1 /************************************************************************** 2 * 3 * Copyright 2010 Pauli Nieminen. 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * 27 **************************************************************************/ 28 /* 29 * Multipart buffer for coping data which is larger than the page size. 30 * 31 * Authors: 32 * Pauli Nieminen <suokkos-at-gmail-dot-com> 33 */ 34 35 #include <sys/cdefs.h> 36 #include <dev/drm2/drm_buffer.h> 37 38 /** 39 * Allocate the drm buffer object. 40 * 41 * buf: Pointer to a pointer where the object is stored. 42 * size: The number of bytes to allocate. 43 */ 44 int drm_buffer_alloc(struct drm_buffer **buf, int size) 45 { 46 int nr_pages = size / PAGE_SIZE + 1; 47 int idx; 48 49 /* Allocating pointer table to end of structure makes drm_buffer 50 * variable sized */ 51 *buf = malloc(sizeof(struct drm_buffer) + nr_pages*sizeof(char *), 52 DRM_MEM_DRIVER, M_ZERO | M_WAITOK); 53 (*buf)->size = size; 54 55 for (idx = 0; idx < nr_pages; ++idx) { 56 (*buf)->data[idx] = 57 malloc(min(PAGE_SIZE, size - idx * PAGE_SIZE), 58 DRM_MEM_DRIVER, M_WAITOK); 59 } 60 61 return 0; 62 } 63 EXPORT_SYMBOL(drm_buffer_alloc); 64 65 /** 66 * Copy the user data to the begin of the buffer and reset the processing 67 * iterator. 68 * 69 * user_data: A pointer the data that is copied to the buffer. 70 * size: The Number of bytes to copy. 71 */ 72 int drm_buffer_copy_from_user(struct drm_buffer *buf, 73 void __user *user_data, int size) 74 { 75 int nr_pages = size / PAGE_SIZE + 1; 76 int idx; 77 78 if (size > buf->size) { 79 DRM_ERROR("Requesting to copy %d bytes to a drm buffer with" 80 " %d bytes space\n", 81 size, buf->size); 82 return -EFAULT; 83 } 84 85 for (idx = 0; idx < nr_pages; ++idx) { 86 87 if (DRM_COPY_FROM_USER(buf->data[idx], 88 (char *)user_data + idx * PAGE_SIZE, 89 min(PAGE_SIZE, size - idx * PAGE_SIZE))) { 90 DRM_ERROR("Failed to copy user data (%p) to drm buffer" 91 " (%p) %dth page.\n", 92 user_data, buf, idx); 93 return -EFAULT; 94 95 } 96 } 97 buf->iterator = 0; 98 return 0; 99 } 100 EXPORT_SYMBOL(drm_buffer_copy_from_user); 101 102 /** 103 * Free the drm buffer object 104 */ 105 void drm_buffer_free(struct drm_buffer *buf) 106 { 107 108 if (buf != NULL) { 109 110 int nr_pages = buf->size / PAGE_SIZE + 1; 111 int idx; 112 for (idx = 0; idx < nr_pages; ++idx) 113 free(buf->data[idx], DRM_MEM_DRIVER); 114 115 free(buf, DRM_MEM_DRIVER); 116 } 117 } 118 EXPORT_SYMBOL(drm_buffer_free); 119 120 /** 121 * Read an object from buffer that may be split to multiple parts. If object 122 * is not split function just returns the pointer to object in buffer. But in 123 * case of split object data is copied to given stack object that is suplied 124 * by caller. 125 * 126 * The processing location of the buffer is also advanced to the next byte 127 * after the object. 128 * 129 * objsize: The size of the objet in bytes. 130 * stack_obj: A pointer to a memory location where object can be copied. 131 */ 132 void *drm_buffer_read_object(struct drm_buffer *buf, 133 int objsize, void *stack_obj) 134 { 135 int idx = drm_buffer_index(buf); 136 int page = drm_buffer_page(buf); 137 void *obj = NULL; 138 139 if (idx + objsize <= PAGE_SIZE) { 140 obj = &buf->data[page][idx]; 141 } else { 142 /* The object is split which forces copy to temporary object.*/ 143 int beginsz = PAGE_SIZE - idx; 144 memcpy(stack_obj, &buf->data[page][idx], beginsz); 145 146 memcpy((char *)stack_obj + beginsz, &buf->data[page + 1][0], 147 objsize - beginsz); 148 149 obj = stack_obj; 150 } 151 152 drm_buffer_advance(buf, objsize); 153 return obj; 154 } 155 EXPORT_SYMBOL(drm_buffer_read_object); 156