/*
 *  linux/drivers/video/fbcmap.c -- Colormap handling for frame buffer devices
 *
 *      Created 15 Jun 1997 by Geert Uytterhoeven
 *
 *      2001 - Documented with DocBook
 *      - Brad Douglas <brad@neruo.com>
 *
 *  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/string.h>
#include <linux/module.h>
#include <linux/fb.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

static u16 red2[] __read_mostly = {
    0x0000, 0xaaaa
};
static u16 green2[] __read_mostly = {
    0x0000, 0xaaaa
};
static u16 blue2[] __read_mostly = {
    0x0000, 0xaaaa
};

static u16 red4[] __read_mostly = {
    0x0000, 0xaaaa, 0x5555, 0xffff
};
static u16 green4[] __read_mostly = {
    0x0000, 0xaaaa, 0x5555, 0xffff
};
static u16 blue4[] __read_mostly = {
    0x0000, 0xaaaa, 0x5555, 0xffff
};

static u16 red8[] __read_mostly = {
    0x0000, 0x0000, 0x0000, 0x0000, 0xaaaa, 0xaaaa, 0xaaaa, 0xaaaa
};
static u16 green8[] __read_mostly = {
    0x0000, 0x0000, 0xaaaa, 0xaaaa, 0x0000, 0x0000, 0x5555, 0xaaaa
};
static u16 blue8[] __read_mostly = {
    0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa
};

static u16 red16[] __read_mostly = {
    0x0000, 0x0000, 0x0000, 0x0000, 0xaaaa, 0xaaaa, 0xaaaa, 0xaaaa,
    0x5555, 0x5555, 0x5555, 0x5555, 0xffff, 0xffff, 0xffff, 0xffff
};
static u16 green16[] __read_mostly = {
    0x0000, 0x0000, 0xaaaa, 0xaaaa, 0x0000, 0x0000, 0x5555, 0xaaaa,
    0x5555, 0x5555, 0xffff, 0xffff, 0x5555, 0x5555, 0xffff, 0xffff
};
static u16 blue16[] __read_mostly = {
    0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa,
    0x5555, 0xffff, 0x5555, 0xffff, 0x5555, 0xffff, 0x5555, 0xffff
};

static const struct fb_cmap default_2_colors = {
    .len=2, .red=red2, .green=green2, .blue=blue2
};
static const struct fb_cmap default_8_colors = {
    .len=8, .red=red8, .green=green8, .blue=blue8
};
static const struct fb_cmap default_4_colors = {
    .len=4, .red=red4, .green=green4, .blue=blue4
};
static const struct fb_cmap default_16_colors = {
    .len=16, .red=red16, .green=green16, .blue=blue16
};



/**
 *      fb_alloc_cmap - allocate a colormap
 *      @cmap: frame buffer colormap structure
 *      @len: length of @cmap
 *      @transp: boolean, 1 if there is transparency, 0 otherwise
 *      @flags: flags for kmalloc memory allocation
 *
 *      Allocates memory for a colormap @cmap.  @len is the
 *      number of entries in the palette.
 *
 *      Returns negative errno on error, or zero on success.
 *
 */

int fb_alloc_cmap_gfp(struct fb_cmap *cmap, int len, int transp, gfp_t flags)
{
        int size = len * sizeof(u16);
        int ret = -ENOMEM;

        flags |= __GFP_NOWARN;

        if (cmap->len != len) {
                fb_dealloc_cmap(cmap);
                if (!len)
                        return 0;

                cmap->red = kmalloc(size, flags);
                if (!cmap->red)
                        goto fail;
                cmap->green = kmalloc(size, flags);
                if (!cmap->green)
                        goto fail;
                cmap->blue = kmalloc(size, flags);
                if (!cmap->blue)
                        goto fail;
                if (transp) {
                        cmap->transp = kmalloc(size, flags);
                        if (!cmap->transp)
                                goto fail;
                } else {
                        cmap->transp = NULL;
                }
        }
        cmap->start = 0;
        cmap->len = len;
        ret = fb_copy_cmap(fb_default_cmap(len), cmap);
        if (ret)
                goto fail;
        return 0;

fail:
        fb_dealloc_cmap(cmap);
        return ret;
}

int fb_alloc_cmap(struct fb_cmap *cmap, int len, int transp)
{
        return fb_alloc_cmap_gfp(cmap, len, transp, GFP_ATOMIC);
}

/**
 *      fb_dealloc_cmap - deallocate a colormap
 *      @cmap: frame buffer colormap structure
 *
 *      Deallocates a colormap that was previously allocated with
 *      fb_alloc_cmap().
 *
 */

void fb_dealloc_cmap(struct fb_cmap *cmap)
{
        kfree(cmap->red);
        kfree(cmap->green);
        kfree(cmap->blue);
        kfree(cmap->transp);

        cmap->red = cmap->green = cmap->blue = cmap->transp = NULL;
        cmap->len = 0;
}

