acornfb.c

S3C44B0X下的LCD （framebuffer）驱动资料与相关代码

	/*
	 * If minimum screen size is greater than that we have
	 * available, reject it.
	 */
	if (min_size > current_par.screen_size)
		return -EINVAL;

	/* Find int 'y', such that y * fll == s * sam < maxsize
	 * y = s * sam / fll; s = maxsize / sam
	 */
	for (size = current_par.screen_size; min_size <= size;
	     size -= sam_size) {
		nr_y = size / font_line_len;

		if (nr_y * font_line_len == size)
			break;
	}

	if (var->accel_flags & FB_ACCELF_TEXT) {
		if (min_size > size) {
			/*
			 * failed, use ypan
			 */
			size = current_par.screen_size;
			var->yres_virtual = size / (font_line_len / fontht);
		} else
			var->yres_virtual = nr_y * fontht;
	}

	current_par.screen_end = current_par.screen_base_p + size;

	/*
	 * Fix yres & yoffset if needed.
	 */
	if (var->yres > var->yres_virtual)
		var->yres = var->yres_virtual;

	if (var->vmode & FB_VMODE_YWRAP) {
		if (var->yoffset > var->yres_virtual)
			var->yoffset = var->yres_virtual;
	} else {
		if (var->yoffset + var->yres > var->yres_virtual)
			var->yoffset = var->yres_virtual - var->yres;
	}

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

#ifdef HAS_VIDC
	/* left_margin must be odd */
	if ((var->left_margin & 1) == 0) {
		var->left_margin -= 1;
		var->right_margin += 1;
	}

	/* right_margin must be odd */
	var->right_margin |= 1;
#elif defined(HAS_VIDC20)
	/* left_margin must be even */
	if (var->left_margin & 1) {
		var->left_margin += 1;
		var->right_margin -= 1;
	}

	/* right_margin must be even */
	if (var->right_margin & 1)
		var->right_margin += 1;
#endif

	if (var->vsync_len < 1)
		var->vsync_len = 1;

	return 0;
}

static int
acornfb_validate_timing(struct fb_var_screeninfo *var,
			struct fb_monspecs *monspecs)
{
	unsigned long hs, vs;

	/*
	 * hs(Hz) = 10^12 / (pixclock * xtotal)
	 * vs(Hz) = hs(Hz) / ytotal
	 *
	 * No need to do long long divisions or anything
	 * like that if you factor it correctly
	 */
	hs = 1953125000 / var->pixclock;
	hs = hs * 512 /
	     (var->xres + var->left_margin + var->right_margin + var->hsync_len);
	vs = hs /
	     (var->yres + var->upper_margin + var->lower_margin + var->vsync_len);

	return (vs >= monspecs->vfmin && vs <= monspecs->vfmax &&
		hs >= monspecs->hfmin && hs <= monspecs->hfmax) ? 0 : -EINVAL;
}

static inline void
acornfb_update_dma(struct fb_var_screeninfo *var)
{
	int off = (var->yoffset * var->xres_virtual *
		   var->bits_per_pixel) >> 3;

#if defined(HAS_MEMC)
	memc_write(VDMA_INIT, off >> 2);
#elif defined(HAS_IOMD)
	iomd_writel(current_par.screen_base_p + off, IOMD_VIDINIT);
#endif
}

static int
acornfb_getcolreg(u_int regno, u_int *red, u_int *green, u_int *blue,
		  u_int *trans, struct fb_info *info)
{
	if (regno >= current_par.palette_size)
		return 1;

	acornfb_palette_decode(regno, red, green, blue, trans);

	return 0;
}

/*
 * We have to take note of the VIDC20's 16-bit palette here.
 * The VIDC20 looks up a 16 bit pixel as follows:
 *
 *   bits   111111
 *          5432109876543210
 *   red            ++++++++  (8 bits,  7 to 0)
 *  green       ++++++++      (8 bits, 11 to 4)
 *   blue   ++++++++          (8 bits, 15 to 8)
 *
 * We use a pixel which looks like:
 *
 *   bits   111111
 *          5432109876543210
 *   red               +++++  (5 bits,  4 to  0)
 *  green         +++++       (5 bits,  9 to  5)
 *   blue    +++++            (5 bits, 14 to 10)
 */
static int
acornfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
		  u_int trans, struct fb_info *info)
{
	union palette pal;
	int bpp = fb_display[current_par.currcon].var.bits_per_pixel;

	if (regno >= current_par.palette_size)
		return 1;

	pal = acornfb_palette_encode(regno, red, green, blue, trans);
	current_par.palette[regno] = pal;

