From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Wesley Cheng <wcheng@codeaurora.org>
Cc: balbi@kernel.org, gregkh@linuxfoundation.org, robh+dt@kernel.org,
agross@kernel.org, linux-arm-msm@vger.kernel.org,
devicetree@vger.kernel.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org, peter.chen@nxp.com,
jackp@codeaurora.org
Subject: Re: [PATCH v6 3/4] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements
Date: Mon, 25 Jan 2021 23:15:00 -0600 [thread overview]
Message-ID: <YA+lVFWlBDvN4MTF@builder.lan> (raw)
In-Reply-To: <99dd9419-a8fd-9eb2-9582-d24f865ecf70@codeaurora.org>
On Mon 25 Jan 22:32 CST 2021, Wesley Cheng wrote:
> On 1/25/2021 5:55 PM, Bjorn Andersson wrote:
> > On Mon 25 Jan 19:14 CST 2021, Wesley Cheng wrote:
> >
> >>
> >>
> >> On 1/22/2021 9:12 AM, Bjorn Andersson wrote:
> >>> On Thu 21 Jan 22:01 CST 2021, Wesley Cheng wrote:
> >>>
> >>
> >> Hi Bjorn,
> >>>
> >>> Under what circumstances should we specify this? And in particular are
> >>> there scenarios (in the Qualcomm platforms) where this must not be set?
> >>> The TXFIFO dynamic allocation is actually a feature within the DWC3
> >> controller, and isn't specifically for QCOM based platforms. It won't
> >> do any harm functionally if this flag is not set, as this is meant for
> >> enhancing performance/bandwidth.
> >>
> >>> In particular, the composition can be changed in runtime, so should we
> >>> set this for all Qualcomm platforms?
> >>>
> >> Ideally yes, if we want to increase bandwith for situations where SS
> >> endpoint bursting is set to a higher value.
> >>
> >>> And if that's the case, can we not just set it from the qcom driver?
> >>>
> >> Since this is a common DWC3 core feature, I think it would make more
> >> sense to have it in DWC3 core instead of a vendor's DWC3 glue driver.
> >>
> >
> > I don't have any objections to implementing it in the core driver, but
> > my question is can we just skip the DT binding and just enable it from
> > the vendor driver?
> >
> > Regards,
> > Bjorn
> >
>
> Hi Bjorn,
>
> I see. I think there are some designs which don't have a DWC3 glue
> driver, so assuming there may be other platforms using this, there may
> not always be a vendor driver to set this.
>
You mean that there are implementations of dwc3 without an associated
glue driver that haven't yet realized that they need this feature?
I would suggest then that we implement the core code necessary, we
enable it from the Qualcomm glue layer and when someone realize that
they need this without a glue driver it's going to be trivial to add the
DT binding.
The alternative is that we're lugging around a requirement to specify
this property in all past, present and future Qualcomm dts files - and
then we'll need to hard code it for ACPI anyways.
Regards,
Bjorn
next prev parent reply other threads:[~2021-01-26 22:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 4:01 [PATCH v6 0/4] Re-introduce TX FIFO resize for larger EP bursting Wesley Cheng
2021-01-22 4:01 ` [PATCH v6 1/4] usb: gadget: udc: core: Introduce check_config to verify USB configuration Wesley Cheng
2021-01-22 5:17 ` Jack Pham
2021-01-26 1:01 ` Wesley Cheng
2021-01-22 16:24 ` Alan Stern
2021-01-26 1:02 ` Wesley Cheng
2021-01-22 4:01 ` [PATCH v6 2/4] usb: gadget: configfs: Check USB configuration before adding Wesley Cheng
2021-01-22 4:01 ` [PATCH v6 3/4] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements Wesley Cheng
2021-01-22 17:12 ` Bjorn Andersson
2021-01-26 1:14 ` Wesley Cheng
2021-01-26 1:55 ` Bjorn Andersson
2021-01-26 4:32 ` Wesley Cheng
2021-01-26 5:15 ` Bjorn Andersson [this message]
2021-01-28 23:08 ` Wesley Cheng
2021-01-23 0:15 ` Thinh Nguyen
2021-01-26 9:51 ` Wesley Cheng
2021-01-26 20:43 ` Thinh Nguyen
2021-01-26 23:26 ` Wesley Cheng
2021-01-27 1:47 ` Thinh Nguyen
2021-01-22 4:01 ` [PATCH v6 4/4] arm64: boot: dts: qcom: sm8150: Enable dynamic TX FIFO resize logic Wesley Cheng
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