linux-kernel - [PATCH 5/5] usb: typec: ucsi: Clear UCSI_CCI_RESET

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Message-Id: <20240320073927.1641788-6-lk@c--e.de>
Date: Wed, 20 Mar 2024 08:39:26 +0100
From: "Christian A. Ehrhardt" <lk@...e.de>
To: linux-kernel@...r.kernel.org
Cc: "Christian A. Ehrhardt" <lk@...e.de>,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Prashant Malani <pmalani@...omium.org>,
	Jameson Thies <jthies@...gle.com>,
	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Samuel Čavoj <samuel@...oj.net>,
	linux-usb@...r.kernel.org,
	Kenneth Crudup <kenny@...ix.com>
Subject: [PATCH 5/5] usb: typec: ucsi: Clear UCSI_CCI_RESET_COMPLETE before reset

Check the UCSI_CCI_RESET_COMPLETE complete flag before starting
another reset. Use a UCSI_SET_NOTIFICATION_ENABLE command to clear
the flag if it is set.

Signed-off-by: Christian A. Ehrhardt <lk@...e.de>
---
 drivers/usb/typec/ucsi/ucsi.c | 36 ++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 63f340dbd867..85e507df7fa8 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1264,13 +1264,47 @@ static int ucsi_reset_connector(struct ucsi_connector *con, bool hard)
 
 static int ucsi_reset_ppm(struct ucsi *ucsi)
 {
-	u64 command = UCSI_PPM_RESET;
+	u64 command;
 	unsigned long tmo;
 	u32 cci;
 	int ret;
 
 	mutex_lock(&ucsi->ppm_lock);
 
+	ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * If UCSI_CCI_RESET_COMPLETE is already set we must clear
+	 * the flag before we start another reset. Send a
+	 * UCSI_SET_NOTIFICATION_ENABLE command to achieve this.
+	 * Ignore a timeout and try the reset anyway if this fails.
+	 */
+	if (cci & UCSI_CCI_RESET_COMPLETE) {
+		command = UCSI_SET_NOTIFICATION_ENABLE;
+		ret = ucsi->ops->async_write(ucsi, UCSI_CONTROL, &command,
+					     sizeof(command));
+		if (ret < 0)
+			goto out;
+
+		tmo = jiffies + msecs_to_jiffies(UCSI_TIMEOUT_MS);
+		do {
+			ret = ucsi->ops->read(ucsi, UCSI_CCI,
+					      &cci, sizeof(cci));
+			if (ret < 0)
+				goto out;
+			if (cci & UCSI_CCI_COMMAND_COMPLETE)
+				break;
+			if (time_is_before_jiffies(tmo))
+				break;
+			msleep(20);
+		} while (1);
+
+		WARN_ON(cci & UCSI_CCI_RESET_COMPLETE);
+	}
+
+	command = UCSI_PPM_RESET;
 	ret = ucsi->ops->async_write(ucsi, UCSI_CONTROL, &command,
 				     sizeof(command));
 	if (ret < 0)
-- 
2.40.1