Nami: Allow power role swap to sink in S0ix

Currently, if a hub is plugged in during S0 and a system is suspended to
S0ix, we will reject any requests from that hub to power role swap if it
becomes powered (note this is not a concern for S5, when we will
disconnect a sinking partner, so on becoming powered the hub would start
a new connection).

This change allows role swaps if we are currently sourcing a partner who
could be providing us power instead.

BUG=b:143572158
BRANCH=nami
TEST=plugged in unpowered 3-in-1 dongle to casta in S0, closed the lid
to trigger S0ix, plugged in power to the dongle and saw power role swap
was accepted

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: I76eea8d74df1b827ae39d54392627e90db0d6a95
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1894766

1 files changed, 9 insertions, 4 deletions

diff --git a/board/nami/usb_pd_policy.c b/board/nami/usb_pd_policy.c
index 65baa5b6cf..294cc9e159 100644
--- a/board/nami/usb_pd_policy.c
+++ b/board/nami/usb_pd_policy.c
@@ -135,11 +135,16 @@ int pd_board_checks(void)
 int pd_check_power_swap(int port)
 {
 	/*
-	 * Allow power swap as long as we are acting as a dual role device,
-	 * otherwise assume our role is fixed (not in S0 or console command
-	 * to fix our role).
+	 * Allow power swap if we are acting as a dual role device.  If we are
+	 * not acting as dual role (ex. suspended), then only allow power swap
+	 * if we are sourcing when we could be sinking.
 	 */
-	return pd_get_dual_role(port) == PD_DRP_TOGGLE_ON ? 1 : 0;
+	if (pd_get_dual_role(port) == PD_DRP_TOGGLE_ON)
+		return 1;
+	else if (pd_get_role(port) == PD_ROLE_SOURCE)
+		return 1;
+
+	return 0;
 }
 
 int pd_check_data_swap(int port, int data_role)