fbmem.c

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/*
 *  linux/drivers/video/fbmem.c
 *
 *  Copyright (C) 1994 Martin Schaller
 *
 *  2001 - Documented with DocBook
 *  - Brad Douglas <[email protected]>
 *
 * 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/compat.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/vt.h>
#include <linux/init.h>
#include <linux/linux_logo.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/console.h>
#include <linux/kmod.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/efi.h>
#include <linux/fb.h>

#include <asm/fb.h>


    /*
     *  Frame buffer device initialization and setup routines
     */

#define FBPIXMAPSIZE    (1024 * 8)

static DEFINE_MUTEX(registration_lock);
struct fb_info *registered_fb[FB_MAX] __read_mostly;
int num_registered_fb __read_mostly;

static struct fb_info *get_fb_info(unsigned int idx)
{
    struct fb_info *fb_info;

    if (idx >= FB_MAX)
        return ERR_PTR(-ENODEV);

    mutex_lock(&registration_lock);
    fb_info = registered_fb[idx];
    if (fb_info)
        atomic_inc(&fb_info->count);
    mutex_unlock(&registration_lock);

    return fb_info;
}

static void put_fb_info(struct fb_info *fb_info)
{
    if (!atomic_dec_and_test(&fb_info->count))
        return;
    if (fb_info->fbops->fb_destroy)
        fb_info->fbops->fb_destroy(fb_info);
}

int lock_fb_info(struct fb_info *info)
{
    mutex_lock(&info->lock);
    if (!info->fbops) {
        mutex_unlock(&info->lock);
        return 0;
    }
    return 1;
}
EXPORT_SYMBOL(lock_fb_info);

/*
 * Helpers
 */

int fb_get_color_depth(struct fb_var_screeninfo *var,
               struct fb_fix_screeninfo *fix)
{
    int depth = 0;

    if (fix->visual == FB_VISUAL_MONO01 ||
        fix->visual == FB_VISUAL_MONO10)
        depth = 1;
    else {
        if (var->green.length == var->blue.length &&
            var->green.length == var->red.length &&
            var->green.offset == var->blue.offset &&
            var->green.offset == var->red.offset)
            depth = var->green.length;
        else
            depth = var->green.length + var->red.length +
                var->blue.length;
    }

    return depth;
}
EXPORT_SYMBOL(fb_get_color_depth);

/*
 * Data padding functions.
 */
void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u32 height)
{
    __fb_pad_aligned_buffer(dst, d_pitch, src, s_pitch, height);
}
EXPORT_SYMBOL(fb_pad_aligned_buffer);

void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx, u32 height,
                u32 shift_high, u32 shift_low, u32 mod)
{
    u8 mask = (u8) (0xfff << shift_high), tmp;
    int i, j;

    for (i = height; i--; ) {
        for (j = 0; j < idx; j++) {
            tmp = dst[j];
            tmp &= mask;
            tmp |= *src >> shift_low;
            dst[j] = tmp;
            tmp = *src << shift_high;
            dst[j+1] = tmp;
            src++;
        }
        tmp = dst[idx];
        tmp &= mask;
        tmp |= *src >> shift_low;
        dst[idx] = tmp;
        if (shift_high < mod) {
            tmp = *src << shift_high;
            dst[idx+1] = tmp;
        }
        src++;
        dst += d_pitch;
    }
}
EXPORT_SYMBOL(fb_pad_unaligned_buffer);

/*
 * we need to lock this section since fb_cursor
 * may use fb_imageblit()
 */
char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size)
{
    u32 align = buf->buf_align - 1, offset;
    char *addr = buf->addr;

    /* If IO mapped, we need to sync before access, no sharing of
     * the pixmap is done
     */
    if (buf->flags & FB_PIXMAP_IO) {
        if (info->fbops->fb_sync && (buf->flags & FB_PIXMAP_SYNC))
            info->fbops->fb_sync(info);
        return addr;
    }

    /* See if we fit in the remaining pixmap space */
    offset = buf->offset + align;
    offset &= ~align;
    if (offset + size > buf->size) {
        /* We do not fit. In order to be able to re-use the buffer,
         * we must ensure no asynchronous DMA'ing or whatever operation
         * is in progress, we sync for that.
         */
        if (info->fbops->fb_sync && (buf->flags & FB_PIXMAP_SYNC))
            info->fbops->fb_sync(info);
        offset = 0;
    }
    buf->offset = offset + size;
    addr += offset;

    return addr;
}

#ifdef CONFIG_LOGO

static inline unsigned safe_shift(unsigned d, int n)
{
    return n < 0 ? d >> -n : d << n;
}

static void fb_set_logocmap(struct fb_info *info,
                   const struct linux_logo *logo)
{
    struct fb_cmap palette_cmap;
    u16 palette_green[16];
    u16 palette_blue[16];
    u16 palette_red[16];
    int i, j, n;
    const unsigned char *clut = logo->clut;

    palette_cmap.start = 0;
    palette_cmap.len = 16;
    palette_cmap.red = palette_red;
    palette_cmap.green = palette_green;
    palette_cmap.blue = palette_blue;
    palette_cmap.transp = NULL;

    for (i = 0; i < logo->clutsize; i += n) {
        n = logo->clutsize - i;
        /* palette_cmap provides space for only 16 colors at once */
        if (n > 16)
            n = 16;
        palette_cmap.start = 32 + i;
        palette_cmap.len = n;
        for (j = 0; j < n; ++j) {
            palette_cmap.red[j] = clut[0] << 8 | clut[0];
            palette_cmap.green[j] = clut[1] << 8 | clut[1];
            palette_cmap.blue[j] = clut[2] << 8 | clut[2];
            clut += 3;
        }
        fb_set_cmap(&palette_cmap, info);
    }
}

static void  fb_set_logo_truepalette(struct fb_info *info,
                        const struct linux_logo *logo,
                        u32 *palette)
{
    static const unsigned char mask[] = { 0,0x80,0xc0,0xe0,0xf0,0xf8,0xfc,0xfe,0xff };
    unsigned char redmask, greenmask, bluemask;
    int redshift, greenshift, blueshift;
    int i;
    const unsigned char *clut = logo->clut;

