Revert "backlight/fbcon: Add FB_EVENT_CONBLANK"

[linux.git] / drivers / video / fbdev / core / fbmem.c

/*
 *  linux/drivers/video/fbmem.c
 *
 *  Copyright (C) 1994 Martin Schaller
 *
 *      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/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 <linux/fbcon.h>
#include <linux/mem_encrypt.h>
#include <linux/pci.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;
EXPORT_SYMBOL(registered_fb);

int num_registered_fb __read_mostly;
EXPORT_SYMBOL(num_registered_fb);

bool fb_center_logo __read_mostly;
EXPORT_SYMBOL(fb_center_logo);

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);
}

/*
 * 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;
}
EXPORT_SYMBOL(fb_get_buffer_offset);

#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 && j < logo->width; 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 (image->width > info->var.xres || image->height > info->var.yres)
                return;

        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) {
                u32 dx = image->dx;

                for (x = 0; x < num && image->dx <= dx; 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) {
                u32 dy = image->dy;

                for (x = 0; x < num && image->dy <= dy; 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->fbops->owner)
                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_array(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);
        }

        if (fb_center_logo) {
                int xres = info->var.xres;
                int yres = info->var.yres;

                if (rotate == FB_ROTATE_CW || rotate == FB_ROTATE_CCW) {
                        xres = info->var.yres;
                        yres = info->var.xres;
                }

                while (n && (n * (logo->width + 8) - 8 > xres))
                        --n;
                image.dx = (xres - n * (logo->width + 8) - 8) / 2;
                image.dy = y ?: (yres - logo->height) / 2;
        } else {
                image.dx = 0;
                image.dy = y;
        }

        image.width = logo->width;
        image.height = logo->height;

        if (rotate) {
                logo_rotate = kmalloc_array(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 image.dy + 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;
        int height;

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

        if (info->flags & FBINFO_MISC_TILEBLITTING ||
            info->fbops->owner)
                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;
                }
        }

        height = fb_logo.logo->height;
        if (fb_center_logo)
                height += (yres - fb_logo.logo->height) / 2;

        return fb_prepare_extra_logos(info, 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 */
EXPORT_SYMBOL(fb_prepare_logo);
EXPORT_SYMBOL(fb_show_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,
};

/*
 * 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_inode(file);
        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;
}
EXPORT_SYMBOL(fb_pan_display);

static int fb_check_caps(struct fb_info *info, struct fb_var_screeninfo *var,
                         u32 activate)
{
        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;
        fbcon_get_requirement(info, &caps);
        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)
                        fbcon_mode_deleted(info, &mode1);

                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;
}
EXPORT_SYMBOL(fb_set_var);

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);
        fbcon_fb_blanked(info, blank);

        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;
}
EXPORT_SYMBOL(fb_blank);

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:
                lock_fb_info(info);
                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;
                console_lock();
                lock_fb_info(info);
                info->flags |= FBINFO_MISC_USEREVENT;
                ret = fb_set_var(info, &var);
                info->flags &= ~FBINFO_MISC_USEREVENT;
                unlock_fb_info(info);
                console_unlock();
                if (!ret && copy_to_user(argp, &var, sizeof(var)))
                        ret = -EFAULT;
                break;
        case FBIOGET_FSCREENINFO:
                lock_fb_info(info);
                fix = info->fix;
                if (info->flags & FBINFO_HIDE_SMEM_START)
                        fix.smem_start = 0;
                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;
                lock_fb_info(info);
                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;
                console_lock();
                lock_fb_info(info);
                ret = fb_pan_display(info, &var);
                unlock_fb_info(info);
                console_unlock();
                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;
                lock_fb_info(info);
                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 >= 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;
                console_lock();
                lock_fb_info(info);
                event.info = info;
                ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
                unlock_fb_info(info);
                console_unlock();
                break;
        case FBIOBLANK:
                console_lock();
                lock_fb_info(info);
                info->flags |= FBINFO_MISC_USEREVENT;
                ret = fb_blank(info, arg);
                info->flags &= ~FBINFO_MISC_USEREVENT;
                unlock_fb_info(info);
                console_unlock();
                break;
        default:
                lock_fb_info(info);
                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));

        if (err)
                return -EFAULT;
        return 0;
}

static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
                              unsigned long arg)
{
        struct fb_fix_screeninfo fix;

        lock_fb_info(info);
        fix = info->fix;
        if (info->flags & FBINFO_HIDE_SMEM_START)
                fix.smem_start = 0;
        unlock_fb_info(info);
        return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
}

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);
                /* fall through */
        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 mmio_pgoff;
        unsigned long start;
        u32 len;

        if (!info)
                return -ENODEV;
        fb = info->fbops;
        mutex_lock(&info->mm_lock);
        if (fb->fb_mmap) {
                int res;

                /*
                 * The framebuffer needs to be accessed decrypted, be sure
                 * SME protection is removed ahead of the call
                 */
                vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
                res = fb->fb_mmap(info, vma);
                mutex_unlock(&info->mm_lock);
                return res;
        }

