[PATCH] usb: cdns3: gadget.c: Set fast access bit

Ravi Gunasekaran r-gunasekaran at ti.com
Fri May 5 14:13:53 CEST 2023

From: Aswath Govindraju <a-govindraju at ti.com>

When the device port is in a low power state [U3/L2/Not Connected],
accesses to usb device registers may take a long time. This could lead to
potential core hang when the controller registers are accessed after the
port is disabled by setting DEVDS field. Setting the fast register access
bit ensures that the PHY clock is keeping up in active state.

Therefore, set fast access bit to ensure the accesses to device registers
are quick even in low power states.

Signed-off-by: Aswath Govindraju <a-govindraju at ti.com>
 drivers/usb/cdns3/gadget.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index fcaeab9cc1..fddc8c931a 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2321,6 +2321,9 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
 	writel(USB_IEN_INIT, &regs->usb_ien);
 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
+	/* Set the Fast access bit */
+	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
 	cdns3_configure_dmult(priv_dev, NULL);
 	cdns3_gadget_pullup(&priv_dev->gadget, 1);
@@ -2378,6 +2381,7 @@ 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 ret;

base-commit: a25dcda452bf6a6de72764a8d990d72e5def643d

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