sa1100fb.c

linux下的VIDEO接口驱动程序

static int
sa1100fb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
		   u_int trans, struct fb_info *info)
{
	struct sa1100fb_info *fbi = (struct sa1100fb_info *)info;
	struct display *disp = get_con_display(info, fbi->currcon);
	u_int val;
	int ret = 1;

	/*
	 * If inverse mode was selected, invert all the colours
	 * rather than the register number.  The register number
	 * is what you poke into the framebuffer to produce the
	 * colour you requested.
	 */
	if (disp->inverse) {
		red   = 0xffff - red;
		green = 0xffff - green;
		blue  = 0xffff - blue;
	}

	/*
	 * If greyscale is true, then we convert the RGB value
	 * to greyscale no mater what visual we are using.
	 */
	if (fbi->fb.var.grayscale)
		red = green = blue = (19595 * red + 38470 * green +
					7471 * blue) >> 16;

	switch (fbi->fb.disp->visual) {
	case FB_VISUAL_TRUECOLOR:
		/*
		 * 12 or 16-bit True Colour.  We encode the RGB value
		 * according to the RGB bitfield information.
		 */
		if (regno < 16) {
			u16 *pal = fbi->fb.pseudo_palette;

			val  = chan_to_field(red, &fbi->fb.var.red);
			val |= chan_to_field(green, &fbi->fb.var.green);
			val |= chan_to_field(blue, &fbi->fb.var.blue);

			pal[regno] = val;
			ret = 0;
		}
		break;

	case FB_VISUAL_STATIC_PSEUDOCOLOR:
	case FB_VISUAL_PSEUDOCOLOR:
		ret = sa1100fb_setpalettereg(regno, red, green, blue, trans, info);
		break;
	}

	return ret;
}

/*
 *  sa1100fb_display_dma_period()
 *    Calculate the minimum period (in picoseconds) between two DMA
 *    requests for the LCD controller.
 */
static unsigned int
sa1100fb_display_dma_period(struct fb_var_screeninfo *var)
{
	unsigned int mem_bits_per_pixel;

	mem_bits_per_pixel = var->bits_per_pixel;
	if (mem_bits_per_pixel == 12)
		mem_bits_per_pixel = 16;

	/*
	 * Period = pixclock * bits_per_byte * bytes_per_transfer
	 *		/ memory_bits_per_pixel;
	 */
	return var->pixclock * 8 * 16 / mem_bits_per_pixel;
}

/*
 *  sa1100fb_decode_var():
 *    Get the video params out of 'var'. If a value doesn't fit, round it up,
 *    if it's too big, return -EINVAL.
 *
 *    Suggestion: Round up in the following order: bits_per_pixel, xres,
 *    yres, xres_virtual, yres_virtual, xoffset, yoffset, grayscale,
 *    bitfields, horizontal timing, vertical timing.
 */
static int
sa1100fb_validate_var(struct fb_var_screeninfo *var,
		      struct sa1100fb_info *fbi)
{
	int ret = -EINVAL;

	if (var->xres < MIN_XRES)
		var->xres = MIN_XRES;
	if (var->yres < MIN_YRES)
		var->yres = MIN_YRES;
	if (var->xres > fbi->max_xres)
		var->xres = fbi->max_xres;
	if (var->yres > fbi->max_yres)
		var->yres = fbi->max_yres;
	var->xres_virtual =
	    var->xres_virtual < var->xres ? var->xres : var->xres_virtual;
	var->yres_virtual =
	    var->yres_virtual < var->yres ? var->yres : var->yres_virtual;

	DPRINTK("var->bits_per_pixel=%d\n", var->bits_per_pixel);
	switch (var->bits_per_pixel) {
#ifdef FBCON_HAS_CFB4
	case 4:		ret = 0; break;
#endif
#ifdef FBCON_HAS_CFB8
	case 8:		ret = 0; break;
#endif
#ifdef FBCON_HAS_CFB16
	case 16:	ret = 0; break;
#endif
	default:
		break;
	}

