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1/*
2 * Copyright © 2008 Intel Corporation
3 * Copyright © 2016 Collabora Ltd
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 *
24 * Based on code from the i915 driver.
25 * Original author: Damien Lespiau <damien.lespiau@intel.com>
26 *
27 */
28
29#include <linux/circ_buf.h>
30#include <linux/ctype.h>
31#include <linux/debugfs.h>
32#include <drm/drmP.h>
33#include "drm_internal.h"
34
35/**
36 * DOC: CRC ABI
37 *
38 * DRM device drivers can provide to userspace CRC information of each frame as
39 * it reached a given hardware component (a "source").
40 *
41 * Userspace can control generation of CRCs in a given CRTC by writing to the
42 * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
43 * Accepted values are source names (which are driver-specific) and the "auto"
44 * keyword, which will let the driver select a default source of frame CRCs
45 * for this CRTC.
46 *
47 * Once frame CRC generation is enabled, userspace can capture them by reading
48 * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
49 * number in the first field and then a number of unsigned integer fields
50 * containing the CRC data. Fields are separated by a single space and the number
51 * of CRC fields is source-specific.
52 *
53 * Note that though in some cases the CRC is computed in a specified way and on
54 * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
55 * computation is performed in an unspecified way and on frame contents that have
56 * been already processed in also an unspecified way and thus userspace cannot
57 * rely on being able to generate matching CRC values for the frame contents that
58 * it submits. In this general case, the maximum userspace can do is to compare
59 * the reported CRCs of frames that should have the same contents.
60 */
61
62static int crc_control_show(struct seq_file *m, void *data)
63{
64 struct drm_crtc *crtc = m->private;
65
66 seq_printf(m, "%s\n", crtc->crc.source);
67
68 return 0;
69}
70
71static int crc_control_open(struct inode *inode, struct file *file)
72{
73 struct drm_crtc *crtc = inode->i_private;
74
75 return single_open(file, crc_control_show, crtc);
76}
77
78static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
79 size_t len, loff_t *offp)
80{
81 struct seq_file *m = file->private_data;
82 struct drm_crtc *crtc = m->private;
83 struct drm_crtc_crc *crc = &crtc->crc;
84 char *source;
85
86 if (len == 0)
87 return 0;
88
89 if (len > PAGE_SIZE - 1) {
90 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
91 PAGE_SIZE);
92 return -E2BIG;
93 }
94
95 source = memdup_user_nul(ubuf, len);
96 if (IS_ERR(source))
97 return PTR_ERR(source);
98
99 if (source[len] == '\n')
100 source[len] = '\0';
101
102 spin_lock_irq(&crc->lock);
103
104 if (crc->opened) {
105 spin_unlock_irq(&crc->lock);
106 kfree(source);
107 return -EBUSY;
108 }
109
110 kfree(crc->source);
111 crc->source = source;
112
113 spin_unlock_irq(&crc->lock);
114
115 *offp += len;
116 return len;
117}
118
119static const struct file_operations drm_crtc_crc_control_fops = {
120 .owner = THIS_MODULE,
121 .open = crc_control_open,
122 .read = seq_read,
123 .llseek = seq_lseek,
124 .release = single_release,
125 .write = crc_control_write
126};
127
128static int crtc_crc_open(struct inode *inode, struct file *filep)
129{
130 struct drm_crtc *crtc = inode->i_private;
131 struct drm_crtc_crc *crc = &crtc->crc;
132 struct drm_crtc_crc_entry *entries = NULL;
133 size_t values_cnt;
134 int ret;
135
136 if (crc->opened)
137 return -EBUSY;
138
139 ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
140 if (ret)
141 return ret;
142
143 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) {
144 ret = -EINVAL;
145 goto err_disable;
146 }
147
148 if (WARN_ON(values_cnt == 0)) {
149 ret = -EINVAL;
150 goto err_disable;
151 }
152
153 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
154 if (!entries) {
155 ret = -ENOMEM;
156 goto err_disable;
157 }
158
159 spin_lock_irq(&crc->lock);
160 crc->entries = entries;
161 crc->values_cnt = values_cnt;
162 crc->opened = true;
163 spin_unlock_irq(&crc->lock);
164
165 return 0;
166
167err_disable:
168 crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
169 return ret;
170}
171
172static int crtc_crc_release(struct inode *inode, struct file *filep)
173{
174 struct drm_crtc *crtc = filep->f_inode->i_private;
175 struct drm_crtc_crc *crc = &crtc->crc;
176 size_t values_cnt;
177
178 spin_lock_irq(&crc->lock);
179 kfree(crc->entries);
180 crc->entries = NULL;
181 crc->head = 0;
182 crc->tail = 0;
183 crc->values_cnt = 0;
184 crc->opened = false;
185 spin_unlock_irq(&crc->lock);
186
187 crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
188
189 return 0;
190}
191
192static int crtc_crc_data_count(struct drm_crtc_crc *crc)
193{
194 assert_spin_locked(&crc->lock);
195 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
196}
197
198/*
199 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
200 * separated, with a newline at the end and null-terminated.
