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WSL2-Linux-Kernel/drivers/video/skeletonfb.c

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/*
* linux/drivers/video/skeletonfb.c -- Skeleton for a frame buffer device
*
* Modified to new api Jan 2001 by James Simmons (jsimmons@transvirtual.com)
*
* Created 28 Dec 1997 by Geert Uytterhoeven
*
*
* I have started rewriting this driver as a example of the upcoming new API
* The primary goal is to remove the console code from fbdev and place it
* into fbcon.c. This reduces the code and makes writing a new fbdev driver
* easy since the author doesn't need to worry about console internals. It
* also allows the ability to run fbdev without a console/tty system on top
* of it.
*
* First the roles of struct fb_info and struct display have changed. Struct
* display will go away. The way the the new framebuffer console code will
* work is that it will act to translate data about the tty/console in
* struct vc_data to data in a device independent way in struct fb_info. Then
* various functions in struct fb_ops will be called to store the device
* dependent state in the par field in struct fb_info and to change the
* hardware to that state. This allows a very clean separation of the fbdev
* layer from the console layer. It also allows one to use fbdev on its own
* which is a bounus for embedded devices. The reason this approach works is
* for each framebuffer device when used as a tty/console device is allocated
* a set of virtual terminals to it. Only one virtual terminal can be active
* per framebuffer device. We already have all the data we need in struct
* vc_data so why store a bunch of colormaps and other fbdev specific data
* per virtual terminal.
*
* As you can see doing this makes the con parameter pretty much useless
* for struct fb_ops functions, as it should be. Also having struct
* fb_var_screeninfo and other data in fb_info pretty much eliminates the
* need for get_fix and get_var. Once all drivers use the fix, var, and cmap
* fbcon can be written around these fields. This will also eliminate the
* need to regenerate struct fb_var_screeninfo, struct fb_fix_screeninfo
* struct fb_cmap every time get_var, get_fix, get_cmap functions are called
* as many drivers do now.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
/*
* This is just simple sample code.
*
* No warranty that it actually compiles.
* Even less warranty that it actually works :-)
*/
/*
* If your driver supports multiple boards, you should make the
* below data types arrays, or allocate them dynamically (using kmalloc()).
*/
/*
* This structure defines the hardware state of the graphics card. Normally
* you place this in a header file in linux/include/video. This file usually
* also includes register information. That allows other driver subsystems
* and userland applications the ability to use the same header file to
* avoid duplicate work and easy porting of software.
*/
struct xxx_par;
/*
* Here we define the default structs fb_fix_screeninfo and fb_var_screeninfo
* if we don't use modedb. If we do use modedb see xxxfb_init how to use it
* to get a fb_var_screeninfo. Otherwise define a default var as well.
*/
static struct fb_fix_screeninfo xxxfb_fix __initdata = {
.id = "FB's name",
.type = FB_TYPE_PACKED_PIXELS,
.visual = FB_VISUAL_PSEUDOCOLOR,
.xpanstep = 1,
.ypanstep = 1,
.ywrapstep = 1,
.accel = FB_ACCEL_NONE,
};
/*
* Modern graphical hardware not only supports pipelines but some
* also support multiple monitors where each display can have its
* its own unique data. In this case each display could be
* represented by a separate framebuffer device thus a separate
* struct fb_info. Now the struct xxx_par represents the graphics
* hardware state thus only one exist per card. In this case the
* struct xxx_par for each graphics card would be shared between
* every struct fb_info that represents a framebuffer on that card.
* This allows when one display changes it video resolution (info->var)
* the other displays know instantly. Each display can always be
* aware of the entire hardware state that affects it because they share
* the same xxx_par struct. The other side of the coin is multiple
* graphics cards that pass data around until it is finally displayed
* on one monitor. Such examples are the voodoo 1 cards and high end
* NUMA graphics servers. For this case we have a bunch of pars, each
* one that represents a graphics state, that belong to one struct
* fb_info. Their you would want to have *par point to a array of device
* states and have each struct fb_ops function deal with all those
* states. I hope this covers every possible hardware design. If not
* feel free to send your ideas at jsimmons@users.sf.net
*/
/*
* If your driver supports multiple boards or it supports multiple
* framebuffers, you should make these arrays, or allocate them
* dynamically (using kmalloc()).
