drm: Add API for capturing frame CRCs

Adds files and directories to debugfs for controlling and reading frame
CRCs, per CRTC:

dri/0/crtc-0/crc
dri/0/crtc-0/crc/control
dri/0/crtc-0/crc/data

Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
start and stop generating frame CRCs and can add entries to the output
by calling drm_crtc_add_crc_entry.

v2:
    - Lots of good fixes suggested by Thierry.
    - Added documentation.
    - Changed the debugfs layout.
    - Moved to allocate the entries circular queue once when frame
      generation gets enabled for the first time.
v3:
    - Use the control file just to select the source, and start and stop
      capture when the data file is opened and closed, respectively.
    - Make variable the number of CRC values per entry, per source.
    - Allocate entries queue each time we start capturing as now there
      isn't a fixed number of CRC values per entry.
    - Store the frame counter in the data file as a 8-digit hex number.
    - For sources that cannot provide useful frame numbers, place
      XXXXXXXX in the frame field.

v4:
    - Build only if CONFIG_DEBUG_FS is enabled.
    - Use memdup_user_nul.
    - Consolidate calculation of the size of an entry in a helper.
    - Add 0x prefix to hex numbers in the data file.
    - Remove unnecessary snprintf and strlen usage in read callback.

v5:
    - Made the crcs array in drm_crtc_crc_entry fixed-size
    - Lots of other smaller improvements suggested by Emil Velikov

v7:
    - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h

v8:
    - Call debugfs_remove_recursive when we fail to create the minor
      device

v9:
    - Register the debugfs directory for a crtc from
      drm_crtc_register_all()

v10:
    - Don't let debugfs failures interrupt CRTC registration (Emil
      Velikov)

v11:
    - Remove extra brace that broke compilation. Sorry!

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1475767268-14379-3-git-send-email-tomeu.vizoso@collabora.com
This commit is contained in:
Tomeu Vizoso 2016-10-06 17:21:06 +02:00 committed by Daniel Vetter
parent 865afb1194
commit 9edbf1fa60
8 changed files with 555 additions and 3 deletions

View File

@ -216,3 +216,9 @@ interfaces. Especially since all hardware-acceleration interfaces to
userspace are driver specific for efficiency and other reasons these
interfaces can be rather substantial. Hence every driver has its own
chapter.
Testing and validation
======================
.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
:doc: CRC ABI

View File

@ -9,7 +9,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \
drm_scatter.o drm_pci.o \
drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o \
drm_info.o drm_debugfs.o drm_encoder_slave.o \
drm_info.o drm_encoder_slave.o \
drm_trace_points.o drm_global.o drm_prime.o \
drm_rect.o drm_vma_manager.o drm_flip_work.o \
drm_modeset_lock.o drm_atomic.o drm_bridge.o \
@ -23,6 +23,7 @@ drm-$(CONFIG_PCI) += ati_pcigart.o
drm-$(CONFIG_DRM_PANEL) += drm_panel.o
drm-$(CONFIG_OF) += drm_of.o
drm-$(CONFIG_AGP) += drm_agpsupport.o
drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \

View File

@ -40,7 +40,7 @@
#include <drm/drm_modeset_lock.h>
#include <drm/drm_atomic.h>
#include <drm/drm_auth.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_debugfs_crc.h>
#include "drm_crtc_internal.h"
#include "drm_internal.h"
@ -122,6 +122,10 @@ static int drm_crtc_register_all(struct drm_device *dev)
int ret = 0;
drm_for_each_crtc(crtc, dev) {
if (drm_debugfs_crtc_add(crtc))
DRM_ERROR("Failed to initialize debugfs entry for CRTC '%s'.\n",
crtc->name);
if (crtc->funcs->late_register)
ret = crtc->funcs->late_register(crtc);
if (ret)
@ -138,9 +142,29 @@ static void drm_crtc_unregister_all(struct drm_device *dev)
drm_for_each_crtc(crtc, dev) {
if (crtc->funcs->early_unregister)
crtc->funcs->early_unregister(crtc);
drm_debugfs_crtc_remove(crtc);
}
}
static int drm_crtc_crc_init(struct drm_crtc *crtc)
{
#ifdef CONFIG_DEBUG_FS
spin_lock_init(&crtc->crc.lock);
init_waitqueue_head(&crtc->crc.wq);
crtc->crc.source = kstrdup("auto", GFP_KERNEL);
if (!crtc->crc.source)
return -ENOMEM;
#endif
return 0;
}
static void drm_crtc_crc_fini(struct drm_crtc *crtc)
{
#ifdef CONFIG_DEBUG_FS
kfree(crtc->crc.source);
#endif
}
/**
* drm_crtc_init_with_planes - Initialise a new CRTC object with
* specified primary and cursor planes.
@ -210,6 +234,12 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
if (cursor)
cursor->possible_crtcs = 1 << drm_crtc_index(crtc);
ret = drm_crtc_crc_init(crtc);
if (ret) {
drm_mode_object_unregister(dev, &crtc->base);
return ret;
}
if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
drm_object_attach_property(&crtc->base, config->prop_active, 0);
drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
@ -236,6 +266,8 @@ void drm_crtc_cleanup(struct drm_crtc *crtc)
* the indices on the drm_crtc after us in the crtc_list.
*/
drm_crtc_crc_fini(crtc);
kfree(crtc->gamma_store);
crtc->gamma_store = NULL;

