drm/nouveau: attempt to get bios from ACPI v3

Some of the laptops with the switchable graphics, seem to not post the secondary GPU at all, and we can't find a copy of the BIOS anywhere except in the ACPI rom retrieval.

This adds support for ACPI ROM retrieval to nouveau.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/nouveau/nouveau_acpi.c

@@ -35,6 +35,7 @@ static struct nouveau_dsm_priv {
 	bool dsm_detected;
 	acpi_handle dhandle;
 	acpi_handle dsm_handle;
+	acpi_handle rom_handle;
 } nouveau_dsm_priv;
 
 static const char nouveau_dsm_muid[] = {
@@ -151,12 +152,13 @@ static bool nouveau_dsm_pci_probe(struct pci_dev *pdev)
 	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);
 	if (!dhandle)
 		return false;
+
 	status = acpi_get_handle(dhandle, "_DSM", &nvidia_handle);
 	if (ACPI_FAILURE(status)) {
 		return false;
 	}
 
-	ret= nouveau_dsm(nvidia_handle, NOUVEAU_DSM_SUPPORTED,
+	ret = nouveau_dsm(nvidia_handle, NOUVEAU_DSM_SUPPORTED,
 			 NOUVEAU_DSM_SUPPORTED_FUNCTIONS, &result);
 	if (ret < 0)
 		return false;
@@ -173,6 +175,7 @@ static bool nouveau_dsm_detect(void)
 	struct pci_dev *pdev = NULL;
 	int has_dsm = 0;
 	int vga_count = 0;
+
 	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 		vga_count++;
 
@@ -204,3 +207,57 @@ void nouveau_unregister_dsm_handler(void)
 {
 	vga_switcheroo_unregister_handler();
 }
+
+/* retrieve the ROM in 4k blocks */
+static int nouveau_rom_call(acpi_handle rom_handle, uint8_t *bios,
+			    int offset, int len)
+{
+	acpi_status status;
+	union acpi_object rom_arg_elements[2], *obj;
+	struct acpi_object_list rom_arg;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL};
+
+	rom_arg.count = 2;
+	rom_arg.pointer = &rom_arg_elements[0];
+
+	rom_arg_elements[0].type = ACPI_TYPE_INTEGER;
+	rom_arg_elements[0].integer.value = offset;
+
+	rom_arg_elements[1].type = ACPI_TYPE_INTEGER;
+	rom_arg_elements[1].integer.value = len;
+
+	status = acpi_evaluate_object(rom_handle, NULL, &rom_arg, &buffer);
+	if (ACPI_FAILURE(status)) {
+		printk(KERN_INFO "failed to evaluate ROM got %s\n", acpi_format_exception(status));
+		return -ENODEV;
+	}
+	obj = (union acpi_object *)buffer.pointer;
+	memcpy(bios+offset, obj->buffer.pointer, len);
+	kfree(buffer.pointer);
+	return len;
+}
+
+bool nouveau_acpi_rom_supported(struct pci_dev *pdev)
+{
+	acpi_status status;
+	acpi_handle dhandle, rom_handle;
+
+	if (!nouveau_dsm_priv.dsm_detected)
+		return false;
+
+	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);
+	if (!dhandle)
+		return false;
+
+	status = acpi_get_handle(dhandle, "_ROM", &rom_handle);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	nouveau_dsm_priv.rom_handle = rom_handle;
+	return true;
+}
+
+int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len)
+{
+	return nouveau_rom_call(nouveau_dsm_priv.rom_handle, bios, offset, len);
+}

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -178,6 +178,25 @@ static void load_vbios_pci(struct drm_device *dev, uint8_t *data)
 	pci_disable_rom(dev->pdev);
 }
 
+static void load_vbios_acpi(struct drm_device *dev, uint8_t *data)
+{
+	int i;
+	int ret;
+	int size = 64 * 1024;
+
+	if (!nouveau_acpi_rom_supported(dev->pdev))
+		return;
+
+	for (i = 0; i < (size / ROM_BIOS_PAGE); i++) {
+		ret = nouveau_acpi_get_bios_chunk(data,
+						  (i * ROM_BIOS_PAGE),
+						  ROM_BIOS_PAGE);
+		if (ret <= 0)
+			break;
+	}
+	return;
+}
+
 struct methods {
 	const char desc[8];
 	void (*loadbios)(struct drm_device *, uint8_t *);
@@ -191,6 +210,7 @@ static struct methods nv04_methods[] = {
 };
 
 static struct methods nv50_methods[] = {
+	{ "ACPI", load_vbios_acpi, true },
 	{ "PRAMIN", load_vbios_pramin, true },
 	{ "PROM", load_vbios_prom, false },
 	{ "PCIROM", load_vbios_pci, true },

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -851,12 +851,17 @@ extern int  nouveau_dma_init(struct nouveau_channel *);
 extern int  nouveau_dma_wait(struct nouveau_channel *, int slots, int size);
 
 /* nouveau_acpi.c */
+#define ROM_BIOS_PAGE 4096
 #if defined(CONFIG_ACPI)
 void nouveau_register_dsm_handler(void);
 void nouveau_unregister_dsm_handler(void);
+int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len);
+bool nouveau_acpi_rom_supported(struct pci_dev *pdev);
 #else
 static inline void nouveau_register_dsm_handler(void) {}
 static inline void nouveau_unregister_dsm_handler(void) {}
+static inline bool nouveau_acpi_rom_supported(struct pci_dev *pdev) { return false; }
+static inline int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len) { return -EINVAL; }
 #endif
 
 /* nouveau_backlight.c */