[PATCH] usb: typec: tcpm: fix warning when handle discover_identity message

[Xu Yang <xu.yang_2@nxp.com>]

Since both source and sink device can send discover_identity message in
PD3, kernel may dump below warning:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 169 at drivers/usb/typec/tcpm/tcpm.c:1446 tcpm_queue_vdm+0xe0/0xf0
Modules linked in:
CPU: 0 PID: 169 Comm: 1-0050 Not tainted 6.1.1-00038-g6a3c36cf1da2-dirty #567
Hardware name: NXP i.MX8MPlus EVK board (DT)
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : tcpm_queue_vdm+0xe0/0xf0
lr : tcpm_queue_vdm+0x2c/0xf0
sp : ffff80000c19bcd0
x29: ffff80000c19bcd0 x28: 0000000000000001 x27: ffff0000d11c8ab8
x26: ffff0000d11cc000 x25: 0000000000000000 x24: 00000000ff008081
x23: 0000000000000001 x22: 00000000ff00a081 x21: ffff80000c19bdbc
x20: 0000000000000000 x19: ffff0000d11c8080 x18: ffffffffffffffff
x17: 0000000000000000 x16: 0000000000000000 x15: ffff0000d716f580
x14: 0000000000000001 x13: ffff0000d716f507 x12: 0000000000000001
x11: 0000000000000000 x10: 0000000000000020 x9 : 00000000000ee098
x8 : 00000000ffffffff x7 : 000000000000001c x6 : ffff0000d716f580
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : ffff80000c19bdbc x1 : 00000000ff00a081 x0 : 0000000000000004
Call trace:
tcpm_queue_vdm+0xe0/0xf0
tcpm_pd_rx_handler+0x340/0x1ab0
kthread_worker_fn+0xcc/0x18c
kthread+0x10c/0x110
ret_from_fork+0x10/0x20
---[ end trace 0000000000000000 ]---

Below sequences may trigger this warning:

tcpm_send_discover_work(work)
  tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0);
   tcpm_queue_vdm(port, header, data, count);
    port->vdm_state = VDM_STATE_READY;

vdm_state_machine_work(work);
			<-- received discover_identity from partner
 vdm_run_state_machine(port);
  port->vdm_state = VDM_STATE_SEND_MESSAGE;
   mod_vdm_delayed_work(port, x);

tcpm_pd_rx_handler(work);
 tcpm_pd_data_request(port, msg);
  tcpm_handle_vdm_request(port, msg->payload, cnt);
   tcpm_queue_vdm(port, response[0], &response[1], rlen - 1);
--> WARN_ON(port->vdm_state > VDM_STATE_DONE);

For this case, since the state machine could still send out discover
identity message later if we skip current discover_identity message.
So we should handle the received message firstly and override the pending
discover_identity message without warning in this case. Then, a delayed
send_discover work will send discover_identity message again.

Fixes: e00943e91678 ("usb: typec: tcpm: PD3.0 sinks can send Discover Identity even in device mode")
cc: <stable@vger.kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 7f39cb9b3429..914bbaf4e25e 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1445,10 +1445,19 @@ static int tcpm_ams_start(struct tcpm_port *port, enum tcpm_ams ams)
 static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
 			   const u32 *data, int cnt)
 {
+	u32 vdo_hdr = port->vdo_data[0];
+
 	WARN_ON(!mutex_is_locked(&port->lock));
 
-	/* Make sure we are not still processing a previous VDM packet */
-	WARN_ON(port->vdm_state > VDM_STATE_DONE);
+	/* If is sending discover_identity, handle received message firstly */
+	if (PD_VDO_SVDM(vdo_hdr) &&
+		PD_VDO_CMD(vdo_hdr) == CMD_DISCOVER_IDENT) {
+		port->send_discover = true;
+		mod_send_discover_delayed_work(port,
+					SEND_DISCOVER_RETRY_MS);
+	} else
+		/* Make sure we are not still processing a previous VDM packet */
+		WARN_ON(port->vdm_state > VDM_STATE_DONE);
 
 	port->vdo_count = cnt + 1;
 	port->vdo_data[0] = header;
@@ -1950,9 +1959,11 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 				res = tcpm_ams_start(port, DISCOVER_IDENTITY);
 				if (res == 0)
 					port->send_discover = false;
-				else if (res == -EAGAIN)
+				else if (res == -EAGAIN) {
+					port->vdo_data[0] = 0;
 					mod_send_discover_delayed_work(port,
 								       SEND_DISCOVER_RETRY_MS);
+				}
 				break;
 			case CMD_DISCOVER_SVID:
 				res = tcpm_ams_start(port, DISCOVER_SVIDS);
@@ -2035,6 +2046,7 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 			unsigned long timeout;
 
 			port->vdm_retries = 0;
+			port->vdo_data[0] = 0;
 			port->vdm_state = VDM_STATE_BUSY;
 			timeout = vdm_ready_timeout(vdo_hdr);
 			mod_vdm_delayed_work(port, timeout);
-- 
2.34.1