diff options
Diffstat (limited to 'drivers/gpu/drm/drm_debugfs_crc.c')
| -rw-r--r-- | drivers/gpu/drm/drm_debugfs_crc.c | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c new file mode 100644 index 000000000000..00e771fb7df2 --- /dev/null +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -0,0 +1,352 @@ +/* + * Copyright © 2008 Intel Corporation + * Copyright © 2016 Collabora Ltd + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + * + * Based on code from the i915 driver. + * Original author: Damien Lespiau <[email protected]> + * + */ + +#include <linux/circ_buf.h> +#include <linux/ctype.h> +#include <linux/debugfs.h> +#include <drm/drmP.h> +#include "drm_internal.h" + +/** + * DOC: CRC ABI + * + * DRM device drivers can provide to userspace CRC information of each frame as + * it reached a given hardware component (a "source"). + * + * Userspace can control generation of CRCs in a given CRTC by writing to the + * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC. + * Accepted values are source names (which are driver-specific) and the "auto" + * keyword, which will let the driver select a default source of frame CRCs + * for this CRTC. + * + * Once frame CRC generation is enabled, userspace can capture them by reading + * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame + * number in the first field and then a number of unsigned integer fields + * containing the CRC data. Fields are separated by a single space and the number + * of CRC fields is source-specific. + * + * Note that though in some cases the CRC is computed in a specified way and on + * the frame contents as supplied by userspace (eDP 1.3), in general the CRC + * computation is performed in an unspecified way and on frame contents that have + * been already processed in also an unspecified way and thus userspace cannot + * rely on being able to generate matching CRC values for the frame contents that + * it submits. In this general case, the maximum userspace can do is to compare + * the reported CRCs of frames that should have the same contents. + */ + +static int crc_control_show(struct seq_file *m, void *data) +{ + struct drm_crtc *crtc = m->private; + + seq_printf(m, "%s\n", crtc->crc.source); + + return 0; +} + +static int crc_control_open(struct inode *inode, struct file *file) +{ + struct drm_crtc *crtc = inode->i_private; + + return single_open(file, crc_control_show, crtc); +} + +static ssize_t crc_control_write(struct file *file, const char __user *ubuf, + size_t len, loff_t *offp) +{ + struct seq_file *m = file->private_data; + struct drm_crtc *crtc = m->private; + struct drm_crtc_crc *crc = &crtc->crc; + char *source; + + if (len == 0) + return 0; + + if (len > PAGE_SIZE - 1) { + DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n", + PAGE_SIZE); + return -E2BIG; + } + + source = memdup_user_nul(ubuf, len); + if (IS_ERR(source)) + return PTR_ERR(source); + + if (source[len] == '\n') + source[len] = '\0'; + + spin_lock_irq(&crc->lock); + + if (crc->opened) { + spin_unlock_irq(&crc->lock); + kfree(source); + return -EBUSY; + } + + kfree(crc->source); + crc->source = source; + + spin_unlock_irq(&crc->lock); + + *offp += len; + return len; +} + +static const struct file_operations drm_crtc_crc_control_fops = { + .owner = THIS_MODULE, + .open = crc_control_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .write = crc_control_write +}; + +static int crtc_crc_open(struct inode *inode, struct file *filep) +{ + struct drm_crtc *crtc = inode->i_private; + struct drm_crtc_crc *crc = &crtc->crc; + struct drm_crtc_crc_entry *entries = NULL; + size_t values_cnt; + int ret; + + if (crc->opened) + return -EBUSY; + + ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt); + if (ret) + return ret; + + if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) { + ret = -EINVAL; + goto err_disable; + } + + if (WARN_ON(values_cnt == 0)) { + ret = -EINVAL; + goto err_disable; + } + + entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); + if (!entries) { + ret = -ENOMEM; + goto err_disable; + } + + spin_lock_irq(&crc->lock); + crc->entries = entries; + crc->values_cnt = values_cnt; + crc->opened = true; + spin_unlock_irq(&crc->lock); + + return 0; + +err_disable: + crtc->funcs->set_crc_source(crtc, NULL, &values_cnt); + return ret; +} + +static int crtc_crc_release(struct inode *inode, struct file *filep) +{ + struct drm_crtc *crtc = filep->f_inode->i_private; + struct drm_crtc_crc *crc = &crtc->crc; + size_t values_cnt; + + spin_lock_irq(&crc->lock); + kfree(crc->entries); + crc->entries = NULL; + crc->head = 0; + crc->tail = 0; + crc->values_cnt = 0; + crc->opened = false; + spin_unlock_irq(&crc->lock); + + crtc->funcs->set_crc_source(crtc, NULL, &values_cnt); + + return 0; +} + +static int crtc_crc_data_count(struct drm_crtc_crc *crc) +{ + assert_spin_locked(&crc->lock); + return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); +} + +/* + * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space + * separated, with a newline at the end and null-terminated. + */ +#define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) +#define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) + +static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, + size_t count, loff_t *pos) +{ + struct drm_crtc *crtc = filep->f_inode->i_private; + struct drm_crtc_crc *crc = &crtc->crc; + struct drm_crtc_crc_entry *entry; + char buf[MAX_LINE_LEN]; + int ret, i; + + spin_lock_irq(&crc->lock); + + if (!crc->source) { + spin_unlock_irq(&crc->lock); + return 0; + } + + /* Nothing to read? */ + while (crtc_crc_data_count(crc) == 0) { + if (filep->f_flags & O_NONBLOCK) { + spin_unlock_irq(&crc->lock); + return -EAGAIN; + } + + ret = wait_event_interruptible_lock_irq(crc->wq, + crtc_crc_data_count(crc), + crc->lock); + if (ret) { + spin_unlock_irq(&crc->lock); + return ret; + } + } + + /* We know we have an entry to be read */ + entry = &crc->entries[crc->tail]; + + if (count < LINE_LEN(crc->values_cnt)) { + spin_unlock_irq(&crc->lock); + return -EINVAL; + } + + BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); + crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); + + spin_unlock_irq(&crc->lock); + + if (entry->has_frame_counter) + sprintf(buf, "0x%08x", entry->frame); + else + sprintf(buf, "XXXXXXXXXX"); + + for (i = 0; i < crc->values_cnt; i++) + sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); + sprintf(buf + 10 + crc->values_cnt * 11, "\n"); + + if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) + return -EFAULT; + + return LINE_LEN(crc->values_cnt); +} + +static const struct file_operations drm_crtc_crc_data_fops = { + .owner = THIS_MODULE, + .open = crtc_crc_open, + .read = crtc_crc_read, + .release = crtc_crc_release, +}; + +/** + * drm_debugfs_crtc_crc_add - Add files to debugfs for capture of frame CRCs + * @crtc: CRTC to whom the frames will belong + * + * Adds files to debugfs directory that allows userspace to control the + * generation of frame CRCs and to read them. + * + * Returns: + * Zero on success, error code on failure. + */ +int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) +{ + struct dentry *crc_ent, *ent; + + if (!crtc->funcs->set_crc_source) + return 0; + + crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); + if (!crc_ent) + return -ENOMEM; + + ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc, + &drm_crtc_crc_control_fops); + if (!ent) + goto error; + + ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc, + &drm_crtc_crc_data_fops); + if (!ent) + goto error; + + return 0; + +error: + debugfs_remove_recursive(crc_ent); + + return -ENOMEM; +} + +/** + * drm_crtc_add_crc_entry - Add entry with CRC information for a frame + * @crtc: CRTC to which the frame belongs + * @has_frame: whether this entry has a frame number to go with + * @frame: number of the frame these CRCs are about + * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt + * + * For each frame, the driver polls the source of CRCs for new data and calls + * this function to add them to the buffer from where userspace reads. + */ +int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, + uint32_t frame, uint32_t *crcs) +{ + struct drm_crtc_crc *crc = &crtc->crc; + struct drm_crtc_crc_entry *entry; + int head, tail; + + assert_spin_locked(&crc->lock); + + /* Caller may not have noticed yet that userspace has stopped reading */ + if (!crc->opened) + return -EINVAL; + + head = crc->head; + tail = crc->tail; + + if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { + DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); + return -ENOBUFS; + } + + entry = &crc->entries[head]; + entry->frame = frame; + entry->has_frame_counter = has_frame; + memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); + + head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); + crc->head = head; + + return 0; +} +EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); |