drm/ttm, drm/vmwgfx: Use a configuration option for the TTM dma page pool

Drivers like vmwgfx may want to test whether the dma page pool is present
or not. Since it's activated by default by TTM if compiled-in, define a
hidden configuration option that the driver can test for.

Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/Kconfig

@@ -179,6 +179,13 @@ config DRM_TTM
 	  GPU memory types. Will be enabled automatically if a device driver
 	  uses it.
 
+config DRM_TTM_DMA_PAGE_POOL
+	bool
+	depends on DRM_TTM && (SWIOTLB || INTEL_IOMMU)
+	default y
+	help
+	  Choose this if you need the TTM dma page pool
+
 config DRM_VRAM_HELPER
 	tristate
 	depends on DRM

drivers/gpu/drm/ttm/Makefile

@@ -4,8 +4,8 @@
 
 ttm-y := ttm_memory.o ttm_tt.o ttm_bo.o \
 	ttm_bo_util.o ttm_bo_vm.o ttm_module.o \
-	ttm_execbuf_util.o ttm_page_alloc.o ttm_bo_manager.o \
-	ttm_page_alloc_dma.o
+	ttm_execbuf_util.o ttm_page_alloc.o ttm_bo_manager.o
 ttm-$(CONFIG_AGP) += ttm_agp_backend.o
+ttm-$(CONFIG_DRM_TTM_DMA_PAGE_POOL) += ttm_page_alloc_dma.o
 
 obj-$(CONFIG_DRM_TTM) += ttm.o

drivers/gpu/drm/ttm/ttm_page_alloc_dma.c

@@ -33,7 +33,6 @@
  *   when freed).
  */
 
-#if defined(CONFIG_SWIOTLB) || defined(CONFIG_INTEL_IOMMU)
 #define pr_fmt(fmt) "[TTM] " fmt
 
 #include <linux/dma-mapping.h>
@@ -1238,5 +1237,3 @@ int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(ttm_dma_page_alloc_debugfs);
-
-#endif

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -576,8 +576,7 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
 	else
 		dev_priv->map_mode = vmw_dma_map_populate;
 
-	/* No TTM coherent page pool? FIXME: Ask TTM instead! */
-        if (!(IS_ENABLED(CONFIG_SWIOTLB) || IS_ENABLED(CONFIG_INTEL_IOMMU)) &&
+        if (!IS_ENABLED(CONFIG_DRM_TTM_DMA_PAGE_POOL) &&
 	    (dev_priv->map_mode == vmw_dma_alloc_coherent))
 		return -EINVAL;
 

include/drm/ttm/ttm_page_alloc.h

@@ -74,7 +74,7 @@ void ttm_unmap_and_unpopulate_pages(struct device *dev, struct ttm_dma_tt *tt);
  */
 int ttm_page_alloc_debugfs(struct seq_file *m, void *data);
 
-#if defined(CONFIG_SWIOTLB) || defined(CONFIG_INTEL_IOMMU)
+#if defined(CONFIG_DRM_TTM_DMA_PAGE_POOL)
 /**
  * Initialize pool allocator.
  */