support for platform devices

Upcoming mobile Kepler GPUs (such as GK20A) use the platform bus instead
of PCI to which Nouveau is tightly dependent. This patch allows Nouveau
to handle platform devices by:

- abstracting PCI-dependent functions that were typically used for
  resource querying and page mapping,
- introducing a nv_device_is_pci() function that allows to make
  PCI-dependent code conditional,
- providing a nouveau_drm_platform_probe() function that takes a GPU
  platform device to be probed.

Core code as well as engine/subdev drivers are updated wherever possible
to make use of these functions. Some older drivers are too dependent on
PCI to be properly updated, but all newer code on which future chips may
depend should at least be runnable with platform devices.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/device/base.c b/drivers/gpu/drm/nouveau/core/engine/device/base.c
index 96559ac..18c8c72 100644
--- a/drivers/gpu/drm/nouveau/core/engine/device/base.c
+++ b/drivers/gpu/drm/nouveau/core/engine/device/base.c
@@ -131,8 +131,8 @@
 	if (ret)
 		return ret;
 
-	mmio_base = pci_resource_start(device->pdev, 0);
-	mmio_size = pci_resource_len(device->pdev, 0);
+	mmio_base = nv_device_resource_start(device, 0);
+	mmio_size = nv_device_resource_len(device, 0);
 
 	/* translate api disable mask into internal mapping */
 	disable = args->debug0;
@@ -448,6 +448,72 @@
 	nouveau_engine_destroy(&device->base);
 }
 
+resource_size_t
+nv_device_resource_start(struct nouveau_device *device, unsigned int bar)
+{
+	if (nv_device_is_pci(device)) {
+		return pci_resource_start(device->pdev, bar);
+	} else {
+		struct resource *res;
+		res = platform_get_resource(device->platformdev,
+					    IORESOURCE_MEM, bar);
+		if (!res)
+			return 0;
+		return res->start;
+	}
+}
+
+resource_size_t
+nv_device_resource_len(struct nouveau_device *device, unsigned int bar)
+{
+	if (nv_device_is_pci(device)) {
+		return pci_resource_len(device->pdev, bar);
+	} else {
+		struct resource *res;
+		res = platform_get_resource(device->platformdev,
+					    IORESOURCE_MEM, bar);
+		if (!res)
+			return 0;
+		return resource_size(res);
+	}
+}
+
+dma_addr_t
+nv_device_map_page(struct nouveau_device *device, struct page *page)
+{
+	dma_addr_t ret;
+
+	if (nv_device_is_pci(device)) {
+		ret = pci_map_page(device->pdev, page, 0, PAGE_SIZE,
+				   PCI_DMA_BIDIRECTIONAL);
+		if (pci_dma_mapping_error(device->pdev, ret))
+			ret = 0;
+	} else {
+		ret = page_to_phys(page);
+	}
+
+	return ret;
+}
+
+void
+nv_device_unmap_page(struct nouveau_device *device, dma_addr_t addr)
+{
+	if (nv_device_is_pci(device))
+		pci_unmap_page(device->pdev, addr, PAGE_SIZE,
+			       PCI_DMA_BIDIRECTIONAL);
+}
+
+int
+nv_device_get_irq(struct nouveau_device *device, bool stall)
+{
+	if (nv_device_is_pci(device)) {
+		return device->pdev->irq;
+	} else {
+		return platform_get_irq_byname(device->platformdev,
+					       stall ? "stall" : "nonstall");
+	}
+}
+
 static struct nouveau_oclass
 nouveau_device_oclass = {
 	.handle = NV_ENGINE(DEVICE, 0x00),
@@ -459,8 +525,8 @@
 };
 
 int
-nouveau_device_create_(struct pci_dev *pdev, u64 name, const char *sname,
-		       const char *cfg, const char *dbg,
+nouveau_device_create_(void *dev, enum nv_bus_type type, u64 name,
+		       const char *sname, const char *cfg, const char *dbg,
 		       int length, void **pobject)
 {
 	struct nouveau_device *device;
@@ -478,7 +544,14 @@
 	if (ret)
 		goto done;
 
-	device->pdev = pdev;
+	switch (type) {
+	case NOUVEAU_BUS_PCI:
+		device->pdev = dev;
+		break;
+	case NOUVEAU_BUS_PLATFORM:
+		device->platformdev = dev;
+		break;
+	}
 	device->handle = name;
 	device->cfgopt = cfg;
 	device->dbgopt = dbg;