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1/*2 * Copyright © 2008 Intel Corporation3 * Copyright © 2016 Collabora Ltd4 *5 * Permission is hereby granted, free of charge, to any person obtaining a6 * copy of this software and associated documentation files (the "Software"),7 * to deal in the Software without restriction, including without limitation8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,9 * and/or sell copies of the Software, and to permit persons to whom the10 * Software is furnished to do so, subject to the following conditions:11 *12 * The above copyright notice and this permission notice (including the next13 * paragraph) shall be included in all copies or substantial portions of the14 * Software.15 *16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS22 * 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 <linux/poll.h>33#include <linux/uaccess.h>34 35#include <drm/drm_crtc.h>36#include <drm/drm_debugfs_crc.h>37#include <drm/drm_drv.h>38#include <drm/drm_print.h>39 40#include "drm_internal.h"41 42/**43 * DOC: CRC ABI44 *45 * DRM device drivers can provide to userspace CRC information of each frame as46 * it reached a given hardware component (a CRC sampling "source").47 *48 * Userspace can control generation of CRCs in a given CRTC by writing to the49 * file dri/0/crtc-N/crc/control in debugfs, with N being the :ref:`index of50 * the CRTC<crtc_index>`. Accepted values are source names (which are51 * driver-specific) and the "auto" keyword, which will let the driver select a52 * default source of frame CRCs for this CRTC.53 *54 * Once frame CRC generation is enabled, userspace can capture them by reading55 * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame56 * number in the first field and then a number of unsigned integer fields57 * containing the CRC data. Fields are separated by a single space and the number58 * of CRC fields is source-specific.59 *60 * Note that though in some cases the CRC is computed in a specified way and on61 * the frame contents as supplied by userspace (eDP 1.3), in general the CRC62 * computation is performed in an unspecified way and on frame contents that have63 * been already processed in also an unspecified way and thus userspace cannot64 * rely on being able to generate matching CRC values for the frame contents that65 * it submits. In this general case, the maximum userspace can do is to compare66 * the reported CRCs of frames that should have the same contents.67 *68 * On the driver side the implementation effort is minimal, drivers only need to69 * implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source.70 * The debugfs files are automatically set up if those vfuncs are set. CRC samples71 * need to be captured in the driver by calling drm_crtc_add_crc_entry().72 * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source73 * may result in a commit (even a full modeset).74 *75 * CRC results must be reliable across non-full-modeset atomic commits, so if a76 * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with77 * CRC generation, then the driver must mark that commit as a full modeset78 * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure79 * consistent results, generic userspace must re-setup CRC generation after a80 * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET.81 */82 83static int crc_control_show(struct seq_file *m, void *data)84{85 struct drm_crtc *crtc = m->private;86 87 if (crtc->funcs->get_crc_sources) {88 size_t count;89 const char *const *sources = crtc->funcs->get_crc_sources(crtc,90 &count);91 size_t values_cnt;92 int i;93 94 if (count == 0 || !sources)95 goto out;96 97 for (i = 0; i < count; i++)98 if (!crtc->funcs->verify_crc_source(crtc, sources[i],99 &values_cnt)) {100 if (strcmp(sources[i], crtc->crc.source))101 seq_printf(m, "%s\n", sources[i]);102 else103 seq_printf(m, "%s*\n", sources[i]);104 }105 }106 return 0;107 108out:109 seq_printf(m, "%s*\n", crtc->crc.source);110 return 0;111}112 113static int