[PATCH v4] drm/i915/mtl: enable local stolen memory

* [PATCH v4] drm/i915/mtl: enable local stolen memory
@ 2022-09-28 11:06 ` Aravind Iddamsetty
  0 siblings, 0 replies; 8+ messages in thread
From: Aravind Iddamsetty @ 2022-09-28 11:06 UTC (permalink / raw)
  To: intel-gfx; +Cc: lucas.demarchi, dri-devel

As an integrated GPU, MTL does not have local memory and
HAS_LMEM() returns false.  However the platform's stolen memory
is presented via BAR2 (i.e., the BAR we traditionally consider
to be the LMEM BAR) and should be managed by the driver the same
way that local memory is on dgpu platforms (which includes
setting the "lmem" bit on page table entries).  We use the term
"local stolen memory" to refer to this model.

BSPEC: 53098, 63830

v2:
1. dropped is_dsm_invalid, updated valid_stolen_size check from Lucas
(Jani, Lucas)
2. drop lmembar_is_igpu_stolen
3. revert to referring GFXMEM_BAR as GEN12_LMEM_BAR (Lucas)

v3:(Jani)
1. rename get_mtl_gms_size to mtl_get_gms_size
2. define register for MMIO address

v4:(Matt)
1. Use REG_FIELD_GET to read GMS value
2. replace the calculations with SZ_256M/SZ_8M

Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Original-author: CQ Tang
---
 drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 83 ++++++++++++++++++----
 drivers/gpu/drm/i915/gt/intel_ggtt.c       |  2 +-
 drivers/gpu/drm/i915/i915_drv.h            |  3 +
 drivers/gpu/drm/i915/i915_reg.h            |  4 ++
 4 files changed, 76 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index c5a4035c99cd..2f8530a0ff62 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -77,9 +77,9 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *i915,
 	mutex_unlock(&i915->mm.stolen_lock);
 }
 
-static bool valid_stolen_size(struct resource *dsm)
+static bool valid_stolen_size(struct drm_i915_private *i915, struct resource *dsm)
 {
-	return dsm->start != 0 && dsm->end > dsm->start;
+	return (dsm->start != 0 || HAS_BAR2_SMEM_STOLEN(i915)) && dsm->end > dsm->start;
 }
 
 static int adjust_stolen(struct drm_i915_private *i915,
@@ -88,7 +88,7 @@ static int adjust_stolen(struct drm_i915_private *i915,
 	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
 	struct intel_uncore *uncore = ggtt->vm.gt->uncore;
 
-	if (!valid_stolen_size(dsm))
+	if (!valid_stolen_size(i915, dsm))
 		return -EINVAL;
 
 	/*
@@ -135,7 +135,7 @@ static int adjust_stolen(struct drm_i915_private *i915,
 		}
 	}
 
-	if (!valid_stolen_size(dsm))
+	if (!valid_stolen_size(i915, dsm))
 		return -EINVAL;
 
 	return 0;
@@ -149,8 +149,11 @@ static int request_smem_stolen(struct drm_i915_private *i915,
 	/*
 	 * With stolen lmem, we don't need to request system memory for the
 	 * address range since it's local to the gpu.
+	 *
+	 * Starting MTL, in IGFX devices the stolen memory is exposed via
+	 * BAR2 and shall be considered similar to stolen lmem.
 	 */
-	if (HAS_LMEM(i915))
+	if (HAS_LMEM(i915) || HAS_BAR2_SMEM_STOLEN(i915))
 		return 0;
 
 	/*
@@ -385,8 +388,6 @@ static void icl_get_stolen_reserved(struct drm_i915_private *i915,
 
 	drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = 0x%016llx\n", reg_val);
 
-	*base = reg_val & GEN11_STOLEN_RESERVED_ADDR_MASK;
-
 	switch (reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK) {
 	case GEN8_STOLEN_RESERVED_1M:
 		*size = 1024 * 1024;
@@ -404,6 +405,12 @@ static void icl_get_stolen_reserved(struct drm_i915_private *i915,
 		*size = 8 * 1024 * 1024;
 		MISSING_CASE(reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK);
 	}
+
+	if (HAS_BAR2_SMEM_STOLEN(i915))
+		/* the base is initialized to stolen top so subtract size to get base */
+		*base -= *size;
+	else
+		*base = reg_val & GEN11_STOLEN_RESERVED_ADDR_MASK;
 }
 
 /*
@@ -833,6 +840,29 @@ static const struct intel_memory_region_ops i915_region_stolen_lmem_ops = {
 	.init_object = _i915_gem_object_stolen_init,
 };
 
