refactor(class/video/usbd_video): zero copy for video data transfer

Signed-off-by: sakumisu <[email protected]>

6 files changed, 83 insertions, 105 deletions

diff --git a/class/video/usbd_video.c b/class/video/usbd_video.c
index f3a28dbd..b94379df 100644
--- a/class/video/usbd_video.c
+++ b/class/video/usbd_video.c
@@ -18,20 +18,14 @@ struct usbd_video_priv {
     uint8_t power_mode;
     uint8_t error_code;
     struct video_entity_info info[3];
-    uint8_t *ep_buf0;
-    uint8_t *ep_buf1;
-    bool ep_buf0_ready;
-    bool ep_buf1_ready;
-    uint32_t ep_buf0_len;
-    uint32_t ep_buf1_len;
-    uint8_t ep_buf_idx;
+    uint8_t *ep_buf;
     bool stream_finish;
-    uint32_t max_packets;
     uint8_t *stream_buf;
     uint32_t stream_len;
     uint32_t stream_offset;
     uint8_t stream_frameid;
     uint32_t stream_headerlen;
+    bool do_copy;
 } g_usbd_video[CONFIG_USBDEV_MAX_BUS];
 
 static int usbd_video_control_request_handler(uint8_t busid, struct usb_setup_packet *setup, uint8_t **data, uint32_t *len)
@@ -756,40 +750,6 @@ static void usbd_video_probe_and_commit_controls_init(uint8_t busid, uint32_t dw
     g_usbd_video[busid].stream_headerlen = 2;
 }
 
-static uint32_t usbd_video_prepare_ep_buf_data(uint8_t busid, uint32_t remain, uint8_t *ep_buf)
-{
-    struct video_payload_header *header;
-    uint32_t len;
-    uint32_t offset;
-
-    len = MIN(remain, (g_usbd_video[busid].probe.dwMaxPayloadTransferSize - g_usbd_video[busid].stream_headerlen) * g_usbd_video[busid].max_packets);
-    offset = 0;
-    while (len > 0) {
-        header = (struct video_payload_header *)&ep_buf[offset];
-        header->bHeaderLength = g_usbd_video[busid].stream_headerlen;
-        header->headerInfoUnion.bmheaderInfo = 0;
-        header->headerInfoUnion.headerInfoBits.endOfHeader = 1;
-        header->headerInfoUnion.headerInfoBits.endOfFrame = 0;
-        header->headerInfoUnion.headerInfoBits.frameIdentifier = g_usbd_video[busid].stream_frameid;
-
-        uint32_t len2 = MIN(len, g_usbd_video[busid].probe.dwMaxPayloadTransferSize - g_usbd_video[busid].stream_headerlen);
-
-        usb_memcpy(&ep_buf[offset + g_usbd_video[busid].stream_headerlen],
-                   &g_usbd_video[busid].stream_buf[g_usbd_video[busid].stream_offset],
-                   len2);
-
-        g_usbd_video[busid].stream_offset += len2;
-        len -= len2;
-        offset += (len2 + g_usbd_video[busid].stream_headerlen);
-
-        if (g_usbd_video[busid].stream_offset == g_usbd_video[busid].stream_len) {
-            header->headerInfoUnion.headerInfoBits.endOfFrame = 1;
-        }
-    }
-
-    return offset;
-}
-
 struct usbd_interface *usbd_video_init_intf(uint8_t busid,
                                             struct usbd_interface *intf,
                                             uint32_t dwFrameInterval,
@@ -817,69 +777,87 @@ struct usbd_interface *usbd_video_init_intf(uint8_t busid,
 
 bool usbd_video_stream_split_transfer(uint8_t busid, uint8_t ep)
 {
-    uint32_t remain;
+    struct video_payload_header *header;
+    static uint32_t offset = 0;
+    static uint32_t len = 0;
+
+    if (g_usbd_video[busid].stream_finish) {
+        g_usbd_video[busid].stream_finish = false;
+        return true;
+    }
+
+    offset = g_usbd_video[busid].stream_offset;
+
+    len = MIN(g_usbd_video[busid].stream_len,
+              g_usbd_video[busid].probe.dwMaxPayloadTransferSize -
+                  g_usbd_video[busid].stream_headerlen);
 
