acornfb.c

S3C44B0X下的LCD （framebuffer）驱动资料与相关代码

/*
 *  linux/drivers/video/acornfb.c
 *
 *  Copyright (C) 1998-2001 Russell King
 *
 * 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.
 *
 * Frame buffer code for Acorn platforms
 *
 * NOTE: Most of the modes with X!=640 will disappear shortly.
 * NOTE: Startup setting of HS & VS polarity not supported.
 *       (do we need to support it if we're coming up in 640x480?)
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/fb.h>

#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach-types.h>
#include <asm/uaccess.h>

#include <video/fbcon.h>
#include <video/fbcon-mfb.h>
#include <video/fbcon-cfb2.h>
#include <video/fbcon-cfb4.h>
#include <video/fbcon-cfb8.h>
#include <video/fbcon-cfb16.h>
#include <video/fbcon-cfb32.h>

#include "acornfb.h"

/*
 * VIDC machines can't do 16 or 32BPP modes.
 */
#ifdef HAS_VIDC
#undef FBCON_HAS_CFB16
#undef FBCON_HAS_CFB32
#endif

/*
 * Default resolution.
 * NOTE that it has to be supported in the table towards
 * the end of this file.
 */
#define DEFAULT_XRES	640
#define DEFAULT_YRES	480
/*
 * The order here defines which BPP we
 * pick depending on which resolutions
 * we have configured.
 */
#if   defined(FBCON_HAS_CFB4)
# define DEFAULT_BPP	4
#elif defined(FBCON_HAS_CFB8)
# define DEFAULT_BPP	8
#elif defined(FBCON_HAS_CFB16)
# define DEFAULT_BPP	16
#elif defined(FBCON_HAS_CFB2)
# define DEFAULT_BPP	2
#elif defined(FBCON_HAS_MFB)
# define DEFAULT_BPP	1
#else
#error No suitable framebuffers configured
#endif


/*
 * define this to debug the video mode selection
 */
#undef DEBUG_MODE_SELECTION

/*
 * Translation from RISC OS monitor types to actual
 * HSYNC and VSYNC frequency ranges.  These are
 * probably not right, but they're the best info I
 * have.  Allow 1% either way on the nominal for TVs.
 */
#define NR_MONTYPES	6
static struct fb_monspecs monspecs[NR_MONTYPES] __initdata = {
	{ 15469, 15781, 49, 51, 0 },	/* TV		*/
	{     0, 99999,  0, 99, 0 },	/* Multi Freq	*/
	{ 58608, 58608, 64, 64, 0 },	/* Hi-res mono	*/
	{ 30000, 70000, 60, 60, 0 },	/* VGA		*/
	{ 30000, 70000, 56, 75, 0 },	/* SVGA		*/
	{ 30000, 70000, 60, 60, 0 }
};

static struct display global_disp;
static struct fb_info fb_info;
static struct acornfb_par current_par;
static struct vidc_timing current_vidc;
static struct fb_var_screeninfo __initdata init_var = {};

extern int acornfb_depth;	/* set by setup.c */
extern unsigned int vram_size;	/* set by setup.c */

#ifdef HAS_VIDC

#define MAX_SIZE	480*1024

/* CTL     VIDC	Actual
 * 24.000  0	 8.000
 * 25.175  0	 8.392
 * 36.000  0	12.000
 * 24.000  1	12.000
 * 25.175  1	12.588
 * 24.000  2	16.000
 * 25.175  2	16.783
 * 36.000  1	18.000
 * 24.000  3	24.000
 * 36.000  2	24.000
 * 25.175  3	25.175
 * 36.000  3	36.000
 */
struct pixclock {
	u_long	min_clock;
	u_long	max_clock;
	u_int	vidc_ctl;
	u_int	vid_ctl;
};

static struct pixclock arc_clocks[] = {
	/* we allow +/-1% on these */
	{ 123750, 126250, VIDC_CTRL_DIV3,   VID_CTL_24MHz },	/*  8.000MHz */
	{  82500,  84167, VIDC_CTRL_DIV2,   VID_CTL_24MHz },	/* 12.000MHz */
	{  61875,  63125, VIDC_CTRL_DIV1_5, VID_CTL_24MHz },	/* 16.000MHz */
	{  41250,  42083, VIDC_CTRL_DIV1,   VID_CTL_24MHz },	/* 24.000MHz */
};

