drm/nouveau/pci: set streaming DMA mask early

Some subdevices (i.e., fb/nv50.c and fb/gf100.c) map a scratch page using
dma_map_page() way before the TTM layer has had a chance to set the DMA
mask. This may prevent the driver from loading at all on platforms whose
system memory is not covered by the default DMA mask of 32-bit (i.e., when
all RAM is above 4 GB).

So set a preliminary DMA mask right after constructing the PCI device, and
base it on the .dma_bits member of the MMU subdevice, which is what the TTM
layer will base the DMA mask on as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
index b1b693219db3f70edbf29ae5f508141937e84e42..8f13bcd4040c9f88127d4b143d7a85dbad460034 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
@@ -1664,14 +1664,31 @@ nvkm_device_pci_new(struct pci_dev *pci_dev, const char *cfg, const char *dbg,
        *pdevice = &pdev->device;
        pdev->pdev = pci_dev;
 
-       return nvkm_device_ctor(&nvkm_device_pci_func, quirk, &pci_dev->dev,
-                               pci_is_pcie(pci_dev) ? NVKM_DEVICE_PCIE :
-                               pci_find_capability(pci_dev, PCI_CAP_ID_AGP) ?
-                               NVKM_DEVICE_AGP : NVKM_DEVICE_PCI,
-                               (u64)pci_domain_nr(pci_dev->bus) << 32 |
-                                    pci_dev->bus->number << 16 |
-                                    PCI_SLOT(pci_dev->devfn) << 8 |
-                                    PCI_FUNC(pci_dev->devfn), name,
-                               cfg, dbg, detect, mmio, subdev_mask,
-                               &pdev->device);
+       ret = nvkm_device_ctor(&nvkm_device_pci_func, quirk, &pci_dev->dev,
+                              pci_is_pcie(pci_dev) ? NVKM_DEVICE_PCIE :
+                              pci_find_capability(pci_dev, PCI_CAP_ID_AGP) ?
+                              NVKM_DEVICE_AGP : NVKM_DEVICE_PCI,
+                              (u64)pci_domain_nr(pci_dev->bus) << 32 |
+                                   pci_dev->bus->number << 16 |
+                                   PCI_SLOT(pci_dev->devfn) << 8 |
+                                   PCI_FUNC(pci_dev->devfn), name,
+                              cfg, dbg, detect, mmio, subdev_mask,
+                              &pdev->device);
+
+       if (ret)
+               return ret;
+
+       /*
+        * Set a preliminary DMA mask based on the .dma_bits member of the
+        * MMU subdevice. This allows other subdevices to create DMA mappings
+        * in their init() or oneinit() methods, which may be called before the
+        * TTM layer sets the DMA mask definitively.
+        * This is necessary for platforms where the default DMA mask of 32
+        * does not cover any system memory, i.e., when all RAM is > 4 GB.
+        */
+       if (subdev_mask & BIT(NVKM_SUBDEV_MMU))
+               dma_set_mask_and_coherent(&pci_dev->dev,
+                               DMA_BIT_MASK(pdev->device.mmu->dma_bits));
+
+       return 0;
 }