On 4/16/2021 4:48 PM, Artur Petrosyan wrote:
> When dwc2 core is in hibernation mode loading
> driver again causes driver fail. Because in
> that mode registers are not accessible.
>
> In order to exit from hibernation checking
> dwc2 core power saving state in "dwc2_driver_remove()"
> function. If core is in hibernation, then checking the
> operational mode of the driver. To check whether dwc2 core
> is operating in host mode or device mode there is one way
> which is retrieving the backup value of "gotgctl" and compare
> the "CurMod" value. If previously core entered hibernation
> in host mode then the exit is performed for host if not then
> exit is performed for device mode. The introduced checking
> is because in hibernation state all registers are not
> accessible.
>
> Signed-off-by: Artur Petrosyan <Arthur.Petrosyan@xxxxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@xxxxxxxxxxxx>
> ---
> drivers/usb/dwc2/platform.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index f8b819cfa80e..8ad33e042a14 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -316,8 +316,23 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
> static int dwc2_driver_remove(struct platform_device *dev)
> {
> struct dwc2_hsotg *hsotg = platform_get_drvdata(dev);
> + struct dwc2_gregs_backup *gr;
> int ret = 0;
>
> + gr = &hsotg->gr_backup;
> +
> + /* Exit Hibernation when driver is removed. */
> + if (hsotg->hibernated) {
> + if (gr->gotgctl & GOTGCTL_CURMODE_HOST)
> + ret = dwc2_exit_hibernation(hsotg, 0, 0, 1);
> + else
> + ret = dwc2_exit_hibernation(hsotg, 0, 0, 0);
> +
> + if (ret)
> + dev_err(hsotg->dev,
> + "exit hibernation failed.\n");
> + }
> +
> /* Exit Partial Power Down when driver is removed. */
> if (hsotg->in_ppd) {
> ret = dwc2_exit_partial_power_down(hsotg, 0, true);
>