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@ -415,5 +415,37 @@ void drm_debugfs_connector_remove(struct drm_connector *connector)
connector->debugfs_entry = NULL;
}
#endif /* CONFIG_DEBUG_FS */
int drm_debugfs_crtc_add(struct drm_crtc *crtc)
{
struct drm_minor *minor = crtc->dev->primary;
struct dentry *root;
char *name;
name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
if (!name)
return -ENOMEM;
root = debugfs_create_dir(name, minor->debugfs_root);
kfree(name);
if (!root)
return -ENOMEM;
crtc->debugfs_entry = root;
if (drm_debugfs_crtc_crc_add(crtc))
goto error;
return 0;
error:
drm_debugfs_crtc_remove(crtc);
return -ENOMEM;
}
void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
{
debugfs_remove_recursive(crtc->debugfs_entry);
crtc->debugfs_entry = NULL;
}
#endif /* CONFIG_DEBUG_FS */

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@ -0,0 +1,351 @@
/*
* 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>
/**
* 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;
}
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);
}
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);

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@ -100,6 +100,9 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
int drm_debugfs_cleanup(struct drm_minor *minor);
int drm_debugfs_connector_add(struct drm_connector *connector);
void drm_debugfs_connector_remove(struct drm_connector *connector);
int drm_debugfs_crtc_add(struct drm_crtc *crtc);
void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
#else
static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
struct dentry *root)
@ -119,4 +122,17 @@ static inline int drm_debugfs_connector_add(struct drm_connector *connector)
static inline void drm_debugfs_connector_remove(struct drm_connector *connector)
{
}
static inline int drm_debugfs_crtc_add(struct drm_crtc *crtc)
{
return 0;
}
static inline void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
{
}
static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
{
return 0;
}
#endif

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@ -47,6 +47,7 @@
#include <drm/drm_plane.h>
#include <drm/drm_blend.h>
#include <drm/drm_color_mgmt.h>
#include <drm/drm_debugfs_crc.h>
struct drm_device;
struct drm_mode_set;
@ -569,6 +570,30 @@ struct drm_crtc_funcs {
* before data structures are torndown.
*/
void (*early_unregister)(struct drm_crtc *crtc);
/**
* @set_crc_source:
*
* Changes the source of CRC checksums of frames at the request of
* userspace, typically for testing purposes. The sources available are
* specific of each driver and a %NULL value indicates that CRC
* generation is to be switched off.
*
* When CRC generation is enabled, the driver should call
* drm_crtc_add_crc_entry() at each frame, providing any information
* that characterizes the frame contents in the crcN arguments, as
* provided from the configured source. Drivers must accept a "auto"
* source name that will select a default source for this CRTC.
*
* This callback is optional if the driver does not support any CRC
* generation functionality.
*
* RETURNS:
*
* 0 on success or a negative error code on failure.
*/
int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
size_t *values_cnt);
};
/**
@ -685,6 +710,22 @@ struct drm_crtc {
* context.
*/
struct drm_modeset_acquire_ctx *acquire_ctx;
#ifdef CONFIG_DEBUG_FS
/**
* @debugfs_entry:
*
* Debugfs directory for this CRTC.
*/
struct dentry *debugfs_entry;
/**
* @crc:
*
* Configuration settings of CRC capture.
*/
struct drm_crtc_crc crc;
#endif
};
/**

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@ -0,0 +1,73 @@
/*
* 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
*/
#ifndef __DRM_DEBUGFS_CRC_H__
#define __DRM_DEBUGFS_CRC_H__
#define DRM_MAX_CRC_NR 10
/**
* struct drm_crtc_crc_entry - entry describing a frame's content
* @has_frame_counter: whether the source was able to provide a frame number
* @frame: number of the frame this CRC is about, if @has_frame_counter is true
* @crc: array of values that characterize the frame
*/
struct drm_crtc_crc_entry {
bool has_frame_counter;
uint32_t frame;
uint32_t crcs[DRM_MAX_CRC_NR];
};
#define DRM_CRC_ENTRIES_NR 128
/**
* struct drm_crtc_crc - data supporting CRC capture on a given CRTC
* @lock: protects the fields in this struct
* @source: name of the currently configured source of CRCs
* @opened: whether userspace has opened the data file for reading
* @entries: array of entries, with size of %DRM_CRC_ENTRIES_NR
* @head: head of circular queue
* @tail: tail of circular queue
* @values_cnt: number of CRC values per entry, up to %DRM_MAX_CRC_NR
* @wq: workqueue used to synchronize reading and writing
*/
struct drm_crtc_crc {
spinlock_t lock;
const char *source;
bool opened;
struct drm_crtc_crc_entry *entries;
int head, tail;
size_t values_cnt;
wait_queue_head_t wq;
};
#if defined(CONFIG_DEBUG_FS)
int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
uint32_t frame, uint32_t *crcs);
#else
static inline int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
uint32_t frame, uint32_t *crcs)
{
return -EINVAL;
}
#endif /* defined(CONFIG_DEBUG_FS) */
#endif /* __DRM_DEBUGFS_CRC_H__ */