        /*
         * Ugh. This can be either the frame buffer mapping, or
         * if pgoff points past it, the mmio mapping.
         */
        start = info->fix.smem_start;
        len = info->fix.smem_len;
        mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
        if (vma->vm_pgoff >= mmio_pgoff) {
                if (info->var.accel_flags) {
                        mutex_unlock(&info->mm_lock);
                        return -EINVAL;
                }

                vma->vm_pgoff -= mmio_pgoff;
                start = info->fix.mmio_start;
                len = info->fix.mmio_len;
        }
        mutex_unlock(&info->mm_lock);

        vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
        /*
         * The framebuffer needs to be accessed decrypted, be sure
         * SME protection is removed
         */
        vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
        fb_pgprotect(file, vma, start);

        return vm_iomap_memory(vma, start, len);
}

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);

        lock_fb_info(info);
        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:
        unlock_fb_info(info);
        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;

        lock_fb_info(info);
        if (info->fbops->fb_release)
                info->fbops->fb_release(info,1);
        module_put(info->fbops->owner);
        unlock_fb_info(info);
        put_fb_info(info);
        return 0;
}

#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
unsigned long get_fb_unmapped_area(struct file *filp,
                                   unsigned long addr, unsigned long len,
                                   unsigned long pgoff, unsigned long flags)
{
        struct fb_info * const info = filp->private_data;
        unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);

        if (pgoff > fb_size || len > fb_size - pgoff)
                return -EINVAL;

        return (unsigned long)info->screen_base + pgoff;
}
#endif

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,
#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
        (defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
         !defined(CONFIG_MMU))
        .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 void 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_each_registered_fb(i) {
                struct apertures_struct *gen_aper;

                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%d: switching to %s from %s\n",
                               i, name, registered_fb[i]->fix.id);
                        do_unregister_framebuffer(registered_fb[i]);
                }
        }
}

static bool lockless_register_fb;
module_param_named_unsafe(lockless_register_fb, lockless_register_fb, bool, 0400);
MODULE_PARM_DESC(lockless_register_fb,
        "Lockless framebuffer registration for debugging [default=off]");

static int do_register_framebuffer(struct fb_info *fb_info)
{
        int i, ret;
        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);

        if (fb_info->skip_vt_switch)
                pm_vt_switch_required(fb_info->dev, false);
        else
                pm_vt_switch_required(fb_info->dev, true);

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

#ifdef CONFIG_GUMSTIX_AM200EPD
        {
                struct fb_event event;
                event.info = fb_info;
                fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
        }
#endif

        if (!lockless_register_fb)
                console_lock();
        else
                atomic_inc(&ignore_console_lock_warning);
        lock_fb_info(fb_info);
        ret = fbcon_fb_registered(fb_info);
        unlock_fb_info(fb_info);

        if (!lockless_register_fb)
                console_unlock();
        else
                atomic_dec(&ignore_console_lock_warning);
        return ret;
}

static void unbind_console(struct fb_info *fb_info)
{
        int i = fb_info->node;

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

        console_lock();
        lock_fb_info(fb_info);
        fbcon_fb_unbind(fb_info);
        unlock_fb_info(fb_info);
        console_unlock();
}

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

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

        if (!fb_info->dev)
                return;

        device_destroy(fb_class, MKDEV(FB_MAJOR, i));

        pm_vt_switch_unregister(fb_info->dev);

        unbind_console(fb_info);

        fb_info->dev = NULL;
}
EXPORT_SYMBOL(unlink_framebuffer);

static void do_unregister_framebuffer(struct fb_info *fb_info)
{
        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[fb_info->node] = NULL;
        num_registered_fb--;
        fb_cleanup_device(fb_info);
#ifdef CONFIG_GUMSTIX_AM200EPD
        {
                struct fb_event event;
                event.info = fb_info;
                fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);
        }
#endif
        console_lock();
        fbcon_fb_unregistered(fb_info);
        console_unlock();

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

/**
 * remove_conflicting_framebuffers - remove firmware-configured framebuffers
 * @a: memory range, users of which are to be removed
 * @name: requesting driver name
 * @primary: also kick vga16fb if present
 *
 * This function removes framebuffer devices (initialized by firmware/bootloader)
 * which use memory range described by @a. If @a is NULL all such devices are
 * removed.
 */
int remove_conflicting_framebuffers(struct apertures_struct *a,
                                    const char *name, bool primary)
{
        bool do_free = false;

        if (!a) {
                a = alloc_apertures(1);
                if (!a)
                        return -ENOMEM;

                a->ranges[0].base = 0;
                a->ranges[0].size = ~0;
                do_free = true;
        }

        mutex_lock(&registration_lock);
        do_remove_conflicting_framebuffers(a, name, primary);
        mutex_unlock(&registration_lock);

        if (do_free)
                kfree(a);

        return 0;
}
EXPORT_SYMBOL(remove_conflicting_framebuffers);

