drm/i915: make dsm struct resource centric

Now that we are using struct resource to track the stolen region, it is
more convenient if we track dsm in a resource as well.

v2: check range_overflow when writing to 32b registers (Chris)
    pepper in some comments (Chris)
v3: refit i915_stolen_to_dma()
v4: kill ggtt->stolen_size
v5: some more polish
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171211151822.20953-6-matthew.auld@intel.com

drivers/char/agp/intel-gtt.c

@@ -1424,12 +1424,10 @@ int intel_gmch_probe(struct pci_dev *bridge_pdev, struct pci_dev *gpu_pdev,
 EXPORT_SYMBOL(intel_gmch_probe);
 
 void intel_gtt_get(u64 *gtt_total,
-		   u32 *stolen_size,
 		   phys_addr_t *mappable_base,
 		   u64 *mappable_end)
 {
 	*gtt_total = intel_private.gtt_total_entries << PAGE_SHIFT;
-	*stolen_size = intel_private.stolen_size;
 	*mappable_base = intel_private.gma_bus_addr;
 	*mappable_end = intel_private.gtt_mappable_entries << PAGE_SHIFT;
 }

drivers/gpu/drm/i915/i915_drv.h

@@ -1538,9 +1538,6 @@ struct i915_gem_mm {
 	 */
 	struct pagevec wc_stash;
 
-	/** Usable portion of the GTT for GEM */
-	dma_addr_t stolen_base; /* limited to low memory (32-bit) */
-
 	/**
 	 * tmpfs instance used for shmem backed objects
 	 */
@@ -2254,6 +2251,15 @@ struct drm_i915_private {
 
 	const struct intel_device_info info;
 
+	/**
+	 * Data Stolen Memory - aka "i915 stolen memory" gives us the start and
+	 * end of stolen which we can optionally use to create GEM objects
+	 * backed by stolen memory. Note that ggtt->stolen_usable_size tells us
+	 * exactly how much of this we are actually allowed to use, given that
+	 * some portion of it is in fact reserved for use by hardware functions.
+	 */
+	struct resource dsm;
+
 	void __iomem *regs;
 
 	struct intel_uncore uncore;

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -3299,8 +3299,6 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 
 	pci_read_config_word(pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 
-	ggtt->stolen_size = resource_size(&intel_graphics_stolen_res);
-
 	if (INTEL_GEN(dev_priv) >= 9) {
 		size = gen8_get_total_gtt_size(snb_gmch_ctl);
 	} else if (IS_CHERRYVIEW(dev_priv)) {
@@ -3363,8 +3361,6 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt)
 		DRM_ERROR("Can't set DMA mask/consistent mask (%d)\n", err);
 	pci_read_config_word(pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 
-	ggtt->stolen_size = resource_size(&intel_graphics_stolen_res);
-
 	size = gen6_get_total_gtt_size(snb_gmch_ctl);
 	ggtt->base.total = (size / sizeof(gen6_pte_t)) << PAGE_SHIFT;
 
@@ -3410,7 +3406,6 @@ static int i915_gmch_probe(struct i915_ggtt *ggtt)
 	}
 
 	intel_gtt_get(&ggtt->base.total,
-		      &ggtt->stolen_size,
 		      &ggtt->mappable_base,
 		      &ggtt->mappable_end);
 
@@ -3482,7 +3477,8 @@ int i915_ggtt_probe_hw(struct drm_i915_private *dev_priv)
 	DRM_INFO("Memory usable by graphics device = %lluM\n",
 		 ggtt->base.total >> 20);
 	DRM_DEBUG_DRIVER("GMADR size = %lldM\n", ggtt->mappable_end >> 20);
-	DRM_DEBUG_DRIVER("GTT stolen size = %uM\n", ggtt->stolen_size >> 20);
+	DRM_DEBUG_DRIVER("GTT stolen size = %lluM\n",
+			 (u64)resource_size(&intel_graphics_stolen_res) >> 20);
 	if (intel_vtd_active())
 		DRM_INFO("VT-d active for gfx access\n");
 

