skeletonfb.c

《linux驱动程序设计从入门到精通》一书中所有的程序代码含驱动和相应的应用程序

 *      xxxfb_pan_display - NOT a required function. Pans the display.
 *      @var: frame buffer variable screen structure
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *	Pan (or wrap, depending on the `vmode' field) the display using the
 *  	`xoffset' and `yoffset' fields of the `var' structure.
 *  	If the values don't fit, return -EINVAL.
 *
 *      Returns negative errno on error, or zero on success.
 */
static int xxxfb_pan_display(struct fb_var_screeninfo *var,
			     const struct fb_info *info)
{
    /* ... */
    return 0;
}

/**
 *      xxxfb_blank - NOT a required function. Blanks the display.
 *      @blank_mode: the blank mode we want. 
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *      Blank the screen if blank_mode != 0, else unblank. Return 0 if
 *      blanking succeeded, != 0 if un-/blanking failed due to e.g. a 
 *      video mode which doesn't support it. Implements VESA suspend
 *      and powerdown modes on hardware that supports disabling hsync/vsync:
 *      blank_mode == 2: suspend vsync
 *      blank_mode == 3: suspend hsync
 *      blank_mode == 4: powerdown
 *
 *      Returns negative errno on error, or zero on success.
 *
 */
static int xxxfb_blank(int blank_mode, const struct fb_info *info)
{
    /* ... */
    return 0;
}

/* ------------ Accelerated Functions --------------------- */

/*
 * We provide our own functions if we have hardware acceleration
 * or non packed pixel format layouts. If we have no hardware 
 * acceleration, we can use a generic unaccelerated function. If using
 * a pack pixel format just use the functions in cfb_*.c. Each file 
 * has one of the three different accel functions we support.
 */

/**
 *      xxxfb_fillrect - REQUIRED function. Can use generic routines if 
 *		 	 non acclerated hardware and packed pixel based.
 *			 Draws a rectangle on the screen.		
 *
 *      @info: frame buffer structure that represents a single frame buffer
 *	@region: The structure representing the rectangular region we 
 *		 wish to draw to.
 *
 *	This drawing operation places/removes a retangle on the screen 
 *	depending on the rastering operation with the value of color which
 *	is in the current color depth format.
 */
void xxfb_fillrect(struct fb_info *p, const struct fb_fillrect *region)
{
/*	Meaning of struct fb_fillrect
 *
 *	@dx: The x and y corrdinates of the upper left hand corner of the 
 *	@dy: area we want to draw to. 
 *	@width: How wide the rectangle is we want to draw.
 *	@height: How tall the rectangle is we want to draw.
 *	@color:	The color to fill in the rectangle with. 
 *	@rop: The raster operation. We can draw the rectangle with a COPY
 *	      of XOR which provides erasing effect. 
 */
}

/**
 *      xxxfb_copyarea - REQUIRED function. Can use generic routines if
 *                       non acclerated hardware and packed pixel based.
 *                       Copies one area of the screen to another area.
 *
 *      @info: frame buffer structure that represents a single frame buffer
 *      @area: Structure providing the data to copy the framebuffer contents
 *	       from one region to another.
 *
 *      This drawing operation copies a rectangular area from one area of the
 *	screen to another area.
 */
void xxxfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) 
{
/*
 *      @dx: The x and y coordinates of the upper left hand corner of the
 *	@dy: destination area on the screen.
 *      @width: How wide the rectangle is we want to copy.
 *      @height: How tall the rectangle is we want to copy.
 *      @sx: The x and y coordinates of the upper left hand corner of the
 *      @sy: source area on the screen.
 */
}


/**
 *      xxxfb_imageblit - REQUIRED function. Can use generic routines if
 *                        non acclerated hardware and packed pixel based.
 *                        Copies a image from system memory to the screen. 
 *
 *      @info: frame buffer structure that represents a single frame buffer
 *	@image:	structure defining the image.
 *
 *      This drawing operation draws a image on the screen. It can be a 
 *	mono image (needed for font handling) or a color image (needed for
 *	tux). 
 */
void xxxfb_imageblit(struct fb_info *p, const struct fb_image *image) 
{
/*
 *      @dx: The x and y coordinates of the upper left hand corner of the
 *	@dy: destination area to place the image on the screen.
 *      @width: How wide the image is we want to copy.
 *      @height: How tall the image is we want to copy.
 *      @fg_color: For mono bitmap images this is color data for     
 *      @bg_color: the foreground and background of the image to
 *		   write directly to the frmaebuffer.
 *	@depth:	How many bits represent a single pixel for this image.
 *	@data: The actual data used to construct the image on the display.
 *	@cmap: The colormap used for color images.   
 */
}

/**
 *	xxxfb_cursor - 	REQUIRED function. If your hardware lacks support
 *			for a cursor you can use the default cursor whose
 *			function is called soft_cursor. It will always 
 *			work since it uses xxxfb_imageblit function which 
 *			is required. 	  	 
 *
 *      @info: frame buffer structure that represents a single frame buffer
 *	@cursor: structure defining the cursor to draw.
 *
 *      This operation is used to set or alter the properities of the
 *	cursor.
 *
 *	Returns negative errno on error, or zero on success.
 */
int xxxfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
/*
 *      @set: 	Which fields we are altering in struct fb_cursor 
 *	@enable: Disable or enable the cursor 
 *      @rop: 	The bit operation we want to do. 
 *      @mask:  This is the cursor mask bitmap. 
 *      @dest:  A image of the area we are going to display the cursor.
 *		Used internally by the driver.	 
 *      @hot:	The hot spot. 
 *	@image:	The actual data for the cursor image.
 */
}

