linux/drivers/gpu/drm/drm_debugfs_crc.c
Maarten Lankhorst 6f8bcc744a drm/atomic: Prepare drm_modeset_lock infrastructure for interruptible waiting, v2.
When we want to make drm_atomic_commit interruptible, there are a lot of
places that call the lock function, which we don't have control over.

Rather than trying to convert every single one, it's easier to toggle
interruptible waiting per acquire_ctx. If drm_modeset_acquire_init is
called with DRM_MODESET_ACQUIRE_INTERRUPTIBLE, then we will perform
interruptible waits in drm_modeset_lock and drm_modeset_backoff.

Changes since v1:
- Fix locking example in drm_modeset_lock.c to be compatible
  with interruptible waiting (xexaxo) and make it default.
  Uninterruptible waiting shouldn't happen except in corner cases,
  but the example will still apply if the flag is removed.
- Add drm_modeset_lock_single_interruptible() to documentation.
- Fix dead link to removed drm_modeset_lock_interruptible() in
  drm_modeset_lock().

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> #v1
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170912133749.6532-2-maarten.lankhorst@linux.intel.com
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
2017-09-13 09:50:52 +02:00

395 lines
10 KiB
C

/*
* 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 <damien.lespiau@intel.com>
*
*/
#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 CRC sampling "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.
*
* On the driver side the implementation effort is minimal, drivers only need to
* implement &drm_crtc_funcs.set_crc_source. The debugfs files are automatically
* set up if that vfunc is set. CRC samples need to be captured in the driver by
* calling drm_crtc_add_crc_entry().
*/
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_data_count(struct drm_crtc_crc *crc)
{
assert_spin_locked(&crc->lock);
return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
}
static void crtc_crc_cleanup(struct drm_crtc_crc *crc)
{
kfree(crc->entries);
crc->entries = NULL;
crc->head = 0;
crc->tail = 0;
crc->values_cnt = 0;
crc->opened = false;
}
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 = 0;
if (drm_drv_uses_atomic_modeset(crtc->dev)) {
ret = drm_modeset_lock_single_interruptible(&crtc->mutex);
if (ret)
return ret;
if (!crtc->state->active)
ret = -EIO;
drm_modeset_unlock(&crtc->mutex);
if (ret)
return ret;
}
spin_lock_irq(&crc->lock);
if (!crc->opened)
crc->opened = true;
else
ret = -EBUSY;
spin_unlock_irq(&crc->lock);
if (ret)
return ret;
ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt);
if (ret)
goto err;
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;
/*
* Only return once we got a first frame, so userspace doesn't have to
* guess when this particular piece of HW will be ready to start
* generating CRCs.
*/
ret = wait_event_interruptible_lock_irq(crc->wq,
crtc_crc_data_count(crc),
crc->lock);
spin_unlock_irq(&crc->lock);
if (ret)
goto err_disable;
return 0;
err_disable:
crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
err:
spin_lock_irq(&crc->lock);
crtc_crc_cleanup(crc);
spin_unlock_irq(&crc->lock);
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;
crtc->funcs->set_crc_source(crtc, NULL, &values_cnt);
spin_lock_irq(&crc->lock);
crtc_crc_cleanup(crc);
spin_unlock_irq(&crc->lock);
return 0;
}
/*
* 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,
};
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;
spin_lock(&crc->lock);
/* Caller may not have noticed yet that userspace has stopped reading */
if (!crc->entries) {
spin_unlock(&crc->lock);
return -EINVAL;
}
head = crc->head;
tail = crc->tail;
if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
spin_unlock(&crc->lock);
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;
spin_unlock(&crc->lock);
wake_up_interruptible(&crc->wq);
return 0;
}
EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);