#ifdef FBCON_HAS_CFB32
	if (bpp == 32 && regno < 16) {
		current_par.cmap.cfb32[regno] =
				regno | regno << 8 | regno << 16;
	}
#endif
#ifdef FBCON_HAS_CFB16
	if (bpp == 16 && regno < 16) {
		int i;

		current_par.cmap.cfb16[regno] =
				regno | regno << 5 | regno << 10;

		pal.p = 0;
		vidc_writel(0x10000000);
		for (i = 0; i < 256; i += 1) {
			pal.vidc20.red   = current_par.palette[ i       & 31].vidc20.red;
			pal.vidc20.green = current_par.palette[(i >> 1) & 31].vidc20.green;
			pal.vidc20.blue  = current_par.palette[(i >> 2) & 31].vidc20.blue;
			vidc_writel(pal.p);
			/* Palette register pointer auto-increments */
		}
	} else
#endif
		acornfb_palette_write(regno, pal);

	return 0;
}

static int
acornfb_get_cmap(struct fb_cmap *cmap, int kspc, int con,
		 struct fb_info *info)
{
	int err = 0;

	if (con == current_par.currcon)
		err = fb_get_cmap(cmap, kspc, acornfb_getcolreg, info);
	else if (fb_display[con].cmap.len)
		fb_copy_cmap(&fb_display[con].cmap, cmap, kspc ? 0 : 2);
	else
		fb_copy_cmap(fb_default_cmap(current_par.palette_size),
			     cmap, kspc ? 0 : 2);
	return err;
}

static int
acornfb_set_cmap(struct fb_cmap *cmap, int kspc, int con,
		 struct fb_info *info)
{
	int err = 0;

	if (!fb_display[con].cmap.len)
		err = fb_alloc_cmap(&fb_display[con].cmap,
				    current_par.palette_size, 0);
	if (!err) {
		if (con == current_par.currcon)
			err = fb_set_cmap(cmap, kspc, acornfb_setcolreg,
					  info);
		else
			fb_copy_cmap(cmap, &fb_display[con].cmap,
				     kspc ? 0 : 1);
	}
	return err;
}

static int
acornfb_decode_var(struct fb_var_screeninfo *var, int con)
{
	int err;

#if defined(HAS_VIDC20)
	var->red.offset    = 0;
	var->red.length    = 8;
	var->green         = var->red;
	var->blue          = var->red;
	var->transp.offset = 0;
	var->transp.length = 4;
#elif defined(HAS_VIDC)
	var->red.length	   = 4;
	var->green         = var->red;
	var->blue          = var->red;
	var->transp.length = 1;
#endif

	switch (var->bits_per_pixel) {
#ifdef FBCON_HAS_MFB
	case 1:
		break;
#endif
#ifdef FBCON_HAS_CFB2
	case 2:
		break;
#endif
#ifdef FBCON_HAS_CFB4
	case 4:
		break;
#endif
#ifdef FBCON_HAS_CFB8
	case 8:
		break;
#endif
#ifdef FBCON_HAS_CFB16
	case 16:
		var->red.offset    = 0;
		var->red.length    = 5;
		var->green.offset  = 5;
		var->green.length  = 5;
		var->blue.offset   = 10;
		var->blue.length   = 5;
		var->transp.offset = 15;
		var->transp.length = 1;
		break;
#endif
#ifdef FBCON_HAS_CFB32
	case 32:
		var->red.offset    = 0;
		var->red.length    = 8;
		var->green.offset  = 8;
		var->green.length  = 8;
		var->blue.offset   = 16;
		var->blue.length   = 8;
		var->transp.offset = 24;
		var->transp.length = 4;
		break;
#endif
	default:
		return -EINVAL;
	}

	/*
	 * Check to see if the pixel rate is valid.
	 */
	if (!var->pixclock || !acornfb_valid_pixrate(var->pixclock))
		return -EINVAL;

	/*
	 * Validate and adjust the resolution to
	 * match the video generator hardware.
	 */
	err = acornfb_adjust_timing(var, con);
	if (err)
		return err;