#ifdef CONFIG_CPU_FREQ
	printk(KERN_DEBUG "dma period = %d ps, clock = %d kHz\n",
		sa1100fb_display_dma_period(var),
		cpufreq_get(smp_processor_id()));
#endif

	return ret;
}

static inline void sa1100fb_set_truecolor(u_int is_true_color)
{
	DPRINTK("true_color = %d\n", is_true_color);

	if (machine_is_assabet()) {
#if 1
		// phase 4 or newer Assabet's
		if (is_true_color)
			ASSABET_BCR_set(ASSABET_BCR_LCD_12RGB);
		else
			ASSABET_BCR_clear(ASSABET_BCR_LCD_12RGB);
#else
		// older Assabet's
		if (is_true_color)
			ASSABET_BCR_clear(ASSABET_BCR_LCD_12RGB);
		else
			ASSABET_BCR_set(ASSABET_BCR_LCD_12RGB);
#endif
	}
}

static void
sa1100fb_hw_set_var(struct fb_var_screeninfo *var, struct sa1100fb_info *fbi)
{
	u_long palette_mem_size;

	fbi->palette_size = var->bits_per_pixel == 8 ? 256 : 16;

	palette_mem_size = fbi->palette_size * sizeof(u16);

	DPRINTK("palette_mem_size = 0x%08lx\n", (u_long) palette_mem_size);

	fbi->palette_cpu = (u16 *)(fbi->map_cpu + PAGE_SIZE - palette_mem_size);
	fbi->palette_dma = fbi->map_dma + PAGE_SIZE - palette_mem_size;

	fb_set_cmap(&fbi->fb.cmap, 1, sa1100fb_setcolreg, &fbi->fb);

	/* Set board control register to handle new color depth */
	sa1100fb_set_truecolor(var->bits_per_pixel >= 16);

#ifdef CONFIG_SA1100_OMNIMETER
#error Do we have to do this here?   We already do it at init time.
	if (machine_is_omnimeter())
		SetLCDContrast(DefaultLCDContrast);
#endif

	sa1100fb_activate_var(var, fbi);

	fbi->palette_cpu[0] = (fbi->palette_cpu[0] &
					 0xcfff) | palette_pbs(var);

}

/*
 * sa1100fb_set_var():
 *	Set the user defined part of the display for the specified console
 */
static int
sa1100fb_set_var(struct fb_var_screeninfo *var, int con, struct fb_info *info)
{
	struct sa1100fb_info *fbi = (struct sa1100fb_info *)info;
	struct fb_var_screeninfo *dvar = get_con_var(&fbi->fb, con);
	struct display *display = get_con_display(&fbi->fb, con);
	int err, chgvar = 0, rgbidx;

	DPRINTK("set_var\n");

	/*
	 * Decode var contents into a par structure, adjusting any
	 * out of range values.
	 */
	err = sa1100fb_validate_var(var, fbi);
	if (err)
		return err;

	if (var->activate & FB_ACTIVATE_TEST)
		return 0;

	if ((var->activate & FB_ACTIVATE_MASK) != FB_ACTIVATE_NOW)
		return -EINVAL;

	if (dvar->xres != var->xres)
		chgvar = 1;
	if (dvar->yres != var->yres)
		chgvar = 1;
	if (dvar->xres_virtual != var->xres_virtual)
		chgvar = 1;
	if (dvar->yres_virtual != var->yres_virtual)
		chgvar = 1;
	if (dvar->bits_per_pixel != var->bits_per_pixel)
		chgvar = 1;
	if (con < 0)
		chgvar = 0;