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -381,7 +381,6 @@ struct i915_ggtt {
 	 * avoid the first page! The upper end of stolen memory is reserved for
 	 * hardware functions and similarly removed from the accessible range.
 	 */
-	u32 stolen_size;		/* Total size of stolen memory */
 	u32 stolen_usable_size;	/* Total size minus reserved ranges */
 	u32 stolen_reserved_base;
 	u32 stolen_reserved_size;

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -76,27 +76,26 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
 	mutex_unlock(&dev_priv->mm.stolen_lock);
 }
 
-static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv)
+static int i915_adjust_stolen(struct drm_i915_private *dev_priv,
+			      struct resource *dsm)
 {
 	struct i915_ggtt *ggtt = &dev_priv->ggtt;
-	dma_addr_t base = intel_graphics_stolen_res.start;
 	struct resource *r;
 
-	GEM_BUG_ON(overflows_type(intel_graphics_stolen_res.start, base));
+	if (dsm->start == 0 || dsm->end <= dsm->start)
+		return -EINVAL;
 
-	if (base == 0 || add_overflows(base, ggtt->stolen_size))
-		return 0;
+	/*
+	 * TODO: We have yet too encounter the case where the GTT wasn't at the
+	 * end of stolen. With that assumption we could simplify this.
+	 */
 
-	/* make sure we don't clobber the GTT if it's within stolen memory */
+	/* Make sure we don't clobber the GTT if it's within stolen memory */
 	if (INTEL_GEN(dev_priv) <= 4 &&
 	    !IS_G33(dev_priv) && !IS_PINEVIEW(dev_priv) && !IS_G4X(dev_priv)) {
-		struct {
-			dma_addr_t start, end;
-		} stolen[2] = {
-			{ .start = base, .end = base + ggtt->stolen_size, },
-			{ .start = base, .end = base + ggtt->stolen_size, },
-		};
-		u64 ggtt_start, ggtt_end;
+		struct resource stolen[2] = {*dsm, *dsm};
+		struct resource ggtt_res;
+		u64 ggtt_start;
 
 		ggtt_start = I915_READ(PGTBL_CTL);
 		if (IS_GEN4(dev_priv))
@@ -104,70 +103,64 @@ static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv)
 				     (ggtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
 		else
 			ggtt_start &= PGTBL_ADDRESS_LO_MASK;
-		ggtt_end = ggtt_start + ggtt_total_entries(ggtt) * 4;
-
-		if (ggtt_start >= stolen[0].start && ggtt_start < stolen[0].end)
-			stolen[0].end = ggtt_start;
-		if (ggtt_end > stolen[1].start && ggtt_end <= stolen[1].end)
-			stolen[1].start = ggtt_end;
-
-		/* pick the larger of the two chunks */
-		if (stolen[0].end - stolen[0].start >
-		    stolen[1].end - stolen[1].start) {
-			base = stolen[0].start;
-			ggtt->stolen_size = stolen[0].end - stolen[0].start;
-		} else {
-			base = stolen[1].start;
-			ggtt->stolen_size = stolen[1].end - stolen[1].start;
-		}
+
+		ggtt_res =
+			(struct resource) DEFINE_RES_MEM(ggtt_start,
+							 ggtt_total_entries(ggtt) * 4);
+
+		if (ggtt_res.start >= stolen[0].start && ggtt_res.start < stolen[0].end)
+			stolen[0].end = ggtt_res.start;
+		if (ggtt_res.end > stolen[1].start && ggtt_res.end <= stolen[1].end)
+			stolen[1].start = ggtt_res.end;
+
+		/* Pick the larger of the two chunks */
+		if (resource_size(&stolen[0]) > resource_size(&stolen[1]))
+			*dsm = stolen[0];
+		else
+			*dsm = stolen[1];
 
 		if (stolen[0].start != stolen[1].start ||
 		    stolen[0].end != stolen[1].end) {
-			dma_addr_t end = base + ggtt->stolen_size - 1;
-
-			DRM_DEBUG_KMS("GTT within stolen memory at 0x%llx-0x%llx\n",
-				      (unsigned long long)ggtt_start,
-				      (unsigned long long)ggtt_end - 1);
-			DRM_DEBUG_KMS("Stolen memory adjusted to %pad - %pad\n",
-				      &base, &end);
+			DRM_DEBUG_KMS("GTT within stolen memory at %pR\n", &ggtt_res);
+			DRM_DEBUG_KMS("Stolen memory adjusted to %pR\n", dsm);
 		}
 	}
 