201 */
202#define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1)
203#define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR))
204
205static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
206 size_t count, loff_t *pos)
207{
208 struct drm_crtc *crtc = filep->f_inode->i_private;
209 struct drm_crtc_crc *crc = &crtc->crc;
210 struct drm_crtc_crc_entry *entry;
211 char buf[MAX_LINE_LEN];
212 int ret, i;
213
214 spin_lock_irq(&crc->lock);
215
216 if (!crc->source) {
217 spin_unlock_irq(&crc->lock);
218 return 0;
219 }
220
221 /* Nothing to read? */
222 while (crtc_crc_data_count(crc) == 0) {
223 if (filep->f_flags & O_NONBLOCK) {
224 spin_unlock_irq(&crc->lock);
225 return -EAGAIN;
226 }
227
228 ret = wait_event_interruptible_lock_irq(crc->wq,
229 crtc_crc_data_count(crc),
230 crc->lock);
231 if (ret) {
232 spin_unlock_irq(&crc->lock);
233 return ret;
234 }
235 }
236
237 /* We know we have an entry to be read */
238 entry = &crc->entries[crc->tail];
239
240 if (count < LINE_LEN(crc->values_cnt)) {
241 spin_unlock_irq(&crc->lock);
242 return -EINVAL;
243 }
244
245 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
246 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);
247
248 spin_unlock_irq(&crc->lock);
249
250 if (entry->has_frame_counter)
251 sprintf(buf, "0x%08x", entry->frame);
252 else
253 sprintf(buf, "XXXXXXXXXX");
254
255 for (i = 0; i < crc->values_cnt; i++)
256 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
257 sprintf(buf + 10 + crc->values_cnt * 11, "\n");
258
259 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
260 return -EFAULT;
261
262 return LINE_LEN(crc->values_cnt);
263}
264
265static const struct file_operations drm_crtc_crc_data_fops = {
266 .owner = THIS_MODULE,
267 .open = crtc_crc_open,
268 .read = crtc_crc_read,
269 .release = crtc_crc_release,
270};
271
272/**
273 * drm_debugfs_crtc_crc_add - Add files to debugfs for capture of frame CRCs
274 * @crtc: CRTC to whom the frames will belong
275 *
276 * Adds files to debugfs directory that allows userspace to control the
277 * generation of frame CRCs and to read them.
278 *
279 * Returns:
280 * Zero on success, error code on failure.
281 */
282int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
283{
284 struct dentry *crc_ent, *ent;
285
286 if (!crtc->funcs->set_crc_source)
287 return 0;
288
289 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
290 if (!crc_ent)
291 return -ENOMEM;
292
293 ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
294 &drm_crtc_crc_control_fops);
295 if (!ent)
296 goto error;
297
298 ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
299 &drm_crtc_crc_data_fops);
300 if (!ent)
301 goto error;
302
303 return 0;
304
305error:
306 debugfs_remove_recursive(crc_ent);
307
308 return -ENOMEM;
309}
310
311/**
312 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
313 * @crtc: CRTC to which the frame belongs
314 * @has_frame: whether this entry has a frame number to go with
315 * @frame: number of the frame these CRCs are about
316 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
317 *
318 * For each frame, the driver polls the source of CRCs for new data and calls
319 * this function to add them to the buffer from where userspace reads.
320 */
321int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
322 uint32_t frame, uint32_t *crcs)
323{
324 struct drm_crtc_crc *crc = &crtc->crc;
325 struct drm_crtc_crc_entry *entry;
326 int head, tail;
327
328 assert_spin_locked(&crc->lock);
329
330 /* Caller may not have noticed yet that userspace has stopped reading */
331 if (!crc->opened)
332 return -EINVAL;
333
334 head = crc->head;
335 tail = crc->tail;
336
337 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
338 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
339 return -ENOBUFS;
340 }
341
342 entry = &crc->entries[head];
343 entry->frame = frame;
344 entry->has_frame_counter = has_frame;
345 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);
346
347 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
348 crc->head = head;
349
350 return 0;
351}
352EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);