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From:   surong pang <surong.pang@gmail.com>
Date:   Fri, 22 Apr 2022 18:43:48 +0800
Message-ID: <CAEDbmAT3SoSsEmTkELSYoykGN+AuPgi2N11V2YwKuaC3nKMEmQ@mail.gmail.com>
Subject: Re: [PATCH V1 1/1] usb/host: Let usb phy shutdown later
To:     Mathias Nyman <mathias.nyman@linux.intel.com>
Cc:     mathias.nyman@intel.com, Greg KH <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Orson.Zhai@unisoc.com, yunguo.wu@unisoc.com
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>>> @@ -398,6 +397,7 @@ static int xhci_plat_remove(struct platform_device =
*dev)
>>>       clk_disable_unprepare(clk);
>>>       clk_disable_unprepare(reg_clk);
>>> +    usb_phy_shutdown(hcd->usb_phy);
>>>       usb_put_hcd(hcd);

Is it ok to put usb_phy_shutdown before usb_put_hcd(hcd)? hcd is
released at usb_put_hcd.

UNISOC DWC3 phy is not divided  USB 2.0/3.0 phy clearly.  Yes, it's
UNISOC's issue.
It UNISOC's dtsi: phys =3D <&ssphy>, <&ssphy>;
If to shutdown phy too earlier,  it will cost 10s timeout to do xhci_reset.
usb_remmove_hcd  --> usb_stop_hcd --> xhci_stop --> xhci_reset  -->
xhci_handshake(&xhci->op_regs->command, CMD_RESET, 0, 10 * 1000 *1000)

I want to know this change is acceptable or not?

hcd->usb_phy =3D devm_usb_get_phy_by_phandle(sysdev, "usb-phy", 0);
Why in xhci_plat_remove, just to shutdown "usb-phy"[0], not to
shutdown "usb-phy"[1] ?

Mathias Nyman <mathias.nyman@linux.intel.com> =E4=BA=8E2022=E5=B9=B44=E6=9C=
=8822=E6=97=A5=E5=91=A8=E4=BA=94 15:51=E5=86=99=E9=81=93=EF=BC=9A
>
> On 22.4.2022 5.10, surong pang wrote:
> > shared_hcd might be freed already here, but hcd should not be freed
> > here, because "usb_put_hcd(hcd)" is called later.
>
> To me it still looks like this patch calls usb_phy_shutdown(hcd->usb_phy)=
 _after_
> usb_put_hcd(hcd):
>
> >>> @@ -398,6 +397,7 @@ static int xhci_plat_remove(struct platform_devic=
e *dev)
> >>>       clk_disable_unprepare(clk);
> >>>       clk_disable_unprepare(reg_clk);
> >>>       usb_put_hcd(hcd);
> >>> +     usb_phy_shutdown(hcd->usb_phy);
>
>
> shared hcd was freed even earlier, before disabling the clocks.
>
> Thanks
> Mathias