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). The new instances of struct fb_info and 17 * the driver private data are both cleared to zero. 18 * 19 * Returns the new structure, or NULL if an error occurred. 20 * 21 */ 22 struct 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 #endif 49 50 return info; 51 #undef PADDING 52 #undef BYTES_PER_LONG 53 } 54 EXPORT_SYMBOL(framebuffer_alloc); 55 56 /** 57 * framebuffer_release - marks the structure available for freeing 58 * 59 * @info: frame buffer info structure 60 * 61 * Drop the reference count of the device embedded in the 62 * framebuffer info structure. 63 * 64 */ 65 void 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 #endif 76 77 kfree(info); 78 } 79 EXPORT_SYMBOL(framebuffer_release); 80