	/*
	 * Validate the timing against the
	 * monitor hardware.
	 */
	return acornfb_validate_timing(var, &fb_info.monspecs);
}

static int
acornfb_get_fix(struct fb_fix_screeninfo *fix, int con, struct fb_info *info)
{
	struct display *display;

	memset(fix, 0, sizeof(struct fb_fix_screeninfo));
	strcpy(fix->id, "Acorn");

	if (con >= 0)
		display = fb_display + con;
	else
		display = &global_disp;

	fix->smem_start	 = current_par.screen_base_p;
	fix->smem_len	 = current_par.screen_size;
	fix->type	 = display->type;
	fix->type_aux	 = display->type_aux;
	fix->xpanstep	 = 0;
	fix->ypanstep	 = display->ypanstep;
	fix->ywrapstep	 = display->ywrapstep;
	fix->visual	 = display->visual;
	fix->line_length = display->line_length;
	fix->accel	 = FB_ACCEL_NONE;

	return 0;
}

static int
acornfb_get_var(struct fb_var_screeninfo *var, int con, struct fb_info *info)
{
	if (con == -1) {
		*var = global_disp.var;
	} else
		*var = fb_display[con].var;

	return 0;
}

static int
acornfb_set_var(struct fb_var_screeninfo *var, int con, struct fb_info *info)
{
	struct display *display;
	int err, chgvar = 0;

	if (con >= 0)
		display = fb_display + con;
	else
		display = &global_disp;

	err = acornfb_decode_var(var, con);
	if (err)
		return err;

	switch (var->activate & FB_ACTIVATE_MASK) {
	case FB_ACTIVATE_TEST:
		return 0;

	case FB_ACTIVATE_NXTOPEN:
	case FB_ACTIVATE_NOW:
		break;

	default:
		return -EINVAL;
	}

	if (con >= 0) {
		if (display->var.xres != var->xres)
			chgvar = 1;
		if (display->var.yres != var->yres)
			chgvar = 1;
		if (display->var.xres_virtual != var->xres_virtual)
			chgvar = 1;
		if (display->var.yres_virtual != var->yres_virtual)
			chgvar = 1;
		if (memcmp(&display->var.red, &var->red, sizeof(var->red)))
			chgvar = 1;
		if (memcmp(&display->var.green, &var->green, sizeof(var->green)))
			chgvar = 1;
		if (memcmp(&display->var.blue, &var->blue, sizeof(var->blue)))
			chgvar = 1;
	}

	display->var = *var;
	display->var.activate &= ~FB_ACTIVATE_ALL;

	if (var->activate & FB_ACTIVATE_ALL)
		global_disp.var = display->var;

	switch (display->var.bits_per_pixel) {
#ifdef FBCON_HAS_MFB
	case 1:
		current_par.palette_size = 2;
		display->dispsw = &fbcon_mfb;
		display->visual = FB_VISUAL_MONO10;
		break;
#endif
#ifdef FBCON_HAS_CFB2
	case 2:
		current_par.palette_size = 4;
		display->dispsw = &fbcon_cfb2;
		display->visual = FB_VISUAL_PSEUDOCOLOR;
		break;
#endif
#ifdef FBCON_HAS_CFB4
	case 4:
		current_par.palette_size = 16;
		display->dispsw = &fbcon_cfb4;
		display->visual = FB_VISUAL_PSEUDOCOLOR;
		break;
#endif
#ifdef FBCON_HAS_CFB8
	case 8:
		current_par.palette_size = VIDC_PALETTE_SIZE;
		display->dispsw = &fbcon_cfb8;
#ifdef HAS_VIDC
		display->visual = FB_VISUAL_STATIC_PSEUDOCOLOR;
#else
		display->visual = FB_VISUAL_PSEUDOCOLOR;
#endif
		break;
#endif
#ifdef FBCON_HAS_CFB16
	case 16:
		current_par.palette_size = 32;
		display->dispsw = &fbcon_cfb16;
		display->dispsw_data = current_par.cmap.cfb16;
		display->visual = FB_VISUAL_DIRECTCOLOR;
		break;
#endif
#ifdef FBCON_HAS_CFB32
	case 32:
		current_par.palette_size = VIDC_PALETTE_SIZE;
		display->dispsw = &fbcon_cfb32;
		display->dispsw_data = current_par.cmap.cfb32;
		display->visual = FB_VISUAL_TRUECOLOR;
		break;
#endif
	default:
		display->dispsw = &fbcon_dummy;
		break;
	}

	display->screen_base	= (char *)current_par.screen_base;
	display->type		= FB_TYPE_PACKED_PIXELS;
	display->type_aux	= 0;
	display->ypanstep	= 1;
	display->ywrapstep	= 1;
	display->line_length	=
	display->next_line      = (var->xres * var->bits_per_pixel) / 8;
	display->can_soft_blank	= display->visual == FB_VISUAL_PSEUDOCOLOR ? 1 : 0;
	display->inverse	= 0;

	if (chgvar && info && info->changevar)
		info->changevar(con);

	if (con == current_par.currcon) {
		struct fb_cmap *cmap;
		unsigned long start, size;
		int control;

