/*
 * fbsysfs.c - framebuffer device class and attributes
 *
 * Copyright (c) 2004 James Simmons <jsimmons@infradead.org>
 * 
 *      This program is free software you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/*
 * Note:  currently there's only stubs for framebuffer_alloc and
 * framebuffer_release here.  The reson for that is that until all drivers
 * are converted to use it a sysfsification will open OOPSable races.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/console.h>
#include <linux/module.h>

#define FB_SYSFS_FLAG_ATTR 1

/**
 * framebuffer_alloc - creates a new frame buffer info structure
 *
 * @size: size of driver private data, can be zero
 * @dev: pointer to the device for this fb, this can be NULL
 *
 * Creates a new frame buffer info structure. Also reserves @size bytes
 * for driver private data (info->par). info->par (if any) will be
 * aligned to sizeof(long).
 *
 * Returns the new structure, or NULL if an error occurred.
 *
 */
struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
{
#define BYTES_PER_LONG (BITS_PER_LONG/8)
#define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))
        int fb_info_size = sizeof(struct fb_info);
        struct fb_info *info;
        char *p;

        if (size)
                fb_info_size += PADDING;

        p = kzalloc(fb_info_size + size, GFP_KERNEL);

        if (!p)
                return NULL;

        info = (struct fb_info *) p;

        if (size)
                info->par = p + fb_info_size;

        info->device = dev;
        info->fbcon_rotate_hint = -1;

#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
        mutex_init(&info->bl_curve_mutex);
#endif

        return info;
#undef PADDING
#undef BYTES_PER_LONG
}
EXPORT_SYMBOL(framebuffer_alloc);

/**
 * framebuffer_release - marks the structure available for freeing
 *
 * @info: frame buffer info structure
 *
 * Drop the reference count of the device embedded in the
 * framebuffer info structure.
 *
 */
void framebuffer_release(struct fb_info *info)
{
        if (!info)
                return;
        kfree(info->apertures);
        kfree(info);
}
EXPORT_SYMBOL(framebuffer_release);

static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
{
        int err;

        var->activate |= FB_ACTIVATE_FORCE;
        console_lock();
        fb_info->flags |= FBINFO_MISC_USEREVENT;
        err = fb_set_var(fb_info, var);
        fb_info->flags &= ~FBINFO_MISC_USEREVENT;
        console_unlock();
        if (err)
                return err;
        return 0;
}

static int mode_string(char *buf, unsigned int offset,
                       const struct fb_videomode *mode)
{
        char m = 'U';
        char v = 'p';

        if (mode->flag & FB_MODE_IS_DETAILED)
                m = 'D';
        if (mode->flag & FB_MODE_IS_VESA)
                m = 'V';
        if (mode->flag & FB_MODE_IS_STANDARD)
                m = 'S';

        if (mode->vmode & FB_VMODE_INTERLACED)
                v = 'i';
        if (mode->vmode & FB_VMODE_DOUBLE)
                v = 'd';

        return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n",
                        m, mode->xres, mode->yres, v, mode->refresh);
}

static ssize_t store_mode(struct device *device, struct device_attribute *attr,
                          const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        char mstr[100];
        struct fb_var_screeninfo var;
        struct fb_modelist *modelist;
        struct fb_videomode *mode;
        struct list_head *pos;
        size_t i;
        int err;

        memset(&var, 0, sizeof(var));

        list_for_each(pos, &fb_info->modelist) {
                modelist = list_entry(pos, struct fb_modelist, list);
                mode = &modelist->mode;
                i = mode_string(mstr, 0, mode);
                if (strncmp(mstr, buf, max(count, i)) == 0) {

                        var = fb_info->var;
                        fb_videomode_to_var(&var, mode);
                        if ((err = activate(fb_info, &var)))
                                return err;
                        fb_info->mode = mode;
                        return count;
                }
        }
        return -EINVAL;
}

static ssize_t show_mode(struct device *device, struct device_attribute *attr,
                         char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);

        if (!fb_info->mode)
                return 0;

        return mode_string(buf, 0, fb_info->mode);
}

static ssize_t store_modes(struct device *device,
                           struct device_attribute *attr,
                           const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        LIST_HEAD(old_list);
        int i = count / sizeof(struct fb_videomode);

        if (i * sizeof(struct fb_videomode) != count)
                return -EINVAL;

        console_lock();
        if (!lock_fb_info(fb_info)) {
                console_unlock();
                return -ENODEV;
        }