-
-	/* Verify that nothing else uses this physical address. Stolen
+	/*
+	 * Verify that nothing else uses this physical address. Stolen
 	 * memory should be reserved by the BIOS and hidden from the
 	 * kernel. So if the region is already marked as busy, something
 	 * is seriously wrong.
 	 */
-	r = devm_request_mem_region(dev_priv->drm.dev, base, ggtt->stolen_size,
+	r = devm_request_mem_region(dev_priv->drm.dev, dsm->start,
+				    resource_size(dsm),
 				    "Graphics Stolen Memory");
 	if (r == NULL) {
 		/*
 		 * One more attempt but this time requesting region from
-		 * base + 1, as we have seen that this resolves the region
+		 * start + 1, as we have seen that this resolves the region
 		 * conflict with the PCI Bus.
 		 * This is a BIOS w/a: Some BIOS wrap stolen in the root
 		 * PCI bus, but have an off-by-one error. Hence retry the
 		 * reservation starting from 1 instead of 0.
 		 * There's also BIOS with off-by-one on the other end.
 		 */
-		r = devm_request_mem_region(dev_priv->drm.dev, base + 1,
-					    ggtt->stolen_size - 2,
+		r = devm_request_mem_region(dev_priv->drm.dev, dsm->start + 1,
+					    resource_size(dsm) - 2,
 					    "Graphics Stolen Memory");
 		/*
 		 * GEN3 firmware likes to smash pci bridges into the stolen
 		 * range. Apparently this works.
 		 */
 		if (r == NULL && !IS_GEN3(dev_priv)) {
-			dma_addr_t end = base + ggtt->stolen_size;
+			DRM_ERROR("conflict detected with stolen region: %pR\n",
+				  dsm);
 
-			DRM_ERROR("conflict detected with stolen region: [%pad - %pad]\n",
-				  &base, &end);
-			base = 0;
+			return -EBUSY;
 		}
 	}
 
-	return base;
+	return 0;
 }
 
 void i915_gem_cleanup_stolen(struct drm_device *dev)
@@ -183,11 +176,10 @@ void i915_gem_cleanup_stolen(struct drm_device *dev)
 static void g4x_get_stolen_reserved(struct drm_i915_private *dev_priv,
 				    dma_addr_t *base, u32 *size)
 {
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	uint32_t reg_val = I915_READ(IS_GM45(dev_priv) ?
 				     CTG_STOLEN_RESERVED :
 				     ELK_STOLEN_RESERVED);
-	dma_addr_t stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
+	dma_addr_t stolen_top = dev_priv->dsm.end + 1;
 
 	if ((reg_val & G4X_STOLEN_RESERVED_ENABLE) == 0) {
 		*base = 0;
@@ -308,7 +300,6 @@ static void chv_get_stolen_reserved(struct drm_i915_private *dev_priv,
 static void bdw_get_stolen_reserved(struct drm_i915_private *dev_priv,
 				    dma_addr_t *base, u32 *size)
 {
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
 	dma_addr_t stolen_top;
 
@@ -318,7 +309,7 @@ static void bdw_get_stolen_reserved(struct drm_i915_private *dev_priv,
 		return;
 	}
 
-	stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
+	stolen_top = dev_priv->dsm.end + 1;
 
 	*base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;
 
@@ -351,14 +342,18 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
 		return 0;
 	}
 
-	if (ggtt->stolen_size == 0)
+	if (resource_size(&intel_graphics_stolen_res) == 0)
 		return 0;
 
-	dev_priv->mm.stolen_base = i915_stolen_to_dma(dev_priv);
-	if (dev_priv->mm.stolen_base == 0)
+	dev_priv->dsm = intel_graphics_stolen_res;
+
+	if (i915_adjust_stolen(dev_priv, &dev_priv->dsm))
 		return 0;
 
