pd: Refactor exit mode.

Refactor pd_exit_mode to be only a DFP function.  Additionally make
pe_init a public function and call it during hard reset.

Signed-off-by: Todd Broch <tbroch@chromium.org>

BRANCH=samus
BUG=chrome-os-partner:33946
TEST=manual, using pdsetmode from later patches see proper exit and
resetting of pe struct.

Change-Id: I45afe1f82926f1c32f4d84eb60c65f1f39b19d81
Reviewed-on: https://chromium-review.googlesource.com/236958
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>

3 files changed, 33 insertions, 24 deletions

diff --git a/common/usb_pd_policy.c b/common/usb_pd_policy.c
index 81a8ab7c85..b9ac431d58 100644
--- a/common/usb_pd_policy.c
+++ b/common/usb_pd_policy.c
@@ -175,7 +175,7 @@ static struct pd_policy pe[PD_PORT_COUNT];
 
 #define AMODE_VALID(port) (pe[port].amode.index != -1)
 
-static void pe_init(int port)
+void pd_dfp_pe_init(int port)
 {
 	memset(&pe[port], 0, sizeof(struct pd_policy));
 	pe[port].amode.index = -1;
@@ -184,7 +184,7 @@ static void pe_init(int port)
 static void dfp_consume_identity(int port, uint32_t *payload)
 {
 	int ptype = PD_IDH_PTYPE(payload[VDO_I(IDH)]);
-	pe_init(port);
+	pd_dfp_pe_init(port);
 	memcpy(&pe[port].identity, payload + 1, sizeof(pe[port].identity));
 	switch (ptype) {
 	case IDH_PTYPE_AMA:
@@ -318,7 +318,7 @@ static void dfp_consume_attention(int port, uint32_t *payload)
 		pe[port].amode.fx->attention(port, payload);
 }
 
-int pd_exit_mode(int port, uint32_t *payload)
+uint32_t pd_dfp_exit_mode(int port)
 {
 	struct svdm_amode_data *modep = &pe[port].amode;
 	if (!modep->fx)
@@ -326,11 +326,19 @@ int pd_exit_mode(int port, uint32_t *payload)
 
 	modep->fx->exit(port);
 
-	if (payload)
-		payload[0] = VDO(modep->fx->svid, 1,
-				 CMD_EXIT_MODE | VDO_OPOS(pd_alt_mode(port)));
-	modep->index = -1;
-	return 1;
+	/*
+	 * TODO(crosbug.com/p/33946) : below needs revisited to allow multiple
+	 * mode entry.  Additionally it should honor OPOS == 7 as DFP's request
+	 * to exit all modes.
+	 */
+	if (pd_is_connected(port)) {
+		modep->index = -1;
+		return VDO(modep->fx->svid, 1,
+			   (CMD_EXIT_MODE | VDO_OPOS(pd_alt_mode(port))));
+	} else {
+		pd_dfp_pe_init(port);
+	}
+	return 0;
 }
 
 #ifdef CONFIG_CMD_USB_PD_PE
@@ -578,16 +586,6 @@ void pd_usb_billboard_deferred(void)
 }
 DECLARE_DEFERRED(pd_usb_billboard_deferred);
 
-#ifndef CONFIG_USB_PD_ALT_MODE_DFP
-int pd_exit_mode(int port, uint32_t *payload)
-{
-#ifdef CONFIG_USB_PD_ALT_MODE
-	svdm_rsp.exit_mode(port, payload);
-#endif
-	return 0;
-}
-#endif /* !CONFIG_USB_PD_ALT_MODE_DFP */
-
 #ifdef CONFIG_USB_PD_ALT_MODE_DFP
 static int hc_remote_pd_discovery(struct host_cmd_handler_args *args)
 {
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index fbf45b2993..586afdcebd 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -369,7 +369,9 @@ static inline void set_state(int port, enum pd_states next_state)
 #endif
 		pd[port].dev_id = 0;
 		pd[port].flags &= ~PD_FLAGS_RESET_ON_DISCONNECT_MASK;
-		pd_exit_mode(port, NULL);
+#ifdef CONFIG_USB_PD_ALT_MODE_DFP
+		pd_dfp_exit_mode(port);
+#endif
 #ifdef CONFIG_USBC_SS_MUX
 		board_set_usb_mux(port, TYPEC_MUX_NONE,
 				  pd[port].polarity);
@@ -784,7 +786,10 @@ static void execute_hard_reset(int port)
 		CPRINTF("HARD RESET (RECV)!\n");
 
 	pd[port].msg_id = 0;
-	pd_exit_mode(port, NULL);
+#ifdef CONFIG_USB_PD_ALT_MODE_DFP
+	pd_dfp_exit_mode(port);
+	pd_dfp_pe_init(port);
+#endif
 
 #ifdef CONFIG_USB_PD_DUAL_ROLE
 	if (pd[port].power_role == PD_ROLE_SINK) {
diff --git a/include/usb_pd.h b/include/usb_pd.h
index b43d78464c..8e7fac1c66 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -892,13 +892,19 @@ int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload);
 int pd_custom_flash_vdm(int port, int cnt, uint32_t *payload);
 
 /**
- * Exit alternate mode
+ * Exit alternate mode on DFP
+ *
+ * @param port     USB-C port number
+ * @return VDO to send to UFP or zero if none
+ */
+uint32_t pd_dfp_exit_mode(int port);
+
+/**
+ * Initialize policy engine for DFP
  *
  * @param port     USB-C port number
- * @param payload  payload data.
- * @return if >0, number of VDOs to send back.
  */
-int pd_exit_mode(int port, uint32_t *payload);
+void pd_dfp_pe_init(int port);
 
 /**
  * Store Device ID & RW hash of device