        list_splice(&fb_info->modelist, &old_list);
        fb_videomode_to_modelist((const struct fb_videomode *)buf, i,
                                 &fb_info->modelist);
        if (fb_new_modelist(fb_info)) {
                fb_destroy_modelist(&fb_info->modelist);
                list_splice(&old_list, &fb_info->modelist);
        } else
                fb_destroy_modelist(&old_list);

        unlock_fb_info(fb_info);
        console_unlock();

        return 0;
}

static ssize_t show_modes(struct device *device, struct device_attribute *attr,
                          char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        unsigned int i;
        struct list_head *pos;
        struct fb_modelist *modelist;
        const struct fb_videomode *mode;

        i = 0;
        list_for_each(pos, &fb_info->modelist) {
                modelist = list_entry(pos, struct fb_modelist, list);
                mode = &modelist->mode;
                i += mode_string(buf, i, mode);
        }
        return i;
}

static ssize_t store_bpp(struct device *device, struct device_attribute *attr,
                         const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        struct fb_var_screeninfo var;
        char ** last = NULL;
        int err;

        var = fb_info->var;
        var.bits_per_pixel = simple_strtoul(buf, last, 0);
        if ((err = activate(fb_info, &var)))
                return err;
        return count;
}

static ssize_t show_bpp(struct device *device, struct device_attribute *attr,
                        char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.bits_per_pixel);
}

static ssize_t store_rotate(struct device *device,
                            struct device_attribute *attr,
                            const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        struct fb_var_screeninfo var;
        char **last = NULL;
        int err;

        var = fb_info->var;
        var.rotate = simple_strtoul(buf, last, 0);

        if ((err = activate(fb_info, &var)))
                return err;

        return count;
}


static ssize_t show_rotate(struct device *device,
                           struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);

        return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.rotate);
}

static ssize_t store_virtual(struct device *device,
                             struct device_attribute *attr,
                             const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        struct fb_var_screeninfo var;
        char *last = NULL;
        int err;

        var = fb_info->var;
        var.xres_virtual = simple_strtoul(buf, &last, 0);
        last++;
        if (last - buf >= count)
                return -EINVAL;
        var.yres_virtual = simple_strtoul(last, &last, 0);

        if ((err = activate(fb_info, &var)))
                return err;
        return count;
}

static ssize_t show_virtual(struct device *device,
                            struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xres_virtual,
                        fb_info->var.yres_virtual);
}

static ssize_t show_stride(struct device *device,
                           struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->fix.line_length);
}

static ssize_t store_blank(struct device *device,
                           struct device_attribute *attr,
                           const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        char *last = NULL;
        int err;

        console_lock();
        fb_info->flags |= FBINFO_MISC_USEREVENT;
        err = fb_blank(fb_info, simple_strtoul(buf, &last, 0));
        fb_info->flags &= ~FBINFO_MISC_USEREVENT;
        console_unlock();
        if (err < 0)
                return err;
        return count;
}

static ssize_t show_blank(struct device *device,
                          struct device_attribute *attr, char *buf)
{
//      struct fb_info *fb_info = dev_get_drvdata(device);
        return 0;
}

static ssize_t store_console(struct device *device,
                             struct device_attribute *attr,
                             const char *buf, size_t count)
{
//      struct fb_info *fb_info = dev_get_drvdata(device);
        return 0;
}

static ssize_t show_console(struct device *device,
                            struct device_attribute *attr, char *buf)
{
//      struct fb_info *fb_info = dev_get_drvdata(device);
        return 0;
}

static ssize_t store_cursor(struct device *device,
                            struct device_attribute *attr,
                            const char *buf, size_t count)
{
//      struct fb_info *fb_info = dev_get_drvdata(device);
        return 0;
}

static ssize_t show_cursor(struct device *device,
                           struct device_attribute *attr, char *buf)
{
//      struct fb_info *fb_info = dev_get_drvdata(device);
        return 0;
}

static ssize_t store_pan(struct device *device,
                         struct device_attribute *attr,
                         const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        struct fb_var_screeninfo var;
        char *last = NULL;
        int err;

        var = fb_info->var;
        var.xoffset = simple_strtoul(buf, &last, 0);
        last++;
        if (last - buf >= count)
                return -EINVAL;
        var.yoffset = simple_strtoul(last, &last, 0);

        console_lock();
        err = fb_pan_display(fb_info, &var);
        console_unlock();

        if (err < 0)
                return err;
        return count;
}

static ssize_t show_pan(struct device *device,
                        struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xoffset,
                        fb_info->var.yoffset);
}

static ssize_t show_name(struct device *device,
                         struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);

        return snprintf(buf, PAGE_SIZE, "%s\n", fb_info->fix.id);
}

static ssize_t store_fbstate(struct device *device,
                             struct device_attribute *attr,
                             const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        u32 state;
        char *last = NULL;

        state = simple_strtoul(buf, &last, 0);

        console_lock();
        if (!lock_fb_info(fb_info)) {
                console_unlock();
                return -ENODEV;
        }

        fb_set_suspend(fb_info, (int)state);

        unlock_fb_info(fb_info);
        console_unlock();

        return count;
}

static ssize_t show_fbstate(struct device *device,
                            struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->state);
}

