/* * 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 - OPTIONAL. If your hardware lacks support * for a cursor, leave this field NULL. * * @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, /* Optional !!! */ .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");