Updating to allow frequency units for clock and trace flags.

Making sure trace frequency is not less than 1/5 of the system frequency.
Showing minimum and maximum available trace speed when out of range.
Making sure MCU is stopped after reset to avoid missing data.
Making sure variables are intiallized.

src/st-trace/trace.c

@@ -98,13 +98,52 @@ static void usage(void) {
   puts("  -V, --version         Print this version");
   puts("  -vXX, --verbose=XX    Specify a specific verbosity level (0..99)");
   puts("  -v, --verbose         Specify a generally verbose logging");
-  puts("  -cXX, --clock=XX      Specify the core frequency in MHz");
-  puts("  -tXX, --trace=XX      Specify the trace frequency in Hz");
+  puts("  -cXX, --clock=XX      Specify the core frequency, optionally followed by");
+  puts("                        k=kHz, m=MHz, or g=GHz (eg. --clock=180m)");
+  puts("  -tXX, --trace=XX      Specify the trace frequency, optionally followed by");
+  puts("                        k=kHz, m=MHz, or g=GHz (eg. --trace=2m)");
   puts("  -n, --no-reset        Do not reset board on connection");
   puts("  -sXX, --serial=XX     Use a specific serial number");
   puts("  -f, --force           Ignore most initialization errors");
 }
 
+static bool parse_frequency(char* text, uint32_t* result)
+{
+  if (text == NULL) {
+    ELOG("Invalid frequency.\n");
+    return false;
+  }
+
+  char* suffix = text;
+  double value = strtod(text, &suffix);
+
+  if (value == 0.0) {
+    ELOG("Invalid frequency.\n");
+    return false;
+  }
+
+  double scale = 1.0;
+  if (*suffix == 'k')
+    scale = 1000;
+  else if (*suffix == 'm')
+    scale = 1000000;
+  else if (*suffix == 'g')
+    scale = 1000000000;
+  else if (*suffix != '\0') {
+    ELOG("Unknown frequency suffix '%s'.\n", suffix);
+    return false;
+  }
+
+  value *= scale;
+  if (value <= 0 || value > 0xFFFFFFFFul) {
+    ELOG("Frequency is out of valid range.\n");
+    return false;
+  }
+
+  *result = (uint32_t)value;
+  return true;
+}
+
 bool parse_options(int argc, char **argv, st_settings_t *settings) {
 
   static struct option long_options[] = {
@@ -150,10 +189,12 @@ bool parse_options(int argc, char **argv, st_settings_t *settings) {
       ugly_init(settings->logging_level);
       break;
     case 'c':
-      settings->core_frequency = atoi(optarg) * 1000000;
+      if (!parse_frequency(optarg, &settings->core_frequency))
+        error = true;
       break;
     case 't':
-      settings->trace_frequency = atoi(optarg);
+      if (!parse_frequency(optarg, &settings->trace_frequency))
+        error = true;
       break;
     case 'n':
       settings->reset_board = false;
@@ -200,8 +241,7 @@ static bool enable_trace(stlink_t *stlink, const st_settings_t *settings,
     if (!settings->force)
       return false;
   }
-
-  if (settings->reset_board && stlink_reset(stlink, RESET_AUTO)) {
+  if (settings->reset_board && stlink_reset(stlink, RESET_SOFT_AND_HALT)) {
     ELOG("Unable to reset device\n");
     if (!settings->force)
       return false;
@@ -268,13 +308,12 @@ static bool enable_trace(stlink_t *stlink, const st_settings_t *settings,
                            STLINK_REG_DWT_CTRL_CYCCNT_ENA);
   stlink_write_debug32(stlink, STLINK_REG_DEMCR, STLINK_REG_DEMCR_TRCENA);
 
-  uint32_t prescaler;
-  stlink_read_debug32(stlink, STLINK_REG_TPI_ACPR_MAX, &prescaler);
+  uint32_t prescaler = 0;
+  stlink_read_debug32(stlink, STLINK_REG_TPI_ACPR, &prescaler);
   if (prescaler) {
     uint32_t system_clock_speed = (prescaler + 1) * trace_frequency;
-    uint32_t system_clock_speed_mhz = (system_clock_speed + 500000) / 1000000;
-    ILOG("Trace Port Interface configured to expect a %d MHz system clock.\n",
-         system_clock_speed_mhz);
+    ILOG("Trace Port Interface configured to expect a %d Hz system clock.\n",
+         system_clock_speed);
   } else {
     WLOG("Trace Port Interface not configured.  Specify the system clock with "
          "a --clock=XX command\n");
@@ -440,13 +479,12 @@ static void check_for_configuration_error(stlink_t *stlink, st_trace_t *trace,
   }
 
   if (error_no_data || error_low_data || error_bad_data) {
-    uint32_t prescaler;
+    uint32_t prescaler = 0;
     stlink_read_debug32(stlink, STLINK_REG_TPI_ACPR, &prescaler);
     if (prescaler) {
       uint32_t system_clock_speed = (prescaler + 1) * trace_frequency;
-      uint32_t system_clock_speed_mhz = (system_clock_speed + 500000) / 1000000;
-      WLOG("Verify the system clock is running at %d MHz.\n",
-           system_clock_speed_mhz);
+      WLOG("Verify the system clock is running at %d Hz.\n",
+           system_clock_speed);
     }
     WLOG("Try specifying the system clock with the --clock=XX command line "
          "option.\n");
@@ -511,7 +549,6 @@ int main(int argc, char **argv) {
   }
   init_chipids (ETC_STLINK_DIR);
 
-
   DLOG("show_help = %s\n", settings.show_help ? "true" : "false");
   DLOG("show_version = %s\n", settings.show_version ? "true" : "false");
   DLOG("logging_level = %d\n", settings.logging_level);
@@ -563,9 +600,18 @@ int main(int argc, char **argv) {
   uint32_t trace_frequency = settings.trace_frequency;
   if (!trace_frequency)
     trace_frequency = STLINK_DEFAULT_TRACE_FREQUENCY;
-  if (trace_frequency > stlink->max_trace_freq) {
-    ELOG("Invalid trace frequency %d (max %d)\n", trace_frequency,
-         stlink->max_trace_freq);
+  uint32_t max_trace_freq = stlink->max_trace_freq;
+  uint32_t min_trace_freq = 0;
+
+  if (settings.core_frequency != 0) {
+    if (max_trace_freq > settings.core_frequency / 5)
+    	max_trace_freq = settings.core_frequency / 5;
+    min_trace_freq = settings.core_frequency / (STLINK_REG_TPI_ACPR_MAX + 1);
+  }
+  if (trace_frequency > max_trace_freq ||
+      trace_frequency < min_trace_freq) {
+    ELOG("Invalid trace frequency %d (min %d max %d)\n", trace_frequency,
+    		min_trace_freq, max_trace_freq);
     if (!settings.force)
       return APP_RESULT_UNSUPPORTED_TRACE_FREQUENCY;
   }