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From: Felipe Balbi <balbi@kernel.org>
To: Tejas Joglekar <Tejas.Joglekar@synopsys.com>,
	Rob Herring <robh@kernel.org>,
	Tejas Joglekar <Tejas.Joglekar@synopsys.com>
Cc: "linux-usb\@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"devicetree\@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	John Youn <John.Youn@synopsys.com>
Subject: Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl
Date: Thu, 16 Apr 2020 11:22:29 +0300
Message-ID: <874ktjsuuy.fsf@kernel.org> (raw)
In-Reply-To: <fe59318a-b3dd-c6af-702e-1ca4aed04a8b@synopsys.com>


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Hi,

Tejas Joglekar <Tejas.Joglekar@synopsys.com> writes:
> Hi,
> On 4/5/2020 7:15 AM, Rob Herring wrote:
>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>>> This commit adds the documentation for consolidate-sgl, and
>>> snps,consolidate-sgl property. These when set enables the quirk for
>>> XHCI driver for consolidation of sg list into a temporary buffer when small
>>> buffer sizes are scattered over the sg list not making up to MPS or total
>>> transfer size within TRB cache size with Synopsys xHC.
>>>
>>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>>> ---
>>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>>  2 files changed, 6 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> index 9946ff9ba735..292d1f7969e4 100644
>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> @@ -104,6 +104,9 @@ Optional properties:
>>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>>  			enable periodic ESS TX threshold.
>>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>>> +			SG buffers of at least MPS size by consolidating smaller SG
>>> +			buffers list into a single buffer.
>> 
>> The preference is not to keep adding properties for every single quirk 
>> or feature. These should be implied by specific compatibles. As Synopsys 
>> knows what quirks/errata/features are in each version of IP, the 
>> compatible strings should reflect those versions. (And yes, I'm sure 
>> there's customer ECO fixes that aren't reflected in the version, but 
>> that's why we have SoC specific compatibles too.) This is the only way 
>> we can fix quirks in the OS without doing DT updates. For comparison, do 
>> you want to have to update your PC BIOS so an OS can work-around issues?
>>
> Yes, I understand what you want to say here. But I think this compatible string
> does not work with the platform drivers with PCI based systems. So based on the vendor 
> id and device id then I need to set the quirk required. 
>
> @Felipe: What do you suggest for setting up quirk without the DT update for dwc3?

We have been using Synopsys controller's revision register, but that's
not visible to xhci driver and we don't have a separate compatible for
each synopsys version on the xhci driver side. One option would be to
add "snps,xhci-foo-bar" to xhci-plat and use that.

-- 
balbi

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  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-27  8:52 [RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC Tejas Joglekar
2020-03-27  8:34 ` [RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl Tejas Joglekar
2020-03-27  9:41   ` [RESENDING RFC " Tejas Joglekar
2020-03-27  9:54   ` Greg KH
2020-03-27 10:11     ` Tejas Joglekar
2020-03-27 10:24       ` Greg KH
2020-03-27 10:28         ` Tejas Joglekar
2020-04-05  1:45   ` Rob Herring
2020-04-14 10:09     ` Tejas Joglekar
2020-04-16  8:22       ` Felipe Balbi [this message]
2020-04-16 16:37         ` Tejas Joglekar
2020-04-17 11:44           ` Mathias Nyman
2020-03-27  8:35 ` [RFC PATCH 2/4] usb: xhci: Set quirk for XHCI_CONSOLIDATE_SG_LIST Tejas Joglekar
2020-03-27  9:42   ` [RESENDING RFC " Tejas Joglekar
2020-03-27  8:35 ` [RFC PATCH 3/4] usb: dwc3: Add device property consolidate-sgl Tejas Joglekar
2020-03-27  9:42   ` [RESENDING RFC " Tejas Joglekar
2020-03-27  8:53 ` [RESENDING RFC PATCH 4/4] usb: xhci: Use temporary buffer to consolidate SG Tejas Joglekar
2020-03-27  9:27   ` Greg KH
2020-03-27 10:05     ` Tejas Joglekar
2020-03-27 10:22       ` Greg KH
2020-03-27 11:25         ` Mathias Nyman
2020-03-27 15:38           ` Raul Rangel
2020-03-27  9:28 ` [RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC Greg KH
2020-03-27  9:43   ` Tejas Joglekar

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