    /*
     * We have to create a temporary palette since console palette is only
     * 16 colors long.
     */
    /* Bug: Doesn't obey msb_right ... (who needs that?) */
    redmask   = mask[info->var.red.length   < 8 ? info->var.red.length   : 8];
    greenmask = mask[info->var.green.length < 8 ? info->var.green.length : 8];
    bluemask  = mask[info->var.blue.length  < 8 ? info->var.blue.length  : 8];
    redshift   = info->var.red.offset   - (8 - info->var.red.length);
    greenshift = info->var.green.offset - (8 - info->var.green.length);
    blueshift  = info->var.blue.offset  - (8 - info->var.blue.length);

    for ( i = 0; i < logo->clutsize; i++) {
        palette[i+32] = (safe_shift((clut[0] & redmask), redshift) |
                 safe_shift((clut[1] & greenmask), greenshift) |
                 safe_shift((clut[2] & bluemask), blueshift));
        clut += 3;
    }
}

static void fb_set_logo_directpalette(struct fb_info *info,
                         const struct linux_logo *logo,
                         u32 *palette)
{
    int redshift, greenshift, blueshift;
    int i;

    redshift = info->var.red.offset;
    greenshift = info->var.green.offset;
    blueshift = info->var.blue.offset;

    for (i = 32; i < 32 + logo->clutsize; i++)
        palette[i] = i << redshift | i << greenshift | i << blueshift;
}

static void fb_set_logo(struct fb_info *info,
                   const struct linux_logo *logo, u8 *dst,
                   int depth)
{
    int i, j, k;
    const u8 *src = logo->data;
    u8 xor = (info->fix.visual == FB_VISUAL_MONO01) ? 0xff : 0;
    u8 fg = 1, d;

    switch (fb_get_color_depth(&info->var, &info->fix)) {
    case 1:
        fg = 1;
        break;
    case 2:
        fg = 3;
        break;
    default:
        fg = 7;
        break;
    }

    if (info->fix.visual == FB_VISUAL_MONO01 ||
        info->fix.visual == FB_VISUAL_MONO10)
        fg = ~((u8) (0xfff << info->var.green.length));

    switch (depth) {
    case 4:
        for (i = 0; i < logo->height; i++)
            for (j = 0; j < logo->width; src++) {
                *dst++ = *src >> 4;
                j++;
                if (j < logo->width) {
                    *dst++ = *src & 0x0f;
                    j++;
                }
            }
        break;
    case 1:
        for (i = 0; i < logo->height; i++) {
            for (j = 0; j < logo->width; src++) {
                d = *src ^ xor;
                for (k = 7; k >= 0; k--) {
                    *dst++ = ((d >> k) & 1) ? fg : 0;
                    j++;
                }
            }
        }
        break;
    }
}

/*
 * Three (3) kinds of logo maps exist.  linux_logo_clut224 (>16 colors),
 * linux_logo_vga16 (16 colors) and linux_logo_mono (2 colors).  Depending on
 * the visual format and color depth of the framebuffer, the DAC, the
 * pseudo_palette, and the logo data will be adjusted accordingly.
 *
 * Case 1 - linux_logo_clut224:
 * Color exceeds the number of console colors (16), thus we set the hardware DAC
 * using fb_set_cmap() appropriately.  The "needs_cmapreset"  flag will be set.
 *
 * For visuals that require color info from the pseudo_palette, we also construct
 * one for temporary use. The "needs_directpalette" or "needs_truepalette" flags
 * will be set.
 *
 * Case 2 - linux_logo_vga16:
 * The number of colors just matches the console colors, thus there is no need
 * to set the DAC or the pseudo_palette.  However, the bitmap is packed, ie,
 * each byte contains color information for two pixels (upper and lower nibble).
 * To be consistent with fb_imageblit() usage, we therefore separate the two
 * nibbles into separate bytes. The "depth" flag will be set to 4.
 *
 * Case 3 - linux_logo_mono:
 * This is similar with Case 2.  Each byte contains information for 8 pixels.
 * We isolate each bit and expand each into a byte. The "depth" flag will
 * be set to 1.
 */
static struct logo_data {
    int depth;
    int needs_directpalette;
    int needs_truepalette;
    int needs_cmapreset;
    const struct linux_logo *logo;
} fb_logo __read_mostly;

static void fb_rotate_logo_ud(const u8 *in, u8 *out, u32 width, u32 height)
{
    u32 size = width * height, i;

    out += size - 1;

    for (i = size; i--; )
        *out-- = *in++;
}

static void fb_rotate_logo_cw(const u8 *in, u8 *out, u32 width, u32 height)
{
    int i, j, h = height - 1;

    for (i = 0; i < height; i++)
        for (j = 0; j < width; j++)
                out[height * j + h - i] = *in++;
}

static void fb_rotate_logo_ccw(const u8 *in, u8 *out, u32 width, u32 height)
{
    int i, j, w = width - 1;

    for (i = 0; i < height; i++)
        for (j = 0; j < width; j++)
            out[height * (w - j) + i] = *in++;
}

static void fb_rotate_logo(struct fb_info *info, u8 *dst,
               struct fb_image *image, int rotate)
{
    u32 tmp;

    if (rotate == FB_ROTATE_UD) {
        fb_rotate_logo_ud(image->data, dst, image->width,
                  image->height);
        image->dx = info->var.xres - image->width - image->dx;
        image->dy = info->var.yres - image->height - image->dy;
    } else if (rotate == FB_ROTATE_CW) {
        fb_rotate_logo_cw(image->data, dst, image->width,
                  image->height);
        tmp = image->width;
        image->width = image->height;
        image->height = tmp;
        tmp = image->dy;
        image->dy = image->dx;
        image->dx = info->var.xres - image->width - tmp;
    } else if (rotate == FB_ROTATE_CCW) {
        fb_rotate_logo_ccw(image->data, dst, image->width,
                   image->height);
        tmp = image->width;
        image->width = image->height;
        image->height = tmp;
        tmp = image->dx;
        image->dx = image->dy;
        image->dy = info->var.yres - image->height - tmp;
    }

    image->data = dst;
}

static void fb_do_show_logo(struct fb_info *info, struct fb_image *image,
                int rotate, unsigned int num)
{
    unsigned int x;

    if (rotate == FB_ROTATE_UR) {
        for (x = 0;
             x < num && image->dx + image->width <= info->var.xres;
             x++) {
            info->fbops->fb_imageblit(info, image);
            image->dx += image->width + 8;
        }
    } else if (rotate == FB_ROTATE_UD) {
        for (x = 0; x < num && image->dx >= 0; x++) {
            info->fbops->fb_imageblit(info, image);
            image->dx -= image->width + 8;
        }
    } else if (rotate == FB_ROTATE_CW) {
        for (x = 0;
             x < num && image->dy + image->height <= info->var.yres;
             x++) {
            info->fbops->fb_imageblit(info, image);
            image->dy += image->height + 8;
        }
    } else if (rotate == FB_ROTATE_CCW) {
        for (x = 0; x < num && image->dy >= 0; x++) {
            info->fbops->fb_imageblit(info, image);
            image->dy -= image->height + 8;
        }
    }
}

static int fb_show_logo_line(struct fb_info *info, int rotate,
                 const struct linux_logo *logo, int y,
                 unsigned int n)
{
    u32 *palette = NULL, *saved_pseudo_palette = NULL;
    unsigned char *logo_new = NULL, *logo_rotate = NULL;
    struct fb_image image;

