[PATCH 4/8] drm/i915/dg1: Reserve first 1MB of local memory
Matthew Auld
matthew.auld at intel.com
Mon Jan 25 18:14:42 UTC 2021
From: Imre Deak <imre.deak at intel.com>
On DG1 A0/B0 steppings the first 1MB of local memory must be reserved.
One reason for this is that the 0xA0000-0xB0000 range is not accessible
by the display, probably since this region is redirected to another
memory location for legacy VGA compatibility.
BSpec: 50586
Testcase: igt/kms_big_fb/linear-64bpp-rotate-0
v2:
- Reserve the memory on B0 as well.
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
drivers/gpu/drm/i915/gt/intel_region_lmem.c | 52 +++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
index 3a990a9506f3..fb1041b82849 100644
--- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
@@ -137,6 +137,48 @@ intel_setup_fake_lmem(struct drm_i915_private *i915)
return mem;
}
+static void get_legacy_lowmem_region(struct intel_uncore *uncore,
+ u64 *start, u32 *size)
+{
+ *start = 0;
+ *size = 0;
+
+ if (!IS_DG1_REVID(uncore->i915, DG1_REVID_A0, DG1_REVID_B0))
+ return;
+
+ *size = SZ_1M;
+
+ DRM_DEBUG_DRIVER("LMEM: reserved legacy low-memory [0x%llx-0x%llx]\n",
+ *start, *start + *size);
+}
+
+static int reserve_lowmem_region(struct intel_uncore *uncore,
+ struct intel_memory_region *mem)
+{
+ u64 reserve_start;
+ u64 reserve_end;
+ u64 region_start;
+ u32 region_size;
+ int ret;
+
+ get_legacy_lowmem_region(uncore, ®ion_start, ®ion_size);
+ reserve_start = region_start;
+ reserve_end = region_start + region_size;
+
+ if (!reserve_end)
+ return 0;
+
+ DRM_INFO("LMEM: reserving low-memory region [0x%llx-0x%llx]\n",
+ reserve_start, reserve_end);
+ ret = i915_buddy_alloc_range(&mem->mm, &mem->reserved,
+ reserve_start,
+ reserve_end - reserve_start);
+ if (ret)
+ DRM_ERROR("LMEM: reserving low memory region failed\n");
+
+ return ret;
+}
+
static struct intel_memory_region *
setup_lmem(struct drm_i915_private *i915)
{
@@ -161,6 +203,16 @@ setup_lmem(struct drm_i915_private *i915)
I915_GTT_PAGE_SIZE_4K,
io_start,
&intel_region_lmem_ops);
+ if (!IS_ERR(mem)) {
+ int err;
+
+ err = reserve_lowmem_region(uncore, mem);
+ if (err) {
+ intel_memory_region_put(mem);
+ return ERR_PTR(err);
+ }
+ }
+
if (!IS_ERR(mem)) {
drm_info(&i915->drm, "Intel graphics LMEM: %pR\n", &mem->region);
drm_info(&i915->drm, "Intel graphics LMEM IO start: %pa\n",
--
2.26.2
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