Revert "shi: Enable SHI interrupt from CS interrupt"

This reverts commit 77ae58a3a32c40d42ac0d66b0ac772c64fb39bf6. Host
command interface still getting wedged.

BUG=chrome-os-partner:55710,chrome-os-partner:55795,chrome-os-partner:56254
BRANCH=None
TEST=None

Change-Id: I2a4d39d222ebfd9aa78cc9f5231c38ebd50e80ce
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/373739

1 files changed, 20 insertions, 43 deletions

diff --git a/chip/npcx/shi.c b/chip/npcx/shi.c
index 154bc3a5d7..6cf030cf7c 100644
--- a/chip/npcx/shi.c
+++ b/chip/npcx/shi.c
@@ -195,15 +195,13 @@ static uint8_t shi_read_buf_pointer(void);
  */
 static void shi_send_response_packet(struct host_packet *pkt)
 {
-	/*
-	 * Disable interrupts. This routine is not called from interrupt
-	 * context and buffer underrun will likely occur if it is
-	 * preempted after writing its initial reply byte. Also, we must be
-	 * sure our state doesn't unexpectedly change, in case we're expected
-	 * to take RESP_NOT_RDY actions.
-	 */
-	interrupt_disable();
 	if (state == SHI_STATE_PROCESSING) {
+		/*
+		* Disable interrupts. This routine is not called from interrupt
+		* context and buffer underrun will likely occur if it is
+		* preempted after writing its initial reply byte.
+		*/
+		interrupt_disable();
 
 		/* Append our past-end byte, which we reserved space for. */
 		((uint8_t *) pkt->response)[pkt->response_size + 0] =
@@ -228,6 +226,8 @@ static void shi_send_response_packet(struct host_packet *pkt)
 #ifdef NPCX_SHI_BYPASS_OVER_256B
 		}
 #endif
+
+		interrupt_enable();
 	}
 	/*
 	 * If we're not processing, then the AP has already terminated the
@@ -239,8 +239,6 @@ static void shi_send_response_packet(struct host_packet *pkt)
 		DEBUG_CPRINTF("END\n");
 	} else
 		DEBUG_CPRINTS("Unexpected state %d in response handler", state);
-
-	interrupt_enable();
 }
 
 void shi_handle_host_package(void)
@@ -295,6 +293,9 @@ void shi_handle_host_package(void)
 /* Parse header for version of spi-protocol */
 static void shi_parse_header(void)
 {
+	/* Disable SHI interrupt until we're sure the size of request package.*/
+	task_disable_irq(NPCX_IRQ_SHI);
+
 	/* We're now inside a transaction */
 	state = SHI_STATE_RECEIVING;
 	DEBUG_CPRINTF("RV-");
@@ -329,6 +330,9 @@ static void shi_parse_header(void)
 		/* Computing total bytes need to receive */
 		shi_params.sz_request = pkt_size;
 
+		/* Enable SHI interrupt & handle request package */
+		task_enable_irq(NPCX_IRQ_SHI);
+
 		shi_handle_host_package();
 	} else {
 		/* Invalid version number */
@@ -497,6 +501,12 @@ static void shi_bad_received_data(void)
 		CPRINTF("%02x ", in_msg[i]);
 	CPRINTF("]\n");
 
+	/*
+	 * Enable SHI interrupt again since we disable it
+	 * at the begin of SHI_STATE_RECEIVING state
+	 */
+	task_enable_irq(NPCX_IRQ_SHI);
+
 	/* Reset shi's state machine for error recovery */
 	shi_reset_prepare();
 
@@ -549,14 +559,6 @@ void shi_int_handler(void)
 			shi_fill_out_status(EC_SPI_NOT_READY);
 
 			state = SHI_STATE_CNL_RESP_NOT_RDY;
-
-			/*
-			 * Disable SHI interrupt, it will remain disabled
-			 * until shi_send_response_packet() is called and
-			 * CS is asserted for a new transaction.
-			 */
-			task_disable_irq(NPCX_IRQ_SHI);
-
 			DEBUG_CPRINTF("CNL-");
 			return;
 		/* Next transaction but we're not ready */
@@ -682,12 +684,6 @@ void shi_cs_event(enum gpio_signal signal)
 
 	DEBUG_CPRINTF("CSL-");
 
-	/*
-	 * Enable SHI interrupt - we will either succeed to parse our host
-	 * command or reset on failure from here.
-	 */
-	task_enable_irq(NPCX_IRQ_SHI);
-
 	/* Read first three bytes to parse which protocol is receiving */
 	shi_parse_header();
 }
@@ -703,9 +699,6 @@ static void shi_reset_prepare(void)
 {
 	uint16_t i;
 
-	/* We no longer care about SHI interrupts, so disable them. */
-	task_disable_irq(NPCX_IRQ_SHI);
-
 	/* Initialize parameters of next transaction */
 	shi_params.rx_msg = in_msg;
 	shi_params.tx_msg = out_msg;
@@ -742,7 +735,6 @@ static void shi_reset_prepare(void)
 static void shi_enable(void)
 {
 	int gpio_flags;
-	int shi_cs_level;
 
 	shi_reset_prepare();
 
@@ -762,23 +754,8 @@ static void shi_enable(void)
 	 */
 	SET_BIT(NPCX_DEVALT(ALT_GROUP_C), NPCX_DEVALTC_SHI_SL);
 
-	/*
-	 * If CS is already asserted prior to enabling our GPIO interrupt then
-	 * we have missed the falling edge and we need to handle the
-	 * deassertion interrupt - to do so, we'll enable the SHI interrupt
-	 * later.
-	 */
-	shi_cs_level = gpio_get_level(GPIO_SHI_CS_L);
-
 	/* Enable SHI_CS_L interrupt */
 	gpio_enable_interrupt(GPIO_SHI_CS_L);
-
-	/*
-	 * Check the CS level again, in case it was asserted after our previous
-	 * check.
-	 */
-	if (!shi_cs_level || !gpio_get_level(GPIO_SHI_CS_L))
-		task_enable_irq(NPCX_IRQ_SHI);
 }
 DECLARE_HOOK(HOOK_CHIPSET_RESUME, shi_enable, HOOK_PRIO_DEFAULT);