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}
95EXPORT_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 */
104int 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}
132EXPORT_SYMBOL(drm_buffer_copy_from_user);
133
134/**
135 * Free the drm buffer object
136 */
137void 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}
150EXPORT_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 */
164void *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}
187EXPORT_SYMBOL(drm_buffer_read_object);
188