From: Johan Hovold <johan@kernel.org>
To: Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Philipp Zabel <p.zabel@pengutronix.de>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <andersson@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 3/9] usb: dwc3: core: Access XHCI address space temporarily to read port info
Date: Wed, 17 May 2023 17:10:38 +0200 [thread overview]
Message-ID: <ZGTubmBViN9rTiZC@hovoldconsulting.com> (raw)
In-Reply-To: <82a8c414-bfa8-5066-fb68-1ac117b76c4e@quicinc.com>
On Wed, May 17, 2023 at 05:51:45PM +0530, Krishna Kurapati PSSNV wrote:
> On 5/17/2023 1:05 PM, Johan Hovold wrote:
> >>>> + temp = readl(regs + DWC3_XHCI_HCSPARAMS1);
> >>>> + if (HCS_MAX_PORTS(temp) != (dwc->num_usb3_ports + dwc->num_usb2_ports)) {
> >>>> + dev_err(dwc->dev,
> >>>> + "Mismatched reported MAXPORTS (%d)\n", HCS_MAX_PORTS(temp));
> >>>> + ret = -EINVAL;
> >>>> + goto unmap_reg;
> >>>> + }
> >>>
> >>> Not sure this is needed either.
> >>>
> >>> Could this risk regressing platforms which does not have currently have
> >>> all PHYs described in DT?
> >>>
> >> No, it doesn't. AFAIK, this only tells how many ports are present as per
> >> the core consultant configuration of the device. I tried to explain what
> >> would happen incase phy's are not present in DT in [2] & [3].
> >
> > Right, whether the PHYs are described in DT is not directly related to
> > this.
> >
> > As long as HCS_MAX_PORTS by definition (assumption) is always
> > (dwc->num_usb3_ports + dwc->num_usb2_ports) any such machines would
> > continue to work.
> >
> > But if you want to catch machines where this assumption does not hold,
> > you could also end up regressing machines which have so far been working
> > despite these numbers not adding up.
> >
> > That may be acceptable, but I'm still not sure what the value of this
> > check is (e.g. as xhci core will handle basic sanity checks like usb2 +
> > usb3 <= max_ports).
> Thanks for the review comments. Ideally the HCC_PARAMS1 must indicate
> total number of ports supported. If not then I believe the core
> consultant configuration is wrong.
>
> According to the spec:
>
> "The MaxPorts value in the HCSPARAMS1 register defines the number of
> Port Register Sets (e.g. PORTSC, PORTPMSC, and PORTLI register sets)."
>
> So shouldn't the (usb2+usb3 ports be equal to MaxPorts to ensure each
> port properly accesses the respective PortSC etc., ?
Sure, that's what is expected, but why do you need to add a check for
this in the glue driver all of a sudden? Your series does not seem to
rely on this. This is the xHCI driver's business (as is parsing these
registers in the first place, really).
Johan
next prev parent reply other threads:[~2023-05-17 15:10 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 [this message]
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
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
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