1 // SPDX-License-Identifier: GPL-2.0-or-later 2 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 structure 10 * 11 * @size: size of driver private data, can be zero 12 * @dev: pointer to the device for this fb, this can be NULL 13 * 14 * Creates a new frame buffer info structure. Also reserves @size bytes 15 * for driver private data (info->par). info->par (if any) will be 16 * aligned to sizeof(long). 17 * 18 * Returns the new structure, or NULL if an error occurred. 19 * 20 */ 21 struct fb_info *framebuffer_alloc(size_t size, struct device *dev) 22 { 23 #define BYTES_PER_LONG (BITS_PER_LONG/8) 24 #define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG)) 25 int fb_info_size = sizeof(struct fb_info); 26 struct fb_info *info; 27 char *p; 28 29 if (size) 30 fb_info_size += PADDING; 31 32 p = kzalloc(fb_info_size + size, GFP_KERNEL); 33 34 if (!p) 35 return NULL; 36 37 info = (struct fb_info *) p; 38 39 if (size) 40 info->par = p + fb_info_size; 41 42 info->device = dev; 43 info->fbcon_rotate_hint = -1; 44 45 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 46 mutex_init(&info->bl_curve_mutex); 47 #endif 48 49 return info; 50 #undef PADDING 51 #undef BYTES_PER_LONG 52 } 53 EXPORT_SYMBOL(framebuffer_alloc); 54 55 /** 56 * framebuffer_release - marks the structure available for freeing 57 * 58 * @info: frame buffer info structure 59 * 60 * Drop the reference count of the device embedded in the 61 * framebuffer info structure. 62 * 63 */ 64 void framebuffer_release(struct fb_info *info) 65 { 66 if (!info) 67 return; 68 69 if (WARN_ON(refcount_read(&info->count))) 70 return; 71 72 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 73 mutex_destroy(&info->bl_curve_mutex); 74 #endif 75 76 kfree(info); 77 } 78 EXPORT_SYMBOL(framebuffer_release); 79