    /* Return if the frame buffer is not mapped or suspended */
    if (logo == NULL || info->state != FBINFO_STATE_RUNNING ||
        info->flags & FBINFO_MODULE)
        return 0;

    image.depth = 8;
    image.data = logo->data;

    if (fb_logo.needs_cmapreset)
        fb_set_logocmap(info, logo);

    if (fb_logo.needs_truepalette ||
        fb_logo.needs_directpalette) {
        palette = kmalloc(256 * 4, GFP_KERNEL);
        if (palette == NULL)
            return 0;

        if (fb_logo.needs_truepalette)
            fb_set_logo_truepalette(info, logo, palette);
        else
            fb_set_logo_directpalette(info, logo, palette);

        saved_pseudo_palette = info->pseudo_palette;
        info->pseudo_palette = palette;
    }

    if (fb_logo.depth <= 4) {
        logo_new = kmalloc(logo->width * logo->height, GFP_KERNEL);
        if (logo_new == NULL) {
            kfree(palette);
            if (saved_pseudo_palette)
                info->pseudo_palette = saved_pseudo_palette;
            return 0;
        }
        image.data = logo_new;
        fb_set_logo(info, logo, logo_new, fb_logo.depth);
    }

    image.dx = 0;
    image.dy = y;
    image.width = logo->width;
    image.height = logo->height;

    if (rotate) {
        logo_rotate = kmalloc(logo->width *
                      logo->height, GFP_KERNEL);
        if (logo_rotate)
            fb_rotate_logo(info, logo_rotate, &image, rotate);
    }

    fb_do_show_logo(info, &image, rotate, n);

    kfree(palette);
    if (saved_pseudo_palette != NULL)
        info->pseudo_palette = saved_pseudo_palette;
    kfree(logo_new);
    kfree(logo_rotate);
    return logo->height;
}


#ifdef CONFIG_FB_LOGO_EXTRA

#define FB_LOGO_EX_NUM_MAX 10
static struct logo_data_extra {
    const struct linux_logo *logo;
    unsigned int n;
} fb_logo_ex[FB_LOGO_EX_NUM_MAX];
static unsigned int fb_logo_ex_num;

void fb_append_extra_logo(const struct linux_logo *logo, unsigned int n)
{
    if (!n || fb_logo_ex_num == FB_LOGO_EX_NUM_MAX)
        return;

    fb_logo_ex[fb_logo_ex_num].logo = logo;
    fb_logo_ex[fb_logo_ex_num].n = n;
    fb_logo_ex_num++;
}

static int fb_prepare_extra_logos(struct fb_info *info, unsigned int height,
                  unsigned int yres)
{
    unsigned int i;

    /* FIXME: logo_ex supports only truecolor fb. */
    if (info->fix.visual != FB_VISUAL_TRUECOLOR)
        fb_logo_ex_num = 0;

    for (i = 0; i < fb_logo_ex_num; i++) {
        if (fb_logo_ex[i].logo->type != fb_logo.logo->type) {
            fb_logo_ex[i].logo = NULL;
            continue;
        }
        height += fb_logo_ex[i].logo->height;
        if (height > yres) {
            height -= fb_logo_ex[i].logo->height;
            fb_logo_ex_num = i;
            break;
        }
    }
    return height;
}

static int fb_show_extra_logos(struct fb_info *info, int y, int rotate)
{
    unsigned int i;

    for (i = 0; i < fb_logo_ex_num; i++)
        y += fb_show_logo_line(info, rotate,
                       fb_logo_ex[i].logo, y, fb_logo_ex[i].n);

    return y;
}

#else /* !CONFIG_FB_LOGO_EXTRA */

static inline int fb_prepare_extra_logos(struct fb_info *info,
                     unsigned int height,
                     unsigned int yres)
{
    return height;
}

static inline int fb_show_extra_logos(struct fb_info *info, int y, int rotate)
{
    return y;
}

#endif /* CONFIG_FB_LOGO_EXTRA */


int fb_prepare_logo(struct fb_info *info, int rotate)
{
    int depth = fb_get_color_depth(&info->var, &info->fix);
    unsigned int yres;

    memset(&fb_logo, 0, sizeof(struct logo_data));

    if (info->flags & FBINFO_MISC_TILEBLITTING ||
        info->flags & FBINFO_MODULE)
        return 0;

    if (info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
        depth = info->var.blue.length;
        if (info->var.red.length < depth)
            depth = info->var.red.length;
        if (info->var.green.length < depth)
            depth = info->var.green.length;
    }

    if (info->fix.visual == FB_VISUAL_STATIC_PSEUDOCOLOR && depth > 4) {
        /* assume console colormap */
        depth = 4;
    }

    /* Return if no suitable logo was found */
    fb_logo.logo = fb_find_logo(depth);

    if (!fb_logo.logo) {
        return 0;
    }

    if (rotate == FB_ROTATE_UR || rotate == FB_ROTATE_UD)
        yres = info->var.yres;
    else
        yres = info->var.xres;

    if (fb_logo.logo->height > yres) {
        fb_logo.logo = NULL;
        return 0;
    }

    /* What depth we asked for might be different from what we get */
    if (fb_logo.logo->type == LINUX_LOGO_CLUT224)
        fb_logo.depth = 8;
    else if (fb_logo.logo->type == LINUX_LOGO_VGA16)
        fb_logo.depth = 4;
    else
        fb_logo.depth = 1;


    if (fb_logo.depth > 4 && depth > 4) {
        switch (info->fix.visual) {
        case FB_VISUAL_TRUECOLOR:
            fb_logo.needs_truepalette = 1;
            break;
        case FB_VISUAL_DIRECTCOLOR:
            fb_logo.needs_directpalette = 1;
            fb_logo.needs_cmapreset = 1;
            break;
        case FB_VISUAL_PSEUDOCOLOR:
            fb_logo.needs_cmapreset = 1;
            break;
        }
    }

    return fb_prepare_extra_logos(info, fb_logo.logo->height, yres);
}

int fb_show_logo(struct fb_info *info, int rotate)
{
    int y;

    y = fb_show_logo_line(info, rotate, fb_logo.logo, 0,
                  num_online_cpus());
    y = fb_show_extra_logos(info, y, rotate);

    return y;
}
#else
int fb_prepare_logo(struct fb_info *info, int rotate) { return 0; }
int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
#endif /* CONFIG_LOGO */

static void *fb_seq_start(struct seq_file *m, loff_t *pos)
{
    mutex_lock(&registration_lock);
    return (*pos < FB_MAX) ? pos : NULL;
}

static void *fb_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
    (*pos)++;
    return (*pos < FB_MAX) ? pos : NULL;
}

static void fb_seq_stop(struct seq_file *m, void *v)
{
    mutex_unlock(&registration_lock);
}

static int fb_seq_show(struct seq_file *m, void *v)
{
    int i = *(loff_t *)v;
    struct fb_info *fi = registered_fb[i];

    if (fi)
        seq_printf(m, "%d %s\n", fi->node, fi->fix.id);
    return 0;
}

static const struct seq_operations proc_fb_seq_ops = {
    .start  = fb_seq_start,
    .next   = fb_seq_next,
    .stop   = fb_seq_stop,
    .show   = fb_seq_show,
};

static int proc_fb_open(struct inode *inode, struct file *file)
{
    return seq_open(file, &proc_fb_seq_ops);
}

static const struct file_operations fb_proc_fops = {
    .owner      = THIS_MODULE,
    .open       = proc_fb_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = seq_release,
};

