Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To:     =?iso-8859-1?Q?Pali_Roh=E1r?= <pali@kernel.org>,
        Mathias Nyman <mathias.nyman@linux.intel.com>
CC:     Peter Chen <peter.chen@nxp.com>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jun Li <jun.li@nxp.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2] usb: host: xhci-plat: fix support for
 XHCI_SKIP_PHY_INIT quirk
Thread-Topic: [PATCH v2] usb: host: xhci-plat: fix support for
 XHCI_SKIP_PHY_INIT quirk
Thread-Index: AQHW2UemNB5r1TTib029sWHXFxYWcaoFwTaAgCCRuICAAoBBAIAPxLcAgADnsXA=
Date:   Tue, 26 Jan 2021 04:27:37 +0000
Message-ID: <TY2PR01MB369295E3D3BF6D5700EC50CCD8BC0@TY2PR01MB3692.jpnprd01.prod.outlook.com>
References: <20201221150903.26630-1-pali@kernel.org>
 <20201223161847.10811-1-pali@kernel.org>
 <20201224055836.GB27629@b29397-desktop>
 <20210113232057.niqamgsqlaw7gojw@pali>
 <88b48c61-65e4-cc24-d90d-5fba92f05f27@linux.intel.com>
 <20210125142028.th4sscs27arhihm2@pali>
In-Reply-To: <20210125142028.th4sscs27arhihm2@pali>
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Hi Pali,

> From: Pali Roh=E1r, Sent: Monday, January 25, 2021 11:20 PM
> On Friday 15 January 2021 15:32:30 Mathias Nyman wrote:
> > On 14.1.2021 1.20, Pali Roh=E1r wrote:
> > > On Thursday 24 December 2020 05:59:05 Peter Chen wrote:
> > >> On 20-12-23 17:18:47, Pali Roh=E1r wrote:
> > >>> Currently init_quirk callbacks for xhci platform drivers are called
> > >>> xhci_plat_setup() function which is called after chip reset complet=
es.
> > >>> It happens in the middle of the usb_add_hcd() function.
> > >>>
> > >>> But XHCI_SKIP_PHY_INIT quirk is checked in the xhci_plat_probe() fu=
nction
> > >>> prior calling usb_add_hcd() function. Therefore this XHCI_SKIP_PHY_=
INIT
> > >>> currently does nothing as prior xhci_plat_setup() it is not set.
> > >>>
> > >>> Quirk XHCI_SKIP_PHY_INIT is only setting hcd->skip_phy_initializati=
on value
> > >>> which really needs to be set prior calling usb_add_hcd() as this fu=
nction
> > >>> at its beginning skips PHY init if this member is set.
> > >>>
> > >>> This patch fixes implementation of the XHCI_SKIP_PHY_INIT quirk by =
calling
> > >>> init_quirk callbacks (via xhci_priv_init_quirk()) prior checking if
> > >>> XHCI_SKIP_PHY_INIT is set. Also checking if either xhci->quirks or
> > >>> priv->quirks contains this XHCI_SKIP_PHY_INIT quirk.
> > >>>
> > >>> Signed-off-by: Pali Roh=E1r <pali@kernel.org>
> > >>>
> > >>> ---
> > >>> Changes in v2:
> > >>> * Check also xhci->quirks as xhci_priv_init_quirk() callbacks are s=
etting xhci->quirks
> > >>> * Tested with "usb: host: xhci: mvebu: make USB 3.0 PHY optional fo=
r Armada 3720" patch
> > >>> * Removed Fixes: line
> > >>> ---
> > >>>  drivers/usb/host/xhci-plat.c | 16 ++++++++--------
> > >>>  1 file changed, 8 insertions(+), 8 deletions(-)
> > >>>
> > >>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-p=
lat.c
> > >>> index 4d34f6005381..0eab7cb5a767 100644
> > >>> --- a/drivers/usb/host/xhci-plat.c
> > >>> +++ b/drivers/usb/host/xhci-plat.c
> > >>> @@ -89,13 +89,6 @@ static void xhci_plat_quirks(struct device *dev,=
 struct xhci_hcd *xhci)
> > >>>  /* called during probe() after chip reset completes */
> > >>>  static int xhci_plat_setup(struct usb_hcd *hcd)
> > >>>  {
> > >>> -	int ret;
> > >>> -
> > >>> -
> > >>> -	ret =3D xhci_priv_init_quirk(hcd);
> > >>> -	if (ret)
> > >>> -		return ret;
> > >>> -
> > >>>  	return xhci_gen_setup(hcd, xhci_plat_quirks);
> > >>>  }
> > >>>
> > >>> @@ -330,7 +323,14 @@ static int xhci_plat_probe(struct platform_dev=
ice *pdev)
> > >>>
> > >>>  	hcd->tpl_support =3D of_usb_host_tpl_support(sysdev->of_node);
> > >>>  	xhci->shared_hcd->tpl_support =3D hcd->tpl_support;
> > >>> -	if (priv && (priv->quirks & XHCI_SKIP_PHY_INIT))
> > >>> +
> > >>> +	if (priv) {
> > >>> +		ret =3D xhci_priv_init_quirk(hcd);
> > >>> +		if (ret)
> > >>> +			goto disable_usb_phy;
> > >>> +	}
> > >>> +
> > >>> +	if ((xhci->quirks & XHCI_SKIP_PHY_INIT) || (priv && (priv->quirks=
 & XHCI_SKIP_PHY_INIT)))
> > >>>  		hcd->skip_phy_initialization =3D 1;
> > >>
> > >> I am not sure if others agree with you move the position of
> > >> xhci_priv_init_quirk, Let's see Mathias opinion.
> > >
> > > Hello! Do you have an opinion how to handle this issue? As currently =
it
> > > is needed for another patch which is fixing issue/regression in xhci-=
mvebu:
> > >
<snip>
> > >
> >
> > I can see the benefit in this.
> > In the xhci-plat case usb_create_hcd and usb_add_hcd are separate steps=
, and
> > we could both copy the xhci_plat_priv .quirks and run the .init_qurks b=
efore
> > adding the hcd.
> > I guess the current way is inherited from pci case where the earliest p=
lace
> > to do this after hcd is created is the hcd->driver->reset callback (whi=
ch is
> > set to xhci_pci_setup() or xhci_plat_setup()).
> >
> > xhci-rcar.c is using the .init_quirk to load firmware, we need to check=
 with
> > them if this change is ok. (added Yoshihiro Shimoda to cc)
>=20
> Yoshihiro, is this change OK?
>=20
> Can we move forward? I really need to now how to handle regression in
> xhci-mvebu driver. And one option is with this patch...

Thank you for asking me about this topic. I tested the patch, but unfortuna=
tely,
this patch is possible to break a rcar platform because a phy initializatio=
n is
needed before the firmware loading if the platform uses the phy. (Note that
upstream code (salvator-common.dtsi) doesn't use the phy for xhci. But,
if we use the phy on other board with this patch, the xhci will not work.)

So, I think we need to add a new function pointer for your case.

Best regards,
Yoshihiro Shimoda

> > Their firmware would be loaded before phy parts are initialized, usb bu=
s
> > registered, or roothub device allocated.
> >
> > Thanks
> > -Mathias