#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
static ssize_t store_bl_curve(struct device *device,
                              struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        u8 tmp_curve[FB_BACKLIGHT_LEVELS];
        unsigned int i;

        /* Some drivers don't use framebuffer_alloc(), but those also
         * don't have backlights.
         */
        if (!fb_info || !fb_info->bl_dev)
                return -ENODEV;

        if (count != (FB_BACKLIGHT_LEVELS / 8 * 24))
                return -EINVAL;

        for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i)
                if (sscanf(&buf[i * 24],
                        "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n",
                        &tmp_curve[i * 8 + 0],
                        &tmp_curve[i * 8 + 1],
                        &tmp_curve[i * 8 + 2],
                        &tmp_curve[i * 8 + 3],
                        &tmp_curve[i * 8 + 4],
                        &tmp_curve[i * 8 + 5],
                        &tmp_curve[i * 8 + 6],
                        &tmp_curve[i * 8 + 7]) != 8)
                        return -EINVAL;

        /* If there has been an error in the input data, we won't
         * reach this loop.
         */
        mutex_lock(&fb_info->bl_curve_mutex);
        for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i)
                fb_info->bl_curve[i] = tmp_curve[i];
        mutex_unlock(&fb_info->bl_curve_mutex);

        return count;
}

static ssize_t show_bl_curve(struct device *device,
                             struct device_attribute *attr, char *buf)
{
        struct fb_info *fb_info = dev_get_drvdata(device);
        ssize_t len = 0;
        unsigned int i;

        /* Some drivers don't use framebuffer_alloc(), but those also
         * don't have backlights.
         */
        if (!fb_info || !fb_info->bl_dev)
                return -ENODEV;

        mutex_lock(&fb_info->bl_curve_mutex);
        for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
                len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n",
                                fb_info->bl_curve + i);
        mutex_unlock(&fb_info->bl_curve_mutex);

        return len;
}
#endif

/* When cmap is added back in it should be a binary attribute
 * not a text one. Consideration should also be given to converting
 * fbdev to use configfs instead of sysfs */
static struct device_attribute device_attrs[] = {
        __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp),
        __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank),
        __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console),
        __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor),
        __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode),
        __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes),
        __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan),
        __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual),
        __ATTR(name, S_IRUGO, show_name, NULL),
        __ATTR(stride, S_IRUGO, show_stride, NULL),
        __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
        __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate),
#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
        __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve),
#endif
};

int fb_init_device(struct fb_info *fb_info)
{
        int i, error = 0;

        dev_set_drvdata(fb_info->dev, fb_info);

        fb_info->class_flag |= FB_SYSFS_FLAG_ATTR;

        for (i = 0; i < ARRAY_SIZE(device_attrs); i++) {
                error = device_create_file(fb_info->dev, &device_attrs[i]);

                if (error)
                        break;
        }

        if (error) {
                while (--i >= 0)
                        device_remove_file(fb_info->dev, &device_attrs[i]);
                fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
        }

        return 0;
}

void fb_cleanup_device(struct fb_info *fb_info)
{
        unsigned int i;

        if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) {
                for (i = 0; i < ARRAY_SIZE(device_attrs); i++)
                        device_remove_file(fb_info->dev, &device_attrs[i]);

                fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
        }
}

#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
/* This function generates a linear backlight curve
 *
 *     0: off
 *   1-7: min
 * 8-127: linear from min to max
 */
void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max)
{
        unsigned int i, flat, count, range = (max - min);

        mutex_lock(&fb_info->bl_curve_mutex);

        fb_info->bl_curve[0] = off;

        for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
                fb_info->bl_curve[flat] = min;

        count = FB_BACKLIGHT_LEVELS * 15 / 16;
        for (i = 0; i < count; ++i)
                fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count);

        mutex_unlock(&fb_info->bl_curve_mutex);
}
EXPORT_SYMBOL_GPL(fb_bl_default_curve);
#endif