TCPMv2: Add common function for DPM entry and exit mode

Added a common entry point into DPM for entering or exiting modes.

BUG=b:155890173
BRANCH=None
TEST=Tested on volteer, able to enter and exit
     1. DisplayPort mode with type-C dock
     2. Thunderbolt mode with a Thunderbolt dock

Signed-off-by: Ayushee <ayushee.shah@intel.com>
Change-Id: I3bb996d96d0fff543ad7a2e1dc8e09d0b17d0171
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2299840
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>
Commit-Queue: Abe Levkoy <alevkoy@chromium.org>

4 files changed, 22 insertions, 43 deletions

diff --git a/common/usbc/usb_pd_dpm.c b/common/usbc/usb_pd_dpm.c
index e2f2c4d356..b84b5b075f 100644
--- a/common/usbc/usb_pd_dpm.c
+++ b/common/usbc/usb_pd_dpm.c
@@ -93,14 +93,16 @@ void dpm_vdm_naked(int port, enum tcpm_transmit_type type, uint16_t svid,
 	}
 }
 
-void dpm_attempt_mode_entry(int port)
+/*
+ * The call to this function requests that the PE send one VDM, whichever is
+ * next in the mode entry sequence. This only happens if preconditions for mode
+ * entry are met.
+ */
+static void dpm_attempt_mode_entry(int port)
 {
 	int vdo_count = 0;
 	uint32_t vdm[VDO_MAX_SIZE];
 
-	if (dpm[port].mode_entry_done)
-		return;
-
 	if (pd_get_data_role(port) != PD_ROLE_DFP)
 		return;
 	/*
@@ -172,15 +174,12 @@ void dpm_attempt_mode_entry(int port)
 	pe_dpm_request(port, DPM_REQUEST_VDM);
 }
 
-void dpm_attempt_mode_exit(int port)
+static void dpm_attempt_mode_exit(int port)
 {
 	int opos;
 	uint16_t svid;
 	uint32_t vdm;
 
-	if (!dpm[port].mode_exit_request)
-		return;
-
 	/* TODO: Add exit mode support for SOP' and SOP'' */
 
 	if (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE) &&
@@ -214,3 +213,11 @@ void dpm_attempt_mode_exit(int port)
 		pe_dpm_request(port, DPM_REQUEST_VDM);
 	}
 }
+
+void dpm_run(int port)
+{
+	if (dpm[port].mode_exit_request)
+		dpm_attempt_mode_exit(port);
+	else if (!dpm[port].mode_entry_done)
+		dpm_attempt_mode_entry(port);
+}
diff --git a/common/usbc/usb_pe_drp_sm.c b/common/usbc/usb_pe_drp_sm.c
index beffd61d60..5a76b00a7a 100644
--- a/common/usbc/usb_pe_drp_sm.c
+++ b/common/usbc/usb_pe_drp_sm.c
@@ -2084,16 +2084,8 @@ static void pe_src_ready_run(int port)
 			return;
 		}
 
-		/*
-		 * TODO b/155890173: Combine the entry and exit mode requests
-		 * so that there is only a single entry point into DPM.
-		 */
-
-		/* No DPM requests; attempt mode exit if needed */
-		dpm_attempt_mode_exit(port);
-
-		/* No DPM requests; attempt mode entry if needed */
-		dpm_attempt_mode_entry(port);
+		/* No DPM requests; attempt mode entry/exit if needed */
+		dpm_run(port);
 	}
 }
 
@@ -2834,15 +2826,9 @@ static void pe_snk_ready_run(int port)
 			return;
 		}
 
-		/*
-		 * TODO b/155890173: Combine the entry and exit mode requests
-		 * so that there is only a single entry point into DPM.
-		 */
-		/* No DPM requests; attempt mode exit if needed */
-		dpm_attempt_mode_exit(port);
+		/* No DPM requests; attempt mode entry/exit if needed */
+		dpm_run(port);
 
-		/* No DPM requests; attempt mode entry if needed */
-		dpm_attempt_mode_entry(port);
 	}
 }
 
diff --git a/include/usb_pd_dpm.h b/include/usb_pd_dpm.h
index d431256e18..2948fd3fbd 100644
--- a/include/usb_pd_dpm.h
+++ b/include/usb_pd_dpm.h
@@ -57,20 +57,10 @@ void dpm_vdm_naked(int port, enum tcpm_transmit_type type, uint16_t svid,
 		uint8_t vdm_cmd);
 
 /*
- * Drives the Policy Engine through the mode entry/configuration process. Each
- * call to this function requests that the PE send one VDM, whichever is next in
- * the mode entry sequence. This only happens if preconditions for mode entry
- * are met.
+ * Drives the Policy Engine through entry/exit mode process
  *
  * @param port USB-C port number
  */
-void dpm_attempt_mode_entry(int port);
-
-/*
- * Drives the Policy Engine through exit mode process for each active mode
- *
- * @param port    USB-C port number
- */
-void dpm_attempt_mode_exit(int port);
+void dpm_run(int port);
 
 #endif  /* __CROS_EC_USB_DPM_H */
diff --git a/test/fake_usbc.c b/test/fake_usbc.c
index 37d1c0bf09..0f92379b38 100644
--- a/test/fake_usbc.c
+++ b/test/fake_usbc.c
@@ -270,11 +270,7 @@ void dpm_set_mode_exit_request(int port)
 {
 }
 
-void dpm_attempt_mode_entry(int port)
-{
-}
-
-void dpm_attempt_mode_exit(int port)
+void dpm_run(int port)
 {
 }