pd: fix possible redundant requests (again)

Another fix for redundant requests. This time there can be
redundant requests if the maximum allowed voltage changes,
but we still fall into the samus PDO index and therefore are
asking for the same voltage. This fixes by checking the voltage
value we actually request vs. the max value we can request.

BUG=none
BRANCH=samus
TEST=samus to samus was causing redundant requests and now it's
not.

Change-Id: Ie49add1a42b86de97cee87f9d4637dd0578e2ce3
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/239950
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>

3 files changed, 13 insertions, 17 deletions

diff --git a/common/usb_pd_policy.c b/common/usb_pd_policy.c
index 05c9363de8..f555288267 100644
--- a/common/usb_pd_policy.c
+++ b/common/usb_pd_policy.c
@@ -117,24 +117,16 @@ int pd_build_request(int cnt, uint32_t *src_caps, uint32_t *rdo,
 
 	pd_extract_pdo_power(src_caps[pdo_index], ma, mv);
 	uw = *ma * *mv;
+	/* Mismatch bit set if less power offered than the operating power */
 	if (uw < (1000 * PD_OPERATING_POWER_MW))
 		flags |= RDO_CAP_MISMATCH;
 
 	if ((src_caps[pdo_index] & PDO_TYPE_MASK) == PDO_TYPE_BATTERY) {
 		int mw = uw / 1000;
 		*rdo = RDO_BATT(pdo_index + 1, mw, mw, flags);
-		CPRINTF("Request [%d] %dmV %dmW",
-			pdo_index, *mv, mw);
 	} else {
 		*rdo = RDO_FIXED(pdo_index + 1, *ma, *ma, flags);
-		CPRINTF("Request [%d] %dmV %dmA",
-			pdo_index, *mv, *ma);
 	}
-	/* Mismatch bit set if less power offered than the operating power */
-	if (flags & RDO_CAP_MISMATCH)
-		CPRINTF(" Mismatch");
-	CPRINTF("\n");
-
 	return EC_SUCCESS;
 }
 
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 9db9b8bd75..d54c20dcac 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -890,7 +890,6 @@ static void pd_store_src_cap(int port, int cnt, uint32_t *src_caps)
 static void pd_send_request_msg(int port, int always_send_request)
 {
 	uint32_t rdo, curr_limit, supply_voltage;
-	int request_mv;
 	int res;
 
 #ifdef CONFIG_CHARGE_MANAGER
@@ -903,12 +902,6 @@ static void pd_send_request_msg(int port, int always_send_request)
 
 	/* Build and send request RDO */
 	/* If this port is not actively charging, select vSafe5V */
-	request_mv = charging ? pd_get_max_voltage() : PD_MIN_MV;
-
-	/* Don't re-request the same voltage */
-	if (!always_send_request && pd[port].prev_request_mv == request_mv)
-		return;
-
 	res = pd_build_request(pd_src_cap_cnt[port], pd_src_caps[port],
 			       &rdo, &curr_limit, &supply_voltage,
 			       charging ? PD_REQUEST_MAX : PD_REQUEST_VSAFE5V);
@@ -920,9 +913,19 @@ static void pd_send_request_msg(int port, int always_send_request)
 		 */
 		return;
 
+	/* Don't re-request the same voltage */
+	if (!always_send_request && pd[port].prev_request_mv == supply_voltage)
+		return;
+
+	CPRINTF("Request [%d] %dmV %dmA", RDO_POS(rdo),
+		supply_voltage, curr_limit);
+	if (rdo & RDO_CAP_MISMATCH)
+		CPRINTF(" Mismatch");
+	CPRINTF("\n");
+
 	pd[port].curr_limit = curr_limit;
 	pd[port].supply_voltage = supply_voltage;
-	pd[port].prev_request_mv = request_mv;
+	pd[port].prev_request_mv = supply_voltage;
 	res = send_request(port, rdo);
 	if (res >= 0)
 		set_state(port, PD_STATE_SNK_REQUESTED);
diff --git a/include/usb_pd.h b/include/usb_pd.h
index 67c049dcf0..a84736cdae 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -76,6 +76,7 @@ enum pd_errors {
 
 /* RDO : Request Data Object */
 #define RDO_OBJ_POS(n)             (((n) & 0x7) << 28)
+#define RDO_POS(rdo)               (((rdo) >> 28) & 0x7)
 #define RDO_GIVE_BACK              (1 << 27)
 #define RDO_CAP_MISMATCH           (1 << 26)
 #define RDO_COMM_CAP               (1 << 25)