TCPMv2: Preserve selected source current in FRS

When executing a fast role swap, ensure that any 3.0 A selected current
is preserved through the select_current_limit_rp in the TC layer.
Additionally, use this selected current to set our current limit when
first attaching as a source.

If FRS is disabled on a port, restore the default Rp value for the
board.

BRANCH=None
BUG=b:180434465
TEST=Check that a 3A FRS device loaded over 1.5 A is able to
successfully complete FRS

Signed-off-by: Diana Z <dzigterman@chromium.org>
Change-Id: I6e6b2f95066a3f8972664c6ac62b450e179e408d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2757096
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2774582
Tested-by: Abe Levkoy <alevkoy@chromium.org>
Commit-Queue: Abe Levkoy <alevkoy@chromium.org>

4 files changed, 23 insertions, 5 deletions

diff --git a/common/mock/usb_tc_sm_mock.c b/common/mock/usb_tc_sm_mock.c
index 07d861f4d4..259170d6bf 100644
--- a/common/mock/usb_tc_sm_mock.c
+++ b/common/mock/usb_tc_sm_mock.c
@@ -56,6 +56,10 @@ void typec_select_src_collision_rp(int port, enum tcpc_rp_value rp)
 	mock_tc_port[port].lcl_rp = rp;
 }
 
+void typec_select_src_current_limit_rp(int port, enum tcpc_rp_value rp)
+{
+}
+
 int tc_is_attached_src(int port)
 {
 	return mock_tc_port[port].attached_src;
diff --git a/common/usbc/usb_pd_dpm.c b/common/usbc/usb_pd_dpm.c
index 32929d2b79..1c579d7630 100644
--- a/common/usbc/usb_pd_dpm.c
+++ b/common/usbc/usb_pd_dpm.c
@@ -584,6 +584,9 @@ void dpm_remove_sink(int port)
 	atomic_clear_bits(&sink_max_pdo_requested, BIT(port));
 	atomic_clear_bits(&non_pd_sink_max_requested, BIT(port));
 
+	/* Restore selected default Rp on the port */
+	typec_select_src_current_limit_rp(port, CONFIG_USB_PD_PULLUP);
+
 	balance_source_ports();
 }
 
diff --git a/common/usbc/usb_pe_drp_sm.c b/common/usbc/usb_pe_drp_sm.c
index 79bdc3166e..85caf0473c 100644
--- a/common/usbc/usb_pe_drp_sm.c
+++ b/common/usbc/usb_pe_drp_sm.c
@@ -931,10 +931,10 @@ static void pe_set_frs_enable(int port, int enable)
 		int curr_limit = *pd_get_snk_caps(port)
 						& PDO_FIXED_FRS_CURR_MASK;
 
-		typec_set_source_current_limit(port,
-					       curr_limit ==
-					       PDO_FIXED_FRS_CURR_3A0_AT_5V ?
-					       TYPEC_RP_3A0 : TYPEC_RP_1A5);
+		typec_select_src_current_limit_rp(port,
+						  curr_limit ==
+						  PDO_FIXED_FRS_CURR_3A0_AT_5V ?
+						  TYPEC_RP_3A0 : TYPEC_RP_1A5);
 		PE_SET_FLAG(port, PE_FLAGS_FAST_ROLE_SWAP_ENABLED);
 	} else {
 		PE_CLR_FLAG(port, PE_FLAGS_FAST_ROLE_SWAP_ENABLED);
@@ -1622,6 +1622,9 @@ static bool sink_dpm_requests(int port)
 		} else if (PE_CHK_DPM_REQUEST(port,
 					      DPM_REQUEST_FRS_DET_DISABLE)) {
 			pe_set_frs_enable(port, 0);
+			/* Restore a default port current limit */
+			typec_select_src_current_limit_rp(port,
+							  CONFIG_USB_PD_PULLUP);
 
 			/* Requires no state change, fall through to false */
 			PE_CLR_DPM_REQUEST(port, DPM_REQUEST_FRS_DET_DISABLE);
diff --git a/common/usbc/usb_tc_drp_acc_trysrc_sm.c b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
index cb7f7866b9..981227f468 100644
--- a/common/usbc/usb_tc_drp_acc_trysrc_sm.c
+++ b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
@@ -2150,10 +2150,14 @@ static void tc_unattached_snk_entry(const int port)
 	 *
 	 * Both CC1 and CC2 pins shall be independently terminated to
 	 * ground through Rd.
+	 *
+	 * Restore default current limit Rp in case we swap to source
 	 */
 	typec_select_pull(port, TYPEC_CC_RD);
+	typec_select_src_current_limit_rp(port, CONFIG_USB_PD_PULLUP);
 	typec_update_cc(port);
 
+
 	prev_data_role = tc[port].data_role;
 	tc[port].data_role = PD_ROLE_DISCONNECTED;
 	/*
@@ -2696,6 +2700,8 @@ static void tc_unattached_src_entry(const int port)
 	 *
 	 * Both CC1 and CC2 pins shall be independently terminated to
 	 * ground through Rp.
+	 *
+	 * Restore default current limit Rp.
 	 */
 	typec_select_pull(port, TYPEC_CC_RP);
 	typec_select_src_current_limit_rp(port, CONFIG_USB_PD_PULLUP);
@@ -2880,9 +2886,11 @@ static void tc_attached_src_entry(const int port)
 	 *
 	 * Both CC1 and CC2 pins shall be independently terminated to
 	 * pulled up through Rp.
+	 *
+	 * Set selected current limit in the hardware.
 	 */
 	typec_select_pull(port, TYPEC_CC_RP);
-	typec_select_src_current_limit_rp(port, CONFIG_USB_PD_PULLUP);
+	typec_set_source_current_limit(port, tc[port].select_current_limit_rp);
 
 	if (IS_ENABLED(CONFIG_USB_PE_SM)) {
 		if (TC_CHK_FLAG(port, TC_FLAGS_PR_SWAP_IN_PROGRESS)) {