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 __FBSDID("$FreeBSD$"); 37 38 #include <dev/drm2/drm_buffer.h> 39 40 /** 41 * Allocate the drm buffer object. 42 * 43 * buf: Pointer to a pointer where the object is stored. 44 * size: The number of bytes to allocate. 45 */ 46 int drm_buffer_alloc(struct drm_buffer **buf, int size) 47 { 48 int nr_pages = size / PAGE_SIZE + 1; 49 int idx; 50 51 /* Allocating pointer table to end of structure makes drm_buffer 52 * variable sized */ 53 *buf = malloc(sizeof(struct drm_buffer) + nr_pages*sizeof(char *), 54 DRM_MEM_DRIVER, M_ZERO | M_WAITOK); 55 56 if (*buf == NULL) { 57 DRM_ERROR("Failed to allocate drm buffer object to hold" 58 " %d bytes in %d pages.\n", 59 size, nr_pages); 60 return -ENOMEM; 61 } 62 63 (*buf)->size = size; 64 65 for (idx = 0; idx < nr_pages; ++idx) { 66 67 (*buf)->data[idx] = 68 malloc(min(PAGE_SIZE, size - idx * PAGE_SIZE), 69 DRM_MEM_DRIVER, M_WAITOK); 70 71 72 if ((*buf)->data[idx] == NULL) { 73 DRM_ERROR("Failed to allocate %dth page for drm" 74 " buffer with %d bytes and %d pages.\n", 75 idx + 1, size, nr_pages); 76 goto error_out; 77 } 78 79 } 80 81 return 0; 82 83 error_out: 84 85 /* Only last element can be null pointer so check for it first. */ 86 if ((*buf)->data[idx]) 87 free((*buf)->data[idx], DRM_MEM_DRIVER); 88 89 for (--idx; idx >= 0; --idx) 90 free((*buf)->data[idx], DRM_MEM_DRIVER); 91 92 free(*buf, DRM_MEM_DRIVER); 93 return -ENOMEM; 94 } 95 EXPORT_SYMBOL(drm_buffer_alloc); 96 97 /** 98 * Copy the user data to the begin of the buffer and reset the processing 99 * iterator. 100 * 101 * user_data: A pointer the data that is copied to the buffer. 102 * size: The Number of bytes to copy. 103 */ 104 int drm_buffer_copy_from_user(struct drm_buffer *buf, 105 void __user *user_data, int size) 106 { 107 int nr_pages = size / PAGE_SIZE + 1; 108 int idx; 109 110 if (size > buf->size) { 111 DRM_ERROR("Requesting to copy %d bytes to a drm buffer with" 112 " %d bytes space\n", 113 size, buf->size); 114 return -EFAULT; 115 } 116 117 for (idx = 0; idx < nr_pages; ++idx) { 118 119 if (DRM_COPY_FROM_USER(buf->data[idx], 120 (char *)user_data + idx * PAGE_SIZE, 121 min(PAGE_SIZE, size - idx * PAGE_SIZE))) { 122 DRM_ERROR("Failed to copy user data (%p) to drm buffer" 123 " (%p) %dth page.\n", 124 user_data, buf, idx); 125 return -EFAULT; 126 127 } 128 } 129 buf->iterator = 0; 130 return 0; 131 } 132 EXPORT_SYMBOL(drm_buffer_copy_from_user); 133 134 /** 135 * Free the drm buffer object 136 */ 137 void drm_buffer_free(struct drm_buffer *buf) 138 { 139 140 if (buf != NULL) { 141 142 int nr_pages = buf->size / PAGE_SIZE + 1; 143 int idx; 144 for (idx = 0; idx < nr_pages; ++idx) 145 free(buf->data[idx], DRM_MEM_DRIVER); 146 147 free(buf, DRM_MEM_DRIVER); 148 } 149 } 150 EXPORT_SYMBOL(drm_buffer_free); 151 152 /** 153 * Read an object from buffer that may be split to multiple parts. If object 154 * is not split function just returns the pointer to object in buffer. But in 155 * case of split object data is copied to given stack object that is suplied 156 * by caller. 157 * 158 * The processing location of the buffer is also advanced to the next byte 159 * after the object. 160 * 161 * objsize: The size of the objet in bytes. 162 * stack_obj: A pointer to a memory location where object can be copied. 163 */ 164 void *drm_buffer_read_object(struct drm_buffer *buf, 165 int objsize, void *stack_obj) 166 { 167 int idx = drm_buffer_index(buf); 168 int page = drm_buffer_page(buf); 169 void *obj = NULL; 170 171 if (idx + objsize <= PAGE_SIZE) { 172 obj = &buf->data[page][idx]; 173 } else { 174 /* The object is split which forces copy to temporary object.*/ 175 int beginsz = PAGE_SIZE - idx; 176 memcpy(stack_obj, &buf->data[page][idx], beginsz); 177 178 memcpy((char *)stack_obj + beginsz, &buf->data[page + 1][0], 179 objsize - beginsz); 180 181 obj = stack_obj; 182 } 183 184 drm_buffer_advance(buf, objsize); 185 return obj; 186 } 187 EXPORT_SYMBOL(drm_buffer_read_object); 188