video: bcm2708_fb: Try allocating on the ARM and passing to VPU

Currently the VPU allocates the contiguous buffer for the
framebuffer.
Try an alternate path first where we use dma_alloc_coherent
and pass the buffer to the VPU. Should the VPU firmware not
support that path, then free the buffer and revert to the
old behaviour of using the VPU allocation.

Signed-off-by: Dave Stevenson <[email protected]>

Author: 6by9

drivers/video/fbdev/bcm2708_fb.c

@@ -98,6 +98,11 @@ struct bcm2708_fb {
 	struct bcm2708_fb_stats stats;
 	unsigned long fb_bus_address;
 	struct { u32 base, length; } gpu;
+
+	bool disable_arm_alloc;
+	unsigned int image_size;
+	dma_addr_t dma_addr;
+	void *cpuaddr;
 };
 
 #define to_bcm2708(info)	container_of(info, struct bcm2708_fb, fb)
@@ -285,21 +290,102 @@ static int bcm2708_fb_set_par(struct fb_info *info)
 		.tag5 = { RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE, 8, 0 },
 			.base = 0,
 			.screen_size = 0,
-		.tag6 = { RPI_FIRMWARE_FRAMEBUFFER_GET_PITCH, 4, 0 },
+		.tag6 = { RPI_FIRMWARE_FRAMEBUFFER_SET_PITCH, 4, 0 },
 			.pitch = 0,
 	};
-	int ret;
+	int ret, image_size;
+
 
 	print_debug("%s(%p) %dx%d (%dx%d), %d, %d\n", __func__, info,
 		    info->var.xres, info->var.yres, info->var.xres_virtual,
 		    info->var.yres_virtual, (int)info->screen_size,
 		    info->var.bits_per_pixel);
 
-	ret = rpi_firmware_property_list(fb->fw, &fbinfo, sizeof(fbinfo));
+	/* Try allocating our own buffer. We can specify all the parameters */
+	image_size = ((info->var.xres * info->var.yres) *
+		      info->var.bits_per_pixel) >> 3;
+
+	if (!fb->disable_arm_alloc &&
+	    (image_size != fb->image_size || !fb->dma_addr)) {
+		if (fb->dma_addr) {
+			dma_free_coherent(info->device, fb->image_size,
+					  fb->cpuaddr, fb->dma_addr);
+			fb->image_size = 0;
+			fb->cpuaddr = NULL;
+			fb->dma_addr = 0;
+		}
+
+		fb->cpuaddr = dma_alloc_coherent(info->device, image_size,
+						 &fb->dma_addr, GFP_ATOMIC);
+
+		if (!fb->cpuaddr) {
+			fb->dma_addr = 0;
+			fb->disable_arm_alloc = true;
+		} else {
+			fb->image_size = image_size;
+		}
+	}
+
+	if (fb->cpuaddr) {
+		fbinfo.base = fb->dma_addr;
+		fbinfo.screen_size = image_size;
+		fbinfo.pitch = (info->var.xres * info->var.bits_per_pixel) >> 3;
+
+		ret = rpi_firmware_property_list(fb->fw, &fbinfo,
+						 sizeof(fbinfo));
+		if (ret || fbinfo.base != fb->dma_addr) {
+			/* Firmware either failed, or assigned a different base
+			 * address (ie it doesn't support being passed an FB
+			 * allocation).
+			 * Destroy the allocation, and don't try again.
+			 */
+			dma_free_coherent(info->device, fb->image_size,
+					  fb->cpuaddr, fb->dma_addr);
+			fb->image_size = 0;
+			fb->cpuaddr = NULL;
+			fb->dma_addr = 0;
+			fb->disable_arm_alloc = true;
+		}
+	} else {
+		/* Our allocation failed - drop into the old scheme of
+		 * allocation by the VPU.
+		 */
+		ret = -ENOMEM;
+	}
+
 	if (ret) {
-		dev_err(info->device,
-			"Failed to allocate GPU framebuffer (%d)\n", ret);
-		return ret;
+		/* Old scheme */
+		const struct fb_alloc_tags fbinfo_old = {
+			.tag1 = { RPI_FIRMWARE_FRAMEBUFFER_SET_PHYSICAL_WIDTH_HEIGHT,
+				  8, 0, },
+				.xres = info->var.xres,
+				.yres = info->var.yres,
+			.tag2 = { RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_WIDTH_HEIGHT,
+				  8, 0, },
+				.xres_virtual = info->var.xres_virtual,
+				.yres_virtual = info->var.yres_virtual,
+			.tag3 = { RPI_FIRMWARE_FRAMEBUFFER_SET_DEPTH, 4, 0 },
+				.bpp = info->var.bits_per_pixel,
+			.tag4 = { RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_OFFSET,
+				  8, 0 },
+				.xoffset = info->var.xoffset,
+				.yoffset = info->var.yoffset,
+			.tag5 = { RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE, 8, 0 },
+				.base = 0,
+				.screen_size = 0,
+			.tag6 = { RPI_FIRMWARE_FRAMEBUFFER_GET_PITCH, 4, 0 },
+				.pitch = 0,
+		};
+		fbinfo = fbinfo_old;
+
+		ret = rpi_firmware_property_list(fb->fw, &fbinfo,
+						 sizeof(fbinfo));
+		if (ret) {
+			dev_err(info->device,
+				"Failed to allocate GPU framebuffer (%d)\n",
+				ret);
+			return ret;
+		}
 	}
 
 	if (info->var.bits_per_pixel <= 8)
@@ -314,9 +400,17 @@ static int bcm2708_fb_set_par(struct fb_info *info)
 	fb->fb.fix.smem_start = fbinfo.base;
 	fb->fb.fix.smem_len = fbinfo.pitch * fbinfo.yres_virtual;
 	fb->fb.screen_size = fbinfo.screen_size;
-	if (fb->fb.screen_base)
-		iounmap(fb->fb.screen_base);
-	fb->fb.screen_base = ioremap_wc(fbinfo.base, fb->fb.screen_size);
+
+	if (!fb->dma_addr) {
+		if (fb->fb.screen_base)
+			iounmap(fb->fb.screen_base);
+
+		fb->fb.screen_base = ioremap_wc(fbinfo.base,
+						fb->fb.screen_size);
+	} else {
+		fb->fb.screen_base = fb->cpuaddr;
+	}
+
 	if (!fb->fb.screen_base) {
 		/* the console may currently be locked */
 		console_trylock();

include/soc/bcm2835/raspberrypi-firmware.h

@@ -128,6 +128,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_FRAMEBUFFER_SET_DEPTH =                  0x00048005,
 	RPI_FIRMWARE_FRAMEBUFFER_SET_PIXEL_ORDER =            0x00048006,
 	RPI_FIRMWARE_FRAMEBUFFER_SET_ALPHA_MODE =             0x00048007,
+	RPI_FIRMWARE_FRAMEBUFFER_SET_PITCH =                  0x00048008,
 	RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_OFFSET =         0x00048009,
 	RPI_FIRMWARE_FRAMEBUFFER_SET_OVERSCAN =               0x0004800a,
 	RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE =                0x0004800b,