[Intel-gfx] [PATCH 10/13] drm/i915: Needs_dmar, not

[Ben Widawsky]

The reasoning behind our code taking two paths depending upon whether or
not we may have been configured for IOMMU isn't clear to me. It should
always be safe to use the pci mapping functions as they are designed to
abstract the decision we were handling in i915.

Aside from simpler code, removing another member for the intel_gtt
struct is a nice motivation.

I ran this by Chris, and he wasn't concerned about the extra kzalloc,
and memory references vs. page_to_phys calculation in the case without
IOMMU.

v2: Update commit message

v3: Remove needs_dmar addition from Haihao upstream

Reviewed-by: Rodrigo Vivi <rodrigo.vivi at gmail.com> (v2)
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
 drivers/char/agp/intel-gtt.c        | 10 ++++++----
 drivers/gpu/drm/i915/i915_gem_gtt.c | 39 +++++++++++++------------------------
 include/drm/intel-gtt.h             |  2 --
 3 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index eb05eb5..a531377 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -84,6 +84,8 @@ static struct _intel_private {
 	 * this is not the full gtt. */
 	unsigned int gtt_mappable_entries;
 	phys_addr_t gma_bus_addr;
+	/* Whether i915 needs to use the dmar apis or not. */
+	unsigned int needs_dmar : 1;
 } intel_private;
 
 #define INTEL_GTT_GEN	intel_private.driver->gen
@@ -299,7 +301,7 @@ static int intel_gtt_setup_scratch_page(void)
 	get_page(page);
 	set_pages_uc(page, 1);
 
-	if (intel_private.base.needs_dmar) {
+	if (intel_private.needs_dmar) {
 		dma_addr = pci_map_page(intel_private.pcidev, page, 0,
 				    PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 		if (pci_dma_mapping_error(intel_private.pcidev, dma_addr))
@@ -615,7 +617,7 @@ static int intel_gtt_init(void)
 
 	intel_private.stolen_size = intel_gtt_stolen_size();
 
-	intel_private.base.needs_dmar = USE_PCI_DMA_API && INTEL_GTT_GEN > 2;
+	intel_private.needs_dmar = USE_PCI_DMA_API && INTEL_GTT_GEN > 2;
 
 	ret = intel_gtt_setup_scratch_page();
 	if (ret != 0) {
@@ -875,7 +877,7 @@ static int intel_fake_agp_insert_entries(struct agp_memory *mem,
 	if (!mem->is_flushed)
 		global_cache_flush();
 
-	if (intel_private.base.needs_dmar) {
+	if (intel_private.needs_dmar) {
 		struct sg_table st;
 
 		ret = intel_gtt_map_memory(mem->pages, mem->page_count, &st);
@@ -919,7 +921,7 @@ static int intel_fake_agp_remove_entries(struct agp_memory *mem,
 
 	intel_gtt_clear_range(pg_start, mem->page_count);
 
-	if (intel_private.base.needs_dmar) {
+	if (intel_private.needs_dmar) {
 		intel_gtt_unmap_memory(mem->sg_list, mem->num_sg);
 		mem->sg_list = NULL;
 		mem->num_sg = 0;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 8da280d..ae96835 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -139,28 +139,23 @@ int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
 			goto err_pt_alloc;
 	}
 
-	if (dev_priv->mm.gtt->needs_dmar) {
-		ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t)
-						*ppgtt->num_pd_entries,
-					     GFP_KERNEL);
-		if (!ppgtt->pt_dma_addr)
-			goto err_pt_alloc;
+	ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t) *ppgtt->num_pd_entries,
+				     GFP_KERNEL);
+	if (!ppgtt->pt_dma_addr)
+		goto err_pt_alloc;
 
-		for (i = 0; i < ppgtt->num_pd_entries; i++) {
-			dma_addr_t pt_addr;
+	for (i = 0; i < ppgtt->num_pd_entries; i++) {
+		dma_addr_t pt_addr;
 
-			pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i],
-					       0, 4096,
-					       PCI_DMA_BIDIRECTIONAL);
+		pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i], 0, 4096,
+				       PCI_DMA_BIDIRECTIONAL);
 
-			if (pci_dma_mapping_error(dev->pdev,
-						  pt_addr)) {
-				ret = -EIO;
-				goto err_pd_pin;
+		if (pci_dma_mapping_error(dev->pdev, pt_addr)) {
+			ret = -EIO;
+			goto err_pd_pin;
 
-			}
-			ppgtt->pt_dma_addr[i] = pt_addr;
 		}
+		ppgtt->pt_dma_addr[i] = pt_addr;
 	}
 
 	ppgtt->scratch_page_dma_addr = dev_priv->mm.gtt->scratch_page_dma;
@@ -295,11 +290,7 @@ void i915_gem_init_ppgtt(struct drm_device *dev)
 	for (i = 0; i < ppgtt->num_pd_entries; i++) {
 		dma_addr_t pt_addr;
 
-		if (dev_priv->mm.gtt->needs_dmar)
-			pt_addr = ppgtt->pt_dma_addr[i];
-		else
-			pt_addr = page_to_phys(ppgtt->pt_pages[i]);
-
+		pt_addr = ppgtt->pt_dma_addr[i];
 		pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
 		pd_entry |= GEN6_PDE_VALID;
 
@@ -726,10 +717,6 @@ int i915_gem_gtt_init(struct drm_device *dev)
 	if (!dev_priv->mm.gtt)
 		return -ENOMEM;
 
-#ifdef CONFIG_INTEL_IOMMU
-	dev_priv->mm.gtt->needs_dmar = 1;
-#endif
-
 	/* For GEN6+ the PTEs for the ggtt live at 2MB + BAR0 */
 	gtt_bus_addr = pci_resource_start(dev->pdev, 0) + (2<<20);
 
diff --git a/include/drm/intel-gtt.h b/include/drm/intel-gtt.h
index 6f53ecd..63157c5 100644
--- a/include/drm/intel-gtt.h
+++ b/include/drm/intel-gtt.h
@@ -4,8 +4,6 @@
 #define	_DRM_INTEL_GTT_H
 
 struct intel_gtt {
-	/*  Whether i915 needs to use the dmar apis or not. */
-	unsigned int needs_dmar : 1;
 	/* Whether we idle the gpu before mapping/unmapping */
 	unsigned int do_idle_maps : 1;
 	/* Share the scratch page dma with ppgtts. */
-- 
1.8.1.1