/*
 * We hold a reference to the fb_info in file->private_data,
 * but if the current registered fb has changed, we don't
 * actually want to use it.
 *
 * So look up the fb_info using the inode minor number,
 * and just verify it against the reference we have.
 */
static struct fb_info *file_fb_info(struct file *file)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    int fbidx = iminor(inode);
    struct fb_info *info = registered_fb[fbidx];

    if (info != file->private_data)
        info = NULL;
    return info;
}

static ssize_t
fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
    unsigned long p = *ppos;
    struct fb_info *info = file_fb_info(file);
    u8 *buffer, *dst;
    u8 __iomem *src;
    int c, cnt = 0, err = 0;
    unsigned long total_size;

    if (!info || ! info->screen_base)
        return -ENODEV;

    if (info->state != FBINFO_STATE_RUNNING)
        return -EPERM;

    if (info->fbops->fb_read)
        return info->fbops->fb_read(info, buf, count, ppos);
    
    total_size = info->screen_size;

    if (total_size == 0)
        total_size = info->fix.smem_len;

    if (p >= total_size)
        return 0;

    if (count >= total_size)
        count = total_size;

    if (count + p > total_size)
        count = total_size - p;

    buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,
             GFP_KERNEL);
    if (!buffer)
        return -ENOMEM;

    src = (u8 __iomem *) (info->screen_base + p);

    if (info->fbops->fb_sync)
        info->fbops->fb_sync(info);

    while (count) {
        c  = (count > PAGE_SIZE) ? PAGE_SIZE : count;
        dst = buffer;
        fb_memcpy_fromfb(dst, src, c);
        dst += c;
        src += c;

        if (copy_to_user(buf, buffer, c)) {
            err = -EFAULT;
            break;
        }
        *ppos += c;
        buf += c;
        cnt += c;
        count -= c;
    }

    kfree(buffer);

    return (err) ? err : cnt;
}

static ssize_t
fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
    unsigned long p = *ppos;
    struct fb_info *info = file_fb_info(file);
    u8 *buffer, *src;
    u8 __iomem *dst;
    int c, cnt = 0, err = 0;
    unsigned long total_size;

    if (!info || !info->screen_base)
        return -ENODEV;

    if (info->state != FBINFO_STATE_RUNNING)
        return -EPERM;

    if (info->fbops->fb_write)
        return info->fbops->fb_write(info, buf, count, ppos);
    
    total_size = info->screen_size;

    if (total_size == 0)
        total_size = info->fix.smem_len;

    if (p > total_size)
        return -EFBIG;

    if (count > total_size) {
        err = -EFBIG;
        count = total_size;
    }

    if (count + p > total_size) {
        if (!err)
            err = -ENOSPC;

        count = total_size - p;
    }

    buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,
             GFP_KERNEL);
    if (!buffer)
        return -ENOMEM;

    dst = (u8 __iomem *) (info->screen_base + p);

    if (info->fbops->fb_sync)
        info->fbops->fb_sync(info);

    while (count) {
        c = (count > PAGE_SIZE) ? PAGE_SIZE : count;
        src = buffer;

        if (copy_from_user(src, buf, c)) {
            err = -EFAULT;
            break;
        }

        fb_memcpy_tofb(dst, src, c);
        dst += c;
        src += c;
        *ppos += c;
        buf += c;
        cnt += c;
        count -= c;
    }

    kfree(buffer);

    return (cnt) ? cnt : err;
}

int
fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
{
    struct fb_fix_screeninfo *fix = &info->fix;
    unsigned int yres = info->var.yres;
    int err = 0;

    if (var->yoffset > 0) {
        if (var->vmode & FB_VMODE_YWRAP) {
            if (!fix->ywrapstep || (var->yoffset % fix->ywrapstep))
                err = -EINVAL;
            else
                yres = 0;
        } else if (!fix->ypanstep || (var->yoffset % fix->ypanstep))
            err = -EINVAL;
    }

    if (var->xoffset > 0 && (!fix->xpanstep ||
                 (var->xoffset % fix->xpanstep)))
        err = -EINVAL;

    if (err || !info->fbops->fb_pan_display ||
        var->yoffset > info->var.yres_virtual - yres ||
        var->xoffset > info->var.xres_virtual - info->var.xres)
        return -EINVAL;

    if ((err = info->fbops->fb_pan_display(var, info)))
        return err;
    info->var.xoffset = var->xoffset;
    info->var.yoffset = var->yoffset;
    if (var->vmode & FB_VMODE_YWRAP)
        info->var.vmode |= FB_VMODE_YWRAP;
    else
        info->var.vmode &= ~FB_VMODE_YWRAP;
    return 0;
}

static int fb_check_caps(struct fb_info *info, struct fb_var_screeninfo *var,
             u32 activate)
{
    struct fb_event event;
    struct fb_blit_caps caps, fbcaps;
    int err = 0;

    memset(&caps, 0, sizeof(caps));
    memset(&fbcaps, 0, sizeof(fbcaps));
    caps.flags = (activate & FB_ACTIVATE_ALL) ? 1 : 0;
    event.info = info;
    event.data = &caps;
    fb_notifier_call_chain(FB_EVENT_GET_REQ, &event);
    info->fbops->fb_get_caps(info, &fbcaps, var);

    if (((fbcaps.x ^ caps.x) & caps.x) ||
        ((fbcaps.y ^ caps.y) & caps.y) ||
        (fbcaps.len < caps.len))
        err = -EINVAL;

    return err;
}

int
fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
{
    int flags = info->flags;
    int ret = 0;

    if (var->activate & FB_ACTIVATE_INV_MODE) {
        struct fb_videomode mode1, mode2;

        fb_var_to_videomode(&mode1, var);
        fb_var_to_videomode(&mode2, &info->var);
        /* make sure we don't delete the videomode of current var */
        ret = fb_mode_is_equal(&mode1, &mode2);

        if (!ret) {
            struct fb_event event;

            event.info = info;
            event.data = &mode1;
            ret = fb_notifier_call_chain(FB_EVENT_MODE_DELETE, &event);
        }

        if (!ret)
            fb_delete_videomode(&mode1, &info->modelist);


        ret = (ret) ? -EINVAL : 0;
        goto done;
    }

    if ((var->activate & FB_ACTIVATE_FORCE) ||
        memcmp(&info->var, var, sizeof(struct fb_var_screeninfo))) {
        u32 activate = var->activate;

