pd: zinger: Turn off pings by default

Turn off sending pings in SRC_READY by default. Added custom VDM
to turn pings back on, which only zinger supports right now.
Changed the "pd ping" console command to be used to enabled/disable
pings in SRC_READY.

BUG=chrome-os-partner:31409
BRANCH=none
TEST=loaded onto samus and zinger. on samus_pd, enabled highest
level of debug info: "pd 0 debug 2" to allow printing ping received.
Then plugged in zinger. By default, we negotiate to SNK_READY and
receive no pings. Then send "pd 0 vdm ping 1" to send VDM to zinger
to enable pings, and verified we start receiving pings. Sending
"pd 0 vdm ping 0" sends VDM to stop sending pings.

Change-Id: I4f64c6fc59bb734146eeca5e3ea3a24954c786b2
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/212965
Reviewed-by: Vic Yang <victoryang@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>

3 files changed, 63 insertions, 14 deletions

diff --git a/board/zinger/usb_pd_policy.c b/board/zinger/usb_pd_policy.c
index f3d817f728..b73b7fbaf0 100644
--- a/board/zinger/usb_pd_policy.c
+++ b/board/zinger/usb_pd_policy.c
@@ -326,6 +326,9 @@ int pd_custom_vdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload)
 		flash_write_rw(CONFIG_FW_RW_SIZE - 32, 4*cnt,
 			       (const char *)(payload+1));
 		break;
+	case VDO_CMD_PING_ENABLE:
+		pd_ping_enable(0, payload[1]);
+		break;
 	default:
 		/* Unknown : do not answer */
 		return 0;
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 91575052fe..0d6fbb7ef6 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -206,6 +206,8 @@ static struct pd_protocol {
 	enum pd_states timeout_state;
 	/* Timeout for the current state. Set to 0 for no timeout. */
 	uint64_t timeout;
+	/* Flag for sending pings in SRC_READY */
+	uint8_t ping_enabled;
 
 #ifdef CONFIG_USB_PD_DUAL_ROLE
 	/* Current limit based on the last request message */
@@ -1057,6 +1059,11 @@ void pd_comm_enable(int enable)
 	pd_comm_enabled = enable;
 }
 
+void pd_ping_enable(int port, int enable)
+{
+	pd[port].ping_enabled = enable;
+}
+
 void pd_task(void)
 {
 	int head;
@@ -1078,6 +1085,7 @@ void pd_task(void)
 	/* Initialize PD protocol state variables for each port. */
 	pd[port].role = PD_ROLE_DEFAULT;
 	pd[port].vdm_state = VDM_STATE_DONE;
+	pd[port].ping_enabled = 0;
 	set_state(port, PD_DEFAULT_STATE);
 
 	/* Ensure the power supply is in the default state */
@@ -1202,16 +1210,21 @@ void pd_task(void)
 			}
 			break;
 		case PD_STATE_SRC_READY:
-			/* Verify that the sink is alive */
-			res = send_control(port, PD_CTRL_PING);
-			if (res >= 0) {
-				/* schedule next keep-alive */
-				timeout = PD_T_SOURCE_ACTIVITY;
+			if (pd[port].ping_enabled) {
+				/* Verify that the sink is alive */
+				res = send_control(port, PD_CTRL_PING);
+				if (res >= 0) {
+					/* schedule next keep-alive */
+					timeout = PD_T_SOURCE_ACTIVITY;
+				} else {
+					/* The sink died ... */
+					pd_power_supply_reset(port);
+					set_state(port,
+						  PD_STATE_SRC_DISCONNECTED);
+					timeout = PD_T_SEND_SOURCE_CAP;
+				}
 			} else {
-				/* The sink died ... */
-				pd_power_supply_reset(port);
-				set_state(port, PD_STATE_SRC_DISCONNECTED);
-				timeout = PD_T_SEND_SOURCE_CAP;
+				timeout = PD_T_SOURCE_ACTIVITY;
 			}
 			break;
 #ifdef CONFIG_USB_PD_DUAL_ROLE
@@ -1545,10 +1558,32 @@ static int command_pd(int argc, char **argv)
 		send_control(port, PD_CTRL_SOFT_RESET);
 		task_wake(PORT_TO_TASK_ID(port));
 	} else if (!strncasecmp(argv[2], "ping", 4)) {
-		pd[port].role = PD_ROLE_SOURCE;
-		pd_set_host_mode(port, 1);
-		set_state(port, PD_STATE_SRC_READY);
-		task_wake(PORT_TO_TASK_ID(port));
+		int enable;
+
+		if (argc > 3) {
+			enable = strtoi(argv[3], &e, 10);
+			if (*e)
+				return EC_ERROR_PARAM3;
+			pd[port].ping_enabled = enable;
+		}
+
+		ccprintf("Pings %s\n", pd[port].ping_enabled ? "on" : "off");
+	} else if (!strncasecmp(argv[2], "vdm", 3)) {
+		if (argc < 4)
+			return EC_ERROR_PARAM_COUNT;
+
+		if (!strncasecmp(argv[3], "ping", 4)) {
+			uint32_t enable;
+			if (argc < 5)
+				return EC_ERROR_PARAM_COUNT;
+			enable = strtoi(argv[4], &e, 10);
+			if (*e)
+				return EC_ERROR_PARAM4;
+			pd_send_vdm(port, USB_VID_GOOGLE, VDO_CMD_PING_ENABLE,
+				    &enable, 1);
+		} else {
+			return EC_ERROR_PARAM_COUNT;
+		}
 	} else if (!strcasecmp(argv[2], "dualrole")) {
 		if (argc < 4) {
 			ccprintf("dual-role toggling: ");
@@ -1603,7 +1638,7 @@ static int command_pd(int argc, char **argv)
 DECLARE_CONSOLE_COMMAND(pd, command_pd,
 			"<port> "
 			"[tx|bist|charger|dev|dump|dualrole|enable"
-			"|soft|hard|clock|ping|state]",
+			"|soft|hard|clock|ping|state|vdm [ping]]",
 			"USB PD",
 			NULL);
 
diff --git a/include/usb_pd.h b/include/usb_pd.h
index 2267a2f84d..fc2d59b6bd 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -127,6 +127,7 @@ enum pd_errors {
 #define VDO_CMD_FLASH_ERASE  VDO_CMD_VENDOR(6)
 #define VDO_CMD_FLASH_WRITE  VDO_CMD_VENDOR(7)
 #define VDO_CMD_FLASH_HASH   VDO_CMD_VENDOR(8)
+#define VDO_CMD_PING_ENABLE  VDO_CMD_VENDOR(10)
 
 #define PD_VDO_VID(vdo) ((vdo) >> 16)
 #define PD_VDO_CMD(vdo) ((vdo) & 0x1f)
@@ -503,4 +504,14 @@ int pd_get_polarity(int port);
  */
 void pd_comm_enable(int enable);
 
+/**
+ * Set the PD pings enabled flag. When source has negotiated power over
+ * PD successfully, it can optionally send pings periodically based on
+ * this enable flag.
+ *
+ * @param port USB-C port number
+ * @param enable Enable flag to set
+ */
+void pd_ping_enable(int port, int enable);
+
 #endif  /* __USB_PD_H */