TCPMv2: Implement mode discovery for port partner

Implement PE_INIT_VDM_Modes_{Request,ACKed,NAKed}. Store mode discovery
state for each discovered SVID and provide accessors for that state.
Consider transmit type when consuming modes.

BUG=b:152420269,b:152419795
TEST=Attach port partner; TCPM discovers modes for previously discovered
TEST=SVIDs and then continues with discovery/mode-entering process.
BRANCH=none

Change-Id: I72a605fa500e7eea0a5fa3b65a74d8b567a78751
Signed-off-by: Abe Levkoy <alevkoy@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2174466
Reviewed-by: Diana Z <dzigterman@chromium.org>

1 files changed, 85 insertions, 6 deletions

diff --git a/common/usb_pd_alt_mode_dfp.c b/common/usb_pd_alt_mode_dfp.c
index d0d337e0ab..1c04c51591 100644
--- a/common/usb_pd_alt_mode_dfp.c
+++ b/common/usb_pd_alt_mode_dfp.c
@@ -366,19 +366,48 @@ void dfp_consume_svids(int port, enum tcpm_transmit_type type, int cnt,
 void dfp_consume_modes(int port, enum tcpm_transmit_type type, int cnt,
 		uint32_t *payload)
 {
+	int svid_idx;
+	struct svid_mode_data *mode_discovery = NULL;
 	struct pd_discovery *disc = pd_get_am_discovery(port, type);
-	int idx = disc->svid_idx;
+	uint16_t response_svid = (uint16_t) PD_VDO_VID(payload[0]);
 
-	disc->svids[idx].mode_cnt = cnt - 1;
+	for (svid_idx = 0; svid_idx < disc->svid_cnt; ++svid_idx) {
+		uint16_t svid = disc->svids[svid_idx].svid;
 
-	if (disc->svids[idx].mode_cnt < 0) {
+		if (svid == response_svid) {
+			mode_discovery = &disc->svids[svid_idx];
+			break;
+		}
+	}
+	if (!mode_discovery) {
+		const struct svid_mode_data *requested_mode_data =
+			pd_get_next_mode(port, type);
+		CPRINTF("C%d: Mode response for undiscovered SVID %x, but TCPM "
+				"requested SVID %x\n",
+				port, response_svid, requested_mode_data->svid);
+		/*
+		 * Although SVIDs discovery seemed like it succeeded before, the
+		 * partner is now responding with undiscovered SVIDs. Discovery
+		 * cannot reasonably continue under these circumstances.
+		 */
+		pd_set_modes_discovery(port, type, requested_mode_data->svid,
+				PD_DISC_FAIL);
+		return;
+	}
+
+	mode_discovery->mode_cnt = cnt - 1;
+	if (mode_discovery->mode_cnt < 1) {
 		CPRINTF("ERR:NOMODE\n");
-	} else {
-		memcpy(disc->svids[idx].mode_vdo, &payload[1],
-		       sizeof(uint32_t) * disc->svids[idx].mode_cnt);
+		pd_set_modes_discovery(port, type, mode_discovery->svid,
+				PD_DISC_FAIL);
+		return;
 	}
 
+	memcpy(mode_discovery->mode_vdo, &payload[1],
+			sizeof(uint32_t) * mode_discovery->mode_cnt);
 	disc->svid_idx++;
+	pd_set_modes_discovery(port, type, mode_discovery->svid,
+			PD_DISC_COMPLETE);
 }
 
 /*
@@ -485,6 +514,56 @@ uint16_t pd_get_svid(int port, uint16_t svid_idx, enum tcpm_transmit_type type)
 	return disc->svids[svid_idx].svid;
 }
 
+void pd_set_modes_discovery(int port, enum tcpm_transmit_type type,
+		uint16_t svid, enum pd_discovery_state disc)
+{
+	struct pd_discovery *pd = pd_get_am_discovery(port, type);
+	int svid_idx;
+
+	for (svid_idx = 0; svid_idx < pd->svid_cnt; ++svid_idx) {
+		struct svid_mode_data *mode_data = &pd->svids[svid_idx];
+
+		if (mode_data->svid != svid)
+			continue;
+
+		mode_data->discovery = disc;
+		return;
+	}
+}
+
+enum pd_discovery_state pd_get_modes_discovery(int port,
+		enum tcpm_transmit_type type)
+{
+	const struct svid_mode_data *mode_data = pd_get_next_mode(port, type);
+
+	/*
+	 * If there are no SVIDs for which to discover modes, mode discovery is
+	 * trivially complete.
+	 */
+	if (!mode_data)
+		return PD_DISC_COMPLETE;
+
+	return mode_data->discovery;
+}
+
+struct svid_mode_data *pd_get_next_mode(int port,
+		enum tcpm_transmit_type type)
+{
+	struct pd_discovery *disc = pd_get_am_discovery(port, type);
+	int svid_idx;
+
+	for (svid_idx = 0; svid_idx < disc->svid_cnt; ++svid_idx) {
+		struct svid_mode_data *mode_data = &disc->svids[svid_idx];
+
+		if (mode_data->discovery == PD_DISC_COMPLETE)
+			continue;
+
+		return mode_data;
+	}
+
+	return NULL;
+}
+
 uint32_t *pd_get_mode_vdo(int port, uint16_t svid_idx,
 		enum tcpm_transmit_type type)
 {