        /* When using FOURCC mode, make sure the red, green, blue and
         * transp fields are set to 0.
         */
        if ((info->fix.capabilities & FB_CAP_FOURCC) &&
            var->grayscale > 1) {
            if (var->red.offset     || var->green.offset    ||
                var->blue.offset    || var->transp.offset   ||
                var->red.length     || var->green.length    ||
                var->blue.length    || var->transp.length   ||
                var->red.msb_right  || var->green.msb_right ||
                var->blue.msb_right || var->transp.msb_right)
                return -EINVAL;
        }

        if (!info->fbops->fb_check_var) {
            *var = info->var;
            goto done;
        }

        ret = info->fbops->fb_check_var(var, info);

        if (ret)
            goto done;

        if ((var->activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW) {
            struct fb_var_screeninfo old_var;
            struct fb_videomode mode;

            if (info->fbops->fb_get_caps) {
                ret = fb_check_caps(info, var, activate);

                if (ret)
                    goto done;
            }

            old_var = info->var;
            info->var = *var;

            if (info->fbops->fb_set_par) {
                ret = info->fbops->fb_set_par(info);

                if (ret) {
                    info->var = old_var;
                    printk(KERN_WARNING "detected "
                        "fb_set_par error, "
                        "error code: %d\n", ret);
                    goto done;
                }
            }

            fb_pan_display(info, &info->var);
            fb_set_cmap(&info->cmap, info);
            fb_var_to_videomode(&mode, &info->var);

            if (info->modelist.prev && info->modelist.next &&
                !list_empty(&info->modelist))
                ret = fb_add_videomode(&mode, &info->modelist);

            if (!ret && (flags & FBINFO_MISC_USEREVENT)) {
                struct fb_event event;
                int evnt = (activate & FB_ACTIVATE_ALL) ?
                    FB_EVENT_MODE_CHANGE_ALL :
                    FB_EVENT_MODE_CHANGE;

                info->flags &= ~FBINFO_MISC_USEREVENT;
                event.info = info;
                event.data = &mode;
                fb_notifier_call_chain(evnt, &event);
            }
        }
    }

 done:
    return ret;
}

int
fb_blank(struct fb_info *info, int blank)
{   
    struct fb_event event;
    int ret = -EINVAL, early_ret;

    if (blank > FB_BLANK_POWERDOWN)
        blank = FB_BLANK_POWERDOWN;

    event.info = info;
    event.data = &blank;

    early_ret = fb_notifier_call_chain(FB_EARLY_EVENT_BLANK, &event);

    if (info->fbops->fb_blank)
        ret = info->fbops->fb_blank(blank, info);

    if (!ret)
        fb_notifier_call_chain(FB_EVENT_BLANK, &event);
    else {
        /*
         * if fb_blank is failed then revert effects of
         * the early blank event.
         */
        if (!early_ret)
            fb_notifier_call_chain(FB_R_EARLY_EVENT_BLANK, &event);
    }

    return ret;
}

static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
            unsigned long arg)
{
    struct fb_ops *fb;
    struct fb_var_screeninfo var;
    struct fb_fix_screeninfo fix;
    struct fb_con2fbmap con2fb;
    struct fb_cmap cmap_from;
    struct fb_cmap_user cmap;
    struct fb_event event;
    void __user *argp = (void __user *)arg;
    long ret = 0;

    switch (cmd) {
    case FBIOGET_VSCREENINFO:
        if (!lock_fb_info(info))
            return -ENODEV;
        var = info->var;
        unlock_fb_info(info);

        ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
        break;
    case FBIOPUT_VSCREENINFO:
        if (copy_from_user(&var, argp, sizeof(var)))
            return -EFAULT;
        if (!lock_fb_info(info))
            return -ENODEV;
        console_lock();
        info->flags |= FBINFO_MISC_USEREVENT;
        ret = fb_set_var(info, &var);
        info->flags &= ~FBINFO_MISC_USEREVENT;
        console_unlock();
        unlock_fb_info(info);
        if (!ret && copy_to_user(argp, &var, sizeof(var)))
            ret = -EFAULT;
        break;
    case FBIOGET_FSCREENINFO:
        if (!lock_fb_info(info))
            return -ENODEV;
        fix = info->fix;
        unlock_fb_info(info);

        ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
        break;
    case FBIOPUTCMAP:
        if (copy_from_user(&cmap, argp, sizeof(cmap)))
            return -EFAULT;
        ret = fb_set_user_cmap(&cmap, info);
        break;
    case FBIOGETCMAP:
        if (copy_from_user(&cmap, argp, sizeof(cmap)))
            return -EFAULT;
        if (!lock_fb_info(info))
            return -ENODEV;
        cmap_from = info->cmap;
        unlock_fb_info(info);
        ret = fb_cmap_to_user(&cmap_from, &cmap);
        break;
    case FBIOPAN_DISPLAY:
        if (copy_from_user(&var, argp, sizeof(var)))
            return -EFAULT;
        if (!lock_fb_info(info))
            return -ENODEV;
        console_lock();
        ret = fb_pan_display(info, &var);
        console_unlock();
        unlock_fb_info(info);
        if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
            return -EFAULT;
        break;
    case FBIO_CURSOR:
        ret = -EINVAL;
        break;
    case FBIOGET_CON2FBMAP:
        if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
            return -EFAULT;
        if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
            return -EINVAL;
        con2fb.framebuffer = -1;
        event.data = &con2fb;
        if (!lock_fb_info(info))
            return -ENODEV;
        event.info = info;
        fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
        unlock_fb_info(info);
        ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
        break;
    case FBIOPUT_CON2FBMAP:
        if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
            return -EFAULT;
        if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
            return -EINVAL;
        if (con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX)
            return -EINVAL;
        if (!registered_fb[con2fb.framebuffer])
            request_module("fb%d", con2fb.framebuffer);
        if (!registered_fb[con2fb.framebuffer]) {
            ret = -EINVAL;
            break;
        }
        event.data = &con2fb;
        if (!lock_fb_info(info))
            return -ENODEV;
        event.info = info;
        ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
        unlock_fb_info(info);
        break;
    case FBIOBLANK:
        if (!lock_fb_info(info))
            return -ENODEV;
        console_lock();
        info->flags |= FBINFO_MISC_USEREVENT;
        ret = fb_blank(info, arg);
        info->flags &= ~FBINFO_MISC_USEREVENT;
        console_unlock();
        unlock_fb_info(info);
        break;
    default:
        if (!lock_fb_info(info))
            return -ENODEV;
        fb = info->fbops;
        if (fb->fb_ioctl)
            ret = fb->fb_ioctl(info, cmd, arg);
        else
            ret = -ENOTTY;
        unlock_fb_info(info);
    }
    return ret;
}