-	stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
+	GEM_BUG_ON(dev_priv->dsm.start == 0);
+	GEM_BUG_ON(dev_priv->dsm.end <= dev_priv->dsm.start);
+
+	stolen_top = dev_priv->dsm.end + 1;
 	reserved_base = 0;
 	reserved_size = 0;
 
@@ -399,12 +394,11 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
 		reserved_base = stolen_top;
 	}
 
-	if (reserved_base < dev_priv->mm.stolen_base ||
+	if (reserved_base < dev_priv->dsm.start ||
 	    reserved_base + reserved_size > stolen_top) {
 		dma_addr_t reserved_top = reserved_base + reserved_size;
-		DRM_ERROR("Stolen reserved area [%pad - %pad] outside stolen memory [%pad - %pad]\n",
-			  &reserved_base, &reserved_top,
-			  &dev_priv->mm.stolen_base, &stolen_top);
+		DRM_ERROR("Stolen reserved area [%pad - %pad] outside stolen memory %pR\n",
+			  &reserved_base, &reserved_top, &dev_priv->dsm);
 		return 0;
 	}
 
@@ -415,9 +409,9 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
 	 * memory, so just consider the start. */
 	reserved_total = stolen_top - reserved_base;
 
-	DRM_DEBUG_KMS("Memory reserved for graphics device: %uK, usable: %uK\n",
-		      ggtt->stolen_size >> 10,
-		      (ggtt->stolen_size - reserved_total) >> 10);
+	DRM_DEBUG_KMS("Memory reserved for graphics device: %lluK, usable: %lluK\n",
+		      (u64)resource_size(&dev_priv->dsm) >> 10,
+		      ((u64)resource_size(&dev_priv->dsm) - reserved_total) >> 10);
 
 	stolen_usable_start = 0;
 	/* WaSkipStolenMemoryFirstPage:bdw+ */
@@ -425,7 +419,7 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
 		stolen_usable_start = 4096;
 
 	ggtt->stolen_usable_size =
-		ggtt->stolen_size - reserved_total - stolen_usable_start;
+		resource_size(&dev_priv->dsm) - reserved_total - stolen_usable_start;
 
 	/* Basic memrange allocator for stolen space. */
 	drm_mm_init(&dev_priv->mm.stolen, stolen_usable_start,
@@ -442,7 +436,8 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 	struct sg_table *st;
 	struct scatterlist *sg;
 
-	GEM_BUG_ON(range_overflows(offset, size, dev_priv->ggtt.stolen_size));
+	GEM_BUG_ON(range_overflows_t(resource_size_t, offset, size,
+				     resource_size(&dev_priv->dsm)));
 
 	/* We hide that we have no struct page backing our stolen object
 	 * by wrapping the contiguous physical allocation with a fake
@@ -462,7 +457,7 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 	sg->offset = 0;
 	sg->length = size;
 
-	sg_dma_address(sg) = (dma_addr_t)dev_priv->mm.stolen_base + offset;
+	sg_dma_address(sg) = (dma_addr_t)dev_priv->dsm.start + offset;
 	sg_dma_len(sg) = size;
 
 	return st;

drivers/gpu/drm/i915/intel_fbc.c

@@ -531,7 +531,6 @@ static int find_compression_threshold(struct drm_i915_private *dev_priv,
 				      int size,
 				      int fb_cpp)
 {
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	int compression_threshold = 1;
 	int ret;
 	u64 end;
@@ -541,7 +540,7 @@ static int find_compression_threshold(struct drm_i915_private *dev_priv,
 	 * If we enable FBC using a CFB on that memory range we'll get FIFO
 	 * underruns, even if that range is not reserved by the BIOS. */
 	if (IS_BROADWELL(dev_priv) || IS_GEN9_BC(dev_priv))
-		end = ggtt->stolen_size - 8 * 1024 * 1024;
+		end = resource_size(&dev_priv->dsm) - 8 * 1024 * 1024;
 	else
 		end = U64_MAX;
 
