Allow clearing core device log buffer.

This is useful to get a fresh environment, such as when
running tests that print to log buffer.

artiq/coredevice/comm_generic.py

@@ -12,23 +12,26 @@ logger = logging.getLogger(__name__)
 
 class _H2DMsgType(Enum):
     LOG_REQUEST = 1
-    IDENT_REQUEST = 2
-    SWITCH_CLOCK = 3
+    LOG_CLEAR = 2
 
-    LOAD_LIBRARY = 4
-    RUN_KERNEL = 5
+    IDENT_REQUEST = 3
+    SWITCH_CLOCK = 4
 
-    RPC_REPLY = 6
-    RPC_EXCEPTION = 7
+    LOAD_LIBRARY = 5
+    RUN_KERNEL = 6
 
-    FLASH_READ_REQUEST = 8
-    FLASH_WRITE_REQUEST = 9
-    FLASH_ERASE_REQUEST = 10
-    FLASH_REMOVE_REQUEST = 11
+    RPC_REPLY = 7
+    RPC_EXCEPTION = 8
+
+    FLASH_READ_REQUEST = 9
+    FLASH_WRITE_REQUEST = 10
+    FLASH_ERASE_REQUEST = 11
+    FLASH_REMOVE_REQUEST = 12
 
 
 class _D2HMsgType(Enum):
     LOG_REPLY = 1
+
     IDENT_REPLY = 2
     CLOCK_SWITCH_COMPLETED = 3
     CLOCK_SWITCH_FAILED = 4
@@ -235,6 +238,11 @@ class CommGeneric:
         self._read_expect(_D2HMsgType.LOG_REPLY)
         return self._read_chunk(self._read_length).decode('utf-8')
 
+    def clear_log(self):
+        self._write_empty(_H2DMsgType.LOG_CLEAR)
+
+        self._read_empty(_D2HMsgType.LOG_REPLY)
+
     def flash_storage_read(self, key):
         self._write_header(_H2DMsgType.FLASH_READ_REQUEST)
         self._write_string(key)

soc/runtime/log.c

@@ -61,3 +61,8 @@ void log_get(char *outbuf)
         j = (j + 1) % LOG_BUFFER_SIZE;
     }
 }
+
+void log_clear()
+{
+    memset(buffer, 0, sizeof(buffer));
+}

soc/runtime/log.h

@@ -12,5 +12,6 @@ void log_va(const char *fmt, va_list args);
 void log(const char *fmt, ...);
 
 void log_get(char *outbuf);
+void log_clear();
 
 #endif /* __LOG_H */

soc/runtime/session.c

@@ -310,6 +310,8 @@ void session_end(void)
 /* host to device */
 enum {
     REMOTEMSG_TYPE_LOG_REQUEST = 1,
+    REMOTEMSG_TYPE_LOG_CLEAR,
+
     REMOTEMSG_TYPE_IDENT_REQUEST,
     REMOTEMSG_TYPE_SWITCH_CLOCK,
 
@@ -328,6 +330,7 @@ enum {
 /* device to host */
 enum {
     REMOTEMSG_TYPE_LOG_REPLY = 1,
+
     REMOTEMSG_TYPE_IDENT_REPLY,
     REMOTEMSG_TYPE_CLOCK_SWITCH_COMPLETED,
     REMOTEMSG_TYPE_CLOCK_SWITCH_FAILED,
@@ -383,6 +386,11 @@ static int process_input(void)
             out_packet_finish();
             break;
 
+        case REMOTEMSG_TYPE_LOG_CLEAR:
+            log_clear();
+            out_packet_empty(REMOTEMSG_TYPE_LOG_REPLY);
+            break;
+
         case REMOTEMSG_TYPE_FLASH_READ_REQUEST: {
 #if SPIFLASH_SECTOR_SIZE - 4 > BUFFER_OUT_SIZE - 9
 #error Output buffer cannot hold the flash storage data