Per USB PD standard, we have to drop duplicate PD messages.
We can not expect lower protocol layers to drop such messages,
since lower layers don't know if a message was dropped somewhere
else in the stack.
Originally-from: Puma Hsu <puma_hsu@xxxxxxx>
Cc: Yueyao Zhu <yueyao.zhu@xxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/staging/typec/pd.h | 10 ++++++++++
drivers/staging/typec/tcpm.c | 29 +++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/drivers/staging/typec/pd.h b/drivers/staging/typec/pd.h
index 8d97bdb95f23..510ef7279900 100644
--- a/drivers/staging/typec/pd.h
+++ b/drivers/staging/typec/pd.h
@@ -92,6 +92,16 @@ static inline unsigned int pd_header_type_le(__le16 header)
return pd_header_type(le16_to_cpu(header));
}
+static inline unsigned int pd_header_msgid(u16 header)
+{
+ return (header >> PD_HEADER_ID_SHIFT) & PD_HEADER_ID_MASK;
+}
+
+static inline unsigned int pd_header_msgid_le(__le16 header)
+{
+ return pd_header_msgid(le16_to_cpu(header));
+}
+
#define PD_MAX_PAYLOAD 7
struct pd_message {
diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
index abba655ba00a..c5d8b129c4f4 100644
--- a/drivers/staging/typec/tcpm.c
+++ b/drivers/staging/typec/tcpm.c
@@ -238,6 +238,7 @@ struct tcpm_port {
unsigned int hard_reset_count;
bool pd_capable;
bool explicit_contract;
+ unsigned int rx_msgid;
/* Partner capabilities/requests */
u32 sink_request;
@@ -1415,6 +1416,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
break;
case SOFT_RESET_SEND:
port->message_id = 0;
+ port->rx_msgid = -1;
if (port->pwr_role == TYPEC_SOURCE)
next_state = SRC_SEND_CAPABILITIES;
else
@@ -1503,6 +1505,22 @@ static void tcpm_pd_rx_handler(struct work_struct *work)
port->attached);
if (port->attached) {
+ enum pd_ctrl_msg_type type = pd_header_type_le(msg->header);
+ unsigned int msgid = pd_header_msgid_le(msg->header);
+
+ /*
+ * USB PD standard, 6.6.1.2:
+ * "... if MessageID value in a received Message is the
+ * same as the stored value, the receiver shall return a
+ * GoodCRC Message with that MessageID value and drop
+ * the Message (this is a retry of an already received
+ * Message). Note: this shall not apply to the Soft_Reset
+ * Message which always has a MessageID value of zero."
+ */
+ if (msgid == port->rx_msgid && type != PD_CTRL_SOFT_RESET)
+ goto done;
+ port->rx_msgid = msgid;
+
/*
* If both ends believe to be DFP/host, we have a data role
* mismatch.
@@ -1520,6 +1538,7 @@ static void tcpm_pd_rx_handler(struct work_struct *work)
}
}
+done:
mutex_unlock(&port->lock);
kfree(event);
}
@@ -1957,6 +1976,12 @@ static void tcpm_reset_port(struct tcpm_port *port)
port->attached = false;
port->pd_capable = false;
+ /*
+ * First Rx ID should be 0; set this to a sentinel of -1 so that
+ * we can check tcpm_pd_rx_handler() if we had seen it before.
+ */
+ port->rx_msgid = -1;
+
port->tcpc->set_pd_rx(port->tcpc, false);
tcpm_init_vbus(port); /* also disables charging */
tcpm_init_vconn(port);
@@ -2170,6 +2195,7 @@ static void run_state_machine(struct tcpm_port *port)
port->pwr_opmode = TYPEC_PWR_MODE_USB;
port->caps_count = 0;
port->message_id = 0;
+ port->rx_msgid = -1;
port->explicit_contract = false;
tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
break;
@@ -2329,6 +2355,7 @@ static void run_state_machine(struct tcpm_port *port)
typec_set_pwr_opmode(port->typec_port, TYPEC_PWR_MODE_USB);
port->pwr_opmode = TYPEC_PWR_MODE_USB;
port->message_id = 0;
+ port->rx_msgid = -1;
port->explicit_contract = false;
tcpm_set_state(port, SNK_DISCOVERY, 0);
break;
@@ -2496,6 +2523,7 @@ static void run_state_machine(struct tcpm_port *port)
/* Soft_Reset states */
case SOFT_RESET:
port->message_id = 0;
+ port->rx_msgid = -1;
tcpm_pd_send_control(port, PD_CTRL_ACCEPT);
if (port->pwr_role == TYPEC_SOURCE)
tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
@@ -2504,6 +2532,7 @@ static void run_state_machine(struct tcpm_port *port)
break;
case SOFT_RESET_SEND:
port->message_id = 0;
+ port->rx_msgid = -1;
if (tcpm_pd_send_control(port, PD_CTRL_SOFT_RESET))
tcpm_set_state_cond(port, hard_reset_state(port), 0);
else
--
2.7.4
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