@@ -615,10 +614,16 @@ static int intel_fbc_alloc_cfb(struct intel_crtc *crtc)
 
 		fbc->compressed_llb = compressed_llb;
 
+		GEM_BUG_ON(range_overflows_t(u64, dev_priv->dsm.start,
+					     fbc->compressed_fb.start,
+					     U32_MAX));
+		GEM_BUG_ON(range_overflows_t(u64, dev_priv->dsm.start,
+					     fbc->compressed_llb->start,
+					     U32_MAX));
 		I915_WRITE(FBC_CFB_BASE,
-			   dev_priv->mm.stolen_base + fbc->compressed_fb.start);
+			   dev_priv->dsm.start + fbc->compressed_fb.start);
 		I915_WRITE(FBC_LL_BASE,
-			   dev_priv->mm.stolen_base + compressed_llb->start);
+			   dev_priv->dsm.start + compressed_llb->start);
 	}
 
 	DRM_DEBUG_KMS("reserved %llu bytes of contiguous stolen space for FBC, threshold: %d\n",

drivers/gpu/drm/i915/intel_pm.c

@@ -7020,7 +7020,7 @@ static void valleyview_check_pctx(struct drm_i915_private *dev_priv)
 {
 	unsigned long pctx_addr = I915_READ(VLV_PCBR) & ~4095;
 
-	WARN_ON(pctx_addr != dev_priv->mm.stolen_base +
+	WARN_ON(pctx_addr != dev_priv->dsm.start +
 			     dev_priv->vlv_pctx->stolen->start);
 }
 
@@ -7035,7 +7035,6 @@ static void cherryview_check_pctx(struct drm_i915_private *dev_priv)
 
 static void cherryview_setup_pctx(struct drm_i915_private *dev_priv)
 {
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	unsigned long pctx_paddr, paddr;
 	u32 pcbr;
 	int pctx_size = 32*1024;
@@ -7043,8 +7042,8 @@ static void cherryview_setup_pctx(struct drm_i915_private *dev_priv)
 	pcbr = I915_READ(VLV_PCBR);
 	if ((pcbr >> VLV_PCBR_ADDR_SHIFT) == 0) {
 		DRM_DEBUG_DRIVER("BIOS didn't set up PCBR, fixing up\n");
-		paddr = (dev_priv->mm.stolen_base +
-			 (ggtt->stolen_size - pctx_size));
+		paddr = dev_priv->dsm.end + 1 - pctx_size;
+		GEM_BUG_ON(paddr > U32_MAX);
 
 		pctx_paddr = (paddr & (~4095));
 		I915_WRITE(VLV_PCBR, pctx_paddr);
@@ -7065,7 +7064,7 @@ static void valleyview_setup_pctx(struct drm_i915_private *dev_priv)
 		/* BIOS set it up already, grab the pre-alloc'd space */
 		int pcbr_offset;
 
-		pcbr_offset = (pcbr & (~4095)) - dev_priv->mm.stolen_base;
+		pcbr_offset = (pcbr & (~4095)) - dev_priv->dsm.start;
 		pctx = i915_gem_object_create_stolen_for_preallocated(dev_priv,
 								      pcbr_offset,
 								      I915_GTT_OFFSET_NONE,
@@ -7089,7 +7088,11 @@ static void valleyview_setup_pctx(struct drm_i915_private *dev_priv)
 		goto out;
 	}
 
-	pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->start;
+	GEM_BUG_ON(range_overflows_t(u64,
+				     dev_priv->dsm.start,
+				     pctx->stolen->start,
+				     U32_MAX));
+	pctx_paddr = dev_priv->dsm.start + pctx->stolen->start;
 	I915_WRITE(VLV_PCBR, pctx_paddr);
 
 out:

include/drm/intel-gtt.h

@@ -5,7 +5,6 @@
 #define	_DRM_INTEL_GTT_H
 
 void intel_gtt_get(u64 *gtt_total,
-		   u32 *stolen_size,
 		   phys_addr_t *mappable_base,
 		   u64 *mappable_end);