npcx: shi: Avoid 'unexpected state' console spam

If SHI finds itself in an unexpected state, we may try to print an error
message for each IBF / IBHF interrupt, which is excessively spammy and
may even lead to EC watchdog. Avoid console spam by not duplicating IBF
/ IBHF / IBEOR error prints, if our state doesn't change.

BUG=chrome-os-partner:54502
BRANCH=None
TEST=Manual on gru. Verify only one print is seen when SHI fails due to
missed initialization.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I331c64c24fa3a68d7c17e052240691076d3532cc
Reviewed-on: https://chromium-review.googlesource.com/356239
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>

1 files changed, 21 insertions, 5 deletions

diff --git a/chip/npcx/shi.c b/chip/npcx/shi.c
index 4d69220893..a843612f04 100644
--- a/chip/npcx/shi.c
+++ b/chip/npcx/shi.c
@@ -490,7 +490,7 @@ static void shi_bad_received_data(void)
 	shi_fill_out_status(EC_SPI_RX_BAD_DATA);
 	state = SHI_STATE_BAD_RECEIVED_DATA;
 
-	CPRINTS("BAD-");
+	CPRINTF("BAD-");
 	CPRINTF("in_msg=[");
 	for (i = 0; i < shi_params.sz_received; i++)
 		CPRINTF("%02x ", in_msg[i]);
@@ -503,6 +503,21 @@ static void shi_bad_received_data(void)
 	task_enable_irq(NPCX_IRQ_SHI);
 }
 
+/*
+ * Avoid spamming the console with prints every IBF / IBHF interrupt, if
+ * we find ourselves in an unexpected state.
+ */
+static int last_error_state = -1;
+
+static void log_unexpected_state(char *isr_name)
+{
+#if !(DEBUG_SHI)
+	if (state != last_error_state)
+		CPRINTS("Unexpected state %d in %s ISR", state, isr_name);
+#endif
+	last_error_state = state;
+}
+
 /* This routine handles all interrupts of this module */
 void shi_int_handler(void)
 {
@@ -542,7 +557,7 @@ void shi_int_handler(void)
 
 		/* Error state for checking*/
 		if (state != SHI_STATE_SENDING)
-			CPRINTS("Unexpected state %d in IBEOR ISR\n", state);
+			log_unexpected_state("IBEOR");
 
 		/* reset SHI and prepare to next transaction again */
 		shi_reset_prepare();
@@ -587,7 +602,7 @@ void shi_int_handler(void)
 #endif
 		else
 			/* Unexpected status */
-			CPRINTS("Unexpected state %d in IBHF ISR\n", state);
+			log_unexpected_state("IBHF");
 	}
 
 	/*
@@ -622,7 +637,7 @@ void shi_int_handler(void)
 			return;
 		else
 			/* Unexpected status */
-			CPRINTS("Unexpected state %d in IBF ISR\n", state);
+			log_unexpected_state("IBF");
 	}
 }
 /*
@@ -657,7 +672,7 @@ void shi_cs_event(enum gpio_signal signal)
 	/* Chip select is low = asserted */
 	if (state != SHI_STATE_READY_TO_RECV) {
 		/* State machine should be reset in EVSTAT_EOR ISR */
-		CPRINTS("Unexpected state %d in CS ISR\n", state);
+		CPRINTS("Unexpected state %d in CS ISR", state);
 		return;
 	}
 
@@ -706,6 +721,7 @@ static void shi_reset_prepare(void)
 
 	/* Ready to receive */
 	state = SHI_STATE_READY_TO_RECV;
+	last_error_state = -1;
 
 	DEBUG_CPRINTF("RDY-");
 }