/**
 *      fb_copy_cmap - copy a colormap
 *      @from: frame buffer colormap structure
 *      @to: frame buffer colormap structure
 *
 *      Copy contents of colormap from @from to @to.
 */

int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to)
{
        unsigned int tooff = 0, fromoff = 0;
        size_t size;

        if (to->start > from->start)
                fromoff = to->start - from->start;
        else
                tooff = from->start - to->start;
        if (fromoff >= from->len || tooff >= to->len)
                return -EINVAL;

        size = min_t(size_t, to->len - tooff, from->len - fromoff);
        if (size == 0)
                return -EINVAL;
        size *= sizeof(u16);

        memcpy(to->red+tooff, from->red+fromoff, size);
        memcpy(to->green+tooff, from->green+fromoff, size);
        memcpy(to->blue+tooff, from->blue+fromoff, size);
        if (from->transp && to->transp)
                memcpy(to->transp+tooff, from->transp+fromoff, size);
        return 0;
}

int fb_cmap_to_user(const struct fb_cmap *from, struct fb_cmap_user *to)
{
        unsigned int tooff = 0, fromoff = 0;
        size_t size;

        if (to->start > from->start)
                fromoff = to->start - from->start;
        else
                tooff = from->start - to->start;
        if (fromoff >= from->len || tooff >= to->len)
                return -EINVAL;

        size = min_t(size_t, to->len - tooff, from->len - fromoff);
        if (size == 0)
                return -EINVAL;
        size *= sizeof(u16);

        if (copy_to_user(to->red+tooff, from->red+fromoff, size))
                return -EFAULT;
        if (copy_to_user(to->green+tooff, from->green+fromoff, size))
                return -EFAULT;
        if (copy_to_user(to->blue+tooff, from->blue+fromoff, size))
                return -EFAULT;
        if (from->transp && to->transp)
                if (copy_to_user(to->transp+tooff, from->transp+fromoff, size))
                        return -EFAULT;
        return 0;
}

/**
 *      fb_set_cmap - set the colormap
 *      @cmap: frame buffer colormap structure
 *      @info: frame buffer info structure
 *
 *      Sets the colormap @cmap for a screen of device @info.
 *
 *      Returns negative errno on error, or zero on success.
 *
 */

int fb_set_cmap(struct fb_cmap *cmap, struct fb_info *info)
{
        int i, start, rc = 0;
        u16 *red, *green, *blue, *transp;
        u_int hred, hgreen, hblue, htransp = 0xffff;

        red = cmap->red;
        green = cmap->green;
        blue = cmap->blue;
        transp = cmap->transp;
        start = cmap->start;

        if (start < 0 || (!info->fbops->fb_setcolreg &&
                          !info->fbops->fb_setcmap))
                return -EINVAL;
        if (info->fbops->fb_setcmap) {
                rc = info->fbops->fb_setcmap(cmap, info);
        } else {
                for (i = 0; i < cmap->len; i++) {
                        hred = *red++;
                        hgreen = *green++;
                        hblue = *blue++;
                        if (transp)
                                htransp = *transp++;
                        if (info->fbops->fb_setcolreg(start++,
                                                      hred, hgreen, hblue,
                                                      htransp, info))
                                break;
                }
        }
        if (rc == 0)
                fb_copy_cmap(cmap, &info->cmap);

        return rc;
}

int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
{
        int rc, size = cmap->len * sizeof(u16);
        struct fb_cmap umap;

        if (size < 0 || size < cmap->len)
                return -E2BIG;

        memset(&umap, 0, sizeof(struct fb_cmap));
        rc = fb_alloc_cmap_gfp(&umap, cmap->len, cmap->transp != NULL,
                                GFP_KERNEL);
        if (rc)
                return rc;
        if (copy_from_user(umap.red, cmap->red, size) ||
            copy_from_user(umap.green, cmap->green, size) ||
            copy_from_user(umap.blue, cmap->blue, size) ||
            (cmap->transp && copy_from_user(umap.transp, cmap->transp, size))) {
                rc = -EFAULT;
                goto out;
        }
        umap.start = cmap->start;
        lock_fb_info(info);
        rc = fb_set_cmap(&umap, info);
        unlock_fb_info(info);
out:
        fb_dealloc_cmap(&umap);
        return rc;
}

/**
 *      fb_default_cmap - get default colormap
 *      @len: size of palette for a depth
 *
 *      Gets the default colormap for a specific screen depth.  @len
 *      is the size of the palette for a particular screen depth.
 *
 *      Returns pointer to a frame buffer colormap structure.
 *
 */

const struct fb_cmap *fb_default_cmap(int len)
{
    if (len <= 2)
        return &default_2_colors;
    if (len <= 4)
        return &default_4_colors;
    if (len <= 8)
        return &default_8_colors;
    return &default_16_colors;
}


/**
 *      fb_invert_cmaps - invert all defaults colormaps
 *
 *      Invert all default colormaps.
 *
 */

void fb_invert_cmaps(void)
{
    u_int i;

    for (i = 0; i < ARRAY_SIZE(red2); i++) {
        red2[i] = ~red2[i];
        green2[i] = ~green2[i];
        blue2[i] = ~blue2[i];
    }
    for (i = 0; i < ARRAY_SIZE(red4); i++) {
        red4[i] = ~red4[i];
        green4[i] = ~green4[i];
        blue4[i] = ~blue4[i];
    }
    for (i = 0; i < ARRAY_SIZE(red8); i++) {
        red8[i] = ~red8[i];
        green8[i] = ~green8[i];
        blue8[i] = ~blue8[i];
    }
    for (i = 0; i < ARRAY_SIZE(red16); i++) {
        red16[i] = ~red16[i];
        green16[i] = ~green16[i];
        blue16[i] = ~blue16[i];
    }
}


    /*
     *  Visible symbols for modules
     */

EXPORT_SYMBOL(fb_alloc_cmap);
EXPORT_SYMBOL(fb_dealloc_cmap);
EXPORT_SYMBOL(fb_copy_cmap);
EXPORT_SYMBOL(fb_set_cmap);
EXPORT_SYMBOL(fb_default_cmap);
EXPORT_SYMBOL(fb_invert_cmaps);