4.14-stable review patch. If anyone has any objections, please let me know.
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From: Adam Thomson Adam.Thomson.Opensource@diasemi.com
[ Upstream commit ab69f61321140ff632d560775bc226259a78dfa2 ]
The expectation in the FUSB302 driver is that a TX_SUCCESS event should occur after a message has been sent, but before a GCRCSENT event is raised to indicate successful receipt of a message from the partner. However in some circumstances it is possible to see the hardware raise a GCRCSENT event before a TX_SUCCESS event is raised. The upshot of this is that the GCRCSENT handling portion of code ends up reporting the GoodCRC message to TCPM because the TX_SUCCESS event hasn't yet arrived to trigger a consumption of it. When TX_SUCCESS is then raised by the chip it ends up consuming the actual message that was meant for TCPM, and this incorrect sequence results in a hard reset from TCPM.
To avoid this problem, this commit updates the message reading code to check whether a GoodCRC message was received or not. Based on this check it will either report that the previous transmission has completed or it will pass the msg data to TCPM for futher processing. This way the incorrect ordering of the events no longer matters.
Signed-off-by: Adam Thomson Adam.Thomson.Opensource@diasemi.com Reviewed-by: Guenter Roeck linux@roeck-us.net Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/typec/fusb302/fusb302.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
--- a/drivers/staging/typec/fusb302/fusb302.c +++ b/drivers/staging/typec/fusb302/fusb302.c @@ -1552,6 +1552,21 @@ static int fusb302_pd_read_message(struc fusb302_log(chip, "PD message header: %x", msg->header); fusb302_log(chip, "PD message len: %d", len);
+ /* + * Check if we've read off a GoodCRC message. If so then indicate to + * TCPM that the previous transmission has completed. Otherwise we pass + * the received message over to TCPM for processing. + * + * We make this check here instead of basing the reporting decision on + * the IRQ event type, as it's possible for the chip to report the + * TX_SUCCESS and GCRCSENT events out of order on occasion, so we need + * to check the message type to ensure correct reporting to TCPM. + */ + if ((!len) && (pd_header_type_le(msg->header) == PD_CTRL_GOOD_CRC)) + tcpm_pd_transmit_complete(chip->tcpm_port, TCPC_TX_SUCCESS); + else + tcpm_pd_receive(chip->tcpm_port, msg); + return ret; }
@@ -1659,13 +1674,12 @@ static irqreturn_t fusb302_irq_intn(int
if (interrupta & FUSB_REG_INTERRUPTA_TX_SUCCESS) { fusb302_log(chip, "IRQ: PD tx success"); - /* read out the received good CRC */ ret = fusb302_pd_read_message(chip, &pd_msg); if (ret < 0) { - fusb302_log(chip, "cannot read in GCRC, ret=%d", ret); + fusb302_log(chip, + "cannot read in PD message, ret=%d", ret); goto done; } - tcpm_pd_transmit_complete(chip->tcpm_port, TCPC_TX_SUCCESS); }
if (interrupta & FUSB_REG_INTERRUPTA_HARDRESET) { @@ -1686,7 +1700,6 @@ static irqreturn_t fusb302_irq_intn(int "cannot read in PD message, ret=%d", ret); goto done; } - tcpm_pd_receive(chip->tcpm_port, &pd_msg); } done: mutex_unlock(&chip->lock);