80 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2 3#include <linux/export.h>4#include <linux/fb.h>5#include <linux/mutex.h>6#include <linux/slab.h>7 8/**9 * framebuffer_alloc - creates a new frame buffer info structure10 *11 * @size: size of driver private data, can be zero12 * @dev: pointer to the device for this fb, this can be NULL13 *14 * Creates a new frame buffer info structure. Also reserves @size bytes15 * for driver private data (info->par). info->par (if any) will be16 * aligned to sizeof(long). The new instances of struct fb_info and17 * the driver private data are both cleared to zero.18 *19 * Returns the new structure, or NULL if an error occurred.20 *21 */22struct fb_info *framebuffer_alloc(size_t size, struct device *dev)23{24#define BYTES_PER_LONG (BITS_PER_LONG/8)25#define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))26 int fb_info_size = sizeof(struct fb_info);27 struct fb_info *info;28 char *p;29 30 if (size)31 fb_info_size += PADDING;32 33 p = kzalloc(fb_info_size + size, GFP_KERNEL);34 35 if (!p)36 return NULL;37 38 info = (struct fb_info *) p;39 40 if (size)41 info->par = p + fb_info_size;42 43 info->device = dev;44 info->fbcon_rotate_hint = -1;45 46#if IS_ENABLED(CONFIG_FB_BACKLIGHT)47 mutex_init(&info->bl_curve_mutex);48#endif49 50 return info;51#undef PADDING52#undef BYTES_PER_LONG53}54EXPORT_SYMBOL(framebuffer_alloc);55 56/**57 * framebuffer_release - marks the structure available for freeing58 *59 * @info: frame buffer info structure60 *61 * Drop the reference count of the device embedded in the62 * framebuffer info structure.63 *64 */65void framebuffer_release(struct fb_info *info)66{67 if (!info)68 return;69 70 if (WARN_ON(refcount_read(&info->count)))71 return;72 73#if IS_ENABLED(CONFIG_FB_BACKLIGHT)74 mutex_destroy(&info->bl_curve_mutex);75#endif76 77 kfree(info);78}79EXPORT_SYMBOL(framebuffer_release);80