	switch (var->bits_per_pixel) {
#ifdef FBCON_HAS_CFB4
	case 4:
		if (fbi->cmap_static)
			display->visual	= FB_VISUAL_STATIC_PSEUDOCOLOR;
		else
			display->visual	= FB_VISUAL_PSEUDOCOLOR;
		display->line_length	= var->xres / 2;
		display->dispsw		= &fbcon_cfb4;
		rgbidx			= RGB_8;
		break;
#endif
#ifdef FBCON_HAS_CFB8
	case 8:
		if (fbi->cmap_static)
			display->visual	= FB_VISUAL_STATIC_PSEUDOCOLOR;
		else
			display->visual	= FB_VISUAL_PSEUDOCOLOR;
		display->line_length	= var->xres;
		display->dispsw		= &fbcon_cfb8;
		rgbidx			= RGB_8;
		break;
#endif
#ifdef FBCON_HAS_CFB16
	case 16:
		display->visual		= FB_VISUAL_TRUECOLOR;
		display->line_length	= var->xres * 2;
		display->dispsw		= &fbcon_cfb16;
		display->dispsw_data	= fbi->fb.pseudo_palette;
		rgbidx			= RGB_16;
		break;
#endif
	default:
		rgbidx = 0;
		display->dispsw = &fbcon_dummy;
		break;
	}

	display->screen_base	= fbi->screen_cpu;
	display->next_line	= display->line_length;
	display->type		= fbi->fb.fix.type;
	display->type_aux	= fbi->fb.fix.type_aux;
	display->ypanstep	= fbi->fb.fix.ypanstep;
	display->ywrapstep	= fbi->fb.fix.ywrapstep;
	display->can_soft_blank	= 1;
	display->inverse	= fbi->cmap_inverse;

	*dvar			= *var;
	dvar->activate		&= ~FB_ACTIVATE_ALL;

	/*
	 * Copy the RGB parameters for this display
	 * from the machine specific parameters.
	 */
	dvar->red		= fbi->rgb[rgbidx]->red;
	dvar->green		= fbi->rgb[rgbidx]->green;
	dvar->blue		= fbi->rgb[rgbidx]->blue;
	dvar->transp		= fbi->rgb[rgbidx]->transp;

	DPRINTK("RGBT length = %d:%d:%d:%d\n",
		dvar->red.length, dvar->green.length, dvar->blue.length,
		dvar->transp.length);

	DPRINTK("RGBT offset = %d:%d:%d:%d\n",
		dvar->red.offset, dvar->green.offset, dvar->blue.offset,
		dvar->transp.offset);

	/*
	 * Update the old var.  The fbcon drivers still use this.
	 * Once they are using fbi->fb.var, this can be dropped.
	 */
	display->var = *dvar;

	/*
	 * If we are setting all the virtual consoles, also set the
	 * defaults used to create new consoles.
	 */
	if (var->activate & FB_ACTIVATE_ALL)
		fbi->fb.disp->var = *dvar;

	/*
	 * If the console has changed and the console has defined
	 * a changevar function, call that function.
	 */
	if (chgvar && info && fbi->fb.changevar)
		fbi->fb.changevar(con);

	/* If the current console is selected, activate the new var. */
	if (con != fbi->currcon)
		return 0;

	sa1100fb_hw_set_var(dvar, fbi);

	return 0;
}

static int
__do_set_cmap(struct fb_cmap *cmap, int kspc, int con,
	      struct fb_info *info)
{
	struct sa1100fb_info *fbi = (struct sa1100fb_info *)info;
	struct fb_cmap *dcmap = get_con_cmap(info, con);
	int err = 0;

	if (con == -1)
		con = fbi->currcon;

	/* no colormap allocated? (we always have "this" colour map allocated) */
	if (con >= 0)
		err = fb_alloc_cmap(&fb_display[con].cmap, fbi->palette_size, 0);

	if (!err && con == fbi->currcon)
		err = fb_set_cmap(cmap, kspc, sa1100fb_setcolreg, info);

	if (!err)
		fb_copy_cmap(cmap, dcmap, kspc ? 0 : 1);

	return err;
}

static int
sa1100fb_set_cmap(struct fb_cmap *cmap, int kspc, int con,
		  struct fb_info *info)
{
	struct display *disp = get_con_display(info, con);

	if (disp->visual == FB_VISUAL_TRUECOLOR ||
	    disp->visual == FB_VISUAL_STATIC_PSEUDOCOLOR)
		return -EINVAL;

	return __do_set_cmap(cmap, kspc, con, info);
}

static int
sa1100fb_get_fix(struct fb_fix_screeninfo *fix, int con, struct fb_info *info)
{
	struct display *display = get_con_display(info, con);

