video: rockchip: vcodec: add buffer recycle mechanism in vpu

when info change, vpu driver doesn't know when to release
buffers. with this mechanism, vpu driver will auto release
when buffer nums bigger than BUFFER_LIST_MAX_NUMS.

Change-Id: Id4fb91257d260bfd2e18388731941c4f0cc191b0
Signed-off-by: Jung Zhao <jung.zhao@rock-chips.com>

drivers/video/rockchip/vcodec/vcodec_iommu_drm.c

@@ -34,6 +34,7 @@
 #include <linux/console.h>
 #include <linux/kref.h>
 #include <linux/fdtable.h>
+#include <linux/ktime.h>
 
 #include "vcodec_iommu_ops.h"
 
@@ -52,6 +53,7 @@ struct vcodec_drm_buffer {
 	struct page **pages;
 	struct kref ref;
 	struct vcodec_iommu_session_info *session_info;
+	ktime_t last_used;
 };
 
 struct vcodec_iommu_drm_info {
@@ -67,8 +69,10 @@ vcodec_drm_get_buffer_no_lock(struct vcodec_iommu_session_info *session_info,
 
 	list_for_each_entry_safe(drm_buffer, n, &session_info->buffer_list,
 				 list) {
-		if (drm_buffer->index == idx)
+		if (drm_buffer->index == idx) {
+			drm_buffer->last_used = ktime_get();
 			return drm_buffer;
+		}
 	}
 
 	return NULL;
@@ -86,6 +90,7 @@ vcodec_drm_get_buffer_fd_no_lock(struct vcodec_iommu_session_info *session_info,
 	list_for_each_entry_safe(drm_buffer, n, &session_info->buffer_list,
 				 list) {
 		if (drm_buffer->dma_buf == dma_buf) {
+			drm_buffer->last_used = ktime_get();
 			dma_buf_put(dma_buf);
 			return drm_buffer;
 		}
@@ -276,6 +281,7 @@ static int vcodec_drm_free(struct vcodec_iommu_session_info *session_info,
 		dma_buf_put(drm_buffer->dma_buf);
 		list_del_init(&drm_buffer->list);
 		kfree(drm_buffer);
+		session_info->buffer_nums--;
 	}
 	mutex_unlock(&session_info->list_mutex);
 
@@ -386,6 +392,7 @@ vcodec_drm_free_fd(struct vcodec_iommu_session_info *session_info, int fd)
 		dma_buf_put(drm_buffer->dma_buf);
 		list_del_init(&drm_buffer->list);
 		kfree(drm_buffer);
+		session_info->buffer_nums--;
 	}
 	mutex_unlock(&session_info->list_mutex);
 
@@ -432,12 +439,15 @@ static int vcodec_drm_import(struct vcodec_iommu_session_info *session_info,
 			     int fd)
 {
 	struct vcodec_drm_buffer *drm_buffer = NULL, *n;
+	struct vcodec_drm_buffer *oldest_buffer = NULL, *loop_buffer = NULL;
 	struct vcodec_iommu_info *iommu_info = session_info->iommu_info;
 	struct vcodec_iommu_drm_info *drm_info = iommu_info->private;
+	struct iommu_domain *domain = drm_info->domain;
 	struct device *dev = session_info->dev;
 	struct dma_buf_attachment *attach;
 	struct sg_table *sgt;
 	struct dma_buf *dma_buf;
+	ktime_t oldest_time = ktime_set(0, 0);
 	int ret = 0;
 
 	dma_buf = dma_buf_get(fd);
@@ -450,6 +460,7 @@ static int vcodec_drm_import(struct vcodec_iommu_session_info *session_info,
 				 &session_info->buffer_list, list) {
 		if (drm_buffer->dma_buf == dma_buf) {
 			dma_buf_put(dma_buf);
+			drm_buffer->last_used = ktime_get();
 			return drm_buffer->index;
 		}
 	}
@@ -462,6 +473,7 @@ static int vcodec_drm_import(struct vcodec_iommu_session_info *session_info,
 
 	drm_buffer->dma_buf = dma_buf;
 	drm_buffer->session_info = session_info;
+	drm_buffer->last_used = ktime_get();
 
 	kref_init(&drm_buffer->ref);
 
@@ -493,10 +505,30 @@ static int vcodec_drm_import(struct vcodec_iommu_session_info *session_info,
 	drm_buffer->attach = attach;
 	drm_buffer->sgt = sgt;
 
+	if (!drm_info->attached)
+		iommu_detach_device(domain, dev);
+
 	mutex_unlock(&iommu_info->iommu_mutex);
 
 	INIT_LIST_HEAD(&drm_buffer->list);
 	mutex_lock(&session_info->list_mutex);
+	session_info->buffer_nums++;
+	if (session_info->buffer_nums > BUFFER_LIST_MAX_NUMS) {
+		list_for_each_entry_safe(loop_buffer, n,
+				 &session_info->buffer_list, list) {
+			if (ktime_to_ns(oldest_time) == 0 ||
+			    ktime_after(oldest_time,
+					loop_buffer->last_used)) {
+				oldest_time = loop_buffer->last_used;
+				oldest_buffer = loop_buffer;
+			}
+		}
+		kref_put(&oldest_buffer->ref, vcodec_drm_clear_map);
+		dma_buf_put(oldest_buffer->dma_buf);
+		list_del_init(&oldest_buffer->list);
+		kfree(oldest_buffer);
+		session_info->buffer_nums--;
+	}
 	drm_buffer->index = session_info->max_idx;
 	list_add_tail(&drm_buffer->list, &session_info->buffer_list);
 	session_info->max_idx++;

drivers/video/rockchip/vcodec/vcodec_iommu_ops.c

@@ -63,6 +63,7 @@ int vcodec_iommu_import(struct vcodec_iommu_info *iommu_info,
 		session_info->mmu_dev = iommu_info->mmu_dev;
 		session_info->dev = iommu_info->dev;
 		session_info->iommu_info = iommu_info;
+		session_info->buffer_nums = 0;
 		mutex_lock(&iommu_info->list_mutex);
 		list_add_tail(&session_info->head, &iommu_info->session_list);
 		mutex_unlock(&iommu_info->list_mutex);

drivers/video/rockchip/vcodec/vcodec_iommu_ops.h

@@ -19,6 +19,8 @@
 #include <linux/platform_device.h>
 #include "vcodec_service.h"
 
+#define BUFFER_LIST_MAX_NUMS	30
+
 #define ALLOCATOR_USE_ION		0x00000000
 #define ALLOCATOR_USE_DRM		0x00000001
 
@@ -65,6 +67,7 @@ struct vcodec_iommu_ops {
 struct vcodec_iommu_session_info {
 	struct list_head head;
 	struct vpu_session *session;
+	int buffer_nums;
 	struct list_head buffer_list;
 	struct mutex list_mutex;
 	int max_idx;