#ifdef CONFIG_ARCH_A5K
static struct pixclock a5k_clocks[] = {
	{ 117974, 120357, VIDC_CTRL_DIV3,   VID_CTL_25MHz },	/*  8.392MHz */
	{  78649,  80238, VIDC_CTRL_DIV2,   VID_CTL_25MHz },	/* 12.588MHz */
	{  58987,  60178, VIDC_CTRL_DIV1_5, VID_CTL_25MHz },	/* 16.588MHz */
	{  55000,  56111, VIDC_CTRL_DIV2,   VID_CTL_36MHz },	/* 18.000MHz */
	{  39325,  40119, VIDC_CTRL_DIV1,   VID_CTL_25MHz },	/* 25.175MHz */
	{  27500,  28055, VIDC_CTRL_DIV1,   VID_CTL_36MHz },	/* 36.000MHz */
};
#endif

static struct pixclock *
acornfb_valid_pixrate(u_long pixclock)
{
	u_int i;

	for (i = 0; i < ARRAY_SIZE(arc_clocks); i++)
		if (pixclock > arc_clocks[i].min_clock &&
		    pixclock < arc_clocks[i].max_clock)
			return arc_clocks + i;

#ifdef CONFIG_ARCH_A5K
	if (machine_is_a5k()) {
		for (i = 0; i < ARRAY_SIZE(a5k_clocks); i++)
			if (pixclock > a5k_clocks[i].min_clock &&
			    pixclock < a5k_clocks[i].max_clock)
				return a5k_clocks + i;
	}
#endif

	return NULL;
}

/* VIDC Rules:
 * hcr  : must be even (interlace, hcr/2 must be even)
 * hswr : must be even
 * hdsr : must be odd
 * hder : must be odd
 *
 * vcr  : must be odd
 * vswr : >= 1
 * vdsr : >= 1
 * vder : >= vdsr
 * if interlaced, then hcr/2 must be even
 */
static void
acornfb_set_timing(struct fb_var_screeninfo *var)
{
	struct pixclock *pclk;
	struct vidc_timing vidc;
	u_int horiz_correction;
	u_int sync_len, display_start, display_end, cycle;
	u_int is_interlaced;
	u_int vid_ctl, vidc_ctl;
	u_int bandwidth;

	memset(&vidc, 0, sizeof(vidc));

	pclk = acornfb_valid_pixrate(var->pixclock);
	vidc_ctl = pclk->vidc_ctl;
	vid_ctl  = pclk->vid_ctl;

	bandwidth = var->pixclock * 8 / var->bits_per_pixel;
	/* 25.175, 4bpp = 79.444ns per byte, 317.776ns per word: fifo = 2,6 */
	if (bandwidth > 143500)
		vidc_ctl |= VIDC_CTRL_FIFO_3_7;
	else if (bandwidth > 71750)
		vidc_ctl |= VIDC_CTRL_FIFO_2_6;
	else if (bandwidth > 35875)
		vidc_ctl |= VIDC_CTRL_FIFO_1_5;
	else
		vidc_ctl |= VIDC_CTRL_FIFO_0_4;

	switch (var->bits_per_pixel) {
	case 1:
		horiz_correction = 19;
		vidc_ctl |= VIDC_CTRL_1BPP;
		break;

	case 2:
		horiz_correction = 11;
		vidc_ctl |= VIDC_CTRL_2BPP;
		break;

	case 4:
		horiz_correction = 7;
		vidc_ctl |= VIDC_CTRL_4BPP;
		break;

	default:
	case 8:
		horiz_correction = 5;
		vidc_ctl |= VIDC_CTRL_8BPP;
		break;
	}

