From 9915d1ba46e30990ea149c7a09d1d2ed0d13a331 Mon Sep 17 00:00:00 2001
From: Fredrik Thulin <fredrik@thulin.net>
Date: Wed, 1 Jun 2016 21:03:05 +0200
Subject: Implement circular buffer UART RX using interrupts.

---
 projects/cli-test/mgmt-cli.c | 60 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 56 insertions(+), 4 deletions(-)

(limited to 'projects/cli-test/mgmt-cli.c')

diff --git a/projects/cli-test/mgmt-cli.c b/projects/cli-test/mgmt-cli.c
index 46faae8..abbd999 100644
--- a/projects/cli-test/mgmt-cli.c
+++ b/projects/cli-test/mgmt-cli.c
@@ -33,10 +33,27 @@
  */
 #include "stm-init.h"
 #include "stm-uart.h"
+#include "stm-led.h"
 #include "mgmt-cli.h"
 
 #include <string.h>
 
+extern uint8_t uart_rx;
+
+struct uart_ringbuf_t {
+    uint32_t enabled, ridx, widx, overflow;
+    uint8_t buf[CLI_UART_RECVBUF_SIZE];
+};
+
+volatile struct uart_ringbuf_t uart_ringbuf = {1, 0, 0, 0, {0}};
+
+#define RINGBUF_RIDX(rb)       (rb.ridx & CLI_UART_RECVBUF_MASK)
+#define RINGBUF_WIDX(rb)       (rb.widx & CLI_UART_RECVBUF_MASK)
+#define RINGBUF_COUNT(rb)      ((unsigned)(rb.widx - rb.ridx))
+#define RINGBUF_FULL(rb)       (RINGBUF_RIDX(rb) == ((rb.widx + 1) & CLI_UART_RECVBUF_MASK))
+#define RINGBUF_READ(rb, dst)  {dst = rb.buf[RINGBUF_RIDX(rb)]; rb.buf[RINGBUF_RIDX(rb)] = '.'; rb.ridx++;}
+#define RINGBUF_WRITE(rb, src) {rb.buf[RINGBUF_WIDX(rb)] = src; rb.widx++;}
+
 void uart_cli_print(struct cli_def *cli __attribute__ ((unused)), const char *buf)
 {
     char crlf[] = "\r\n";
@@ -46,8 +63,23 @@ void uart_cli_print(struct cli_def *cli __attribute__ ((unused)), const char *bu
 
 int uart_cli_read(struct cli_def *cli __attribute__ ((unused)), void *buf, size_t count)
 {
-    if (uart_recv_char2(STM_UART_MGMT, buf, count) != HAL_OK) {
-	return -1;
+    uint32_t timeout = 0xffffff;
+
+    /* Always explicitly enable the RX interrupt when we get here.
+     * Prevents us getting stuck waiting for an interrupt that will never come.
+     */
+    __HAL_UART_FLUSH_DRREGISTER(&huart_mgmt);
+    HAL_UART_Receive_IT(&huart_mgmt, (uint8_t *) &uart_rx, 1);
+
+    while (count && timeout--) {
+	if (RINGBUF_COUNT(uart_ringbuf)) {
+	    RINGBUF_READ(uart_ringbuf, *(uint8_t *) buf);
+	    buf++;
+	    count--;
+	} else {
+	    led_toggle(LED_GREEN);
+	    HAL_Delay(10);
+	}
     }
     return 1;
 }
@@ -83,7 +115,11 @@ int embedded_cli_loop(struct cli_def *cli)
 
 	    n = cli_loop_read_next_char(cli, &ctx, &c);
 
-	    //cli_print(cli, "Next char: '%c' (n == %i)", c, n);
+	    /*
+	    cli_print(cli, "Next char: '%c'/%i, ringbuf ridx %i, widx %i (%i/%i) - count %i",
+		      c, (int) c, uart_ringbuf.ridx, uart_ringbuf.widx, RINGBUF_RIDX(uart_ringbuf),
+		      RINGBUF_WIDX(uart_ringbuf), RINGBUF_COUNT(uart_ringbuf));
+	    */
 	    if (n == CLI_LOOP_CTRL_BREAK)
 		break;
 	    if (n == CLI_LOOP_CTRL_CONTINUE)
@@ -98,7 +134,7 @@ int embedded_cli_loop(struct cli_def *cli)
 
 	if (ctx.l < 0) break;
 
-	//cli_print(cli, "Process command: '%s'", ctx.cmd);
+	/* cli_print(cli, "Process command: '%s'", ctx.cmd); */
 	n = cli_loop_process_cmd(cli, &ctx);
 	if (n == CLI_LOOP_CTRL_BREAK)
 	    break;
@@ -107,6 +143,22 @@ int embedded_cli_loop(struct cli_def *cli)
     return CLI_OK;
 }
 
+/* Interrupt service routine to be called when data has been received on the MGMT UART. */
+void mgmt_cli_uart_isr(const uint8_t *buf, size_t count)
+{
+    if (! uart_ringbuf.enabled) return;
+
+    while (count) {
+	if (RINGBUF_FULL(uart_ringbuf)) {
+	    uart_ringbuf.overflow++;
+	    return;
+	}
+	RINGBUF_WRITE(uart_ringbuf, *buf);
+	buf++;
+	count--;
+    }
+}
+
 void mgmt_cli_init(struct cli_def *cli)
 {
     cli_init(cli);
-- 
cgit v1.2.3