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

Hi Ravi,

On 05/05/2023 15:13, Ravi Gunasekaran wrote:

From: Aswath Govindraju a-govindraju@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@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);

Should this be done in cdns3_gadget_udc_start() so it is symmetric?

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

cheers, -roger