From 6bbe2a90a0bb4af8dd99c3565e907fe9b5e7fd88 Mon Sep 17 00:00:00 2001

From: Badhri Jagan Sridharan <badhri@google.com>

Date: Mon, 17 Aug 2020 11:38:27 -0700

Subject: [PATCH] usb: typec: tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart

Git-commit: 6bbe2a90a0bb4af8dd99c3565e907fe9b5e7fd88

Patch-mainline: v5.10-rc1

References: git-fixes

The patch addresses the compliance test failures while running

TD.PD.CP.E3, TD.PD.CP.E4, TD.PD.CP.E5 of the "Deterministic PD

Compliance MOI" test plan published in https://www.usb.org/usbc.

For a product to be Type-C compliant, it's expected that these tests

are run on usb.org certified Type-C compliance tester as mentioned in

https://www.usb.org/usbc.

The purpose of the tests TD.PD.CP.E3, TD.PD.CP.E4, TD.PD.CP.E5 is to

verify the PR_SWAP response of the device. While doing so, the test

asserts that Source Capabilities message is NOT received from the test

device within tSwapSourceStart min (20 ms) from the time the last bit

of GoodCRC corresponding to the RS_RDY message sent by the UUT was

sent. If it does then the test fails.

This is in line with the requirements from the USB Power Delivery

Specification Revision 3.0, Version 1.2:

"6.6.8.1 SwapSourceStartTimer

The SwapSourceStartTimer Shall be used by the new Source, after a

Power Role Swap or Fast Role Swap, to ensure that it does not send

Source_Capabilities Message before the new Sink is ready to receive

the

Source_Capabilities Message. The new Source Shall Not send the

Source_Capabilities Message earlier than tSwapSourceStart after the

last bit of the EOP of GoodCRC Message sent in response to the PS_RDY

Message sent by the new Source indicating that its power supply is

ready."

The patch makes sure that TCPM does not send the Source_Capabilities

Message within tSwapSourceStart(20ms) by transitioning into

SRC_STARTUP only after  tSwapSourceStart(20ms).

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

Link: https://lore.kernel.org/r/20200817183828.1895015-1-badhri@google.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/usb/typec/tcpm/tcpm.c | 2 +-

 include/linux/usb/pd.h        | 1 +

 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c

index 3ef37202ee37..d38347bd3335 100644

--- a/drivers/usb/typec/tcpm/tcpm.c

+++ b/drivers/usb/typec/tcpm/tcpm.c

@@ -3555,7 +3555,7 @@ static void run_state_machine(struct tcpm_port *port)

 		 */

 		tcpm_set_pwr_role(port, TYPEC_SOURCE);

 		tcpm_pd_send_control(port, PD_CTRL_PS_RDY);

-		tcpm_set_state(port, SRC_STARTUP, 0);

+		tcpm_set_state(port, SRC_STARTUP, PD_T_SWAP_SRC_START);

 		break;

 	case VCONN_SWAP_ACCEPT:

diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h

index b6c233e79bd4..1df895e4680b 100644

--- a/include/linux/usb/pd.h

+++ b/include/linux/usb/pd.h

@@ -473,6 +473,7 @@ static inline unsigned int rdo_max_power(u32 rdo)

 #define PD_T_ERROR_RECOVERY	100	/* minimum 25 is insufficient */

 #define PD_T_SRCSWAPSTDBY      625     /* Maximum of 650ms */

 #define PD_T_NEWSRC            250     /* Maximum of 275ms */

+#define PD_T_SWAP_SRC_START	20	/* Minimum of 20ms */

 #define PD_T_DRP_TRY		100	/* 75 - 150 ms */

 #define PD_T_DRP_TRYWAIT	600	/* 400 - 800 ms */

-- 

2.16.4