V4L/DVB: uvcvideo: Cache control min, max, res and def query results

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

2 files changed, 74 insertions, 49 deletions

diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
index f4e5ba26096..5ff50139084 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -23,9 +23,13 @@
 
 #include "uvcvideo.h"
 
-#define UVC_CTRL_NDATA          2
 #define UVC_CTRL_DATA_CURRENT   0
 #define UVC_CTRL_DATA_BACKUP    1
+#define UVC_CTRL_DATA_MIN       2
+#define UVC_CTRL_DATA_MAX       3
+#define UVC_CTRL_DATA_RES       4
+#define UVC_CTRL_DATA_DEF       5
+#define UVC_CTRL_DATA_LAST      6
 
 /* ------------------------------------------------------------------------
  * Controls
@@ -755,6 +759,49 @@ struct uvc_control *uvc_find_control(struct uvc_video_chain *chain,
         return ctrl;
 }
 
+static int uvc_ctrl_populate_cache(struct uvc_video_chain *chain,
+        struct uvc_control *ctrl)
+{
+        int ret;
+
+        if (ctrl->info->flags & UVC_CONTROL_GET_DEF) {
+                ret = uvc_query_ctrl(chain->dev, UVC_GET_DEF, ctrl->entity->id,
+                                     chain->dev->intfnum, ctrl->info->selector,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF),
+                                     ctrl->info->size);
+                if (ret < 0)
+                        return ret;
+        }
+
+        if (ctrl->info->flags & UVC_CONTROL_GET_MIN) {
+                ret = uvc_query_ctrl(chain->dev, UVC_GET_MIN, ctrl->entity->id,
+                                     chain->dev->intfnum, ctrl->info->selector,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN),
+                                     ctrl->info->size);
+                if (ret < 0)
+                        return ret;
+        }
+        if (ctrl->info->flags & UVC_CONTROL_GET_MAX) {
+                ret = uvc_query_ctrl(chain->dev, UVC_GET_MAX, ctrl->entity->id,
+                                     chain->dev->intfnum, ctrl->info->selector,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX),
+                                     ctrl->info->size);
+                if (ret < 0)
+                        return ret;
+        }
+        if (ctrl->info->flags & UVC_CONTROL_GET_RES) {
+                ret = uvc_query_ctrl(chain->dev, UVC_GET_RES, ctrl->entity->id,
+                                     chain->dev->intfnum, ctrl->info->selector,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES),
+                                     ctrl->info->size);
+                if (ret < 0)
+                        return ret;
+        }
+
+        ctrl->cached = 1;
+        return 0;
+}
+
 int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
         struct v4l2_queryctrl *v4l2_ctrl)
 {
@@ -762,17 +809,12 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
         struct uvc_control_mapping *mapping;
         struct uvc_menu_info *menu;
         unsigned int i;
-        __u8 *data;
         int ret;
 
         ctrl = uvc_find_control(chain, v4l2_ctrl->id, &mapping);
         if (ctrl == NULL)
                 return -EINVAL;
 
-        data = kmalloc(ctrl->info->size, GFP_KERNEL);
-        if (data == NULL)
-                return -ENOMEM;
-
         memset(v4l2_ctrl, 0, sizeof *v4l2_ctrl);
         v4l2_ctrl->id = mapping->id;
         v4l2_ctrl->type = mapping->v4l2_type;
@@ -782,14 +824,15 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
         if (!(ctrl->info->flags & UVC_CONTROL_SET_CUR))
                 v4l2_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
 
-        if (ctrl->info->flags & UVC_CONTROL_GET_DEF) {
-                ret = uvc_query_ctrl(chain->dev, UVC_GET_DEF, ctrl->entity->id,
-                                     chain->dev->intfnum, ctrl->info->selector,
-                                     data, ctrl->info->size);
+        if (!ctrl->cached) {
+                ret = uvc_ctrl_populate_cache(chain, ctrl);
                 if (ret < 0)
-                        goto out;
-                v4l2_ctrl->default_value =
-                        mapping->get(mapping, UVC_GET_DEF, data);
+                        return ret;
+        }
+
+        if (ctrl->info->flags & UVC_CONTROL_GET_DEF) {
+                v4l2_ctrl->default_value = mapping->get(mapping, UVC_GET_DEF,
+                                uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF));
         }
 
         switch (mapping->v4l2_type) {
@@ -806,56 +849,37 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
                         }
                 }
 