-    if (g_usbd_video[busid].ep_buf1_ready && (g_usbd_video[busid].ep_buf_idx == 0)) {    /* callback: buf1 ready and buf0 was sent */
-        g_usbd_video[busid].ep_buf0_ready = false;
-        g_usbd_video[busid].ep_buf_idx = 1;
-        usbd_ep_start_write(busid, ep, g_usbd_video[busid].ep_buf1, g_usbd_video[busid].ep_buf1_len);
-    } else if (g_usbd_video[busid].ep_buf0_ready && (g_usbd_video[busid].ep_buf_idx == 1)) {    /* callback: buf0 ready and buf1 was sent */
-        g_usbd_video[busid].ep_buf1_ready = false;
-        g_usbd_video[busid].ep_buf_idx = 0;
-        usbd_ep_start_write(busid, ep, g_usbd_video[busid].ep_buf0, g_usbd_video[busid].ep_buf0_len);
+    if (g_usbd_video[busid].do_copy) {
+        header = (struct video_payload_header *)&g_usbd_video[busid].ep_buf[0];
+        usb_memcpy(&g_usbd_video[busid].ep_buf[g_usbd_video[busid].stream_headerlen], &g_usbd_video[busid].stream_buf[offset], len);
     } else {
-        if (g_usbd_video[busid].stream_finish) {
-            return true;
-        }
+        header = (struct video_payload_header *)&g_usbd_video[busid].stream_buf[offset - g_usbd_video[busid].stream_headerlen];
     }
 
-    if (!g_usbd_video[busid].ep_buf0_ready) {
-        remain = g_usbd_video[busid].stream_len - g_usbd_video[busid].stream_offset;
-        if (remain == 0) {
-            g_usbd_video[busid].stream_frameid ^= 1;
-            g_usbd_video[busid].stream_finish = true;
-        } else {
-            g_usbd_video[busid].ep_buf0_len = usbd_video_prepare_ep_buf_data(busid, remain, g_usbd_video[busid].ep_buf0);
-            g_usbd_video[busid].ep_buf0_ready = true;
-            if (!g_usbd_video[busid].ep_buf1_ready) {
-                g_usbd_video[busid].ep_buf_idx = 0;
-                usbd_ep_start_write(busid, ep, g_usbd_video[busid].ep_buf0, g_usbd_video[busid].ep_buf0_len);
-            }
-        }
+    header->bHeaderLength = g_usbd_video[busid].stream_headerlen;
+    header->headerInfoUnion.bmheaderInfo = 0;
+    header->headerInfoUnion.headerInfoBits.endOfHeader = 1;
+    header->headerInfoUnion.headerInfoBits.endOfFrame = 0;
+    header->headerInfoUnion.headerInfoBits.frameIdentifier = g_usbd_video[busid].stream_frameid;
+
+    g_usbd_video[busid].stream_offset += len;
+    g_usbd_video[busid].stream_len -= len;
+
+    if (g_usbd_video[busid].stream_len == 0) {
+        header->headerInfoUnion.headerInfoBits.endOfFrame = 1;
+        g_usbd_video[busid].stream_frameid ^= 1;
+        g_usbd_video[busid].stream_finish = true;
     }
 
-    if (!g_usbd_video[busid].ep_buf1_ready) {
-        remain = g_usbd_video[busid].stream_len - g_usbd_video[busid].stream_offset;
-        if (remain == 0) {
-            g_usbd_video[busid].stream_frameid ^= 1;
-            g_usbd_video[busid].stream_finish = true;
-        } else {
-            g_usbd_video[busid].ep_buf1_len = usbd_video_prepare_ep_buf_data(busid, remain, g_usbd_video[busid].ep_buf1);
-            g_usbd_video[busid].ep_buf1_ready = true;
-        }
+    if (g_usbd_video[busid].do_copy) {
+        usbd_ep_start_write(busid, ep,
+                            g_usbd_video[busid].ep_buf,
+                            g_usbd_video[busid].stream_headerlen + len);
+    } else {
+        usbd_ep_start_write(busid, ep,
+                            &g_usbd_video[busid].stream_buf[offset - g_usbd_video[busid].stream_headerlen],
+                            g_usbd_video[busid].stream_headerlen + len);
     }
 
