[PATCH v2 3/3] ath6kl: cold reset target after host warm boot

[Kalle Valo <kvalo@qca.qualcomm.com>]

Julien reported that ar6004 usb device fails to initialise
after host has been rebooted and power is still on for the ar6004 device. He
found out that doing a cold reset fixes the issue.

I wasn't sure what would be the best way to detect if target needs a reset so I
settled on checking a timeout from htc_wait_recv_ctrl_message().

Reported-by: Julien Massot <jmassot@aldebaran-robotics.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath6kl/htc_pipe.c |    2 +-
 drivers/net/wireless/ath/ath6kl/init.c     |   13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath6kl/htc_pipe.c b/drivers/net/wireless/ath/ath6kl/htc_pipe.c
index c02d9d3..67aa924 100644
--- a/drivers/net/wireless/ath/ath6kl/htc_pipe.c
+++ b/drivers/net/wireless/ath/ath6kl/htc_pipe.c
@@ -1168,7 +1168,7 @@ static int htc_wait_recv_ctrl_message(struct htc_target *target)
 
 	if (count <= 0) {
 		ath6kl_warn("htc pipe control receive timeout!\n");
-		return -ECOMM;
+		return -ETIMEDOUT;
 	}
 
 	return 0;
diff --git a/drivers/net/wireless/ath/ath6kl/init.c b/drivers/net/wireless/ath/ath6kl/init.c
index 8b01ec3..4ad45bb 100644
--- a/drivers/net/wireless/ath/ath6kl/init.c
+++ b/drivers/net/wireless/ath/ath6kl/init.c
@@ -1658,7 +1658,18 @@ static int __ath6kl_init_hw_start(struct ath6kl *ar)
 	 * size.
 	 */
 	ret = ath6kl_htc_wait_target(ar->htc_target);
-	if (ret) {
+
+	if (ret == -ETIMEDOUT) {
+		/*
+		 * Most likely USB target is in odd state after reboot and
+		 * needs a reset. A cold reset makes the whole device
+		 * disappear from USB bus and initialisation starts from
+		 * beginning.
+		 */
+		ath6kl_warn("htc wait target timed out, resetting device\n");
+		ath6kl_init_hw_reset(ar);
+		goto err_power_off;
+	} else if (ret) {
 		ath6kl_err("htc wait target failed: %d\n", ret);
 		goto err_power_off;
 	}