nouveau/ttm/PCIe: Use dma_addr if TTM has set it.

If the TTM layer has used the DMA API to setup pages that are
TTM_PAGE_FLAG_DMA32 (look at patch titled: "ttm: Utilize the
DMA API for pages that have TTM_PAGE_FLAG_DMA32 set"), lets
use it when programming the GART in the PCIe type cards.

This patch skips doing the pci_map_page (and pci_unmap_page) if
there is a DMA addresses passed in for that page. If the dma_address
is zero (or DMA_ERROR_CODE), then we continue on with our old
behaviour.

[v2: Added a review-by tag]

Reviewed-by: Thomas Hellstrom <thomas@shipmail.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 21 insertions, 7 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_sgdma.c b/drivers/gpu/drm/nouveau/nouveau_sgdma.c
index edc140ab4df1..bbdd982cbb3e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_sgdma.c
+++ b/drivers/gpu/drm/nouveau/nouveau_sgdma.c
@@ -12,6 +12,7 @@ struct nouveau_sgdma_be {
         struct drm_device *dev;
 
         dma_addr_t *pages;
+        bool *ttm_alloced;
         unsigned nr_pages;
 
         unsigned pte_start;
@@ -35,15 +36,25 @@ nouveau_sgdma_populate(struct ttm_backend *be, unsigned long num_pages,
         if (!nvbe->pages)
                 return -ENOMEM;
 
+        nvbe->ttm_alloced = kmalloc(sizeof(bool) * num_pages, GFP_KERNEL);
+        if (!nvbe->ttm_alloced)
+                return -ENOMEM;
+
         nvbe->nr_pages = 0;
         while (num_pages--) {
-                nvbe->pages[nvbe->nr_pages] =
-                        pci_map_page(dev->pdev, pages[nvbe->nr_pages], 0,
+                if (dma_addrs[nvbe->nr_pages] != DMA_ERROR_CODE) {
+                        nvbe->pages[nvbe->nr_pages] =
+                                        dma_addrs[nvbe->nr_pages];
+                        nvbe->ttm_alloced[nvbe->nr_pages] = true;
+                } else {
+                        nvbe->pages[nvbe->nr_pages] =
+                                pci_map_page(dev->pdev, pages[nvbe->nr_pages], 0,
                                      PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
-                if (pci_dma_mapping_error(dev->pdev,
-                                          nvbe->pages[nvbe->nr_pages])) {
-                        be->func->clear(be);
-                        return -EFAULT;
+                        if (pci_dma_mapping_error(dev->pdev,
+                                                  nvbe->pages[nvbe->nr_pages])) {
+                                be->func->clear(be);
+                                return -EFAULT;
+                        }
                 }
 
                 nvbe->nr_pages++;
@@ -66,11 +77,14 @@ nouveau_sgdma_clear(struct ttm_backend *be)
                         be->func->unbind(be);
 
                 while (nvbe->nr_pages--) {
-                        pci_unmap_page(dev->pdev, nvbe->pages[nvbe->nr_pages],
+                        if (!nvbe->ttm_alloced[nvbe->nr_pages])
+                                pci_unmap_page(dev->pdev, nvbe->pages[nvbe->nr_pages],
                                        PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
                 }
                 kfree(nvbe->pages);
+                kfree(nvbe->ttm_alloced);
                 nvbe->pages = NULL;
+                nvbe->ttm_alloced = NULL;
                 nvbe->nr_pages = 0;
         }
 }