crc_control_open(struct inode *inode, struct file *file)114{115 struct drm_crtc *crtc = inode->i_private;116 117 return single_open(file, crc_control_show, crtc);118}119 120static ssize_t crc_control_write(struct file *file, const char __user *ubuf,121 size_t len, loff_t *offp)122{123 struct seq_file *m = file->private_data;124 struct drm_crtc *crtc = m->private;125 struct drm_crtc_crc *crc = &crtc->crc;126 char *source;127 size_t values_cnt;128 int ret;129 130 if (len == 0)131 return 0;132 133 if (len > PAGE_SIZE - 1) {134 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",135 PAGE_SIZE);136 return -E2BIG;137 }138 139 source = memdup_user_nul(ubuf, len);140 if (IS_ERR(source))141 return PTR_ERR(source);142 143 if (source[len - 1] == '\n')144 source[len - 1] = '\0';145 146 ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);147 if (ret) {148 kfree(source);149 return ret;150 }151 152 spin_lock_irq(&crc->lock);153 154 if (crc->opened) {155 spin_unlock_irq(&crc->lock);156 kfree(source);157 return -EBUSY;158 }159 160 kfree(crc->source);161 crc->source = source;162 163 spin_unlock_irq(&crc->lock);164 165 *offp += len;166 return len;167}168 169static const struct file_operations drm_crtc_crc_control_fops = {170 .owner = THIS_MODULE,171 .open = crc_control_open,172 .read = seq_read,173 .llseek = seq_lseek,174 .release = single_release,175 .write = crc_control_write176};177 178static int crtc_crc_data_count(struct drm_crtc_crc *crc)179{180 assert_spin_locked(&crc->lock);181 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);182}183 184static void crtc_crc_cleanup(struct drm_crtc_crc *crc)185{186 kfree(crc->entries);187 crc->overflow = false;188 crc->entries = NULL;189 crc->head = 0;190 crc->tail = 0;191 crc->values_cnt = 0;192 crc->opened = false;193}194 195static int crtc_crc_open(struct inode *inode, struct file *filep)196{197 struct drm_crtc *crtc = inode->i_private;198 struct drm_crtc_crc *crc = &crtc->crc;199 struct drm_crtc_crc_entry *entries = NULL;200 size_t values_cnt;201 int ret = 0;202 203 if (drm_drv_uses_atomic_modeset(crtc->dev)) {204 ret = drm_modeset_lock_single_interruptible(&crtc->mutex);205 if (ret)206 return ret;207 208 if (!crtc->state->active)209 ret = -EIO;210 drm_modeset_unlock(&crtc->mutex);211 212 if (ret)213 return ret;214 }215 216 ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);217 if (ret)218 return ret;219 220 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR))221 return -EINVAL;222 223 if (WARN_ON(values_cnt == 0))224 return -EINVAL;225 226 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);227 if (!entries)228 return -ENOMEM;229 230 spin_lock_irq(&crc->lock);231 if (!crc->opened) {232 crc->opened = true;233 crc->entries = entries;234 crc->values_cnt = values_cnt;235 } else {236 ret = -EBUSY;237 }238 spin_unlock_irq(&crc->lock);239 240 if (ret) {241 kfree(entries);242 return ret;243 }244 245 ret = crtc->funcs->set_crc_source(crtc, crc->source);246 if (ret)247 goto err;248 249 return 0;250 251err:252 spin_lock_irq(&crc->lock);253 crtc_crc_cleanup(crc);254 spin_unlock_irq(&crc->lock);255 return ret;256}257 258static int crtc_crc_release(struct inode *inode, struct file *filep)259{260 struct drm_crtc *crtc = filep->f_inode->i_private;261 struct drm_crtc_crc *crc = &crtc->crc;262 263 /* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */264 spin_lock_irq(&crc->lock);265 crc->opened = false;266 spin_unlock_irq(&crc->lock);267 268 crtc->funcs->set_crc_source(crtc, NULL);269 270 spin_lock_irq(&crc->lock);271 crtc_crc_cleanup(crc);272 spin_unlock_irq(&crc->lock);273 274 return 0;275}276 277/*278 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space279 * separated, with a newline at the end and null-terminated.280 */281#define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1)282#define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR))283 284static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,285 size_t count, loff_t *pos)286{287 struct drm_crtc *crtc = filep->f_inode->i_private;288 