[PATCH 6/7] usb: bdc: Halt controller on suspend

Al Cooper
2020-07-17T15:23:58Z

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>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.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 47bcc9f6afbd..ac989adefe9d 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