From: Johan Hovold <johan@kernel.org>
To: Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>
Cc: Bjorn Andersson <andersson@kernel.org>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Philipp Zabel <p.zabel@pengutronix.de>,
Andy Gross <agross@kernel.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Felipe Balbi <balbi@kernel.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
quic_pkondeti@quicinc.com, quic_ppratap@quicinc.com,
quic_wcheng@quicinc.com, quic_jackp@quicinc.com,
quic_harshq@quicinc.com, ahalaney@redhat.com
Subject: Re: [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper
Date: Thu, 8 Jun 2023 11:42:29 +0200 [thread overview]
Message-ID: <ZIGihYS5EacISEFm@hovoldconsulting.com> (raw)
In-Reply-To: <99cded6f-6a71-ffce-8479-c7c0726bfb8e@quicinc.com>
On Thu, Jun 08, 2023 at 01:21:02AM +0530, Krishna Kurapati PSSNV wrote:
> On 6/7/2023 5:07 PM, Johan Hovold wrote:
> > So there at least two issues with this series:
> >
> > 1. accessing xhci registers from the dwc3 core
> > 2. accessing driver data of a child device
> >
> > 1. The first part about accessing xhci registers goes against the clear
> > separation between glue, core and xhci that Felipe tried to maintain.
> >
> > I'm not entirely against doing this from the core driver before
> > registering the xhci platform device as the registers are unmapped
> > afterwards. But if this is to be allowed, then the implementation should
> > be shared with xhci rather than copied verbatim.
> >
> > The alternative that avoids this issue entirely could indeed be to
> > simply count the number of PHYs described in DT as Rob initially
> > suggested. Why would that not work?
> >
> The reason why I didn't want to read the Phy's from DT is explained in
> [1]. I felt it makes the code unreadable and its very tricky to read the
> phy's properly, so we decided we would initialize phy's for all ports
> and if a phy is missing in DT, the corresponding member in
> dwc->usbX_generic_phy[] would be NULL and any phy op on it would be a NOP.
That doesn't sound too convincing. Can't you just iterate over the PHYs
described in DT and determine the maximum port number used for HS and
SS?
> Also as per Krzysztof suggestion on [2], we can add a compatible to read
> number of phy's / ports present. This avoids accessing xhci members
> atleast in driver core. But the layering violations would still be present.
Yes, but if the information is already available in DT it's better to use
it rather than re-encode it in the driver.
> > 2. The driver is already accessing driver data of the child device so
> > arguably your series is not really making things much worse than they
> > already are.
> >
> > I've just sent a couple of fixes to address some of the symptoms of
> > this layering violation here:
> >
> > https://lore.kernel.org/lkml/20230607100540.31045-1-johan+linaro@kernel.org/
> >
>
> As you pointed out offline to me that using xhci event notifiers I
> mentioned on [3], if it is not acceptable to use them as notifications
> to check whether we are in host mode, I believe the only way would be to
> use the patches you pushed in.
I still think we'll end up using callbacks from the xhci/core into the
glue driver, but dedicated ones rather than using usb_register_notify().
The fixes I posted can work as a stop-gap solution until then.
> > Getting this fixed properly is going to take a bit of work, and
> > depending on how your multiport wake up implementation is going to look
> > like, adding support for multiport controllers may not make this much
> > harder to address.
> >
> > So perhaps we can indeed merge support for multiport and then get back
> > to cleaning this up.
> So, you are referring to use the patches you pushed today as a partial
> way to cleanup layering violations and merge multiport on top of it ? If
> so, I am fine with it. I can rebase my changes on top of them.
Right. A bit depending on how your wakeup implementation looks like, it
seems we can merge multiport support and then address the layering
issues which are already present in the driver.
