1 /**************************************************************************
3 * Copyright 2010 Pauli Nieminen.
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:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
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.
27 **************************************************************************/
29 * Multipart buffer for coping data which is larger than the page size.
32 * Pauli Nieminen <suokkos-at-gmail-dot-com>
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include <dev/drm2/drm_buffer.h>
41 * Allocate the drm buffer object.
43 * buf: Pointer to a pointer where the object is stored.
44 * size: The number of bytes to allocate.
46 int drm_buffer_alloc(struct drm_buffer **buf, int size)
48 int nr_pages = size / PAGE_SIZE + 1;
51 /* Allocating pointer table to end of structure makes drm_buffer
53 *buf = malloc(sizeof(struct drm_buffer) + nr_pages*sizeof(char *),
54 DRM_MEM_DRIVER, M_ZERO | M_WAITOK);
57 DRM_ERROR("Failed to allocate drm buffer object to hold"
58 " %d bytes in %d pages.\n",
65 for (idx = 0; idx < nr_pages; ++idx) {
68 malloc(min(PAGE_SIZE, size - idx * PAGE_SIZE),
69 DRM_MEM_DRIVER, M_WAITOK);
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);
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);
89 for (--idx; idx >= 0; --idx)
90 free((*buf)->data[idx], DRM_MEM_DRIVER);
92 free(*buf, DRM_MEM_DRIVER);
95 EXPORT_SYMBOL(drm_buffer_alloc);
98 * Copy the user data to the begin of the buffer and reset the processing
101 * user_data: A pointer the data that is copied to the buffer.
102 * size: The Number of bytes to copy.
104 int drm_buffer_copy_from_user(struct drm_buffer *buf,
105 void __user *user_data, int size)
107 int nr_pages = size / PAGE_SIZE + 1;
110 if (size > buf->size) {
111 DRM_ERROR("Requesting to copy %d bytes to a drm buffer with"
117 for (idx = 0; idx < nr_pages; ++idx) {
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);
132 EXPORT_SYMBOL(drm_buffer_copy_from_user);
135 * Free the drm buffer object
137 void drm_buffer_free(struct drm_buffer *buf)
142 int nr_pages = buf->size / PAGE_SIZE + 1;
144 for (idx = 0; idx < nr_pages; ++idx)
145 free(buf->data[idx], DRM_MEM_DRIVER);
147 free(buf, DRM_MEM_DRIVER);
150 EXPORT_SYMBOL(drm_buffer_free);
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
158 * The processing location of the buffer is also advanced to the next byte
161 * objsize: The size of the objet in bytes.
162 * stack_obj: A pointer to a memory location where object can be copied.
164 void *drm_buffer_read_object(struct drm_buffer *buf,
165 int objsize, void *stack_obj)
167 int idx = drm_buffer_index(buf);
168 int page = drm_buffer_page(buf);
171 if (idx + objsize <= PAGE_SIZE) {
172 obj = &buf->data[page][idx];
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);
178 memcpy((char *)stack_obj + beginsz, &buf->data[page + 1][0],
184 drm_buffer_advance(buf, objsize);
187 EXPORT_SYMBOL(drm_buffer_read_object);