Add BCM2708 arch framebuffer implementation for rPi.

It uses the mailbox mechanism to instruct the VideoCore to configure
the desired video mode and fills it with a black and white test
pattern.

src/system/boot/platform/raspberrypi_arm/Jamfile

@@ -34,6 +34,8 @@ BootMergeObject boot_platform_raspberrypi_arm.o :
 	serial.cpp
 	video.cpp
 
+	arch_framebuffer_bcm2708.cpp
+
 	$(genericPlatformSources)
 	: -fno-pic
 	: boot_platform_generic.a

src/system/boot/platform/raspberrypi_arm/arch_framebuffer_bcm2708.cpp

@@ -0,0 +1,181 @@
+/*
+ * Copyright 2012 Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Michael Lotz, mmlr@mlotz.ch
+ */
+
+#include <string.h>
+
+#include <arm_mmu.h>
+
+#include "arch_mmu.h"
+
+#include "arch_framebuffer.h"
+
+#include "bcm2708.h"
+#include "mailbox.h"
+#include "platform_debug.h"
+
+
+struct framebuffer_config {
+	uint32	width;
+	uint32	height;
+	uint32	virtual_width;
+	uint32	virtual_height;
+	uint32	bytes_per_row;			// from GPU
+	uint32	bits_per_pixel;
+	uint32	x_offset;
+	uint32	y_offset;
+	uint32	frame_buffer_address;	// from GPU
+	uint32	screen_size;			// from GPU
+	uint16	color_map[256];
+};
+
+
+static framebuffer_config sFramebufferConfig __attribute__((aligned(16)));
+
+
+class ArchFramebufferBCM2708 : public ArchFramebuffer {
+public:
+							ArchFramebufferBCM2708();
+virtual						~ArchFramebufferBCM2708();
+
+virtual	status_t			Init();
+virtual	status_t			Probe();
+virtual	status_t			SetDefaultMode();
+virtual	status_t			SetVideoMode(int width, int height, int depth);
+};
+
+
+static ArchFramebufferBCM2708 sArchFramebuffer;
+
+
+extern "C" ArchFramebuffer*
+arch_get_framebuffer_arm_bcm2708()
+{
+	return &sArchFramebuffer;
+}
+
+
+ArchFramebufferBCM2708::ArchFramebufferBCM2708()
+	:	ArchFramebuffer(0)
+{
+}
+
+
+ArchFramebufferBCM2708::~ArchFramebufferBCM2708()
+{
+}
+
+
+status_t
+ArchFramebufferBCM2708::Init()
+{
+	return B_OK;
+}
+
+
+status_t
+ArchFramebufferBCM2708::Probe()
+{
+	return B_OK;
+}
+
+
+status_t
+ArchFramebufferBCM2708::SetDefaultMode()
+{
+	status_t result;
+	do {
+		result = SetVideoMode(1920, 1080, 16);
+	} while (result != B_OK);
+
+	return B_OK;
+}
+
+
+status_t
+ArchFramebufferBCM2708::SetVideoMode(int width, int height, int depth)
+{
+	debug_assert(((uint32)&sFramebufferConfig & 0x0f) == 0);
+
+	sFramebufferConfig.width = width;
+	sFramebufferConfig.height = height;
+	sFramebufferConfig.virtual_width = sFramebufferConfig.width;
+	sFramebufferConfig.virtual_height = sFramebufferConfig.height;
+	sFramebufferConfig.bytes_per_row = 0; // from GPU
+	sFramebufferConfig.bits_per_pixel = depth;
+	sFramebufferConfig.x_offset = 0;
+	sFramebufferConfig.y_offset = 0;
+	sFramebufferConfig.frame_buffer_address = 0; // from GPU
+	sFramebufferConfig.screen_size = 0; // from GPU
+
+	if (depth < 16) {
+		const int colorMapEntries = sizeof(sFramebufferConfig.color_map)
+			/ sizeof(sFramebufferConfig.color_map[0]);
+		for (int i = 0; i < colorMapEntries; i++)
+			sFramebufferConfig.color_map[i] = 0x1111 * i;
+	}
+
+	status_t result = write_mailbox(ARM_MAILBOX_CHANNEL_FRAMEBUFFER,
+		(uint32)&sFramebufferConfig | BCM2708_VIDEO_CORE_L2_COHERENT);
+	if (result != B_OK)
+		return result;
+
+	uint32 value;
+	result = read_mailbox(ARM_MAILBOX_CHANNEL_FRAMEBUFFER, value);
+	if (result != B_OK)
+		return result;
+
+	if (value != 0) {
+		dprintf("failed to configure framebuffer: %" B_PRIx32 "\n", value);
+		debug_toggle_led(5, DEBUG_DELAY_SHORT);
+		return B_ERROR;
+	}
+
+	if (sFramebufferConfig.frame_buffer_address == 0) {
+		dprintf("didn't get the framebuffer address\n");
+		debug_toggle_led(10, DEBUG_DELAY_SHORT);
+		return B_ERROR;
+	}
+
+	debug_assert(sFramebufferConfig.x_offset == 0
+		&& sFramebufferConfig.y_offset == 0
+		&& sFramebufferConfig.width == (uint32)width
+		&& sFramebufferConfig.height == (uint32)height
+		&& sFramebufferConfig.virtual_width == sFramebufferConfig.width
+		&& sFramebufferConfig.virtual_height == sFramebufferConfig.height
+		&& sFramebufferConfig.bits_per_pixel == (uint32)depth
+		&& sFramebufferConfig.bytes_per_row
+			>= sFramebufferConfig.bits_per_pixel / 8
+				* sFramebufferConfig.width
+		&& sFramebufferConfig.screen_size >= sFramebufferConfig.bytes_per_row
+			* sFramebufferConfig.height);
+
+#if 1
+	fBase = BCM2708_BUS_TO_PHYSICAL(sFramebufferConfig.frame_buffer_address);
+#else
+	// TODO: Enable when the MMU works.
+	fBase = (addr_t)mmu_map_physical_memory(
+			BCM2708_BUS_TO_PHYSICAL(sFramebufferConfig.frame_buffer_address),
+			sFramebufferConfig.screen_size, MMU_L2_FLAG_AP_RW | MMU_L2_FLAG_C);
+#endif
+
+	uint8* line = (uint8*)fBase;
+	for (uint32 y = 0; y < sFramebufferConfig.height; y++) {
+		volatile uint16* pixel = (volatile uint16*)line;
+		for (uint32 x = 0; x < sFramebufferConfig.width; x++)
+			*(pixel++) = y % 2 == 0 ? 0xffff : 0x0000;
+
+		line += sFramebufferConfig.bytes_per_row;
+	}
+
+	fCurrentWidth = width;
+	fCurrentHeight = height;
+	fCurrentDepth = depth;
+	fCurrentBytesPerRow = sFramebufferConfig.bytes_per_row;
+	return B_OK;
+}
+