-                ret = 0;
-                goto out;
+                return 0;
 
         case V4L2_CTRL_TYPE_BOOLEAN:
                 v4l2_ctrl->minimum = 0;
                 v4l2_ctrl->maximum = 1;
                 v4l2_ctrl->step = 1;
-                ret = 0;
-                goto out;
+                return 0;
 
         case V4L2_CTRL_TYPE_BUTTON:
                 v4l2_ctrl->minimum = 0;
                 v4l2_ctrl->maximum = 0;
                 v4l2_ctrl->step = 0;
-                ret = 0;
-                goto out;
+                return 0;
 
         default:
                 break;
         }
 
-        if (ctrl->info->flags & UVC_CONTROL_GET_MIN) {
-                ret = uvc_query_ctrl(chain->dev, UVC_GET_MIN, ctrl->entity->id,
-                                     chain->dev->intfnum, ctrl->info->selector,
-                                     data, ctrl->info->size);
-                if (ret < 0)
-                        goto out;
-                v4l2_ctrl->minimum = mapping->get(mapping, UVC_GET_MIN, data);
-        }
-        if (ctrl->info->flags & UVC_CONTROL_GET_MAX) {
-                ret = uvc_query_ctrl(chain->dev, UVC_GET_MAX, ctrl->entity->id,
-                                     chain->dev->intfnum, ctrl->info->selector,
-                                     data, ctrl->info->size);
-                if (ret < 0)
-                        goto out;
-                v4l2_ctrl->maximum = mapping->get(mapping, UVC_GET_MAX, data);
-        }
-        if (ctrl->info->flags & UVC_CONTROL_GET_RES) {
-                ret = uvc_query_ctrl(chain->dev, UVC_GET_RES, ctrl->entity->id,
-                                     chain->dev->intfnum, ctrl->info->selector,
-                                     data, ctrl->info->size);
-                if (ret < 0)
-                        goto out;
-                v4l2_ctrl->step = mapping->get(mapping, UVC_GET_RES, data);
-        }
+        if (ctrl->info->flags & UVC_CONTROL_GET_MIN)
+                v4l2_ctrl->minimum = mapping->get(mapping, UVC_GET_MIN,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN));
 
-        ret = 0;
-out:
-        kfree(data);
-        return ret;
+        if (ctrl->info->flags & UVC_CONTROL_GET_MAX)
+                v4l2_ctrl->maximum = mapping->get(mapping, UVC_GET_MAX,
+                                     uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
+
+        if (ctrl->info->flags & UVC_CONTROL_GET_RES)
+                v4l2_ctrl->step = mapping->get(mapping, UVC_GET_RES,
+                                  uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES));
+
+        return 0;
 }
 
 
@@ -1246,7 +1270,7 @@ static void uvc_ctrl_add_ctrl(struct uvc_device *dev,
         }
 
         ctrl->info = info;
-        ctrl->data = kmalloc(ctrl->info->size * UVC_CTRL_NDATA, GFP_KERNEL);
+        ctrl->data = kmalloc(ctrl->info->size * UVC_CTRL_DATA_LAST, GFP_KERNEL);
         uvc_trace(UVC_TRACE_CONTROL, "Added control %pUl/%u to device %s "
                 "entity %u\n", ctrl->info->entity, ctrl->info->selector,
                 dev->udev->devpath, entity->id);
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index 0c7966fdb83..2bba059259e 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -245,7 +245,8 @@ struct uvc_control {
                            uvc_control_info. */
         __u8 dirty : 1,
              loaded : 1,
-             modified : 1;
+             modified : 1,
+             cached : 1;
 
         __u8 *data;
 };