On 11/05/23 11:00 am, Pawel Laszczak wrote:
+Pawel & Peter
On 09/05/2023 08:58, Ravi Gunasekaran wrote:
Hi Roger,
On 05/05/23 6:02 pm, Roger Quadros wrote:
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, ®s->usb_ien); writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, ®s->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_gadget_config() is called in cdns3_gadget_udc_start() and cdns3_gadget_resume(). These settings seems to be needed during resume as well.
But this bit was never cleared in suspend so why do you need to set it again it in resume?
In my opinion setting PUSB_PWR_FST_REG_ACCESS is not needed in cdns3_gadget_resume, but it should not have any negative impact for driver. The cdns3_gadget_config function seems like a good place for setting this bit.
In the suspend(), USB_CONF_CFGRST (register: usb_conf.CFGRST) is set, resetting the USB device configuration. Does this mean PUSB_PWR_FST_REG_ACCESS will also be reset?
Setting usb_conf.CFGRST doesn't reset the PUSB_PWR_FST_REG_ACCESS.
Regards, Pawel
Regards, Ravi
Regards, Pawel Laszczak
The commit log says that this bit must be kept set in low power states.
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