static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    struct fb_info *info = file_fb_info(file);

    if (!info)
        return -ENODEV;
    return do_fb_ioctl(info, cmd, arg);
}

#ifdef CONFIG_COMPAT
struct fb_fix_screeninfo32 {
    char            id[16];
    compat_caddr_t      smem_start;
    u32         smem_len;
    u32         type;
    u32         type_aux;
    u32         visual;
    u16         xpanstep;
    u16         ypanstep;
    u16         ywrapstep;
    u32         line_length;
    compat_caddr_t      mmio_start;
    u32         mmio_len;
    u32         accel;
    u16         reserved[3];
};

struct fb_cmap32 {
    u32         start;
    u32         len;
    compat_caddr_t  red;
    compat_caddr_t  green;
    compat_caddr_t  blue;
    compat_caddr_t  transp;
};

static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
              unsigned long arg)
{
    struct fb_cmap_user __user *cmap;
    struct fb_cmap32 __user *cmap32;
    __u32 data;
    int err;

    cmap = compat_alloc_user_space(sizeof(*cmap));
    cmap32 = compat_ptr(arg);

    if (copy_in_user(&cmap->start, &cmap32->start, 2 * sizeof(__u32)))
        return -EFAULT;

    if (get_user(data, &cmap32->red) ||
        put_user(compat_ptr(data), &cmap->red) ||
        get_user(data, &cmap32->green) ||
        put_user(compat_ptr(data), &cmap->green) ||
        get_user(data, &cmap32->blue) ||
        put_user(compat_ptr(data), &cmap->blue) ||
        get_user(data, &cmap32->transp) ||
        put_user(compat_ptr(data), &cmap->transp))
        return -EFAULT;

    err = do_fb_ioctl(info, cmd, (unsigned long) cmap);

    if (!err) {
        if (copy_in_user(&cmap32->start,
                 &cmap->start,
                 2 * sizeof(__u32)))
            err = -EFAULT;
    }
    return err;
}

static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
                  struct fb_fix_screeninfo32 __user *fix32)
{
    __u32 data;
    int err;

    err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));

    data = (__u32) (unsigned long) fix->smem_start;
    err |= put_user(data, &fix32->smem_start);

    err |= put_user(fix->smem_len, &fix32->smem_len);
    err |= put_user(fix->type, &fix32->type);
    err |= put_user(fix->type_aux, &fix32->type_aux);
    err |= put_user(fix->visual, &fix32->visual);
    err |= put_user(fix->xpanstep, &fix32->xpanstep);
    err |= put_user(fix->ypanstep, &fix32->ypanstep);
    err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
    err |= put_user(fix->line_length, &fix32->line_length);

    data = (__u32) (unsigned long) fix->mmio_start;
    err |= put_user(data, &fix32->mmio_start);

    err |= put_user(fix->mmio_len, &fix32->mmio_len);
    err |= put_user(fix->accel, &fix32->accel);
    err |= copy_to_user(fix32->reserved, fix->reserved,
                sizeof(fix->reserved));

    return err;
}

static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
                  unsigned long arg)
{
    mm_segment_t old_fs;
    struct fb_fix_screeninfo fix;
    struct fb_fix_screeninfo32 __user *fix32;
    int err;

    fix32 = compat_ptr(arg);

    old_fs = get_fs();
    set_fs(KERNEL_DS);
    err = do_fb_ioctl(info, cmd, (unsigned long) &fix);
    set_fs(old_fs);

    if (!err)
        err = do_fscreeninfo_to_user(&fix, fix32);

    return err;
}

static long fb_compat_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg)
{
    struct fb_info *info = file_fb_info(file);
    struct fb_ops *fb;
    long ret = -ENOIOCTLCMD;

    if (!info)
        return -ENODEV;
    fb = info->fbops;
    switch(cmd) {
    case FBIOGET_VSCREENINFO:
    case FBIOPUT_VSCREENINFO:
    case FBIOPAN_DISPLAY:
    case FBIOGET_CON2FBMAP:
    case FBIOPUT_CON2FBMAP:
        arg = (unsigned long) compat_ptr(arg);
    case FBIOBLANK:
        ret = do_fb_ioctl(info, cmd, arg);
        break;

    case FBIOGET_FSCREENINFO:
        ret = fb_get_fscreeninfo(info, cmd, arg);
        break;

    case FBIOGETCMAP:
    case FBIOPUTCMAP:
        ret = fb_getput_cmap(info, cmd, arg);
        break;

    default:
        if (fb->fb_compat_ioctl)
            ret = fb->fb_compat_ioctl(info, cmd, arg);
        break;
    }
    return ret;
}
#endif

static int
fb_mmap(struct file *file, struct vm_area_struct * vma)
{
    struct fb_info *info = file_fb_info(file);
    struct fb_ops *fb;
    unsigned long off;
    unsigned long start;
    u32 len;

    if (!info)
        return -ENODEV;
    if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
        return -EINVAL;
    off = vma->vm_pgoff << PAGE_SHIFT;
    fb = info->fbops;
    if (!fb)
        return -ENODEV;
    mutex_lock(&info->mm_lock);
    if (fb->fb_mmap) {
        int res;
        res = fb->fb_mmap(info, vma);
        mutex_unlock(&info->mm_lock);
        return res;
    }

    /* frame buffer memory */
    start = info->fix.smem_start;
    len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.smem_len);
    if (off >= len) {
        /* memory mapped io */
        off -= len;
        if (info->var.accel_flags) {
            mutex_unlock(&info->mm_lock);
            return -EINVAL;
        }
        start = info->fix.mmio_start;
        len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.mmio_len);
    }
    mutex_unlock(&info->mm_lock);
    start &= PAGE_MASK;
    if ((vma->vm_end - vma->vm_start + off) > len)
        return -EINVAL;
    off += start;
    vma->vm_pgoff = off >> PAGE_SHIFT;
    /* VM_IO | VM_DONTEXPAND | VM_DONTDUMP are set by io_remap_pfn_range()*/
    vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
    fb_pgprotect(file, vma, off);
    if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
                 vma->vm_end - vma->vm_start, vma->vm_page_prot))
        return -EAGAIN;
    return 0;
}

static int
fb_open(struct inode *inode, struct file *file)
__acquires(&info->lock)
__releases(&info->lock)
{
    int fbidx = iminor(inode);
    struct fb_info *info;
    int res = 0;

    info = get_fb_info(fbidx);
    if (!info) {
        request_module("fb%d", fbidx);
        info = get_fb_info(fbidx);
        if (!info)
            return -ENODEV;
    }
    if (IS_ERR(info))
        return PTR_ERR(info);

