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 */
46int 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
83error_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
96/**
97 * Copy the user data to the begin of the buffer and reset the processing
98 * iterator.
99 *
100 *   user_data: A pointer the data that is copied to the buffer.
101 *   size: The Number of bytes to copy.
102 */
103int drm_buffer_copy_from_user(struct drm_buffer *buf,
104			      void __user *user_data, int size)
105{
106	int nr_pages = size / PAGE_SIZE + 1;
107	int idx;
108
109	if (size > buf->size) {
110		DRM_ERROR("Requesting to copy %d bytes to a drm buffer with"
111				" %d bytes space\n",
112				size, buf->size);
113		return -EFAULT;
114	}
115
116	for (idx = 0; idx < nr_pages; ++idx) {
117
118		if (DRM_COPY_FROM_USER(buf->data[idx],
119			(char *)user_data + idx * PAGE_SIZE,
120			min(PAGE_SIZE, size - idx * PAGE_SIZE))) {
121			DRM_ERROR("Failed to copy user data (%p) to drm buffer"
122					" (%p) %dth page.\n",
123					user_data, buf, idx);
124			return -EFAULT;
125
126		}
127	}
128	buf->iterator = 0;
129	return 0;
130}
131
132/**
133 * Free the drm buffer object
134 */
135void 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
149/**
150 * Read an object from buffer that may be split to multiple parts. If object
151 * is not split function just returns the pointer to object in buffer. But in
152 * case of split object data is copied to given stack object that is suplied
153 * by caller.
154 *
155 * The processing location of the buffer is also advanced to the next byte
156 * after the object.
157 *
158 *   objsize: The size of the objet in bytes.
159 *   stack_obj: A pointer to a memory location where object can be copied.
160 */
161void *drm_buffer_read_object(struct drm_buffer *buf,
162		int objsize, void *stack_obj)
163{
164	int idx = drm_buffer_index(buf);
165	int page = drm_buffer_page(buf);
166	void *obj = NULL;
167
168	if (idx + objsize <= PAGE_SIZE) {
169		obj = &buf->data[page][idx];
170	} else {
171		/* The object is split which forces copy to temporary object.*/
172		int beginsz = PAGE_SIZE - idx;
173		memcpy(stack_obj, &buf->data[page][idx], beginsz);
174
175		memcpy((char *)stack_obj + beginsz, &buf->data[page + 1][0],
176				objsize - beginsz);
177
178		obj = stack_obj;
179	}
180
181	drm_buffer_advance(buf, objsize);
182	return obj;
183}
184