From 25c89d453df5781b8863476ef6652bb5f5765602 Mon Sep 17 00:00:00 2001
From: Piotr Binkowski <pbinkowski@antmicro.com>
Date: Mon, 23 Dec 2019 15:01:42 +0100
Subject: [PATCH] firmware/eth_stream: add double buffering

---
 firmware/eth_stream.c | 13 ++++++++++---
 firmware/eth_stream.h |  4 +++-
 firmware/processor.c  |  2 +-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/firmware/eth_stream.c b/firmware/eth_stream.c
index 548e62ec9..3d8267d36 100644
--- a/firmware/eth_stream.c
+++ b/firmware/eth_stream.c
@@ -13,6 +13,8 @@ static int eth_stream_in_pos;
 static int eth_stream_out_pos;
 static int eth_stream_out_state;
 
+int eth_stream_in_fb_index;
+
 static unsigned int eth_stream_out_next_fb;
 static unsigned int eth_stream_out_size;
 
@@ -42,6 +44,8 @@ void eth_stream_init(void)
 			(tcp_socket_event_callback_t) eth_stream_out_event_cb);
 	tcp_socket_listen(&eth_stream_socket_out, ETH_STREAM_PORT_OUT);
 
+	eth_stream_in_fb_index = 0;
+
 	printf("Ethernet streamer listening on ports %d(in) %d(out)\n", ETH_STREAM_PORT_IN, ETH_STREAM_PORT_OUT);
 #endif
 }
@@ -54,6 +58,8 @@ int eth_stream_in_event_cb(struct tcp_socket *s, void *ptr, tcp_socket_event_t e
 			eth_stream_in_pos = 0;
 			break;
 		case TCP_SOCKET_CLOSED:
+			eth_stream_in_fb_index = (eth_stream_in_fb_index + 1) % 4;
+			break;
 		case TCP_SOCKET_TIMEDOUT:
 		case TCP_SOCKET_ABORTED:
 		default:
@@ -64,14 +70,15 @@ int eth_stream_in_event_cb(struct tcp_socket *s, void *ptr, tcp_socket_event_t e
 
 int eth_stream_in_data_cb(struct tcp_socket *s, void *ptr, const char *rxbuf, int rxlen)
 {
-	uint8_t *fb_base = (uint8_t*)fb_ptrdiff_to_main_ram(FRAMEBUFFER_BASE_ETH_IN);
+	char idx = (eth_stream_in_fb_index + 1) % 4;
+	uint8_t *fb_base = (uint8_t*)fb_ptrdiff_to_main_ram(eth_stream_in_framebuffer_base(idx));
 	memcpy(fb_base + eth_stream_in_pos, rxbuf, rxlen);
 	eth_stream_in_pos += rxlen;
 	return 0;
 }
 
-unsigned int eth_stream_in_framebuffer_base(void) {
-	return FRAMEBUFFER_BASE_ETH_IN;
+unsigned int eth_stream_in_framebuffer_base(char n) {
+	return FRAMEBUFFER_BASE_ETH_IN + n * FRAMEBUFFER_SIZE;
 }
 
 int eth_stream_out_event_cb(struct tcp_socket *s, void *ptr, tcp_socket_event_t event)
diff --git a/firmware/eth_stream.h b/firmware/eth_stream.h
index c42584c03..0fbc2c06f 100644
--- a/firmware/eth_stream.h
+++ b/firmware/eth_stream.h
@@ -22,6 +22,8 @@ enum {
 	ETH_STREAM_OUT_STATE_CLOSE,
 };
 
+extern int eth_stream_in_fb_index;
+
 void eth_stream_init(void);
 
 int eth_stream_in_event_cb(struct tcp_socket *s, void *ptr, tcp_socket_event_t event);
@@ -30,7 +32,7 @@ int eth_stream_in_data_cb(struct tcp_socket *s, void *ptr, const char *rxbuf, in
 int eth_stream_out_event_cb(struct tcp_socket *s, void *ptr, tcp_socket_event_t event);
 int eth_stream_out_data_cb(struct tcp_socket *s, void *ptr, const char *rxbuf, int rxlen);
 
-unsigned int eth_stream_in_framebuffer_base(void);
+unsigned int eth_stream_in_framebuffer_base(char n);
 
 void eth_stream_out_service(void);
 void eth_stream_out_base_write(unsigned int value);
diff --git a/firmware/processor.c b/firmware/processor.c
index 55ace6627..c8f281113 100644
--- a/firmware/processor.c
+++ b/firmware/processor.c
@@ -745,7 +745,7 @@ void processor_update(void)
 		hdmi_out0_core_initiator_base_write(pattern_framebuffer_base());
 
 	if(processor_hdmi_out0_source == VIDEO_IN_ETH)
-		hdmi_out0_core_initiator_base_write(eth_stream_in_framebuffer_base());
+		hdmi_out0_core_initiator_base_write(eth_stream_in_framebuffer_base(eth_stream_in_fb_index));
 #endif
 
 #ifdef CSR_HDMI_OUT1_BASE