*/
static struct fb_info info;
/*
* Each one represents the state of the hardware. Most hardware have
* just one hardware state. These here represent the default state(s).
*/
static struct xxx_par __initdata current_par;
int xxxfb_init(void);
int xxxfb_setup(char*);
/**
* xxxfb_open - Optional function. Called when the framebuffer is
* first accessed.
* @info: frame buffer structure that represents a single frame buffer
* @user: tell us if the userland (value=1) or the console is accessing
* the framebuffer.
*
* This function is the first function called in the framebuffer api.
* Usually you don't need to provide this function. The case where it
* is used is to change from a text mode hardware state to a graphics
* mode state.
*
* Returns negative errno on error, or zero on success.
*/
static int xxxfb_open(const struct fb_info *info, int user)
{
return 0;
}
/**
* xxxfb_release - Optional function. Called when the framebuffer
* device is closed.
* @info: frame buffer structure that represents a single frame buffer
* @user: tell us if the userland (value=1) or the console is accessing
* the framebuffer.
*
* Thus function is called when we close /dev/fb or the framebuffer
* console system is released. Usually you don't need this function.
* The case where it is usually used is to go from a graphics state
* to a text mode state.
*
* Returns negative errno on error, or zero on success.
*/
static int xxxfb_release(const struct fb_info *info, int user)
{
return 0;
}
/**
* xxxfb_check_var - Optional function. Validates a var passed in.
* @var: frame buffer variable screen structure
* @info: frame buffer structure that represents a single frame buffer
*
* Checks to see if the hardware supports the state requested by
* var passed in. This function does not alter the hardware state!!!
* This means the data stored in struct fb_info and struct xxx_par do
* not change. This includes the var inside of struct fb_info.
* Do NOT change these. This function can be called on its own if we
* intent to only test a mode and not actually set it. The stuff in
* modedb.c is a example of this. If the var passed in is slightly
* off by what the hardware can support then we alter the var PASSED in
* to what we can do. If the hardware doesn't support mode change
* a -EINVAL will be returned by the upper layers. You don't need to
* implement this function then. If you hardware doesn't support
* changing the resolution then this function is not needed. In this
* case the driver woudl just provide a var that represents the static
* state the screen is in.
*
* Returns negative errno on error, or zero on success.
*/
static int xxxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
const struct xxx_par *par = (const struct xxx_par *) info->par;
/* ... */
return 0;
}
/**
* xxxfb_set_par - Optional function. Alters the hardware state.
* @info: frame buffer structure that represents a single frame buffer
*
* Using the fb_var_screeninfo in fb_info we set the resolution of the
* this particular framebuffer. This function alters the par AND the
* fb_fix_screeninfo stored in fb_info. It doesn't not alter var in
* fb_info since we are using that data. This means we depend on the
* data in var inside fb_info to be supported by the hardware.
* xxxfb_check_var is always called before xxxfb_set_par to ensure this.
* Again if you can't change the resolution you don't need this function.
*
* Returns negative errno on error, or zero on success.
*/
static int xxxfb_set_par(struct fb_info *info)
{
struct xxx_par *par = (struct xxx_par *) info->par;
/* ... */
return 0;
}
/**
* xxxfb_setcolreg - Optional function. Sets a color register.
* @regno: Which register in the CLUT we are programming
* @red: The red value which can be up to 16 bits wide
* @green: The green value which can be up to 16 bits wide
* @blue: The blue value which can be up to 16 bits wide.
* @transp: If supported, the alpha value which can be up to 16 bits wide.
* @info: frame buffer info structure
*
* Set a single color register. The values supplied have a 16 bit
* magnitude which needs to be scaled in this function for the hardware.
* Things to take into consideration are how many color registers, if
* any, are supported with the current color visual. With truecolor mode
* no color palettes are supported. Here a pseudo palette is created
* which we store the value in pseudo_palette in struct fb_info. For
* pseudocolor mode we have a limited color palette. To deal with this
* we can program what color is displayed for a particular pixel value.
* DirectColor is similar in that we can program each color field. If
* we have a static colormap we don't need to implement this function.
*
* Returns negative errno on error, or zero on success.
