[Intel-gfx] [PATCH v2] drm/i915: Check stolen memory size before calling drm_mm_init

[José Roberto de Souza]

From: Steve Carbonari <steven.carbonari at intel.com>

Add check for zero usable stolen memory before calling drm_mm_init
to support configurations where stolen memory exists but is fully
reserved.

Also skip memory test in such case.

v2:
- convert stolen_usable_size to u64 so build do not break
depending on PHYS_ADDR_T_64BIT config.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
Signed-off-by: Steve Carbonari <steven.carbonari at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 9 ++++++---
 drivers/gpu/drm/i915/intel_memory_region.c | 5 +++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index 1de73a6449652..44972da1d4e95 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -496,13 +496,16 @@ static int i915_gem_init_stolen(struct intel_memory_region *mem)
 	 * memory, so just consider the start. */
 	reserved_total = stolen_top - reserved_base;
 
+	i915->stolen_usable_size =
+		resource_size(&i915->dsm) - reserved_total;
+
 	drm_dbg(&i915->drm,
 		"Memory reserved for graphics device: %lluK, usable: %lluK\n",
 		(u64)resource_size(&i915->dsm) >> 10,
-		((u64)resource_size(&i915->dsm) - reserved_total) >> 10);
+		(u64)i915->stolen_usable_size >> 10);
 
-	i915->stolen_usable_size =
-		resource_size(&i915->dsm) - reserved_total;
+	if (i915->stolen_usable_size == 0)
+		return 0;
 
 	/* Basic memrange allocator for stolen space. */
 	drm_mm_init(&i915->mm.stolen, 0, i915->stolen_usable_size);
diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
index c70d7e286a512..329f46f71cdce 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -205,6 +205,11 @@ static int intel_memory_region_memtest(struct intel_memory_region *mem,
 	if (!mem->io_start)
 		return 0;
 
+	if ((mem->type == INTEL_MEMORY_STOLEN_LOCAL ||
+	     mem->type == INTEL_MEMORY_STOLEN_SYSTEM) &&
+	    !drm_mm_initialized(&i915->mm.stolen))
+		return 0;
+
 	if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) || i915->params.memtest)
 		err = iomemtest(mem, i915->params.memtest, caller);
 
-- 
2.35.1