[PATCH 01/10] drm: crc: Introduce verify_crc_source callback

[Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>]

This patch adds a new callback function "verify_crc_source" which will
be used during setting the crc source in control node and while opening
data node for crc reading. This will help in avoiding setting of wrong
string for source.

Signed-off-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
---
 drivers/gpu/drm/drm_debugfs_crc.c | 15 +++++++++++++++
 include/drm/drm_crtc.h            | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 9f8312137cad..c6a725b79ac6 100644
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -87,6 +87,8 @@ static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
 	struct drm_crtc *crtc = m->private;
 	struct drm_crtc_crc *crc = &crtc->crc;
 	char *source;
+	size_t values_cnt;
+	int ret = 0;
 
 	if (len == 0)
 		return 0;
@@ -104,6 +106,12 @@ static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
 	if (source[len] == '\n')
 		source[len] = '\0';
 
+	if (crtc->funcs->verify_crc_source) {
+		ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
+		if (ret)
+			return ret;
+	}
+
 	spin_lock_irq(&crc->lock);
 
 	if (crc->opened) {
@@ -167,6 +175,13 @@ static int crtc_crc_open(struct inode *inode, struct file *filep)
 			return ret;
 	}
 
+	if (crtc->funcs->verify_crc_source) {
+		ret = crtc->funcs->verify_crc_source(crtc, crc->source,
+						     &values_cnt);
+		if (ret)
+			return ret;
+	}
+
 	spin_lock_irq(&crc->lock);
 	if (!crc->opened)
 		crc->opened = true;
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 23eddbccab10..1a6dcbf91744 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -661,6 +661,21 @@ struct drm_crtc_funcs {
 	 */
 	int (*set_crc_source)(struct drm_crtc *crtc, const char *source,
 			      size_t *values_cnt);
+	/**
+	 * @verify_crc_source:
+	 *
+	 * verifies the source of CRC checksums of frames before setting the
+	 * source for CRC and during crc open.
+	 *
+	 * 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 (*verify_crc_source)(struct drm_crtc *crtc, const char *source,
+				 size_t *values_cnt);
 
 	/**
 	 * @atomic_print_state:
-- 
2.16.2

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