Re: [PATCH v11 2/4] drm: Add API for capturing frame CRCs
From: Tomeu Vizoso
Date: Mon Oct 10 2016 - 07:31:42 EST
Adding Benjamin Gaignard to CC in case he wants to comment on the
usage of the registration functions, as suggested by Daniel Vetter.
Regards,
Tomeu
On 6 October 2016 at 17:21, Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxxxx>
> ---
>
> Documentation/gpu/drm-uapi.rst | 6 +
> drivers/gpu/drm/Makefile | 3 +-
> drivers/gpu/drm/drm_crtc.c | 34 +++-
> drivers/gpu/drm/drm_debugfs.c | 34 +++-
> drivers/gpu/drm/drm_debugfs_crc.c | 351 ++++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/drm_internal.h | 16 ++
> include/drm/drm_crtc.h | 41 +++++
> include/drm/drm_debugfs_crc.h | 73 ++++++++
> 8 files changed, 555 insertions(+), 3 deletions(-)
> create mode 100644 drivers/gpu/drm/drm_debugfs_crc.c
> create mode 100644 include/drm/drm_debugfs_crc.h
>
> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
> index 1ba301cebe16..de3ac9f90f8f 100644
> --- a/Documentation/gpu/drm-uapi.rst
> +++ b/Documentation/gpu/drm-uapi.rst
> @@ -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
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 25c720454017..74579d2e796e 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -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 \
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 2d7bedf28647..60403bf7a4ff 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -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;
>
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index 1205790ed960..800055c39cdb 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -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 */
> diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
> new file mode 100644
> index 000000000000..4129405d17c0
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> @@ -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@xxxxxxxxx>
> + *
> + */
> +
> +#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);
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index e66af289a016..abd209863ef4 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -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
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 61932f55f788..0908b2cf6c2c 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -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;
> @@ -564,6 +565,30 @@ 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);
> };
>
> /**
> @@ -680,6 +705,22 @@ 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
> };
>
> /**
> diff --git a/include/drm/drm_debugfs_crc.h b/include/drm/drm_debugfs_crc.h
> new file mode 100644
> index 000000000000..7d63b1d4adb9
> --- /dev/null
> +++ b/include/drm/drm_debugfs_crc.h
> @@ -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__ */
> --
> 2.7.4
>