     return false;
 }
 
-int usbd_video_stream_start_write(uint8_t busid, uint8_t ep, uint8_t *ep_buf0, uint8_t *ep_buf1, uint32_t ep_bufsize, uint8_t *stream_buf, uint32_t stream_len)
+int usbd_video_stream_start_write(uint8_t busid, uint8_t ep, uint8_t *ep_buf, uint8_t *stream_buf, uint32_t stream_len, bool do_copy)
 {
+    struct video_payload_header *header;
+
     if ((usb_device_is_configured(busid) == 0) || (stream_len == 0)) {
         return -1;
     }
 
-    g_usbd_video[busid].ep_buf0 = ep_buf0;
-    g_usbd_video[busid].ep_buf1 = ep_buf1;
-    g_usbd_video[busid].ep_buf0_ready = false;
-    g_usbd_video[busid].ep_buf1_ready = false;
-    g_usbd_video[busid].ep_buf_idx = 0;
-    g_usbd_video[busid].stream_finish = false;
-    g_usbd_video[busid].max_packets = ep_bufsize / g_usbd_video[busid].probe.dwMaxPayloadTransferSize;
+    g_usbd_video[busid].ep_buf = ep_buf;
     g_usbd_video[busid].stream_buf = stream_buf;
     g_usbd_video[busid].stream_len = stream_len;
     g_usbd_video[busid].stream_offset = 0;
+    g_usbd_video[busid].stream_finish = false;
+    g_usbd_video[busid].do_copy = do_copy;
+
+    uint32_t len = MIN(g_usbd_video[busid].stream_len,
+                       g_usbd_video[busid].probe.dwMaxPayloadTransferSize -
+                           g_usbd_video[busid].stream_headerlen);
+
+    header = (struct video_payload_header *)&ep_buf[0];
+    header->bHeaderLength = g_usbd_video[busid].stream_headerlen;
+    header->headerInfoUnion.bmheaderInfo = 0;
+    header->headerInfoUnion.headerInfoBits.endOfHeader = 1;
+    header->headerInfoUnion.headerInfoBits.endOfFrame = 0;
+    header->headerInfoUnion.headerInfoBits.frameIdentifier = g_usbd_video[busid].stream_frameid;
+
+    usb_memcpy(&ep_buf[g_usbd_video[busid].stream_headerlen], stream_buf, len);
+    g_usbd_video[busid].stream_offset += len;
+    g_usbd_video[busid].stream_len -= len;
 
-    usbd_video_stream_split_transfer(busid, ep);
+    usbd_ep_start_write(busid, ep, ep_buf, g_usbd_video[busid].stream_headerlen + len);
     return 0;
 }
 
diff --git a/class/video/usbd_video.h b/class/video/usbd_video.h
index a2a98bb8..a2061fdc 100644
--- a/class/video/usbd_video.h
+++ b/class/video/usbd_video.h
@@ -22,7 +22,7 @@ void usbd_video_open(uint8_t busid, uint8_t intf);
 void usbd_video_close(uint8_t busid, uint8_t intf);
 
 bool usbd_video_stream_split_transfer(uint8_t busid, uint8_t ep);
-int usbd_video_stream_start_write(uint8_t busid, uint8_t ep, uint8_t *ep_buf0, uint8_t *ep_buf1, uint32_t ep_bufsize, uint8_t *stream_buf, uint32_t stream_len);
+int usbd_video_stream_start_write(uint8_t busid, uint8_t ep, uint8_t *ep_buf, uint8_t *stream_buf, uint32_t stream_len, bool do_copy);
 
 #ifdef __cplusplus
 }
diff --git a/demo/video_static_h264_template.c b/demo/video_static_h264_template.c
index 60737672..a472244b 100644
--- a/demo/video_static_h264_template.c
+++ b/demo/video_static_h264_template.c
@@ -7,8 +7,6 @@
 #include "usbd_video.h"
 #include "cherryusb_h264.h"
 