/**
 * remove_conflicting_pci_framebuffers - remove firmware-configured framebuffers for PCI devices
 * @pdev: PCI device
 * @res_id: index of PCI BAR configuring framebuffer memory
 * @name: requesting driver name
 *
 * This function removes framebuffer devices (eg. initialized by firmware)
 * using memory range configured for @pdev's BAR @res_id.
 *
 * The function assumes that PCI device with shadowed ROM drives a primary
 * display and so kicks out vga16fb.
 */
int remove_conflicting_pci_framebuffers(struct pci_dev *pdev, int res_id, const char *name)
{
        struct apertures_struct *ap;
        bool primary = false;
        int err, idx, bar;
        bool res_id_found = false;

        for (idx = 0, bar = 0; bar < PCI_ROM_RESOURCE; bar++) {
                if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
                        continue;
                idx++;
        }

        ap = alloc_apertures(idx);
        if (!ap)
                return -ENOMEM;

        for (idx = 0, bar = 0; bar < PCI_ROM_RESOURCE; bar++) {
                if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
                        continue;
                ap->ranges[idx].base = pci_resource_start(pdev, bar);
                ap->ranges[idx].size = pci_resource_len(pdev, bar);
                pci_info(pdev, "%s: bar %d: 0x%lx -> 0x%lx\n", __func__, bar,
                         (unsigned long)pci_resource_start(pdev, bar),
                         (unsigned long)pci_resource_end(pdev, bar));
                idx++;
                if (res_id == bar)
                        res_id_found = true;
        }
        if (!res_id_found)
                pci_warn(pdev, "%s: passed res_id (%d) is not a memory bar\n",
                         __func__, res_id);

#ifdef CONFIG_X86
        primary = pdev->resource[PCI_ROM_RESOURCE].flags &
                                        IORESOURCE_ROM_SHADOW;
#endif
        err = remove_conflicting_framebuffers(ap, name, primary);
        kfree(ap);
        return err;
}
EXPORT_SYMBOL(remove_conflicting_pci_framebuffers);

/**
 *      register_framebuffer - registers a frame buffer device
 *      @fb_info: frame buffer info structure
 *
 *      Registers a frame buffer device @fb_info.
 *
 *      Returns negative errno on error, or zero for success.
 *
 */
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;
}
EXPORT_SYMBOL(register_framebuffer);

/**
 *      unregister_framebuffer - releases a frame buffer device
 *      @fb_info: frame buffer info structure
 *
 *      Unregisters a frame buffer device @fb_info.
 *
 *      Returns negative errno on error, or zero for success.
 *
 *      This function will also notify the framebuffer console
 *      to release the driver.
 *
 *      This is meant to be called within a driver's module_exit()
 *      function. If this is called outside module_exit(), ensure
 *      that the driver implements fb_open() and fb_release() to
 *      check that no processes are using the device.
 */
void
unregister_framebuffer(struct fb_info *fb_info)
{
        mutex_lock(&registration_lock);
        do_unregister_framebuffer(fb_info);
        mutex_unlock(&registration_lock);
}
EXPORT_SYMBOL(unregister_framebuffer);

/**
 *      fb_set_suspend - low level driver signals suspend
 *      @info: framebuffer affected
 *      @state: 0 = resuming, !=0 = suspending
 *
 *      This is meant to be used by low level drivers to
 *      signal suspend/resume to the core & clients.
 *      It must be called with the console semaphore held
 */
void fb_set_suspend(struct fb_info *info, int state)
{
        WARN_CONSOLE_UNLOCKED();

        if (state) {
                fbcon_suspended(info);
                info->state = FBINFO_STATE_SUSPENDED;
        } else {
                info->state = FBINFO_STATE_RUNNING;
                fbcon_resumed(info);
        }
}
EXPORT_SYMBOL(fb_set_suspend);

/**
 *      fbmem_init - init frame buffer subsystem
 *
 *      Initialize the frame buffer subsystem.
 *
 *      NOTE: This function is _only_ to be called by drivers/char/mem.c.
 *
 */

static int __init
fbmem_init(void)
{
        int ret;

        if (!proc_create_seq("fb", 0, NULL, &proc_fb_seq_ops))
                return -ENOMEM;

        ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
        if (ret) {
                printk("unable to get major %d for fb devs\n", FB_MAJOR);
                goto err_chrdev;
        }

        fb_class = class_create(THIS_MODULE, "graphics");
        if (IS_ERR(fb_class)) {
                ret = PTR_ERR(fb_class);
                pr_warn("Unable to create fb class; errno = %d\n", ret);
                fb_class = NULL;
                goto err_class;
        }

        fb_console_init();

        return 0;

err_class:
        unregister_chrdev(FB_MAJOR, "fb");
err_chrdev:
        remove_proc_entry("fb", NULL);
        return ret;
}

#ifdef MODULE
module_init(fbmem_init);
static void __exit
fbmem_exit(void)
{
        fb_console_exit();

        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_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);
                }
        }

        if (list_empty(&info->modelist))
                return 1;

        fbcon_new_modelist(info);

        return 0;
}

MODULE_LICENSE("GPL");