*/
static int xxxfb_setcolreg(unsigned regno, unsigned red, unsigned green,
unsigned blue, unsigned transp,
const struct fb_info *info)
{
if (regno >= 256) /* no. of hw registers */
return -EINVAL;
/*
* Program hardware... do anything you want with transp
*/
/* grayscale works only partially under directcolor */
if (info->var.grayscale) {
/* grayscale = 0.30*R + 0.59*G + 0.11*B */
red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8;
}
/* Directcolor:
* var->{color}.offset contains start of bitfield
* var->{color}.length contains length of bitfield
* {hardwarespecific} contains width of DAC
* cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
* RAMDAC[X] is programmed to (red, green, blue)
*
* Pseudocolor:
* uses offset = 0 && length = DAC register width.
* var->{color}.offset is 0
* var->{color}.length contains widht of DAC
* cmap is not used
* DAC[X] is programmed to (red, green, blue)
* Truecolor:
* does not use RAMDAC (usually has 3 of them).
* var->{color}.offset contains start of bitfield
* var->{color}.length contains length of bitfield
* cmap is programmed to (red << red.offset) | (green << green.offset) |
* (blue << blue.offset) | (transp << transp.offset)
* RAMDAC does not exist
*/
#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
switch (info->fix.visual) {
case FB_VISUAL_TRUECOLOR:
case FB_VISUAL_PSEUDOCOLOR:
red = CNVT_TOHW(red, info->var.red.length);
green = CNVT_TOHW(green, info->var.green.length);
blue = CNVT_TOHW(blue, info->var.blue.length);
transp = CNVT_TOHW(transp, info->var.transp.length);
break;
case FB_VISUAL_DIRECTCOLOR:
/* example here assumes 8 bit DAC. Might be different
* for your hardware */
red = CNVT_TOHW(red, 8);
green = CNVT_TOHW(green, 8);
blue = CNVT_TOHW(blue, 8);
/* hey, there is bug in transp handling... */
transp = CNVT_TOHW(transp, 8);
break;
}
#undef CNVT_TOHW
/* Truecolor has hardware independent palette */
if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
u32 v;
if (regno >= 16)
return -EINVAL;
v = (red << info->var.red.offset) |
(green << info->var.green.offset) |
(blue << info->var.blue.offset) |
(transp << info->var.transp.offset);
switch (info->var.bits_per_pixel) {
case 8:
/* Yes some hand held devices have this. */
((u8*)(info->pseudo_palette))[regno] = v;
break;
case 16:
((u16*)(info->pseudo_palette))[regno] = v;
break;
case 24:
case 32:
((u32*)(info->pseudo_palette))[regno] = v;
break;
}
return 0;
}
/* ... */
return 0;
}
/**
* 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.
*
* NOTES ON FLAGS (cursor->set):
*
* FB_CUR_SETIMAGE - the cursor image has changed (cursor->image.data)
* FB_CUR_SETPOS - the cursor position has changed (cursor->image.dx|dy)
* FB_CUR_SETHOT - the cursor hot spot has changed (cursor->hot.dx|dy)
* FB_CUR_SETCMAP - the cursor colors has changed (cursor->fg_color|bg_color)
* FB_CUR_SETSHAPE - the cursor bitmask has changed (cursor->mask)
* FB_CUR_SETSIZE - the cursor size has changed (cursor->width|height)
* FB_CUR_SETALL - everything has changed
*
* NOTES ON ROPs (cursor->rop, Raster Operation)
*
* ROP_XOR - cursor->image.data XOR cursor->mask
* ROP_COPY - curosr->image.data AND cursor->mask
*
* OTHER NOTES:
*
* - fbcon only supports a 2-color cursor (cursor->image.depth = 1)
* - The fb_cursor structure, @cursor, _will_ always contain valid
* fields, whether any particular bitfields in cursor->set is set
* or not.
*/
}
/**
* 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;
/*
* For kernel boot options (in 'video=xxxfb:<options>' format)
*/
#ifndef MODULE
char *option = NULL;
if (fb_get_options("xxxfb", &option))
return -ENODEV;
xxxfb_setup(option);
#endif
/*
* Here we set the screen_base to the virtual 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);
fb_dealloc_cmap(&info.cmap);
/* ... */
}
/*
* 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
*/
module_init(xxxfb_init);
module_exit(xxxfb_cleanup);
MODULE_LICENSE("GPL");
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