1 files changed, 438 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 000000000..bbc3bc4ba
--- /dev/null
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -0,0 +1,438 @@
+/*
+ * 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 <linux/poll.h>
+#include <linux/uaccess.h>
+
+#include <drm/drm_crtc.h>
+#include <drm/drm_debugfs_crc.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_print.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 :ref:`index of
+ * the CRTC<crtc_index>`. 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 and &drm_crtc_funcs.verify_crc_source.
+ * The debugfs files are automatically set up if those vfuncs are set. CRC samples
+ * need to be captured in the driver by calling drm_crtc_add_crc_entry().
+ * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source
+ * may result in a commit (even a full modeset).
+ *
+ * CRC results must be reliable across non-full-modeset atomic commits, so if a
+ * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with
+ * CRC generation, then the driver must mark that commit as a full modeset
+ * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure
+ * consistent results, generic userspace must re-setup CRC generation after a
+ * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET.
+ */
+
+static int crc_control_show(struct seq_file *m, void *data)
+{
+	struct drm_crtc *crtc = m->private;
+
+	if (crtc->funcs->get_crc_sources) {
+		size_t count;
+		const char *const *sources = crtc->funcs->get_crc_sources(crtc,
+									&count);
+		size_t values_cnt;
+		int i;
+
+		if (count == 0 || !sources)
+			goto out;
+
+		for (i = 0; i < count; i++)
+			if (!crtc->funcs->verify_crc_source(crtc, sources[i],
+							    &values_cnt)) {
+				if (strcmp(sources[i], crtc->crc.source))
+					seq_printf(m, "%s\n", sources[i]);
+				else
+					seq_printf(m, "%s*\n", sources[i]);
+			}
+	}
+	return 0;
+
+out:
+	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;
+	size_t values_cnt;
+	int ret;
+
+	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 - 1] == '\n')
+		source[len - 1] = '\0';
+
+	ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
+	if (ret) {
+		kfree(source);
+		return ret;
+	}
+
+	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->overflow = false;
+	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;
+	}
+
+	ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);
+	if (ret)
+		return ret;
+
+	if (WARN_ON(values_cnt > DRM_MAX_CRC_NR))
+		return -EINVAL;
+
+	if (WARN_ON(values_cnt == 0))
+		return -EINVAL;
+
+	entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
+	if (!entries)
+		return -ENOMEM;
+
+	spin_lock_irq(&crc->lock);
+	if (!crc->opened) {
+		crc->opened = true;
+		crc->entries = entries;
+		crc->values_cnt = values_cnt;
+	} else {
+		ret = -EBUSY;
+	}
+	spin_unlock_irq(&crc->lock);
+
+	if (ret) {
+		kfree(entries);
+		return ret;
+	}
+
+	ret = crtc->funcs->set_crc_source(crtc, crc->source);
+	if (ret)
+		goto err;
+
+	return 0;
+
+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;
+
+	/* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */
+	spin_lock_irq(&crc->lock);
+	crc->opened = false;
+	spin_unlock_irq(&crc->lock);
+
+	crtc->funcs->set_crc_source(crtc, NULL);
+
+	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 __poll_t crtc_crc_poll(struct file *file, poll_table *wait)
+{
+	struct drm_crtc *crtc = file->f_inode->i_private;
+	struct drm_crtc_crc *crc = &crtc->crc;
+	__poll_t ret = 0;
+
+	poll_wait(file, &crc->wq, wait);
+
+	spin_lock_irq(&crc->lock);
+	if (crc->source && crtc_crc_data_count(crc))
+		ret |= EPOLLIN | EPOLLRDNORM;
+	spin_unlock_irq(&crc->lock);
+
+	return ret;
+}
+
+static const struct file_operations drm_crtc_crc_data_fops = {
+	.owner = THIS_MODULE,
+	.open = crtc_crc_open,
+	.read = crtc_crc_read,
+	.poll = crtc_crc_poll,
+	.release = crtc_crc_release,
+};
+
+void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+{
+	struct dentry *crc_ent;
+
+	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
+		return;
+
+	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
+
+	debugfs_create_file("control", S_IRUGO | S_IWUSR, crc_ent, crtc,
+			    &drm_crtc_crc_control_fops);
+	debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
+			    &drm_crtc_crc_data_fops);
+}
+
+/**
+ * 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;
+	unsigned long flags;
+
+	spin_lock_irqsave(&crc->lock, flags);
+
+	/* Caller may not have noticed yet that userspace has stopped reading */
+	if (!crc->entries) {
+		spin_unlock_irqrestore(&crc->lock, flags);
+		return -EINVAL;
+	}
+
+	head = crc->head;
+	tail = crc->tail;
+
+	if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
+		bool was_overflow = crc->overflow;
+
+		crc->overflow = true;
+		spin_unlock_irqrestore(&crc->lock, flags);
+
+		if (!was_overflow)
+			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_irqrestore(&crc->lock, flags);
+
+	wake_up_interruptible(&crc->wq);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);