32 guc_fw_size, u32 huc_fw_size)
+{
+       const u32 ctx_rsvd = context_reserved_size(i915);
+       u32 size;
+
+       size = wopcm_size - ctx_rsvd;
+       if (unlikely(range_overflows(guc_wopcm_base, guc_wopcm_size, size))) {
+               dev_err(i915->drm.dev,
+                       "WOPCM: invalid GuC region layout: %uK + %uK > %uK\n",
+                       guc_wopcm_base / SZ_1K, guc_wopcm_size / SZ_1K,
+                       size / SZ_1K);
+               return false;
+       }
+
+       size = guc_fw_size + GUC_WOPCM_RESERVED + GUC_WOPCM_STACK_RESERVED;
+       if (unlikely(guc_wopcm_size < size)) {
+               dev_err(i915->drm.dev, "WOPCM: no space for %s: %uK < %uK\n",
+                       intel_uc_fw_type_repr(INTEL_UC_FW_TYPE_GUC),
+                       guc_wopcm_size / SZ_1K, size / SZ_1K);
+               return false;
+       }
+
+       size = huc_fw_size + WOPCM_RESERVED_SIZE;
+       if (unlikely(guc_wopcm_base < size)) {
+               dev_err(i915->drm.dev, "WOPCM: no space for %s: %uK < %uK\n",
+                       intel_uc_fw_type_repr(INTEL_UC_FW_TYPE_HUC),
+                       guc_wopcm_base / SZ_1K, size / SZ_1K);
+               return false;
+       }
+
+       return check_hw_restrictions(i915, guc_wopcm_base, guc_wopcm_size,
+                                    huc_fw_size);
 }
 
 /**
@@ -172,8 +208,6 @@ void intel_wopcm_init(struct intel_wopcm *wopcm)
        u32 ctx_rsvd = context_reserved_size(i915);
        u32 guc_wopcm_base;
        u32 guc_wopcm_size;
-       u32 guc_wopcm_rsvd;
-       int err;
 
        if (!guc_fw_size)
                return;
@@ -183,39 +217,36 @@ void intel_wopcm_init(struct intel_wopcm *wopcm)
        GEM_BUG_ON(wopcm->guc.size);
        GEM_BUG_ON(guc_fw_size >= wopcm->size);
        GEM_BUG_ON(huc_fw_size >= wopcm->size);
+       GEM_BUG_ON(ctx_rsvd + WOPCM_RESERVED_SIZE >= wopcm->size);
 
        if (i915_inject_probe_failure(i915))
                return;
 
-       guc_wopcm_base = ALIGN(huc_fw_size + WOPCM_RESERVED_SIZE,
-                              GUC_WOPCM_OFFSET_ALIGNMENT);
-       if ((guc_wopcm_base + ctx_rsvd) >= wopcm->size) {
-               DRM_ERROR("GuC WOPCM base (%uKiB) is too big.\n",
-                         guc_wopcm_base / 1024);
-               return;
-       }
+       /*
+        * Aligned value of guc_wopcm_base will determine available WOPCM space
+        * for HuC firmware and mandatory reserved area.
+        */
+       guc_wopcm_base = huc_fw_size + WOPCM_RESERVED_SIZE;
+       guc_wopcm_base = ALIGN(guc_wopcm_base, GUC_WOPCM_OFFSET_ALIGNMENT);
+
+       /*
+        * Need to clamp guc_wopcm_base now to make sure the following math is
+        * correct. Formal check of whole WOPCM layout will be done below.
+        */
+       guc_wopcm_base = min(guc_wopcm_base, wopcm->size - ctx_rsvd);
 
-       guc_wopcm_size = wopcm->size - guc_wopcm_base - ctx_rsvd;
+       /* Aligned remainings of usable WOPCM space can be assigned to GuC. */
+       guc_wopcm_size = wopcm->size - ctx_rsvd - guc_wopcm_base;
        guc_wopcm_size &= GUC_WOPCM_SIZE_MASK;
 
-       DRM_DEBUG_DRIVER("Calculated GuC WOPCM Region: [%uKiB, %uKiB)\n",
-                        guc_wopcm_base / 1024, guc_wopcm_size / 1024);
+       DRM_DEV_DEBUG_DRIVER(i915->drm.dev, "Calculated GuC WOPCM [%uK, %uK)\n",
+                            guc_wopcm_base / SZ_1K, guc_wopcm_size / SZ_1K);
 
-       guc_wopcm_rsvd = GUC_WOPCM_RESERVED + GUC_WOPCM_STACK_RESERVED;
-       if ((guc_fw_size + guc_wopcm_rsvd) > guc_wopcm_size) {
-               DRM_ERROR("Need %uKiB WOPCM for GuC, %uKiB available.\n",
-                         (guc_fw_size + guc_wopcm_rsvd) / 1024,
-                         guc_wopcm_size / 1024);
-               return;
+       if (__check_layout(i915, wopcm->size, guc_wopcm_base, guc_wopcm_size,
+                          guc_fw_size, huc_fw_size)) {
+               wopcm->guc.base = guc_wopcm_base;
+               wopcm->guc.size = guc_wopcm_size;
+               GEM_BUG_ON(!wopcm->guc.base);
+               GEM_BUG_ON(!wopcm->guc.size);
        }
-
-       err = check_hw_restriction(i915, guc_wopcm_base, guc_wopcm_size,
-                                  huc_fw_size);
-       if (err)
-               return;
-
-       wopcm->guc.base = guc_wopcm_base;
-       wopcm->guc.size = guc_wopcm_size;
-       GEM_BUG_ON(!wopcm->guc.base);
-       GEM_BUG_ON(!wopcm->guc.size);
 }