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From 91d5f4dfeaa72957bb8349c8af2da36a615b05a4 Mon Sep 17 00:00:00 2001
From: Ahmad Fatoum <a.fatoum@pengutronix.de>
Date: Wed, 21 Apr 2021 09:27:04 +0200
Subject: [PATCH master] usb: dwc2: increase timeout for waiting on host mode

Commit 26459ab7803a ("usb: dwc2: Rework wait for host mode during
core reset") effectively reduced the timeout on switch to host mode
from 200ms to 110 us, which is insufficient for the IP on the Raspberry
Pi 3b, leading to:

  dwc2 3f980000.usb@7e980000.of: dwc2_wait_for_mode: Couldn't set host mode

and an unusable USB (and Ethernet) after.

Bump up the timeout to 200ms and help future debugging by logging how
much time it actually took. For the Raspberry 3b I got a value of 49ms.

Note that this is also called from dwc2_force_mode, so worst case is
that a stuck IP delays barebox startup by 200ms.
An error message would alert to this fact, so it can be corrected.

Fixes: 26459ab7803a ("usb: dwc2: Rework wait for host mode during core reset")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.pengutronix.de/20210421072704.520-1-a.fatoum@pengutronix.de
---
 drivers/usb/dwc2/core.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index 5d04a07b0393..7813344ffa65 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -688,19 +688,23 @@ int dwc2_get_dr_mode(struct dwc2 *dwc2)
  */
 void dwc2_wait_for_mode(struct dwc2 *dwc2, bool host_mode)
 {
-	unsigned int timeout = 110 * USECOND;
-	int ret;
+	unsigned int timeout = 200 * MSECOND;
+	uint64_t start;
 
 	dev_vdbg(dwc2->dev, "Waiting for %s mode\n",
 		 host_mode ? "host" : "device");
 
-	ret = wait_on_timeout(timeout, dwc2_is_host_mode(dwc2) == host_mode);
-	if (ret)
-		dev_err(dwc2->dev, "%s: Couldn't set %s mode\n",
-				 __func__, host_mode ? "host" : "device");
+	start = get_time_ns();
+	while (dwc2_is_host_mode(dwc2) != host_mode) {
+		if (is_timeout(start, timeout)) {
+			dev_err(dwc2->dev, "%s: Couldn't set %s mode\n",
+				__func__, host_mode ? "host" : "device");
+			return;
+		}
+	}
 
-	dev_vdbg(dwc2->dev, "%s mode set\n",
-		 host_mode ? "Host" : "Device");
+	dev_vdbg(dwc2->dev, "%s mode set after %lluns\n",
+		 host_mode ? "Host" : "Device", get_time_ns() - start);
 }
 
 /**
-- 
2.29.2