	if (var->sync & FB_SYNC_COMP_HIGH_ACT) /* should be FB_SYNC_COMP */
		vidc_ctl |= VIDC_CTRL_CSYNC;
	else {
		if (!(var->sync & FB_SYNC_HOR_HIGH_ACT))
			vid_ctl |= VID_CTL_HS_NHSYNC;

		if (!(var->sync & FB_SYNC_VERT_HIGH_ACT))
			vid_ctl |= VID_CTL_VS_NVSYNC;
	}

	sync_len	= var->hsync_len;
	display_start	= sync_len + var->left_margin;
	display_end	= display_start + var->xres;
	cycle		= display_end + var->right_margin;

	/* if interlaced, then hcr/2 must be even */
	is_interlaced = (var->vmode & FB_VMODE_MASK) == FB_VMODE_INTERLACED;

	if (is_interlaced) {
		vidc_ctl |= VIDC_CTRL_INTERLACE;
		if (cycle & 2) {
			cycle += 2;
			var->right_margin += 2;
		}
	}

	vidc.h_cycle		= (cycle - 2) / 2;
	vidc.h_sync_width	= (sync_len - 2) / 2;
	vidc.h_border_start	= (display_start - 1) / 2;
	vidc.h_display_start	= (display_start - horiz_correction) / 2;
	vidc.h_display_end	= (display_end - horiz_correction) / 2;
	vidc.h_border_end	= (display_end - 1) / 2;
	vidc.h_interlace	= (vidc.h_cycle + 1) / 2;

	sync_len	= var->vsync_len;
	display_start	= sync_len + var->upper_margin;
	display_end	= display_start + var->yres;
	cycle		= display_end + var->lower_margin;

	if (is_interlaced)
		cycle = (cycle - 3) / 2;
	else
		cycle = cycle - 1;

	vidc.v_cycle		= cycle;
	vidc.v_sync_width	= sync_len - 1;
	vidc.v_border_start	= display_start - 1;
	vidc.v_display_start	= vidc.v_border_start;
	vidc.v_display_end	= display_end - 1;
	vidc.v_border_end	= vidc.v_display_end;

	if (machine_is_a5k())
		__raw_writeb(vid_ctl, IOEB_VID_CTL);

	if (memcmp(&current_vidc, &vidc, sizeof(vidc))) {
		current_vidc = vidc;

		vidc_writel(0xe0000000 | vidc_ctl);
		vidc_writel(0x80000000 | (vidc.h_cycle << 14));
		vidc_writel(0x84000000 | (vidc.h_sync_width << 14));
		vidc_writel(0x88000000 | (vidc.h_border_start << 14));
		vidc_writel(0x8c000000 | (vidc.h_display_start << 14));
		vidc_writel(0x90000000 | (vidc.h_display_end << 14));
		vidc_writel(0x94000000 | (vidc.h_border_end << 14));
		vidc_writel(0x98000000);
		vidc_writel(0x9c000000 | (vidc.h_interlace << 14));
		vidc_writel(0xa0000000 | (vidc.v_cycle << 14));
		vidc_writel(0xa4000000 | (vidc.v_sync_width << 14));
		vidc_writel(0xa8000000 | (vidc.v_border_start << 14));
		vidc_writel(0xac000000 | (vidc.v_display_start << 14));
		vidc_writel(0xb0000000 | (vidc.v_display_end << 14));
		vidc_writel(0xb4000000 | (vidc.v_border_end << 14));
		vidc_writel(0xb8000000);
		vidc_writel(0xbc000000);
	}
#ifdef DEBUG_MODE_SELECTION
	printk(KERN_DEBUG "VIDC registers for %dx%dx%d:\n", var->xres,
	       var->yres, var->bits_per_pixel);
	printk(KERN_DEBUG " H-cycle          : %d\n", vidc.h_cycle);
	printk(KERN_DEBUG " H-sync-width     : %d\n", vidc.h_sync_width);
	printk(KERN_DEBUG " H-border-start   : %d\n", vidc.h_border_start);
	printk(KERN_DEBUG " H-display-start  : %d\n", vidc.h_display_start);
	printk(KERN_DEBUG " H-display-end    : %d\n", vidc.h_display_end);
	printk(KERN_DEBUG " H-border-end     : %d\n", vidc.h_border_end);
	printk(KERN_DEBUG " H-interlace      : %d\n", vidc.h_interlace);
	printk(KERN_DEBUG " V-cycle          : %d\n", vidc.v_cycle);
	printk(KERN_DEBUG " V-sync-width     : %d\n", vidc.v_sync_width);
	printk(KERN_DEBUG " V-border-start   : %d\n", vidc.v_border_start);
	printk(KERN_DEBUG " V-display-start  : %d\n", vidc.v_display_start);
	printk(KERN_DEBUG " V-display-end    : %d\n", vidc.v_display_end);
	printk(KERN_DEBUG " V-border-end     : %d\n", vidc.v_border_end);
	printk(KERN_DEBUG " VIDC Ctrl (E)    : 0x%08X\n", vidc_ctl);
	printk(KERN_DEBUG " IOEB Ctrl        : 0x%08X\n", vid_ctl);
#endif
}

static inline void
acornfb_palette_write(u_int regno, union palette pal)
{
	vidc_writel(pal.p);
}

static inline union palette
acornfb_palette_encode(u_int regno, u_int red, u_int green, u_int blue,
		       u_int trans)
{
	union palette pal;

	pal.p = 0;
	pal.vidc.reg   = regno;
	pal.vidc.red   = red >> 12;
	pal.vidc.green = green >> 12;
	pal.vidc.blue  = blue >> 12;
	return pal;
}

static void
acornfb_palette_decode(u_int regno, u_int *red, u_int *green, u_int *blue,
		       u_int *trans)
{
	*red   = EXTEND4(current_par.palette[regno].vidc.red);
	*green = EXTEND4(current_par.palette[regno].vidc.green);
	*blue  = EXTEND4(current_par.palette[regno].vidc.blue);
	*trans = current_par.palette[regno].vidc.trans ? -1 : 0;
}
#endif

#ifdef HAS_VIDC20
#include <asm/arch/acornfb.h>

#define MAX_SIZE	2*1024*1024

/* VIDC20 has a different set of rules from the VIDC:
 *  hcr  : must be multiple of 4
 *  hswr : must be even
 *  hdsr : must be even
 *  hder : must be even
 *  vcr  : >= 2, (interlace, must be odd)
 *  vswr : >= 1
 *  vdsr : >= 1
 *  vder : >= vdsr
 */
static void
acornfb_set_timing(struct fb_var_screeninfo *var)
{
	struct vidc_timing vidc;
	u_int vcr, fsize;
	u_int ext_ctl, dat_ctl;
	u_int words_per_line;

	memset(&vidc, 0, sizeof(vidc));

	vidc.h_sync_width	= var->hsync_len - 8;
	vidc.h_border_start	= vidc.h_sync_width + var->left_margin + 8 - 12;
	vidc.h_display_start	= vidc.h_border_start + 12 - 18;
	vidc.h_display_end	= vidc.h_display_start + var->xres;
	vidc.h_border_end	= vidc.h_display_end + 18 - 12;
	vidc.h_cycle		= vidc.h_border_end + var->right_margin + 12 - 8;
	vidc.h_interlace	= vidc.h_cycle / 2;
	vidc.v_sync_width	= var->vsync_len - 1;
	vidc.v_border_start	= vidc.v_sync_width + var->upper_margin;
	vidc.v_display_start	= vidc.v_border_start;
	vidc.v_display_end	= vidc.v_display_start + var->yres;
	vidc.v_border_end	= vidc.v_display_end;
	vidc.control		= acornfb_default_control();

	vcr = var->vsync_len + var->upper_margin + var->yres +
	      var->lower_margin;