	*fix = info->fix;

	fix->line_length = display->line_length;
	fix->visual	 = display->visual;
	return 0;
}

static int
sa1100fb_get_var(struct fb_var_screeninfo *var, int con, struct fb_info *info)
{
	*var = *get_con_var(info, con);
	return 0;
}

static int
sa1100fb_get_cmap(struct fb_cmap *cmap, int kspc, int con, struct fb_info *info)
{
	struct fb_cmap *dcmap = get_con_cmap(info, con);
	fb_copy_cmap(dcmap, cmap, kspc ? 0 : 2);
	return 0;
}

static struct fb_ops sa1100fb_ops = {
	owner:		THIS_MODULE,
	fb_get_fix:	sa1100fb_get_fix,
	fb_get_var:	sa1100fb_get_var,
	fb_set_var:	sa1100fb_set_var,
	fb_get_cmap:	sa1100fb_get_cmap,
	fb_set_cmap:	sa1100fb_set_cmap,
};

/*
 *  sa1100fb_switch():       
 *	Change to the specified console.  Palette and video mode
 *      are changed to the console's stored parameters.
 *
 *	Uh oh, this can be called from a tasklet (IRQ)
 */
static int sa1100fb_switch(int con, struct fb_info *info)
{
	struct sa1100fb_info *fbi = (struct sa1100fb_info *)info;
	struct display *disp;
	struct fb_cmap *cmap;

	DPRINTK("con=%d info->modename=%s\n", con, fbi->fb.modename);

	if (con == fbi->currcon)
		return 0;

	if (fbi->currcon >= 0) {
		disp = fb_display + fbi->currcon;

		/*
		 * Save the old colormap and video mode.
		 */
		disp->var = fbi->fb.var;

		if (disp->cmap.len)
			fb_copy_cmap(&fbi->fb.cmap, &disp->cmap, 0);
	}

	fbi->currcon = con;
	disp = fb_display + con;

	/*
	 * Make sure that our colourmap contains 256 entries.
	 */
	fb_alloc_cmap(&fbi->fb.cmap, 256, 0);

	if (disp->cmap.len)
		cmap = &disp->cmap;
	else
		cmap = fb_default_cmap(1 << disp->var.bits_per_pixel);

	fb_copy_cmap(cmap, &fbi->fb.cmap, 0);

	fbi->fb.var = disp->var;
	fbi->fb.var.activate = FB_ACTIVATE_NOW;

	sa1100fb_set_var(&fbi->fb.var, con, info);
	return 0;
}

/*
 * Formal definition of the VESA spec:
 *  On
 *  	This refers to the state of the display when it is in full operation
 *  Stand-By
 *  	This defines an optional operating state of minimal power reduction with
 *  	the shortest recovery time
 *  Suspend
 *  	This refers to a level of power management in which substantial power
 *  	reduction is achieved by the display.  The display can have a longer 
 *  	recovery time from this state than from the Stand-by state
 *  Off
 *  	This indicates that the display is consuming the lowest level of power
 *  	and is non-operational. Recovery from this state may optionally require
 *  	the user to manually power on the monitor
 *
 *  Now, the fbdev driver adds an additional state, (blank), where they
 *  turn off the video (maybe by colormap tricks), but don't mess with the
 *  video itself: think of it semantically between on and Stand-By.
 *
 *  So here's what we should do in our fbdev blank routine:
 *
 *  	VESA_NO_BLANKING (mode 0)	Video on,  front/back light on
 *  	VESA_VSYNC_SUSPEND (mode 1)  	Video on,  front/back light off
 *  	VESA_HSYNC_SUSPEND (mode 2)  	Video on,  front/back light off
 *  	VESA_POWERDOWN (mode 3)		Video off, front/back light off
 *
 *  This will match the matrox implementation.
 */
/*
 * sa1100fb_blank():
 *	Blank the display by setting all palette values to zero.  Note, the 
 * 	12 and 16 bpp modes don't really use the palette, so this will not
 *      blank the display in all modes.