[GitHub] andrzej-kaczmarek closed pull request #1399: RTT console fixes

[GitBox <gi...@apache.org>]

andrzej-kaczmarek closed pull request #1399: RTT console fixes
URL: https://github.com/apache/mynewt-core/pull/1399
 
 
   

This is a PR merged from a forked repository.
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diff --git a/sys/console/full/src/rtt_console.c b/sys/console/full/src/rtt_console.c
index 0191372205..1bc9c58441 100644
--- a/sys/console/full/src/rtt_console.c
+++ b/sys/console/full/src/rtt_console.c
@@ -30,7 +30,76 @@
 static struct hal_timer rtt_timer;
 #endif
 
-static const char CR = '\r';
+#if MYNEWT_VAL(CONSOLE_RTT_RETRY_COUNT) > 0
+
+static void
+rtt_console_wait_for_retry(void)
+{
+    uint32_t ticks;
+
+    if (os_arch_in_isr()) {
+#if MYNEWT_VAL(CONSOLE_RTT_RETRY_IN_ISR)
+        os_cputime_delay_usecs(MYNEWT_VAL(CONSOLE_RTT_RETRY_DELAY_MS) * 1000);
+#endif
+    } else {
+        ticks = max(1, os_time_ms_to_ticks32(MYNEWT_VAL(CONSOLE_RTT_RETRY_DELAY_MS)));
+        os_time_delay(ticks);
+    }
+}
+
+static void
+rtt_console_write_ch(char c)
+{
+    static int rtt_console_retries_left = MYNEWT_VAL(CONSOLE_RTT_RETRY_COUNT);
+    os_sr_t sr;
+    int ret;
+
+    while (1) {
+        OS_ENTER_CRITICAL(sr);
+        ret = SEGGER_RTT_WriteNoLock(0, &c, 1);
+        OS_EXIT_CRITICAL(sr);
+
+        /*
+         * In case write failed we can wait a bit and retry to allow host pull
+         * some data from buffer. However, in case there is no host connected
+         * we should not spend time retrying over and over again so need to be
+         * smarter here:
+         * - each successful write resets retry counter to predefined value
+         * - each failed write will retry until success or retry counter drops
+         *   to zero
+         * This means that if we failed to write some character after number of
+         * retries (which means that most likely there is no host connected to
+         * read data), we stop retrying until successful write (which means that
+         * host is reading data).
+         */
+
+        if (ret) {
+            rtt_console_retries_left = MYNEWT_VAL(CONSOLE_RTT_RETRY_COUNT);
+            break;
+        }
+
+        if (!rtt_console_retries_left) {
+            break;
+        }
+
+        rtt_console_wait_for_retry();
+        rtt_console_retries_left--;
+    }
+}
+
+#else
+
+static void
+rtt_console_write_ch(char c)
+{
+    os_sr_t sr;
+
+    OS_ENTER_CRITICAL(sr);
+    SEGGER_RTT_WriteNoLock(0, &c, 1);
+    OS_EXIT_CRITICAL(sr);
+}
+
+#endif
 
 int
 console_out(int character)
@@ -42,13 +111,13 @@ console_out(int character)
     }
 
     if ('\n' == c) {
-        SEGGER_RTT_WriteWithOverwriteNoLock(0, &CR, 1);
+        rtt_console_write_ch('\r');
         console_is_midline = 0;
     } else {
         console_is_midline = 1;
     }
 
-    SEGGER_RTT_WriteWithOverwriteNoLock(0, &c, 1);
+    rtt_console_write_ch(c);
 
     return character;
 }
diff --git a/sys/console/full/syscfg.yml b/sys/console/full/syscfg.yml
index 647160e28f..92e4382a2b 100644
--- a/sys/console/full/syscfg.yml
+++ b/sys/console/full/syscfg.yml
@@ -72,6 +72,20 @@ syscfg.defs:
         description: 'Console UART device.'
         value: '"uart0"'
 
+    CONSOLE_RTT_RETRY_COUNT:
+        description: >
+            Number of retries to write data in case buffer is full. This allows
+            to wait for host to read data from buffer in case there's a lot of
+            data to write which do not fit in buffer.
+        value: 2
+    CONSOLE_RTT_RETRY_DELAY_MS:
+        description: >
+            Delay (in miliseconds) between each write retry.
+        value: 2
+    CONSOLE_RTT_RETRY_IN_ISR:
+        description: >
+            Set to non-zero to enable write retries also in ISR.
+        value: 0
     CONSOLE_RTT_INPUT_POLL_INTERVAL_MAX:
         description: >
             Maximum interval (milliseconds) to poll for RTT input.


 

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