-#define MAX_PACKETS_IN_ONE_TRANSFER 1
-
 #define VIDEO_IN_EP  0x81
 #define VIDEO_INT_EP 0x83
 
@@ -282,7 +280,8 @@ void video_init(uint8_t busid, uintptr_t reg_base)
     usbd_initialize(busid, reg_base, usbd_event_handler);
 }
 
-USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[2][40 * 1024];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[MAX_PAYLOAD_SIZE];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t frame_buffer[32 * 1024];
 
 void video_test(uint8_t busid)
 {
@@ -294,7 +293,8 @@ void video_test(uint8_t busid)
     while (1) {
         if (tx_flag) {
             iso_tx_busy = true;
-            usbd_video_stream_start_write(busid, VIDEO_IN_EP, &packet_buffer[0][0], &packet_buffer[1][0], MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE, (uint8_t *)cherryusb_h264, sizeof(cherryusb_h264));
+            memcpy(frame_buffer, cherryusb_h264, sizeof(cherryusb_h264)); // cherryusb_h264 is a static yuyv frame buffer, so we need copy it to frame_buffer
+            usbd_video_stream_start_write(busid, VIDEO_IN_EP, packet_buffer, (uint8_t *)frame_buffer, sizeof(cherryusb_h264), false);
             while (iso_tx_busy) {
                 if (tx_flag == 0) {
                     break;
diff --git a/demo/video_static_mjpeg_template.c b/demo/video_static_mjpeg_template.c
index 0e77b38d..667a2fbb 100644
--- a/demo/video_static_mjpeg_template.c
+++ b/demo/video_static_mjpeg_template.c
@@ -7,8 +7,6 @@
 #include "usbd_video.h"
 #include "cherryusb_mjpeg.h"
 
-#define MAX_PACKETS_IN_ONE_TRANSFER 1
-
 #define VIDEO_IN_EP  0x81
 #define VIDEO_INT_EP 0x83
 
@@ -282,7 +280,8 @@ void video_init(uint8_t busid, uintptr_t reg_base)
     usbd_initialize(busid, reg_base, usbd_event_handler);
 }
 
-USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[2][MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[MAX_PAYLOAD_SIZE];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t frame_buffer[32 * 1024];
 
 void video_test(uint8_t busid)
 {
@@ -291,7 +290,8 @@ void video_test(uint8_t busid)
     while (1) {
         if (tx_flag) {
             iso_tx_busy = true;
-            usbd_video_stream_start_write(busid, VIDEO_IN_EP, &packet_buffer[0][0], &packet_buffer[1][0], MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE, (uint8_t *)cherryusb_mjpeg, sizeof(cherryusb_mjpeg));
+            memcpy(frame_buffer, cherryusb_mjpeg, sizeof(cherryusb_mjpeg)); // cherryusb_mjpeg is a static MJPEG frame buffer, so we need copy it to frame_buffer
+            usbd_video_stream_start_write(busid, VIDEO_IN_EP, packet_buffer, (uint8_t *)frame_buffer, sizeof(cherryusb_mjpeg), false);
             while (iso_tx_busy) {
                 if (tx_flag == 0) {
                     break;
diff --git a/demo/video_static_yuyv_template.c b/demo/video_static_yuyv_template.c
index 1aca76d0..6b5da39d 100644
--- a/demo/video_static_yuyv_template.c
+++ b/demo/video_static_yuyv_template.c
@@ -7,8 +7,6 @@
 #include "usbd_video.h"
 #include "cherryusb_yuyv.h"
 
-#define MAX_PACKETS_IN_ONE_TRANSFER 1
-
 #define VIDEO_IN_EP  0x81
 #define VIDEO_INT_EP 0x83
 
@@ -286,7 +284,8 @@ void video_init(uint8_t busid, uintptr_t reg_base)
     usbd_initialize(busid, reg_base, usbd_event_handler);
 }
 
-USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[2][MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[MAX_PAYLOAD_SIZE];
+USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t frame_buffer[32 * 1024];
 
 void video_test(uint8_t busid)
 {
@@ -295,7 +294,8 @@ void video_test(uint8_t busid)
     while (1) {
         if (tx_flag) {
             iso_tx_busy = true;
-            usbd_video_stream_start_write(busid, VIDEO_IN_EP, &packet_buffer[0][0], &packet_buffer[1][0], MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE, (uint8_t *)cherryusb_yuyv, sizeof(cherryusb_yuyv));
+            memcpy(frame_buffer, cherryusb_yuyv, sizeof(cherryusb_yuyv)); // cherryusb_yuyv is a static yuyv frame buffer, so we need copy it to frame_buffer
+            usbd_video_stream_start_write(busid, VIDEO_IN_EP, packet_buffer, (uint8_t *)frame_buffer, sizeof(cherryusb_yuyv), false);
             while (iso_tx_busy) {
                 if (tx_flag == 0) {
                     break;
diff --git a/docs/source/demo/usbd_video.rst b/docs/source/demo/usbd_video.rst
index a3e085d3..e215abde 100644
--- a/docs/source/demo/usbd_video.rst
+++ b/docs/source/demo/usbd_video.rst
@@ -45,13 +45,11 @@ demo 包含 **video_static_yuyv_template**, **video_static_mjpeg_template**, **v
     USB_ENDPOINT_DESCRIPTOR_INIT(VIDEO_IN_EP, 0x05, VIDEO_PACKET_SIZE, 0x01),
 
 
-- 使用 `usbd_video_stream_start_write` 传输数据
+- 使用 `usbd_video_stream_start_write` 传输数据, 最后 **do_copy** 选项表示是否将数据 copy 到 packet_buffer,
+如果不选择 copy， 则会直接在原图像数据中填充头部信息，并直接发送，达到 zero copy 功能。
 
-1，传输采用双缓冲的形式， **MAX_PACKETS_IN_ONE_TRANSFER** 表示一次传输可以携带多少个 **MAX_PAYLOAD_SIZE**，通常 IP 只能为 1。
+- 因为提供的是静态数据，不能被修改，因此需要重新给一个 frame_buffer 用于图像传输，在实际对接 camera 场景中是动态数据，直接使用 camera 的数据缓冲区即可。
 
-2，在中断完成中，调用 `usbd_video_stream_split_transfer` 继续下一次传输，直到返回为 true 表示传输完成。这边的分裂传输只是表示将图片数据拆成 **MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE** 份传输。
-
-3，通常 IP 不支持一次传输非常大的数据，比如传输 1MB，因此需要做分裂传输，但是会增加中断次数。并且一次传输非常大数据也是需要足够的 RAM。
 
 .. code-block:: C
 
@@ -63,7 +61,8 @@ demo 包含 **video_static_yuyv_template**, **video_static_mjpeg_template**, **v
         }
     }
 
-    USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[2][MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE];
+    USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t packet_buffer[MAX_PAYLOAD_SIZE];
+    USB_NOCACHE_RAM_SECTION USB_MEM_ALIGNX uint8_t frame_buffer[32 * 1024];
 
     void video_test(uint8_t busid)
     {
@@ -72,7 +71,8 @@ demo 包含 **video_static_yuyv_template**, **video_static_mjpeg_template**, **v
         while (1) {
             if (tx_flag) {
                 iso_tx_busy = true;
-                usbd_video_stream_start_write(busid, VIDEO_IN_EP, &packet_buffer[0][0], &packet_buffer[1][0], MAX_PACKETS_IN_ONE_TRANSFER * MAX_PAYLOAD_SIZE, (uint8_t *)cherryusb_mjpeg, sizeof(cherryusb_mjpeg));
+                memcpy(frame_buffer, cherryusb_mjpeg, sizeof(cherryusb_mjpeg)); // cherryusb_mjpeg is a static MJPEG frame buffer, so we need copy it to frame_buffer
+                usbd_video_stream_start_write(busid, VIDEO_IN_EP, packet_buffer, (uint8_t *)frame_buffer, sizeof(cherryusb_mjpeg), false);
                 while (iso_tx_busy) {
                     if (tx_flag == 0) {
                         break;