    mutex_lock(&info->lock);
    if (!try_module_get(info->fbops->owner)) {
        res = -ENODEV;
        goto out;
    }
    file->private_data = info;
    if (info->fbops->fb_open) {
        res = info->fbops->fb_open(info,1);
        if (res)
            module_put(info->fbops->owner);
    }
#ifdef CONFIG_FB_DEFERRED_IO
    if (info->fbdefio)
        fb_deferred_io_open(info, inode, file);
#endif
out:
    mutex_unlock(&info->lock);
    if (res)
        put_fb_info(info);
    return res;
}

static int 
fb_release(struct inode *inode, struct file *file)
__acquires(&info->lock)
__releases(&info->lock)
{
    struct fb_info * const info = file->private_data;

    mutex_lock(&info->lock);
    if (info->fbops->fb_release)
        info->fbops->fb_release(info,1);
    module_put(info->fbops->owner);
    mutex_unlock(&info->lock);
    put_fb_info(info);
    return 0;
}

static const struct file_operations fb_fops = {
    .owner =    THIS_MODULE,
    .read =     fb_read,
    .write =    fb_write,
    .unlocked_ioctl = fb_ioctl,
#ifdef CONFIG_COMPAT
    .compat_ioctl = fb_compat_ioctl,
#endif
    .mmap =     fb_mmap,
    .open =     fb_open,
    .release =  fb_release,
#ifdef HAVE_ARCH_FB_UNMAPPED_AREA
    .get_unmapped_area = get_fb_unmapped_area,
#endif
#ifdef CONFIG_FB_DEFERRED_IO
    .fsync =    fb_deferred_io_fsync,
#endif
    .llseek =   default_llseek,
};

struct class *fb_class;
EXPORT_SYMBOL(fb_class);

static int fb_check_foreignness(struct fb_info *fi)
{
    const bool foreign_endian = fi->flags & FBINFO_FOREIGN_ENDIAN;

    fi->flags &= ~FBINFO_FOREIGN_ENDIAN;

#ifdef __BIG_ENDIAN
    fi->flags |= foreign_endian ? 0 : FBINFO_BE_MATH;
#else
    fi->flags |= foreign_endian ? FBINFO_BE_MATH : 0;
#endif /* __BIG_ENDIAN */

    if (fi->flags & FBINFO_BE_MATH && !fb_be_math(fi)) {
        pr_err("%s: enable CONFIG_FB_BIG_ENDIAN to "
               "support this framebuffer\n", fi->fix.id);
        return -ENOSYS;
    } else if (!(fi->flags & FBINFO_BE_MATH) && fb_be_math(fi)) {
        pr_err("%s: enable CONFIG_FB_LITTLE_ENDIAN to "
               "support this framebuffer\n", fi->fix.id);
        return -ENOSYS;
    }

    return 0;
}

static bool apertures_overlap(struct aperture *gen, struct aperture *hw)
{
    /* is the generic aperture base the same as the HW one */
    if (gen->base == hw->base)
        return true;
    /* is the generic aperture base inside the hw base->hw base+size */
    if (gen->base > hw->base && gen->base < hw->base + hw->size)
        return true;
    return false;
}

static bool fb_do_apertures_overlap(struct apertures_struct *gena,
                    struct apertures_struct *hwa)
{
    int i, j;
    if (!hwa || !gena)
        return false;

    for (i = 0; i < hwa->count; ++i) {
        struct aperture *h = &hwa->ranges[i];
        for (j = 0; j < gena->count; ++j) {
            struct aperture *g = &gena->ranges[j];
            printk(KERN_DEBUG "checking generic (%llx %llx) vs hw (%llx %llx)\n",
                (unsigned long long)g->base,
                (unsigned long long)g->size,
                (unsigned long long)h->base,
                (unsigned long long)h->size);
            if (apertures_overlap(g, h))
                return true;
        }
    }

    return false;
}

static int do_unregister_framebuffer(struct fb_info *fb_info);

#define VGA_FB_PHYS 0xA0000
static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
                     const char *name, bool primary)
{
    int i;

    /* check all firmware fbs and kick off if the base addr overlaps */
    for (i = 0 ; i < FB_MAX; i++) {
        struct apertures_struct *gen_aper;
        if (!registered_fb[i])
            continue;

        if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
            continue;

        gen_aper = registered_fb[i]->apertures;
        if (fb_do_apertures_overlap(gen_aper, a) ||
            (primary && gen_aper && gen_aper->count &&
             gen_aper->ranges[0].base == VGA_FB_PHYS)) {

            printk(KERN_INFO "fb: conflicting fb hw usage "
                   "%s vs %s - removing generic driver\n",
                   name, registered_fb[i]->fix.id);
            do_unregister_framebuffer(registered_fb[i]);
        }
    }
}

static int do_register_framebuffer(struct fb_info *fb_info)
{
    int i;
    struct fb_event event;
    struct fb_videomode mode;

    if (fb_check_foreignness(fb_info))
        return -ENOSYS;

    do_remove_conflicting_framebuffers(fb_info->apertures, fb_info->fix.id,
                     fb_is_primary_device(fb_info));

    if (num_registered_fb == FB_MAX)
        return -ENXIO;

    num_registered_fb++;
    for (i = 0 ; i < FB_MAX; i++)
        if (!registered_fb[i])
            break;
    fb_info->node = i;
    atomic_set(&fb_info->count, 1);
    mutex_init(&fb_info->lock);
    mutex_init(&fb_info->mm_lock);

    fb_info->dev = device_create(fb_class, fb_info->device,
                     MKDEV(FB_MAJOR, i), NULL, "fb%d", i);
    if (IS_ERR(fb_info->dev)) {
        /* Not fatal */
        printk(KERN_WARNING "Unable to create device for framebuffer %d; errno = %ld\n", i, PTR_ERR(fb_info->dev));
        fb_info->dev = NULL;
    } else
        fb_init_device(fb_info);

    if (fb_info->pixmap.addr == NULL) {
        fb_info->pixmap.addr = kmalloc(FBPIXMAPSIZE, GFP_KERNEL);
        if (fb_info->pixmap.addr) {
            fb_info->pixmap.size = FBPIXMAPSIZE;
            fb_info->pixmap.buf_align = 1;
            fb_info->pixmap.scan_align = 1;
            fb_info->pixmap.access_align = 32;
            fb_info->pixmap.flags = FB_PIXMAP_DEFAULT;
        }
    }   
    fb_info->pixmap.offset = 0;

    if (!fb_info->pixmap.blit_x)
        fb_info->pixmap.blit_x = ~(u32)0;

    if (!fb_info->pixmap.blit_y)
        fb_info->pixmap.blit_y = ~(u32)0;

    if (!fb_info->modelist.prev || !fb_info->modelist.next)
        INIT_LIST_HEAD(&fb_info->modelist);

