ccdblock can block EC-CR50 communication

This patch introduces 'EC_CR50_COMM' a new option for ccdblock
console command.
It can be useful for system rescue purpose like you want to
force cr50 to yield EC_UART (especially TX) port to servo.

BUG=chromium:1047287
BRANCH=cr50, cr50-mp
TEST=ran manually ccdblock.

> ccdstate
AP:      off
AP UART: off
EC:      on
Rdd:     connected
Servo:   undetectable
CCD EXT: enabled
State flags: UARTEC+TX I2C SPI
CCD ports blocked: (none)
>
>
> ccdblock EC_CR50_COMM enable
CCD ports blocked: EC_CR50_COMM
> [73.386550 CCD state: UARTEC I2C SPI]
>
> ccdstate
AP:      off
AP UART: off
EC:      on
Rdd:     connected
Servo:   disconnected
CCD EXT: enabled
State flags: UARTEC I2C SPI
CCD ports blocked: EC_CR50_COMM
>
>
> ccdblock EC_CR50_COMM disable
CCD ports blocked: (none)
> [104.781623 CCD state: UARTEC+TX I2C SPI]
ccdstate
AP:      off
AP UART: off
EC:      on
Rdd:     connected
Servo:   undetectable
CCD EXT: enabled
State flags: UARTEC+TX I2C SPI
CCD ports blocked: (none)

Change-Id: I7816c201054f1793906bd19d4b58755593d2fbac
Signed-off-by: Namyoon Woo <namyoon@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2042118
Reviewed-by: Mary Ruthven <mruthven@chromium.org>

3 files changed, 48 insertions, 4 deletions

diff --git a/board/cr50/ec_comm.c b/board/cr50/ec_comm.c
index d9b01c92e2..c4a3603c82 100644
--- a/board/cr50/ec_comm.c
+++ b/board/cr50/ec_comm.c
@@ -73,3 +73,26 @@ int ec_comm_is_uart_in_packet_mode(int uart)
 {
 	return uart == ec_comm_ctx.uart;
 }
+
+void ec_comm_block(int block)
+{
+	static int is_blocked;
+
+	if (is_blocked == block)
+		return;
+
+	if (block) {
+		gpio_disable_interrupt(GPIO_EC_PACKET_MODE_EN);
+		gpio_disable_interrupt(GPIO_EC_PACKET_MODE_DIS);
+
+		if (ec_comm_is_uart_in_packet_mode(UART_EC))
+			ec_comm_packet_mode_dis(GPIO_EC_PACKET_MODE_DIS);
+	} else {
+		gpio_enable_interrupt(GPIO_EC_PACKET_MODE_EN);
+		gpio_enable_interrupt(GPIO_EC_PACKET_MODE_DIS);
+	}
+
+	is_blocked = block;
+
+	/* Note: ccd_update_state() should be called to change UART status. */
+}
diff --git a/board/cr50/ec_comm.h b/board/cr50/ec_comm.h
index 37732e69c2..9e84a715e1 100644
--- a/board/cr50/ec_comm.h
+++ b/board/cr50/ec_comm.h
@@ -24,6 +24,12 @@ int ec_comm_is_uart_in_packet_mode(int uart);
  *         0 otherwise.
  */
 int ec_comm_process_packet(uint8_t ch);
+/*
+ * Block or unblock EC-CR50 communication.
+ * @param block   non-zero value blocks EC-CR50 communication.
+ *                Zero value unblocks it.
+ */
+void ec_comm_block(int block);
 /* Reset EC EFS context */
 void ec_efs_reset(void);
 /* Set EC-EFS boot_mode */
diff --git a/board/cr50/rdd.c b/board/cr50/rdd.c
index 2e5ccc7e81..228f076831 100644
--- a/board/cr50/rdd.c
+++ b/board/cr50/rdd.c
@@ -56,7 +56,13 @@ enum ccd_block_flags {
 	 * uart while servo is connected, it could break the hardware and the
 	 * ccd uart could become permanently unusable.
 	 */
-	CCD_BLOCK_IGNORE_SERVO = BIT(3)
+	CCD_BLOCK_IGNORE_SERVO = BIT(3),
+
+	/*
+	 * This will block EC-CR50-communication. CR50 should not enable EC
+	 * UART.
+	 */
+	CCD_BLOCK_EC_CR50_COMM = BIT(4)
 };
 
 /* Which UARTs are blocked by console command */
@@ -300,9 +306,11 @@ static void ccd_state_change_hook(void)
 	/*
 	 * EC UART flags are cleared if ccd ext is not detected or if ccd block
 	 * EC UART is enabled. EC-CR50 comm trumps both of those conditions.
-	 * Re-enable the EC UART flags if EC-CR50 comm is enabled.
+	 * Re-enable the EC UART flags if EC-CR50 comm is enabled and
+	 * CCD_BLOCK_EC_CR50_COMM must be off in ccd_block bitmap.
 	 */
-	if (ec_comm_is_uart_in_packet_mode(UART_EC))
+	if (ec_comm_is_uart_in_packet_mode(UART_EC) &&
+	    !(ccd_block & CCD_BLOCK_EC_CR50_COMM))
 		flags_want |= (CCD_ENABLE_UART_EC | CCD_ENABLE_UART_EC_TX);
 
 	/*
@@ -442,6 +450,8 @@ static void print_ccd_ports_blocked(void)
 		ccputs("\nWARNING: enabling UART while servo is connected may "
 		       "damage hardware");
 	}
+	if (ccd_block & CCD_BLOCK_EC_CR50_COMM)
+		ccputs(" EC_CR50_COMM");
 	if (!ccd_block)
 		ccputs(" (none)");
 	ccputs("\n");
@@ -484,6 +494,8 @@ static int command_ccd_block(int argc, char **argv)
 			block_flag = CCD_BLOCK_SERVO_SHARED;
 		else if (!strcasecmp(argv[1], "IGNORE_SERVO"))
 			block_flag = CCD_BLOCK_IGNORE_SERVO;
+		else if (!strcasecmp(argv[1], "EC_CR50_COMM"))
+			block_flag = CCD_BLOCK_EC_CR50_COMM;
 		else
 			return EC_ERROR_PARAM1;
 
@@ -497,6 +509,8 @@ static int command_ccd_block(int argc, char **argv)
 
 		if (block_flag == CCD_BLOCK_IGNORE_SERVO)
 			servo_ignore(new_state);
+		else if (block_flag == CCD_BLOCK_EC_CR50_COMM)
+			ec_comm_block(new_state);
 
 		/* Update blocked state in deferred function */
 		ccd_update_state();
@@ -507,5 +521,6 @@ static int command_ccd_block(int argc, char **argv)
 	return EC_SUCCESS;
 }
 DECLARE_CONSOLE_COMMAND(ccdblock, command_ccd_block,
-			"[<AP | EC | SERVO | IGNORE_SERVO> [BOOLEAN]]",
+			"[<AP | EC | SERVO | IGNORE_SERVO | EC_CR50_COMM>"
+			" [BOOLEAN]]",
 			"Force CCD ports disabled");