> [1]:
> https://lore.kernel.org/all/4eb26a54-148b-942f-01c6-64e66541de8b@quicinc.com/
> [2]:
> https://lore.kernel.org/all/ca729f62-672e-d3de-4069-e2205c97e7d8@linaro.org/
> [3]:
> https://lore.kernel.org/all/37fd026e-ecb1-3584-19f3-f8c1e5a9d20a@quicinc.com/
Johan
next prev parent reply other threads:[~2023-06-08 9:42 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-14 5:49 [PATCH v8 0/9] Add multiport support for DWC3 controllers Krishna Kurapati
2023-05-14 5:49 ` [PATCH v8 1/9] dt-bindings: usb: qcom,dwc3: Add bindings for SC8280 Multiport Krishna Kurapati
2023-05-14 9:46 ` Krzysztof Kozlowski
2023-05-16 10:59 ` Johan Hovold
2023-05-17 11:10 ` Krishna Kurapati PSSNV
2023-05-17 11:44 ` Johan Hovold
2023-05-17 12:19 ` Krishna Kurapati PSSNV
2023-05-17 12:55 ` Johan Hovold
2023-05-14 5:49 ` [PATCH v8 2/9] dt-bindings: usb: Add bindings for multiport properties on DWC3 controller Krishna Kurapati
2023-05-14 5:49 ` [PATCH v8 3/9] usb: dwc3: core: Access XHCI address space temporarily to read port info Krishna Kurapati
2023-05-15 21:08 ` Bjorn Andersson
2023-05-16 2:12 ` Krishna Kurapati PSSNV
2023-05-16 22:39 ` Thinh Nguyen
2023-05-16 12:11 ` Johan Hovold
2023-05-16 15:02 ` Krishna Kurapati PSSNV
2023-05-17 3:10 ` Krishna Kurapati PSSNV
2023-05-17 3:21 ` Thinh Nguyen
2023-05-17 7:46 ` Johan Hovold
2023-05-17 23:21 ` Thinh Nguyen
2023-06-07 11:56 ` Johan Hovold
2023-05-17 7:35 ` Johan Hovold
2023-05-17 12:21 ` Krishna Kurapati PSSNV
2023-05-17 15:10 ` Johan Hovold
2023-05-14 5:49 ` [PATCH v8 4/9] usb: dwc3: core: Skip setting event buffers for host only controllers Krishna Kurapati
2023-05-15 21:19 ` Bjorn Andersson
2023-05-16 12:17 ` Johan Hovold
2023-05-16 14:28 ` Krishna Kurapati PSSNV
2023-05-14 5:49 ` [PATCH v8 5/9] usb: dwc3: core: Refactor PHY logic to support Multiport Controller Krishna Kurapati
2023-05-15 21:47 ` Bjorn Andersson
2023-05-16 2:31 ` Krishna Kurapati PSSNV
2023-05-17 16:17 ` Johan Hovold
2023-05-14 5:49 ` [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper Krishna Kurapati
2023-05-15 22:27 ` Bjorn Andersson
2023-05-16 2:19 ` Krishna Kurapati PSSNV
2023-05-17 16:37 ` Johan Hovold
2023-05-20 17:48 ` Krishna Kurapati PSSNV
2023-06-07 11:37 ` Johan Hovold
2023-06-07 19:51 ` Krishna Kurapati PSSNV
2023-06-08 9:42 ` Johan Hovold [this message]
2023-06-08 15:23 ` Krishna Kurapati PSSNV
2023-06-08 17:57 ` Thinh Nguyen
2023-06-09 8:18 ` Johan Hovold
2023-06-09 18:16 ` Thinh Nguyen
2023-06-15 4:20 ` Krishna Kurapati PSSNV
2023-06-15 21:08 ` Thinh Nguyen
2023-06-21 7:38 ` Johan Hovold
2023-06-22 4:39 ` Krishna Kurapati PSSNV
2023-06-21 7:34 ` Johan Hovold
2023-06-22 22:41 ` Thinh Nguyen
2023-05-26 2:55 ` Bjorn Andersson
2023-05-26 15:25 ` Krishna Kurapati PSSNV
2023-06-07 11:44 ` Johan Hovold
2023-06-07 19:55 ` Krishna Kurapati PSSNV
2023-06-08 9:44 ` Johan Hovold
2023-06-07 12:16 ` Johan Hovold
2023-06-27 15:43 ` Johan Hovold
2023-07-02 19:05 ` Krishna Kurapati PSSNV
2023-07-14 9:00 ` Johan Hovold
2023-07-14 10:38 ` Krishna Kurapati PSSNV
2023-07-21 11:16 ` Johan Hovold
2023-07-21 12:10 ` Konrad Dybcio
2023-07-21 12:54 ` Johan Hovold
2023-08-11 16:48 ` Konrad Dybcio
2023-08-12 8:58 ` Krishna Kurapati PSSNV
2023-05-14 5:49 ` [PATCH v8 7/9] arm64: dts: qcom: sc8280xp: Add multiport controller node for SC8280 Krishna Kurapati
2023-05-15 14:26 ` Johan Hovold
2023-05-15 15:32 ` Krishna Kurapati PSSNV
2023-05-16 10:54 ` Johan Hovold
2023-05-16 14:24 ` Krishna Kurapati PSSNV
2023-05-16 14:42 ` Johan Hovold
2023-05-16 14:44 ` Krishna Kurapati PSSNV
2023-05-14 5:49 ` [PATCH v8 8/9] arm64: dts: qcom: sa8295p: Enable tertiary controller and its 4 USB ports Krishna Kurapati
2023-05-14 5:49 ` [PATCH v8 9/9] arm64: dts: qcom: sa8540-ride: Enable first port of tertiary usb controller Krishna Kurapati
2023-05-15 2:40 ` [PATCH v8 0/9] Add multiport support for DWC3 controllers Bjorn Andersson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZIGihYS5EacISEFm@hovoldconsulting.com \
--to=johan@kernel.org \
--cc=Thinh.Nguyen@synopsys.com \
--cc=agross@kernel.org \
--cc=ahalaney@redhat.com \
--cc=andersson@kernel.org \
--cc=balbi@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=konrad.dybcio@linaro.org \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=p.zabel@pengutronix.de \
--cc=quic_harshq@quicinc.com \
--cc=quic_jackp@quicinc.com \
--cc=quic_kriskura@quicinc.com \
--cc=quic_pkondeti@quicinc.com \
--cc=quic_ppratap@quicinc.com \
--cc=quic_wcheng@quicinc.com \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).