    fb_var_to_videomode(&mode, &fb_info->var);
    fb_add_videomode(&mode, &fb_info->modelist);
    registered_fb[i] = fb_info;

    event.info = fb_info;
    if (!lock_fb_info(fb_info))
        return -ENODEV;
    fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
    unlock_fb_info(fb_info);
    return 0;
}

static int do_unregister_framebuffer(struct fb_info *fb_info)
{
    struct fb_event event;
    int i, ret = 0;

    i = fb_info->node;
    if (i < 0 || i >= FB_MAX || registered_fb[i] != fb_info)
        return -EINVAL;

    if (!lock_fb_info(fb_info))
        return -ENODEV;
    event.info = fb_info;
    ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
    unlock_fb_info(fb_info);

    if (ret)
        return -EINVAL;

    unlink_framebuffer(fb_info);
    if (fb_info->pixmap.addr &&
        (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT))
        kfree(fb_info->pixmap.addr);
    fb_destroy_modelist(&fb_info->modelist);
    registered_fb[i] = NULL;
    num_registered_fb--;
    fb_cleanup_device(fb_info);
    event.info = fb_info;
    fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);

    /* this may free fb info */
    put_fb_info(fb_info);
    return 0;
}

int unlink_framebuffer(struct fb_info *fb_info)
{
    int i;

    i = fb_info->node;
    if (i < 0 || i >= FB_MAX || registered_fb[i] != fb_info)
        return -EINVAL;

    if (fb_info->dev) {
        device_destroy(fb_class, MKDEV(FB_MAJOR, i));
        fb_info->dev = NULL;
    }
    return 0;
}
EXPORT_SYMBOL(unlink_framebuffer);

void remove_conflicting_framebuffers(struct apertures_struct *a,
                     const char *name, bool primary)
{
    mutex_lock(&registration_lock);
    do_remove_conflicting_framebuffers(a, name, primary);
    mutex_unlock(&registration_lock);
}
EXPORT_SYMBOL(remove_conflicting_framebuffers);

int
register_framebuffer(struct fb_info *fb_info)
{
    int ret;

    mutex_lock(&registration_lock);
    ret = do_register_framebuffer(fb_info);
    mutex_unlock(&registration_lock);

    return ret;
}

int
unregister_framebuffer(struct fb_info *fb_info)
{
    int ret;

    mutex_lock(&registration_lock);
    ret = do_unregister_framebuffer(fb_info);
    mutex_unlock(&registration_lock);

    return ret;
}

void fb_set_suspend(struct fb_info *info, int state)
{
    struct fb_event event;

    event.info = info;
    if (state) {
        fb_notifier_call_chain(FB_EVENT_SUSPEND, &event);
        info->state = FBINFO_STATE_SUSPENDED;
    } else {
        info->state = FBINFO_STATE_RUNNING;
        fb_notifier_call_chain(FB_EVENT_RESUME, &event);
    }
}

static int __init
fbmem_init(void)
{
    proc_create("fb", 0, NULL, &fb_proc_fops);

    if (register_chrdev(FB_MAJOR,"fb",&fb_fops))
        printk("unable to get major %d for fb devs\n", FB_MAJOR);

    fb_class = class_create(THIS_MODULE, "graphics");
    if (IS_ERR(fb_class)) {
        printk(KERN_WARNING "Unable to create fb class; errno = %ld\n", PTR_ERR(fb_class));
        fb_class = NULL;
    }
    return 0;
}

#ifdef MODULE
module_init(fbmem_init);
static void __exit
fbmem_exit(void)
{
    remove_proc_entry("fb", NULL);
    class_destroy(fb_class);
    unregister_chrdev(FB_MAJOR, "fb");
}

module_exit(fbmem_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Framebuffer base");
#else
subsys_initcall(fbmem_init);
#endif

int fb_new_modelist(struct fb_info *info)
{
    struct fb_event event;
    struct fb_var_screeninfo var = info->var;
    struct list_head *pos, *n;
    struct fb_modelist *modelist;
    struct fb_videomode *m, mode;
    int err = 1;

    list_for_each_safe(pos, n, &info->modelist) {
        modelist = list_entry(pos, struct fb_modelist, list);
        m = &modelist->mode;
        fb_videomode_to_var(&var, m);
        var.activate = FB_ACTIVATE_TEST;
        err = fb_set_var(info, &var);
        fb_var_to_videomode(&mode, &var);
        if (err || !fb_mode_is_equal(m, &mode)) {
            list_del(pos);
            kfree(pos);
        }
    }

    err = 1;

    if (!list_empty(&info->modelist)) {
        if (!lock_fb_info(info))
            return -ENODEV;
        event.info = info;
        err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event);
        unlock_fb_info(info);
    }

    return err;
}

static char *video_options[FB_MAX] __read_mostly;
static int ofonly __read_mostly;

int fb_get_options(char *name, char **option)
{
    char *opt, *options = NULL;
    int retval = 0;
    int name_len = strlen(name), i;

    if (name_len && ofonly && strncmp(name, "offb", 4))
        retval = 1;

    if (name_len && !retval) {
        for (i = 0; i < FB_MAX; i++) {
            if (video_options[i] == NULL)
                continue;
            if (!video_options[i][0])
                continue;
            opt = video_options[i];
            if (!strncmp(name, opt, name_len) &&
                opt[name_len] == ':')
                options = opt + name_len + 1;
        }
    }
    if (options && !strncmp(options, "off", 3))
        retval = 1;

    if (option)
        *option = options;

    return retval;
}

#ifndef MODULE

static int __init video_setup(char *options)
{
    int i, global = 0;

    if (!options || !*options)
        global = 1;

    if (!global && !strncmp(options, "ofonly", 6)) {
        ofonly = 1;
        global = 1;
    }

    if (!global && !strchr(options, ':')) {
        fb_mode_option = options;
        global = 1;
    }

    if (!global) {
        for (i = 0; i < FB_MAX; i++) {
            if (video_options[i] == NULL) {
                video_options[i] = options;
                break;
            }

        }
    }

    return 1;
}
__setup("video=", video_setup);
#endif

    /*
     *  Visible symbols for modules
     */

EXPORT_SYMBOL(register_framebuffer);
EXPORT_SYMBOL(unregister_framebuffer);
EXPORT_SYMBOL(num_registered_fb);
EXPORT_SYMBOL(registered_fb);
EXPORT_SYMBOL(fb_show_logo);
EXPORT_SYMBOL(fb_set_var);
EXPORT_SYMBOL(fb_blank);
EXPORT_SYMBOL(fb_pan_display);
EXPORT_SYMBOL(fb_get_buffer_offset);
EXPORT_SYMBOL(fb_set_suspend);
EXPORT_SYMBOL(fb_get_options);

MODULE_LICENSE("GPL");