Snow: Dont hang when trying to pmic-reset board

Old Snow board (non-MP) don't have the capability to hard-reset their
pmics unless they've been manually fixed to do so.  This means that if
you have an old board, with a new copy of the EC on it and it tries to
hard-reset the system, it will hang forever and trigger the watchdog.

Since there's no way for the EC to check if the hardware fix exists on
its board, this adds a timeout after trying to reset.  If the board has
the fix, it will reset before the timeout expires.  Otherwise, it will
print a warning message before returning, to prevent it hanging.

Additionally, it also fixes the places board_hard_reset() is called to
deal with the new possibility of it returning.

BUG=chrome-os-partner:13508
TEST=On a machine with the hardware rework and one without it, go to the
EC console and run "pmu reset" to try and force a reset.  The one with
the fix should reset immediately, and the one without should warn you
that it tried (and failed) to reset.
BRANCH=snow

Change-Id: I493122ee4da539f363a31f624ab9dd7db8068ec8
Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/32043
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

2 files changed, 12 insertions, 4 deletions

diff --git a/board/snow/board.c b/board/snow/board.c
index 7ca50704a5..14c7277a71 100644
--- a/board/snow/board.c
+++ b/board/snow/board.c
@@ -25,6 +25,8 @@
 #define INT_BOTH_FLOATING	(GPIO_INPUT | GPIO_INT_BOTH)
 #define INT_BOTH_PULL_UP	(GPIO_INPUT | GPIO_PULL_UP | GPIO_INT_BOTH)
 
+#define HARD_RESET_TIMEOUT_MS 5
+
 /* GPIO interrupt handlers prototypes */
 #ifndef CONFIG_TASK_GAIAPOWER
 #define gaia_power_event NULL
@@ -305,9 +307,12 @@ void board_hard_reset(void)
 {
 	/* Force a hard reset of tps Chrome */
 	gpio_set_level(GPIO_PMIC_RESET, 1);
-	/* Hang until the power is cut */
-	while (1)
-		;
+
+	/* Delay while the power is cut */
+	udelay(HARD_RESET_TIMEOUT_MS * 1000);
+
+	/* Shouldn't get here unless the board doesn't have this capability */
+	panic_puts("Hard reset failed! (this board may not be capable)\n");
 }
 
 #ifdef CONFIG_PMU_BOARD_INIT
diff --git a/common/pmu_tps65090.c b/common/pmu_tps65090.c
index faba493fb4..3af89ad5bb 100644
--- a/common/pmu_tps65090.c
+++ b/common/pmu_tps65090.c
@@ -561,8 +561,11 @@ static int command_pmu(int argc, char **argv)
 	if (argc > 1) {
 		repeat = strtoi(argv[1], &e, 0);
 		if (*e) {
-			if (strlen(argv[1]) >= 1 && argv[1][0] == 'r')
+			if (strlen(argv[1]) >= 1 && argv[1][0] == 'r') {
 				board_hard_reset();
+				/* If this returns, there was an error */
+				return EC_ERROR_UNKNOWN;
+			}
 
 			ccputs("Invalid repeat count\n");
 			return EC_ERROR_INVAL;