struct drm_crtc_crc *crc = &crtc->crc;289 struct drm_crtc_crc_entry *entry;290 char buf[MAX_LINE_LEN];291 int ret, i;292 293 spin_lock_irq(&crc->lock);294 295 if (!crc->source) {296 spin_unlock_irq(&crc->lock);297 return 0;298 }299 300 /* Nothing to read? */301 while (crtc_crc_data_count(crc) == 0) {302 if (filep->f_flags & O_NONBLOCK) {303 spin_unlock_irq(&crc->lock);304 return -EAGAIN;305 }306 307 ret = wait_event_interruptible_lock_irq(crc->wq,308 crtc_crc_data_count(crc),309 crc->lock);310 if (ret) {311 spin_unlock_irq(&crc->lock);312 return ret;313 }314 }315 316 /* We know we have an entry to be read */317 entry = &crc->entries[crc->tail];318 319 if (count < LINE_LEN(crc->values_cnt)) {320 spin_unlock_irq(&crc->lock);321 return -EINVAL;322 }323 324 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);325 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);326 327 spin_unlock_irq(&crc->lock);328 329 if (entry->has_frame_counter)330 sprintf(buf, "0x%08x", entry->frame);331 else332 sprintf(buf, "XXXXXXXXXX");333 334 for (i = 0; i < crc->values_cnt; i++)335 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);336 sprintf(buf + 10 + crc->values_cnt * 11, "\n");337 338 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))339 return -EFAULT;340 341 return LINE_LEN(crc->values_cnt);342}343 344static __poll_t crtc_crc_poll(struct file *file, poll_table *wait)345{346 struct drm_crtc *crtc = file->f_inode->i_private;347 struct drm_crtc_crc *crc = &crtc->crc;348 __poll_t ret = 0;349 350 poll_wait(file, &crc->wq, wait);351 352 spin_lock_irq(&crc->lock);353 if (crc->source && crtc_crc_data_count(crc))354 ret |= EPOLLIN | EPOLLRDNORM;355 spin_unlock_irq(&crc->lock);356 357 return ret;358}359 360static const struct file_operations drm_crtc_crc_data_fops = {361 .owner = THIS_MODULE,362 .open = crtc_crc_open,363 .read = crtc_crc_read,364 .poll = crtc_crc_poll,365 .release = crtc_crc_release,366};367 368void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)369{370 struct dentry *crc_ent;371 372 if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)373 return;374 375 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);376 377 debugfs_create_file("control", S_IRUGO | S_IWUSR, crc_ent, crtc,378 &drm_crtc_crc_control_fops);379 debugfs_create_file("data", S_IRUGO, crc_ent, crtc,380 &drm_crtc_crc_data_fops);381}382 383/**384 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame385 * @crtc: CRTC to which the frame belongs386 * @has_frame: whether this entry has a frame number to go with387 * @frame: number of the frame these CRCs are about388 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt389 *390 * For each frame, the driver polls the source of CRCs for new data and calls391 * this function to add them to the buffer from where userspace reads.392 */393int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,394 uint32_t frame, uint32_t *crcs)395{396 struct drm_crtc_crc *crc = &crtc->crc;397 struct drm_crtc_crc_entry *entry;398 int head, tail;399 unsigned long flags;400 401 spin_lock_irqsave(&crc->lock, flags);402 403 /* Caller may not have noticed yet that userspace has stopped reading */404 if (!crc->entries) {405 spin_unlock_irqrestore(&crc->lock, flags);406 return -EINVAL;407 }408 409 head = crc->head;410 tail = crc->tail;411 412 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {413 bool was_overflow = crc->overflow;414 415 crc->overflow = true;416 spin_unlock_irqrestore(&crc->lock, flags);417 418 if (!was_overflow)419 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");420 421 return -ENOBUFS;422 }423 424 entry = &crc->entries[head];425 entry->frame = frame;426 entry->has_frame_counter = has_frame;427 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);428 429 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);430 crc->head = head;431 432 spin_unlock_irqrestore(&crc->lock, flags);433 434 wake_up_interruptible(&crc->wq);435 436 return 0;437}438EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);439