aedrix-kernel/drivers/bcm2835_videocore.c

/*
    Copyright (C) 2012, Aaron Lindsay <aaron@aclindsay.com>

    This file is part of Aedrix.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <framebuffer.h>
#include <init.h>
#include <kmalloc.h>
#include <print.h>
#include <types.h>

#include <drivers/bcm2835_mailbox.h>
#include <drivers/fb.h>

struct bcm2835_config {
	volatile uint32 width;
	volatile uint32 height;
	volatile uint32 vwidth;
	volatile uint32 vheight;
	volatile uint32 pitch;
	volatile uint32 color_depth;
	volatile uint32 xoffset;
	volatile uint32 yoffset;
	volatile uint32 fb_base_addr;
	volatile uint32 size;
};

#define MAILBOX_BUFFER_SIZE (32*4*2)
#define FB_WIDTH 1024
#define FB_HEIGHT 768

struct fbdev bcm2835_fb_device;

int bcm2835_videocore_init_dev(struct fb *f, unsigned int color_depth) {
	struct bcm2835_config *cfg;
	uint32 result;
	void *mailbox_buffer_orig, *mailbox_buffer;

	if (!(mailbox_buffer_orig = kmalloc(MAILBOX_BUFFER_SIZE))) {
		return -1;
	}

	/* Round mailbox buffer to multiple of 0x10 because the low 4 bits of
	the mailbox are used to send the channel, and therefore can't hold the low 4
	bits of the address */
	if ((uint32)mailbox_buffer_orig & 0xf)
		mailbox_buffer = (void *)((uint32)mailbox_buffer_orig & ~0xf) + 0x10;
	else
		mailbox_buffer = mailbox_buffer_orig;

	cfg = (struct bcm2835_config *)mailbox_buffer;
	cfg->width = FB_WIDTH;
	cfg->height = FB_HEIGHT;
	cfg->vwidth = FB_WIDTH;
	cfg->vheight = FB_HEIGHT;
	cfg->pitch = 0;
	cfg->color_depth = color_depth;
	cfg->xoffset = 0;
	cfg->yoffset = 0;
	cfg->fb_base_addr = 0;
	cfg->size = 0;

	mailbox_write(MBOX_FB, (uint32)cfg);
	result = mailbox_read(MBOX_FB);

	if (result) {
		print("Error: did not request a proper framebuffer\n");
		return -1;
	}

	if (!cfg->fb_base_addr) {
		int i;
		print("BCM2835 VideoCore returned success from framebuffer "
				"setup mailbox call, but framebuffer address is "
				"not yet available. Waiting...\n");
		for (i = 0; i < 1<<30 && !cfg->fb_base_addr; i++);

		if (!cfg->fb_base_addr) {

			print("Error: VideoCore did not provide framebuffer "
					"base address.\n");
			return -1;
		}
		print("VideoCore provided framebuffer base address after %d loops.\n", i);
	}

	f->device = &bcm2835_fb_device;
	f->device->fbaddr = (void*)cfg->fb_base_addr;
	f->width = cfg->width;
	f->device->pixelwidth = cfg->width;
	f->height = cfg->height;
	f->device->pixelheight = cfg->height;

	f->color_depth = color_depth;
	f->device->color_depth = color_depth;

	return 0;
}

struct fb_dev videocore_dev = {
	.name ="bcm2835_videocore",
	.init = &bcm2835_videocore_init_dev
};

void bcm2835_videocore_init() {
	fb_register_device(&videocore_dev);
}

device_initcall(bcm2835_videocore_init);