ACPICA: Debugger: Convert some mechanisms to OSPM specific

The following mechanisms are OSPM specific:
1. Redirect output destination to console: no file redirection will be
   needed by an in-kernel debugger, there is even no file can be accessed
   when the debugger is running in the kernel mode.
2. Output command prompts: programs other than acpiexec can have different
   prompt characters and the prompt characters may be implemented as a
   special character sequence to form a char device IO protocol.
3. Command ready/complete handshake: OSPM debugger may wait more conditions
   to implement OSPM specific semantics (for example, FIFO full/empty
   conditions for O_NONBLOCK or IO open/close conditions).
Leaving such OSPM specific stuffs in the ACPICA debugger core blocks
Linux debugger IO driver implementation.

Several new OSL APIs are provided by this patch:
1. acpi_os_initialize_command_signals: initialize command handshake mechanism
   or any other OSPM specific stuffs.
2. acpi_os_terminate_command_signals: reversal of
   acpi_os_initialize_command_signals.
3. acpi_os_wait_command_ready: putting debugger task into wait state when a
   command is not ready. OSPMs can terminate command loop by returning
   AE_CTRL_TERMINATE from this API. Normally, wait_event() or
   wait_for_multiple_object() may be used to implement this API.
4. acpi_os_notify_command_complete: putting user task into running state when a
   command has been completed. OSPMs can terminate command loop by
   returning AE_CTRL_TERMINATE from this API. Normally, wake_up() or
   set_event() may be used to implement this API.
This patch also converts current command signaling implementation into a
generic debugger layer (osgendbg.c) to be used by the existing OSPMs or
acpiexec, in return, Linux can have chance to implement its own command
handshake mechanism. This patch also implements acpiexec batch mode in a
multi-threading mode comaptible style as a demo (this can be confirmed by
configuring acpiexec into DEBUGGER_MULTI_THREADED mode where the batch mode
is still working). Lv Zheng.

Note that the OSPM specific command handshake mechanism is required by
Linux kernel because:
1. Linux kernel trends to use wait queue to synchronize two threads, using
   mutexes to achieve that will cause false "dead lock" warnings.
2. The command handshake mechanism implemented by ACPICA is implemented in
   this way because of a design issue in debugger IO streaming. Debugger IO
   outputs are simply cached using a giant buffer, this should be tuned by
   Linux in the future.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 19 insertions, 78 deletions

diff --git a/drivers/acpi/acpica/dbinput.c b/drivers/acpi/acpica/dbinput.c
index fe93f6776553..2bf8e6b90d5b 100644
--- a/drivers/acpi/acpica/dbinput.c
+++ b/drivers/acpi/acpica/dbinput.c
@@ -53,8 +53,6 @@ static u32 acpi_db_get_line(char *input_buffer);
 
 static u32 acpi_db_match_command(char *user_command);
 
-static void acpi_db_single_thread(void);
-
 static void acpi_db_display_command_info(char *command, u8 display_all);
 
 static void acpi_db_display_help(char *command);
@@ -1149,55 +1147,16 @@ acpi_db_command_dispatch(char *input_buffer,
 
 void ACPI_SYSTEM_XFACE acpi_db_execute_thread(void *context)
 {
-	acpi_status status = AE_OK;
-	acpi_status Mstatus;
-
-	while (status != AE_CTRL_TERMINATE && !acpi_gbl_db_terminate_loop) {
-		acpi_gbl_method_executing = FALSE;
-		acpi_gbl_step_to_next_call = FALSE;
-
-		Mstatus = acpi_os_acquire_mutex(acpi_gbl_db_command_ready,
-						ACPI_WAIT_FOREVER);
-		if (ACPI_FAILURE(Mstatus)) {
-			return;
-		}
-
-		status =
-		    acpi_db_command_dispatch(acpi_gbl_db_line_buf, NULL, NULL);
 
-		acpi_os_release_mutex(acpi_gbl_db_command_complete);
-	}
+	(void)acpi_db_user_commands();
 	acpi_gbl_db_threads_terminated = TRUE;
 }
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_db_single_thread
- *
- * PARAMETERS:  None
- *
- * RETURN:      None
- *
- * DESCRIPTION: Debugger execute thread. Waits for a command line, then
- *              simply dispatches it.
- *
- ******************************************************************************/
-
-static void acpi_db_single_thread(void)
-{
-
-	acpi_gbl_method_executing = FALSE;
-	acpi_gbl_step_to_next_call = FALSE;
-
-	(void)acpi_db_command_dispatch(acpi_gbl_db_line_buf, NULL, NULL);
-}
-
-/*******************************************************************************
- *
  * FUNCTION:    acpi_db_user_commands
  *
- * PARAMETERS:  prompt              - User prompt (depends on mode)
- *              op                  - Current executing parse op
+ * PARAMETERS:  None
  *
  * RETURN:      None
  *
@@ -1206,7 +1165,7 @@ static void acpi_db_single_thread(void)
  *
  ******************************************************************************/
 
-acpi_status acpi_db_user_commands(char prompt, union acpi_parse_object *op)
+acpi_status acpi_db_user_commands(void)
 {
 	acpi_status status = AE_OK;
 
@@ -1216,49 +1175,31 @@ acpi_status acpi_db_user_commands(char prompt, union acpi_parse_object *op)
 
 	while (!acpi_gbl_db_terminate_loop) {
 
-		/* Force output to console until a command is entered */
-
-		acpi_db_set_output_destination(ACPI_DB_CONSOLE_OUTPUT);
-
-		/* Different prompt if method is executing */
-
-		if (!acpi_gbl_method_executing) {
-			acpi_os_printf("%1c ", ACPI_DEBUGGER_COMMAND_PROMPT);
-		} else {
-			acpi_os_printf("%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT);
-		}
-
-		/* Get the user input line */
+		/* Wait the readiness of the command */
 
-		status = acpi_os_get_line(acpi_gbl_db_line_buf,
-					  ACPI_DB_LINE_BUFFER_SIZE, NULL);
+		status = acpi_os_wait_command_ready();
 		if (ACPI_FAILURE(status)) {
-			ACPI_EXCEPTION((AE_INFO, status,
-					"While parsing command line"));
-			return (status);
+			break;
 		}
 
-		/* Check for single or multithreaded debug */
+		/* Just call to the command line interpreter */
 
-		if (acpi_gbl_debugger_configuration & DEBUGGER_MULTI_THREADED) {
-			/*
-			 * Signal the debug thread that we have a command to execute,
-			 * and wait for the command to complete.
-			 */
-			acpi_os_release_mutex(acpi_gbl_db_command_ready);
+		acpi_gbl_method_executing = FALSE;
+		acpi_gbl_step_to_next_call = FALSE;
 
-			status =
-			    acpi_os_acquire_mutex(acpi_gbl_db_command_complete,
-						  ACPI_WAIT_FOREVER);
-			if (ACPI_FAILURE(status)) {
-				return (status);
-			}
-		} else {
-			/* Just call to the command line interpreter */
+		(void)acpi_db_command_dispatch(acpi_gbl_db_line_buf, NULL,
+					       NULL);
+
+		/* Notify the completion of the command */
 
-			acpi_db_single_thread();
+		status = acpi_os_notify_command_complete();
+		if (ACPI_FAILURE(status)) {
+			break;
 		}
 	}
 
+	if (ACPI_FAILURE(status) && status != AE_CTRL_TERMINATE) {
+		ACPI_EXCEPTION((AE_INFO, status, "While parsing command line"));
+	}
 	return (status);
 }