drm: crc: Introduce verify_crc_source callback

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

Changes since V1:
 - do not yet verify_crc_source during open.
Changes since V1:
 - improve callback description

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713135942.25061-2-mahesh1.kumar@intel.com

diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 9996119..72bfd8a 100644 (file)
--- 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;
 
        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) {

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 92e7fc7..9dcbce9 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -746,6 +746,22 @@ 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. Source parameter can be NULL
+        * while disabling crc source.
+        *
+        * 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: