[PATCH AUTOSEL 5.7 50/60] usb: bdc: Halt controller on suspend

Sasha Levin
2020-08-10T19:27:01Z

From: Danesh Petigara <danesh.petigara@broadcom.com>

[ Upstream commit 5fc453d7de3d0c345812453823a3a56783c5f82c ]

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>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 5fde5a8b065c1..2dca11f0a7444 100644
--- a/drivers/usb/gadget/udc/bdc/bdc_core.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
@@ -603,9 +603,14 @@ 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)
--
2.25.1