1 files changed, 34 insertions, 7 deletions
diff --git a/gm_platform/fw/serial.h b/gm_platform/fw/serial.h
index c10393a..39ffd18 100644
--- a/gm_platform/fw/serial.h
+++ b/gm_platform/fw/serial.h
@@ -27,19 +27,46 @@
 #include <stdarg.h>
 #include <errno.h>
 
+#include "global.h"
+
 struct dma_tx_buf {
-    size_t xfr_start; /* Start index of running DMA transfer */
-    size_t xfr_end; /* End index of running DMA transfer plus one */
-    size_t wr_pos; /* Next index to be written */
+    /* The following fields are accessed only from DMA ISR */
+    ssize_t xfr_start; /* Start index of running DMA transfer */
+    ssize_t xfr_end; /* End index of running DMA transfer plus one */
+    uint8_t cur_packet;
+
+    /* The following fields are written only from non-interrupt code */
+    ssize_t wr_pos; /* Next index to be written */
+    ssize_t packet_start[8];
+
+    /* The following may be accessed by anything */
     uint8_t data[512];
-    size_t packet_starts[5];
+};
+
+struct __attribute__((__packed__)) ll_pkt {
+    uint32_t crc32;
+    /* CRC computed over entire packet starting here */
+    uint8_t pid;
+    uint8_t _pad;
+    uint8_t data[];
+};
+
+enum ctrl_pkt_type {
+    CTRL_PKT_RESET = 1,
+    CTRL_PKT_ACK = 2,
+    CTRL_PKT_RETRANSMIT = 3,
+};
+
+struct __attribute__((__packed__)) ctrl_pkt {
+    uint8_t type;
+    uint8_t orig_id;
 };
 
 extern volatile struct dma_tx_buf usart_tx_buf;
 
 void usart_dma_init(void);
-int usart_dma_fifo_push(volatile struct dma_tx_buf *buf, char c);
-void usart_send_packet(const uint8_t *data, size_t len);
-int usart_send_packet_nonblocking(const uint8_t *data, size_t len);
+int usart_dma_fifo_push(volatile struct dma_tx_buf *buf, uint8_t c);
+int usart_send_packet_nonblocking(struct ll_pkt *pkt, size_t pkt_len);
+int usart_ack_packet(uint8_t idx);
 
 #endif // __SERIAL_H__