[PATCH 2/5] usb: cdns3: gadget: set fast access bit

[Peter Chen <peter.chen@xxxxxxx>]

Below is the recommendation from Cadence designer:
	Using this bit to be sure that PHY clock is keeping up in active
	state. It's good to keep Fast Access bit enabled as long as there
	is any access to USB register.

It is used to fix the potential ARM core hang when visit controller
register after DEVDS (.pullup is cleared) is set, the threaded irq
may be scheduled at that time.

Cc: Pawel Laszczak <pawell@xxxxxxxxxxx>
Reviewed-by: Jun Li <jun.li@xxxxxxx>
Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
---
 drivers/usb/cdns3/gadget.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 2551901e8470..03b54c239944 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2783,6 +2783,8 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
 	/* enable generic interrupt*/
 	writel(USB_IEN_INIT, &regs->usb_ien);
 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
+	/*  keep Fast Access bit */
+	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
 
 	cdns3_configure_dmult(priv_dev, NULL);
 }
@@ -2866,6 +2868,7 @@ static int cdns3_gadget_udc_stop(struct usb_gadget *gadget)
 
 	/* disable interrupt for device */
 	writel(0, &priv_dev->regs->usb_ien);
+	writel(0, &priv_dev->regs->usb_pwr);
 	writel(USB_CONF_DEVDS, &priv_dev->regs->usb_conf);
 
 	return 0;
-- 
2.17.1