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 54 if (*buf == NULL) { 55 DRM_ERROR("Failed to allocate drm buffer object to hold" 56 " %d bytes in %d pages.\n", 57 size, nr_pages); 58 return -ENOMEM; 59 } 60 61 (*buf)->size = size; 62 63 for (idx = 0; idx < nr_pages; ++idx) { 64 65 (*buf)->data[idx] = 66 malloc(min(PAGE_SIZE, size - idx * PAGE_SIZE), 67 DRM_MEM_DRIVER, M_WAITOK); 68 69 70 if ((*buf)->data[idx] == NULL) { 71 DRM_ERROR("Failed to allocate %dth page for drm" 72 " buffer with %d bytes and %d pages.\n", 73 idx + 1, size, nr_pages); 74 goto error_out; 75 } 76 77 } 78 79 return 0; 80 81 error_out: 82 83 /* Only last element can be null pointer so check for it first. */ 84 if ((*buf)->data[idx]) 85 free((*buf)->data[idx], DRM_MEM_DRIVER); 86 87 for (--idx; idx >= 0; --idx) 88 free((*buf)->data[idx], DRM_MEM_DRIVER); 89 90 free(*buf, DRM_MEM_DRIVER); 91 return -ENOMEM; 92 } 93 EXPORT_SYMBOL(drm_buffer_alloc); 94 95 /** 96 * Copy the user data to the begin of the buffer and reset the processing 97 * iterator. 98 * 99 * user_data: A pointer the data that is copied to the buffer. 100 * size: The Number of bytes to copy. 101 */ 102 int drm_buffer_copy_from_user(struct drm_buffer *buf, 103 void __user *user_data, int size) 104 { 105 int nr_pages = size / PAGE_SIZE + 1; 106 int idx; 107 108 if (size > buf->size) { 109 DRM_ERROR("Requesting to copy %d bytes to a drm buffer with" 110 " %d bytes space\n", 111 size, buf->size); 112 return -EFAULT; 113 } 114 115 for (idx = 0; idx < nr_pages; ++idx) { 116 117 if (DRM_COPY_FROM_USER(buf->data[idx], 118 (char *)user_data + idx * PAGE_SIZE, 119 min(PAGE_SIZE, size - idx * PAGE_SIZE))) { 120 DRM_ERROR("Failed to copy user data (%p) to drm buffer" 121 " (%p) %dth page.\n", 122 user_data, buf, idx); 123 return -EFAULT; 124 125 } 126 } 127 buf->iterator = 0; 128 return 0; 129 } 130 EXPORT_SYMBOL(drm_buffer_copy_from_user); 131 132 /** 133 * Free the drm buffer object 134 */ 135 void drm_buffer_free(struct drm_buffer *buf) 136 { 137 138 if (buf != NULL) { 139 140 int nr_pages = buf->size / PAGE_SIZE + 1; 141 int idx; 142 for (idx = 0; idx < nr_pages; ++idx) 143 free(buf->data[idx], DRM_MEM_DRIVER); 144 145 free(buf, DRM_MEM_DRIVER); 146 } 147 } 148 EXPORT_SYMBOL(drm_buffer_free); 149 150 /** 151 * Read an object from buffer that may be split to multiple parts. If object 152 * is not split function just returns the pointer to object in buffer. But in 153 * case of split object data is copied to given stack object that is suplied 154 * by caller. 155 * 156 * The processing location of the buffer is also advanced to the next byte 157 * after the object. 158 * 159 * objsize: The size of the objet in bytes. 160 * stack_obj: A pointer to a memory location where object can be copied. 161 */ 162 void *drm_buffer_read_object(struct drm_buffer *buf, 163 int objsize, void *stack_obj) 164 { 165 int idx = drm_buffer_index(buf); 166 int page = drm_buffer_page(buf); 167 void *obj = NULL; 168 169 if (idx + objsize <= PAGE_SIZE) { 170 obj = &buf->data[page][idx]; 171 } else { 172 /* The object is split which forces copy to temporary object.*/ 173 int beginsz = PAGE_SIZE - idx; 174 memcpy(stack_obj, &buf->data[page][idx], beginsz); 175 176 memcpy((char *)stack_obj + beginsz, &buf->data[page + 1][0], 177 objsize - beginsz); 178 179 obj = stack_obj; 180 } 181 182 drm_buffer_advance(buf, objsize); 183 return obj; 184 } 185 EXPORT_SYMBOL(drm_buffer_read_object); 186