trace: add support for 'trace wipe'

Implement a 'trace wipe' command to delete the currently accumulated
trace data. This comes handy when someone needs to trace a particular
command. For example:

  => trace pause; trace wipe
  => trace resume; dhcp; trace pause
  => trace stats
  => trace calls 0x02100000 0x10000000
  => tftpput $profbase $profoffset 192.168.0.16:trace.bin

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/cmd/trace.c b/cmd/trace.c
index 937e6a6..d360087 100644 (file)
--- a/cmd/trace.c
+++ b/cmd/trace.c
@@ -100,6 +100,10 @@ int do_trace(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
        case 's':
                trace_print_stats();
                break;
+       case 'w':
+               if (trace_wipe())
+                       return CMD_RET_FAILURE;
+               break;
        default:
                return CMD_RET_USAGE;
        }
@@ -113,6 +117,7 @@ U_BOOT_CMD(
        "stats                        - display tracing statistics\n"
        "trace pause                        - pause tracing\n"
        "trace resume                       - resume tracing\n"
+       "trace wipe                         - wipe traces\n"
        "trace funclist [<addr> <size>]     - dump function list into buffer\n"
        "trace calls  [<addr> <size>]       "
                "- dump function call trace into buffer"

diff --git a/include/trace.h b/include/trace.h
index 763d6d1..782eaae 100644 (file)
--- a/include/trace.h
+++ b/include/trace.h
@@ -100,6 +100,8 @@ void trace_set_enabled(int enabled);
 
 int trace_early_init(void);
 
+int trace_clear(void);
+
 /**
  * Init the trace system
  *

diff --git a/lib/trace.c b/lib/trace.c
index cabbe47..def9f91 100644 (file)
--- a/lib/trace.c
+++ b/lib/trace.c
@@ -351,14 +351,8 @@ static int get_func_count(void)
        return gd->mon_len / FUNC_SITE_SIZE;
 }
 
-/**
- * trace_init() - initialize the tracing system and enable it
- *
- * @buff:      Pointer to trace buffer
- * @buff_size: Size of trace buffer
- * Return:     0 if ok
- */
-int notrace trace_init(void *buff, size_t buff_size)
+static int notrace trace_init_(void *buff, size_t buff_size, bool copy_early,
+                              bool enable)
 {
        int func_count = get_func_count();
        size_t needed;
@@ -368,7 +362,7 @@ int notrace trace_init(void *buff, size_t buff_size)
                return func_count;
        trace_save_gd();
 
-       if (!was_disabled) {
+       if (copy_early) {
 #ifdef CONFIG_TRACE_EARLY
                ulong used, count;
                char *end;
@@ -394,9 +388,6 @@ int notrace trace_init(void *buff, size_t buff_size)
                }
                puts("\n");
                memcpy(buff, hdr, used);
-#else
-               puts("trace: already enabled\n");
-               return -EALREADY;
 #endif
        }
        hdr = (struct trace_hdr *)buff;
@@ -419,13 +410,41 @@ int notrace trace_init(void *buff, size_t buff_size)
        hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
        hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;
 
-       puts("trace: enabled\n");
-       trace_enabled = 1;
+       printf("trace: initialized, %senabled\n", enable ? "" : "not ");
+       trace_enabled = enable;
        trace_inited = 1;
 
        return 0;
 }
 
+/**
+ * trace_init() - initialize the tracing system and enable it
+ *
+ * @buff:      Pointer to trace buffer
+ * @buff_size: Size of trace buffer
+ * Return:     0 if ok
+ */
+int notrace trace_init(void *buff, size_t buff_size)
+{
+       /* If traces are enabled already, we may have early traces to copy */
+       return trace_init_(buff, buff_size, trace_enabled, true);
+}
+
+/**
+ * trace_clear() - clear accumulated traced data
+ *
+ * May be called with tracing enabled or disabled.
+ */
+int notrace trace_clear(void)
+{
+       bool was_enabled = trace_enabled;
+
+       if (trace_enabled)
+               trace_enabled = 0;
+       return trace_init_(gd->trace_buff, CONFIG_TRACE_BUFFER_SIZE,
+                          false, was_enabled);
+}
+
 #ifdef CONFIG_TRACE_EARLY
 /**
  * trace_early_init() - initialize the tracing system for early tracing