host_command: Add send_result() to the arg structure

It's a bit odd that the drivers package up a command to be processed
by host_command, but then host_command calls a global function to
pass the response back.

This adds ambiguity in the host_send_response() implementations as to
whether the command being responded to really is using the same
buffers that the driver set up.

Add a function pointer to the command, and have host_command call
that. Add status to the args structure also, which removes some of
the special case logic for error handling.

BUG=chrome-os-partner:11317
TEST=manual and a bit ad-hoc:
(note, this testing is not completed yet)
Check that snow and link still process commands correctly over I2C
from U-Boot. At this stage only the old interface is supported.
SMDK5250 # mkbp test
Old interface:

New interface:
Version 0: ec_command() returned error
Test failed with error -1
SMDK5250 #

Change-Id: Ic4afdcd7689666cc0f6af228abc6cffe41b0fcbf
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27468

1 files changed, 13 insertions, 8 deletions

diff --git a/common/host_command.c b/common/host_command.c
index 1420e79434..1a1c21fd40 100644
--- a/common/host_command.c
+++ b/common/host_command.c
@@ -49,15 +49,19 @@ void host_command_received(struct host_cmd_handler_args *args)
 	if (args->command == EC_CMD_REBOOT) {
 		system_reset(SYSTEM_RESET_HARD);
 		/* Reset should never return; if it does, post an error */
-		host_send_response(EC_RES_ERROR);
-		return;
+		args->result = EC_RES_ERROR;
 	}
 
-	/* Save the command */
-	pending_args = args;
+	/* If the driver has signalled an error, send the response now */
+	if (args->result) {
+		args->send_response(args);
+	} else {
+		/* Save the command */
+		pending_args = args;
 
-	/* Wake up the task to handle the command */
-	task_set_event(TASK_ID_HOSTCMD, TASK_EVENT_CMD_PENDING, 0);
+		/* Wake up the task to handle the command */
+		task_set_event(TASK_ID_HOSTCMD, TASK_EVENT_CMD_PENDING, 0);
+	}
 }
 
 /*
@@ -224,8 +228,9 @@ void host_command_task(void)
 		int evt = task_wait_event(-1);
 		/* process it */
 		if ((evt & TASK_EVENT_CMD_PENDING) && pending_args) {
-			enum ec_status res = host_command_process(pending_args);
-			host_send_response(res);
+			pending_args->result =
+					host_command_process(pending_args);
+			pending_args->send_response(pending_args);
 		}
 	}
 }