+static int mtl_get_gms_size(struct intel_uncore *uncore)
+{
+	u16 ggc, gms;
+
+	ggc = intel_uncore_read16(uncore, GGC);
+
+	/* check GGMS, should be fixed 0x3 (8MB) */
+	if ((ggc & GGMS_MASK) != GGMS_MASK)
+		return -EIO;
+
+	/* return valid GMS value, -EIO if invalid */
+	gms = REG_FIELD_GET(GMS_MASK, ggc);
+	switch (gms) {
+	case 0x0 ... 0x04:
+		return gms * 32;
+	case 0xf0 ... 0xfe:
+		return (gms - 0xf0 + 1) * 4;
+	default:
+		MISSING_CASE(gms);
+		return -EIO;
+	}
+}
+
 struct intel_memory_region *
 i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 			   u16 instance)
@@ -843,6 +873,7 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 	struct intel_memory_region *mem;
 	resource_size_t io_start, io_size;
 	resource_size_t min_page_size;
+	int ret;
 
 	if (WARN_ON_ONCE(instance))
 		return ERR_PTR(-ENODEV);
@@ -850,12 +881,8 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 	if (!i915_pci_resource_valid(pdev, GEN12_LMEM_BAR))
 		return ERR_PTR(-ENXIO);
 
-	/* Use DSM base address instead for stolen memory */
-	dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE) & GEN12_BDSM_MASK;
-	if (IS_DG1(uncore->i915)) {
+	if (HAS_BAR2_SMEM_STOLEN(i915) || IS_DG1(i915)) {
 		lmem_size = pci_resource_len(pdev, GEN12_LMEM_BAR);
-		if (WARN_ON(lmem_size < dsm_base))
-			return ERR_PTR(-ENODEV);
 	} else {
 		resource_size_t lmem_range;
 
@@ -864,13 +891,39 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 		lmem_size *= SZ_1G;
 	}
 
-	dsm_size = lmem_size - dsm_base;
-	if (pci_resource_len(pdev, GEN12_LMEM_BAR) < lmem_size) {
+	if (HAS_BAR2_SMEM_STOLEN(i915)) {
+		/*
+		 * MTL dsm size is in GGC register, not the bar size.
+		 * also MTL uses offset to DSMBASE in ptes, so i915
+		 * uses dsm_base = 0 to setup stolen region.
+		 */
+		ret = mtl_get_gms_size(uncore);
+		if (ret < 0) {
+			drm_err(&i915->drm, "invalid MTL GGC register setting\n");
+			return ERR_PTR(ret);
+		}
+
+		dsm_base = 0;
+		dsm_size = (resource_size_t)(ret * SZ_1M);
+
+		GEM_BUG_ON(pci_resource_len(pdev, GEN12_LMEM_BAR) != SZ_256M);
+		GEM_BUG_ON((dsm_size + SZ_8M) > lmem_size);
+	} else {
+		/* Use DSM base address instead for stolen memory */
+		dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE);
+		if (WARN_ON(lmem_size < dsm_base))
+			return ERR_PTR(-ENODEV);
+		dsm_size = lmem_size - dsm_base;
+	}
+
+	io_size = dsm_size;
+	if (pci_resource_len(pdev, GEN12_LMEM_BAR) < dsm_size) {
 		io_start = 0;
 		io_size = 0;
+	} else if (HAS_BAR2_SMEM_STOLEN(i915)) {
+		io_start = pci_resource_start(pdev, GEN12_LMEM_BAR) + SZ_8M;
 	} else {
 		io_start = pci_resource_start(pdev, GEN12_LMEM_BAR) + dsm_base;
-		io_size = dsm_size;
 	}
 
 	min_page_size = HAS_64K_PAGES(i915) ? I915_GTT_PAGE_SIZE_64K :
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 30cf5c3369d9..b31fe0fb013f 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -931,7 +931,7 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 	unsigned int size;
 	u16 snb_gmch_ctl;
 
-	if (!HAS_LMEM(i915)) {
+	if (!HAS_LMEM(i915) && !HAS_BAR2_SMEM_STOLEN(i915)) {
 		if (!i915_pci_resource_valid(pdev, GTT_APERTURE_BAR))
 			return -ENXIO;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 84a2f6b16f57..90ed8e6db2fe 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -974,6 +974,9 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 
 #define HAS_ONE_EU_PER_FUSE_BIT(i915)	(INTEL_INFO(i915)->has_one_eu_per_fuse_bit)
 
+#define HAS_BAR2_SMEM_STOLEN(i915) (!HAS_LMEM(i915) && \
+				    GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70))
+
 /* intel_device_info.c */
 static inline struct intel_device_info *
 mkwrite_device_info(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5003a5ffbc6a..2126e441199d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7967,6 +7967,10 @@ enum skl_power_gate {
 							   _ICL_PIPE_DSS_CTL2_PB, \
 							   _ICL_PIPE_DSS_CTL2_PC)
 
+#define GGC				_MMIO(0x108040)
+#define   GMS_MASK			REG_GENMASK(15, 8)
+#define   GGMS_MASK			REG_GENMASK(7, 6)
+
 #define GEN12_GSMBASE			_MMIO(0x108100)
 #define GEN12_DSMBASE			_MMIO(0x1080C0)
 #define   GEN12_BDSM_MASK		REG_GENMASK64(63, 20)
-- 
2.25.1


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