/**
 *	xxxfb_rotate -  NOT a required function. If your hardware
 *			supports rotation the whole screen then 
 *			you would provide a hook for this. 
 *
 *      @info: frame buffer structure that represents a single frame buffer
 *	@angle: The angle we rotate the screen.   
 *
 *      This operation is used to set or alter the properities of the
 *	cursor.
 */
void xxxfb_rotate(struct fb_info *info, int angle)
{
}

/**
 *	xxxfb_poll - NOT a required function. The purpose of this
 *		     function is to provide a way for some process
 *		     to wait until a specific hardware event occurs
 *		     for the framebuffer device.
 * 				 
 *      @info: frame buffer structure that represents a single frame buffer
 *	@wait: poll table where we store process that await a event.     
 */
void xxxfb_poll(struct fb_info *info, poll_table *wait)
{
}

/**
 *	xxxfb_sync - NOT a required function. Normally the accel engine 
 *		     for a graphics card take a specific amount of time.
 *		     Often we have to wait for the accelerator to finish
 *		     its operation before we can write to the framebuffer
 *		     so we can have consistent display output. 
 *
 *      @info: frame buffer structure that represents a single frame buffer
 */
void xxxfb_sync(struct fb_info *info)
{
}

    /*
     *  Initialization
     */

int __init xxxfb_init(void)
{
    int cmap_len, retval;	
   
    /* 
     * Here we set the screen_base to the vitrual memory address
     * for the framebuffer. Usually we obtain the resource address
     * from the bus layer and then translate it to virtual memory
     * space via ioremap. Consult ioport.h. 
     */
    info.screen_base = framebuffer_virtual_memory;	
    info.fbops = &xxxfb_ops;
    info.fix = xxxfb_fix;
    info.pseudo_palette = pseudo_palette;

    /*
     * Set up flags to indicate what sort of acceleration your
     * driver can provide (pan/wrap/copyarea/etc.) and whether it
     * is a module -- see FBINFO_* in include/linux/fb.h
     */
    info.flags = FBINFO_DEFAULT;
    info.par = current_par;

    /*
     * This should give a reasonable default video mode. The following is
     * done when we can set a video mode. 
     */
    if (!mode_option)
	mode_option = "640x480@60";	 	

    retval = fb_find_mode(&info.var, &info, mode_option, NULL, 0, NULL, 8);
  
    if (!retval || retval == 4)
	return -EINVAL;			

    /* This has to been done !!! */	
    fb_alloc_cmap(&info.cmap, cmap_len, 0);
	
    /* 
     * The following is done in the case of having hardware with a static 
     * mode. If we are setting the mode ourselves we don't call this. 
     */	
    info.var = xxxfb_var;
	
    if (register_framebuffer(&info) < 0)
	return -EINVAL;
    printk(KERN_INFO "fb%d: %s frame buffer device\n", info.node,
	   info.fix.id);
    return 0;
}

    /*
     *  Cleanup
     */

static void __exit xxxfb_cleanup(void)
{
    /*
     *  If your driver supports multiple boards, you should unregister and
     *  clean up all instances.
     */

    unregister_framebuffer(info);
    /* ... */
}

    /*
     *  Setup
     */

/* 
 * Only necessary if your driver takes special options,
 * otherwise we fall back on the generic fb_setup().
 */
int __init xxxfb_setup(char *options)
{
    /* Parse user speficied options (`video=xxxfb:') */
}

/* ------------------------------------------------------------------------- */

    /*
     *  Frame buffer operations
     */

static struct fb_ops xxxfb_ops = {
	.owner		= THIS_MODULE,
	.fb_open	= xxxfb_open,
	.fb_read	= xxxfb_read,
	.fb_write	= xxxfb_write,
	.fb_release	= xxxfb_release,
	.fb_check_var	= xxxfb_check_var,
	.fb_set_par	= xxxfb_set_par,	
	.fb_setcolreg	= xxxfb_setcolreg,
	.fb_blank	= xxxfb_blank,
	.fb_pan_display	= xxxfb_pan_display,	
	.fb_fillrect	= xxxfb_fillrect, 	/* Needed !!! */ 
	.fb_copyarea	= xxxfb_copyarea,	/* Needed !!! */ 
	.fb_imageblit	= xxxfb_imageblit,	/* Needed !!! */
	.fb_cursor	= xxxfb_cursor,		/* Needed !!! */
	.fb_rotate	= xxxfb_rotate,
	.fb_poll	= xxxfb_poll,
	.fb_sync	= xxxfb_sync,
	.fb_ioctl	= xxxfb_ioctl,
	.fb_mmap	= xxxfb_mmap,	
};

/* ------------------------------------------------------------------------- */


    /*
     *  Modularization
     */

#ifdef MODULE
module_init(xxxfb_init);
#endif 
module_exit(xxxfb_cleanup);

MODULE_LICENSE("GPL");