	if ((var->vmode & FB_VMODE_MASK) == FB_VMODE_INTERLACED) {
		vidc.v_cycle = (vcr - 3) / 2;
		vidc.control |= VIDC20_CTRL_INT;
	} else
		vidc.v_cycle = vcr - 2;

	switch (var->bits_per_pixel) {
	case  1: vidc.control |= VIDC20_CTRL_1BPP;	break;
	case  2: vidc.control |= VIDC20_CTRL_2BPP;	break;
	case  4: vidc.control |= VIDC20_CTRL_4BPP;	break;
	default:
	case  8: vidc.control |= VIDC20_CTRL_8BPP;	break;
	case 16: vidc.control |= VIDC20_CTRL_16BPP;	break;
	case 32: vidc.control |= VIDC20_CTRL_32BPP;	break;
	}

	acornfb_vidc20_find_rates(&vidc, var);
	fsize = var->vsync_len + var->upper_margin + var->lower_margin - 1;

	if (memcmp(&current_vidc, &vidc, sizeof(vidc))) {
		current_vidc = vidc;

		vidc_writel(VIDC20_CTRL| vidc.control);
		vidc_writel(0xd0000000 | vidc.pll_ctl);
		vidc_writel(0x80000000 | vidc.h_cycle);
		vidc_writel(0x81000000 | vidc.h_sync_width);
		vidc_writel(0x82000000 | vidc.h_border_start);
		vidc_writel(0x83000000 | vidc.h_display_start);
		vidc_writel(0x84000000 | vidc.h_display_end);
		vidc_writel(0x85000000 | vidc.h_border_end);
		vidc_writel(0x86000000);
		vidc_writel(0x87000000 | vidc.h_interlace);
		vidc_writel(0x90000000 | vidc.v_cycle);
		vidc_writel(0x91000000 | vidc.v_sync_width);
		vidc_writel(0x92000000 | vidc.v_border_start);
		vidc_writel(0x93000000 | vidc.v_display_start);
		vidc_writel(0x94000000 | vidc.v_display_end);
		vidc_writel(0x95000000 | vidc.v_border_end);
		vidc_writel(0x96000000);
		vidc_writel(0x97000000);
	}

	iomd_writel(fsize, IOMD_FSIZE);

	ext_ctl = acornfb_default_econtrol();

	if (var->sync & FB_SYNC_COMP_HIGH_ACT) /* should be FB_SYNC_COMP */
		ext_ctl |= VIDC20_ECTL_HS_NCSYNC | VIDC20_ECTL_VS_NCSYNC;
	else {
		if (var->sync & FB_SYNC_HOR_HIGH_ACT)
			ext_ctl |= VIDC20_ECTL_HS_HSYNC;
		else
			ext_ctl |= VIDC20_ECTL_HS_NHSYNC;

		if (var->sync & FB_SYNC_VERT_HIGH_ACT)
			ext_ctl |= VIDC20_ECTL_VS_VSYNC;
		else
			ext_ctl |= VIDC20_ECTL_VS_NVSYNC;
	}

	vidc_writel(VIDC20_ECTL | ext_ctl);

	words_per_line = var->xres * var->bits_per_pixel / 32;

	if (current_par.using_vram && current_par.screen_size == 2048*1024)
		words_per_line /= 2;

	/* RiscPC doesn't use the VIDC's VRAM control. */
	dat_ctl = VIDC20_DCTL_VRAM_DIS | VIDC20_DCTL_SNA | words_per_line;

	/* The data bus width is dependent on both the type
	 * and amount of video memory.
	 *     DRAM	32bit low
	 * 1MB VRAM	32bit
	 * 2MB VRAM	64bit
	 */
	if (current_par.using_vram && current_par.vram_half_sam == 2048) {
		dat_ctl |= VIDC20_DCTL_BUS_D63_0;
	} else 
		dat_ctl |= VIDC20_DCTL_BUS_D31_0;

	vidc_writel(VIDC20_DCTL | dat_ctl);

