diff mbox series

[v3,1/4] usb: typec: tcpm: Correct the responses in SVDM Version 2.0 DFP

Message ID 20210601123151.3441914-2-kyletso@google.com (mailing list archive)
State Accepted
Commit f41bfc7e9c7c1d721c8752f1853cde43e606ad43
Headers show
Series Add the support of SVDM Version 2.0 VDOs | expand

Commit Message

Kyle Tso June 1, 2021, 12:31 p.m. UTC
In USB PD Spec Rev 3.1 Ver 1.0, section "6.12.5 Applicability of
Structured VDM Commands", DFP is allowed and recommended to respond to
Discovery Identity with ACK. And in section "6.4.4.2.5.1 Commands other
than Attention", NAK should be returned only when receiving Messages
with invalid fields, Messages in wrong situation, or unrecognize
Messages.

Still keep the original design for SVDM Version 1.0 for backward
compatibilities.

Fixes: 193a68011fdc ("staging: typec: tcpm: Respond to Discover Identity commands")
Signed-off-by: Kyle Tso <kyletso@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
changes since v2:
- no change

 drivers/usb/typec/tcpm/tcpm.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 0db685d5d9c0..617f48cdd90c 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1575,19 +1575,25 @@  static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
 			if (PD_VDO_VID(p[0]) != USB_SID_PD)
 				break;
 
-			if (PD_VDO_SVDM_VER(p[0]) < svdm_version)
+			if (PD_VDO_SVDM_VER(p[0]) < svdm_version) {
 				typec_partner_set_svdm_version(port->partner,
 							       PD_VDO_SVDM_VER(p[0]));
+				svdm_version = PD_VDO_SVDM_VER(p[0]);
+			}
 
 			tcpm_ams_start(port, DISCOVER_IDENTITY);
-			/* 6.4.4.3.1: Only respond as UFP (device) */
-			if (port->data_role == TYPEC_DEVICE &&
+			/*
+			 * PD2.0 Spec 6.10.3: respond with NAK as DFP (data host)
+			 * PD3.1 Spec 6.4.4.2.5.1: respond with NAK if "invalid field" or
+			 * "wrong configuation" or "Unrecognized"
+			 */
+			if ((port->data_role == TYPEC_DEVICE || svdm_version >= SVDM_VER_2_0) &&
 			    port->nr_snk_vdo) {
 				/*
 				 * Product Type DFP and Connector Type are not defined in SVDM
 				 * version 1.0 and shall be set to zero.
 				 */
-				if (typec_get_negotiated_svdm_version(typec) < SVDM_VER_2_0)
+				if (svdm_version < SVDM_VER_2_0)
 					response[1] = port->snk_vdo[0] & ~IDH_DFP_MASK
 						      & ~IDH_CONN_MASK;
 				else