path: root/drivers/video/s3c-fb.c

/* linux/drivers/video/s3c-fb.c
 *
 * Copyright 2008 Openmoko Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * Samsung SoC Framebuffer driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/fb.h>
#include <linux/io.h>

#include <mach/map.h>
#include <mach/regs-fb.h>
#include <plat/fb.h>

/* This driver will export a number of framebuffer interfaces depending
 * on the configuration passed in via the platform data. Each fb instance
 * maps to a hardware window. Currently there is no support for runtime
 * setting of the alpha-blending functions that each window has, so only
 * window 0 is actually useful.
 *
 * Window 0 is treated specially, it is used for the basis of the LCD
 * output timings and as the control for the output power-down state.
*/

/* note, some of the functions that get called are derived from including
 * <mach/regs-fb.h> as they are specific to the architecture that the code
 * is being built for.
*/

#ifdef CONFIG_FB_S3C_DEBUG_REGWRITE
#undef writel
#define writel(v, r) do { \
	printk(KERN_DEBUG "%s: %08x => %p\n", __func__, (unsigned int)v, r); \
	__raw_writel(v, r); } while(0)
#endif /* FB_S3C_DEBUG_REGWRITE */

struct s3c_fb;

/**
 * struct s3c_fb_win - per window private data for each framebuffer.
 * @windata: The platform data supplied for the window configuration.
 * @parent: The hardware that this window is part of.
 * @fbinfo: Pointer pack to the framebuffer info for this window.
 * @palette_buffer: Buffer/cache to hold palette entries.
 * @pseudo_palette: For use in TRUECOLOUR modes for entries 0..15/
 * @index: The window number of this window.
 * @palette: The bitfields for changing r/g/b into a hardware palette entry.
 */
struct s3c_fb_win {
	struct s3c_fb_pd_win	*windata;
	struct s3c_fb		*parent;
	struct fb_info		*fbinfo;
	struct s3c_fb_palette	 palette;

	u32			*palette_buffer;
	u32			 pseudo_palette[16];
	unsigned int		 index;
};

/**
 * struct s3c_fb - overall hardware state of the hardware
 * @dev: The device that we bound to, for printing, etc.
 * @regs_res: The resource we claimed for the IO registers.
 * @bus_clk: The clk (hclk) feeding our interface and possibly pixclk.
 * @regs: The mapped hardware registers.
 * @enabled: A bitmask of enabled hardware windows.
 * @pdata: The platform configuration data passed with the device.
 * @windows: The hardware windows that have been claimed.
 */
struct s3c_fb {
	struct device		*dev;
	struct resource		*regs_res;
	struct clk		*bus_clk;
	void __iomem		*regs;

	unsigned char		 enabled;

	struct s3c_fb_platdata	*pdata;
	struct s3c_fb_win	*windows[S3C_FB_MAX_WIN];
};

/**
 * s3c_fb_win_has_palette() - determine if a mode has a palette
 * @win: The window number being queried.
 * @bpp: The number of bits per pixel to test.
 *
 * Work out if the given window supports palletised data at the specified bpp.
 */
static int s3c_fb_win_has_palette(unsigned int win, unsigned int bpp)
{
	return s3c_fb_win_pal_size(win) <= (1 << bpp);
}

/**
 * s3c_fb_check_var() - framebuffer layer request to verify a given mode.
 * @var: The screen information to verify.
 * @info: The framebuffer device.
 *
 * Framebuffer layer call to verify the given information and allow us to
 * update various information depending on the hardware capabilities.
 */
static int s3c_fb_check_var(struct fb_var_screeninfo *var,
			    struct fb_info *info)
{
	struct s3c_fb_win *win = info->par;
	struct s3c_fb_pd_win *windata = win->windata;
	struct s3c_fb *sfb = win->parent;

	dev_dbg(sfb->dev, "checking parameters\n");

	var->xres_virtual = max((unsigned int)windata->virtual_x, var->xres);
	var->yres_virtual = max((unsigned int)windata->virtual_y, var->yres);

	if (!s3c_fb_validate_win_bpp(win->index, var->bits_per_pixel)) {
		dev_dbg(sfb->dev, "win %d: unsupported bpp %d\n",
			win->index, var->bits_per_pixel);
		return -EINVAL;
	}

	/* always ensure these are zero, for drop through cases below */
	var->transp.offset = 0;
	var->transp.length = 0;

	switch (var->bits_per_pixel) {
	case 1:
	case 2:
	case 4:
	case 8:
		if (!s3c_fb_win_has_palette(win->index, var->bits_per_pixel)) {
			/* non palletised, A:1,R:2,G:3,B:2 mode */
			var->red.offset		= 4;
			var->green.offset	= 2;
			var->blue.offset	= 0;
			var->red.length		= 5;
			var->green.length	= 3;
			var->blue.length	= 2;
			var->transp.offset	= 7;
			var->transp.length	= 1;
		} else {
			var->red.offset	= 0;
			var->red.length	= var->bits_per_pixel;
			var->green	= var->red;
			var->blue	= var->red;
		}
		break;

	case 19:
		/* 666 with one bit alpha/transparency */
		var->transp.offset	= 18;