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From:   Al Cooper <alcooperx@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Danesh Petigara <danesh.petigara@broadcom.com>,
        Al Cooper <alcooperx@gmail.com>, devicetree@vger.kernel.org,
        Felipe Balbi <balbi@kernel.org>,
        Florian Fainelli <florian.fainelli@broadcom.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
        Sasi Kumar <sasi.kumar@broadcom.com>
Subject: [PATCH v2 6/7] usb: bdc: Halt controller on suspend
Date:   Tue, 21 Jul 2020 10:43:25 -0400
Message-Id: <20200721144326.7976-7-alcooperx@gmail.com>
In-Reply-To: <20200721144326.7976-1-alcooperx@gmail.com>
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From: Danesh Petigara <danesh.petigara@broadcom.com>

GISB bus error kernel panics have been observed during S2 transition
tests on the 7271t platform. The errors are a result of the BDC
interrupt handler trying to access BDC register space after the
system's suspend callbacks have completed.

Adding a suspend hook to the BDC driver that halts the controller before
S2 entry thus preventing unwanted access to the BDC register space during
this transition.

Signed-off-by: Danesh Petigara <danesh.petigara@broadcom.com>
Signed-off-by: Al Cooper <alcooperx@gmail.com>
---
 drivers/usb/gadget/udc/bdc/bdc_core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/bdc/bdc_core.c b/drivers/usb/gadget/udc/bdc/bdc_core.c
index 2c2f7aef7ba7..c1650247ea39 100644
--- a/drivers/usb/gadget/udc/bdc/bdc_core.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
@@ -607,9 +607,14 @@ static int bdc_remove(struct platform_device *pdev)
 static int bdc_suspend(struct device *dev)
 {
 	struct bdc *bdc = dev_get_drvdata(dev);
+	int ret;
 
-	clk_disable_unprepare(bdc->clk);
-	return 0;
+	/* Halt the controller */
+	ret = bdc_stop(bdc);
+	if (!ret)
+		clk_disable_unprepare(bdc->clk);
+
+	return ret;
 }
 
 static int bdc_resume(struct device *dev)
-- 
2.17.1