#ifdef DEBUG_MODE_SELECTION
	printk(KERN_DEBUG "VIDC registers for %dx%dx%d:\n", var->xres,
	       var->yres, var->bits_per_pixel);
	printk(KERN_DEBUG " H-cycle          : %d\n", vidc.h_cycle);
	printk(KERN_DEBUG " H-sync-width     : %d\n", vidc.h_sync_width);
	printk(KERN_DEBUG " H-border-start   : %d\n", vidc.h_border_start);
	printk(KERN_DEBUG " H-display-start  : %d\n", vidc.h_display_start);
	printk(KERN_DEBUG " H-display-end    : %d\n", vidc.h_display_end);
	printk(KERN_DEBUG " H-border-end     : %d\n", vidc.h_border_end);
	printk(KERN_DEBUG " H-interlace      : %d\n", vidc.h_interlace);
	printk(KERN_DEBUG " V-cycle          : %d\n", vidc.v_cycle);
	printk(KERN_DEBUG " V-sync-width     : %d\n", vidc.v_sync_width);
	printk(KERN_DEBUG " V-border-start   : %d\n", vidc.v_border_start);
	printk(KERN_DEBUG " V-display-start  : %d\n", vidc.v_display_start);
	printk(KERN_DEBUG " V-display-end    : %d\n", vidc.v_display_end);
	printk(KERN_DEBUG " V-border-end     : %d\n", vidc.v_border_end);
	printk(KERN_DEBUG " Ext Ctrl  (C)    : 0x%08X\n", ext_ctl);
	printk(KERN_DEBUG " PLL Ctrl  (D)    : 0x%08X\n", vidc.pll_ctl);
	printk(KERN_DEBUG " Ctrl      (E)    : 0x%08X\n", vidc.control);
	printk(KERN_DEBUG " Data Ctrl (F)    : 0x%08X\n", dat_ctl);
	printk(KERN_DEBUG " Fsize            : 0x%08X\n", fsize);
#endif
}

static inline void
acornfb_palette_write(u_int regno, union palette pal)
{
	vidc_writel(0x10000000 | regno);
	vidc_writel(pal.p);
}

static inline union palette
acornfb_palette_encode(u_int regno, u_int red, u_int green, u_int blue,
		       u_int trans)
{
	union palette pal;

	pal.p = 0;
	pal.vidc20.red   = red >> 8;
	pal.vidc20.green = green >> 8;
	pal.vidc20.blue  = blue >> 8;
	return pal;
}

static void
acornfb_palette_decode(u_int regno, u_int *red, u_int *green, u_int *blue,
		       u_int *trans)
{
	*red   = EXTEND8(current_par.palette[regno].vidc20.red);
	*green = EXTEND8(current_par.palette[regno].vidc20.green);
	*blue  = EXTEND8(current_par.palette[regno].vidc20.blue);
	*trans = EXTEND4(current_par.palette[regno].vidc20.ext);
}
#endif

/*
 * Before selecting the timing parameters, adjust
 * the resolution to fit the rules.
 */
static int
acornfb_adjust_timing(struct fb_var_screeninfo *var, int con)
{
	u_int font_line_len;
	u_int fontht;
	u_int sam_size, min_size, size;
	u_int nr_y;

	/* xres must be even */
	var->xres = (var->xres + 1) & ~1;

	/*
	 * We don't allow xres_virtual to differ from xres
	 */
	var->xres_virtual = var->xres;
	var->xoffset = 0;

	/*
	 * Find the font height
	 */
	if (con == -1)
		fontht = fontheight(&global_disp);
	else
		fontht = fontheight(fb_display + con);

	if (fontht == 0)
		fontht = 8;

	if (current_par.using_vram)
		sam_size = current_par.vram_half_sam * 2;
	else
		sam_size = 16;

	/*
	 * Now, find a value for yres_virtual which allows
	 * us to do ywrap scrolling.  The value of
	 * yres_virtual must be such that the end of the
	 * displayable frame buffer must be aligned with
	 * the start of a font line.
	 */
	font_line_len = var->xres * var->bits_per_pixel * fontht / 8;
	min_size = var->xres * var->yres * var->bits_per_pixel / 8;