#if defined(HAS_MEMC)
		start   = 0;
		size    = current_par.screen_size - VDMA_XFERSIZE;
		control = 0;

		memc_write(VDMA_START, start);
		memc_write(VDMA_END, size >> 2);
#elif defined(HAS_IOMD)

		start = current_par.screen_base_p;
		size  = current_par.screen_end;

		if (current_par.using_vram) {
			size -= current_par.vram_half_sam;
			control = DMA_CR_E | (current_par.vram_half_sam / 256);
		} else {
			size -= 16;
			control = DMA_CR_E | DMA_CR_D | 16;
		}

		iomd_writel(start,   IOMD_VIDSTART);
		iomd_writel(size,    IOMD_VIDEND);
		iomd_writel(control, IOMD_VIDCR);
#endif
		acornfb_update_dma(var);
		acornfb_set_timing(var);

		if (display->cmap.len)
			cmap = &display->cmap;
		else
			cmap = fb_default_cmap(current_par.palette_size);

		fb_set_cmap(cmap, 1, acornfb_setcolreg, info);
	}
	return 0;
}

static int
acornfb_pan_display(struct fb_var_screeninfo *var, int con,
		    struct fb_info *info)
{
	u_int y_bottom;

	if (var->xoffset)
		return -EINVAL;

	y_bottom = var->yoffset;

	if (!(var->vmode & FB_VMODE_YWRAP))
		y_bottom += var->yres;

	if (y_bottom > fb_display[con].var.yres_virtual)
		return -EINVAL;

	acornfb_update_dma(var);

	fb_display[con].var.yoffset = var->yoffset;
	if (var->vmode & FB_VMODE_YWRAP)
		fb_display[con].var.vmode |= FB_VMODE_YWRAP;
	else
		fb_display[con].var.vmode &= ~FB_VMODE_YWRAP;

	return 0;
}

/*
 * Note that we are entered with the kernel locked.
 */
static int
acornfb_mmap(struct fb_info *info, struct file *file, struct vm_area_struct *vma)
{
	unsigned long off, start;
	u32 len;

	off = vma->vm_pgoff << PAGE_SHIFT;

	start = current_par.screen_base_p;
	len = PAGE_ALIGN(start & ~PAGE_MASK) + current_par.screen_size;
	start &= PAGE_MASK;
	if ((vma->vm_end - vma->vm_start + off) > len)
		return -EINVAL;
	off += start;
	vma->vm_pgoff = off >> PAGE_SHIFT;

#ifdef CONFIG_CPU_32
	pgprot_val(vma->vm_page_prot) &= ~L_PTE_CACHEABLE;
#endif

	/*
	 * Don't alter the page protection flags; we want to keep the area
	 * cached for better performance.  This does mean that we may miss
	 * some updates to the screen occasionally, but process switches
	 * should cause the caches and buffers to be flushed often enough.
	 */
	if (io_remap_page_range(vma->vm_start, off,
				vma->vm_end - vma->vm_start,
				vma->vm_page_prot))
		return -EAGAIN;
	return 0;
}

static struct fb_ops acornfb_ops = {
	owner:		THIS_MODULE,
	fb_get_fix:	acornfb_get_fix,
	fb_get_var:	acornfb_get_var,
	fb_set_var:	acornfb_set_var,
	fb_get_cmap:	acornfb_get_cmap,
	fb_set_cmap:	acornfb_set_cmap,
	fb_pan_display:	acornfb_pan_display,
	fb_mmap:	acornfb_mmap,
};

static int
acornfb_updatevar(int con, struct fb_info *info)
{
	if (con == current_par.currcon)
		acornfb_update_dma(&fb_display[con].var);

	return 0;
}

static int
acornfb_switch(int con, struct fb_info *info)
{
	struct fb_cmap *cmap;

	if (current_par.currcon >= 0) {