From patchwork Thu May 28 01:46:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wesley Cheng X-Patchwork-Id: 11574173 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 29EF6913 for ; Thu, 28 May 2020 01:46:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11BC7208DB for ; Thu, 28 May 2020 01:46:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="FFHb7eho" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726775AbgE1BqU (ORCPT ); Wed, 27 May 2020 21:46:20 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:25237 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726616AbgE1BqT (ORCPT ); Wed, 27 May 2020 21:46:19 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1590630378; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=gsae93ir+ItLa/44z4Kb7YzT3RCzLDKMFjSmE3LcBIY=; b=FFHb7eho5bS5Ce6HfizikK0wPMSC3aKrgL0fxKUKCd6MDqDYNCx2LS3IviGcrpBW1gSuYaBl Hw2mbcihbNiczlMJzmoTVZbU6wPSB01OKe5yQ1DhAk6Zaf5X9zo0iANx04v8zw7mh2igHe47 KDNb/oX7Q7Wyc40sE/IetPh0rhk= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyIxZTE2YSIsICJsaW51eC11c2JAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 5ecf17e344a25e0052c67b7e (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 28 May 2020 01:46:11 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id B59ADC43387; Thu, 28 May 2020 01:46:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=ALL_TRUSTED,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.0 Received: from wcheng-linux.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: wcheng) by smtp.codeaurora.org (Postfix) with ESMTPSA id 56E69C433C9; Thu, 28 May 2020 01:46:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 56E69C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=wcheng@codeaurora.org From: Wesley Cheng To: robh+dt@kernel.org, bjorn.andersson@linaro.org, balbi@kernel.org, gregkh@linuxfoundation.org, agross@kernel.org Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-usb@vger.kernel.org, Wesley Cheng Subject: [RFC v3 0/3] Re-introduce TX FIFO resize for larger EP bursting Date: Wed, 27 May 2020 18:46:00 -0700 Message-Id: <1590630363-3934-1-git-send-email-wcheng@codeaurora.org> X-Mailer: git-send-email 1.9.1 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Changes in V3: - Removed "Reviewed-by" tags - Renamed series back to RFC - Modified logic to ensure that fifo_size is reset if we pass the minimum threshold. Tested with binding multiple FDs requesting 6 FIFOs. Changes in V2: - Modified TXFIFO resizing logic to ensure that each EP is reserved a FIFO. - Removed dev_dbg() prints and fixed typos from patches - Added some more description on the dt-bindings commit message Currently, there is no functionality to allow for resizing the TXFIFOs, and relying on the HW default setting for the TXFIFO depth. In most cases, the HW default is probably sufficient, but for USB compositions that contain multiple functions that require EP bursting, the default settings might not be enough. Also to note, the current SW will assign an EP to a function driver w/o checking to see if the TXFIFO size for that particular EP is large enough. (this is a problem if there are multiple HW defined values for the TXFIFO size) It is mentioned in the SNPS databook that a minimum of TX FIFO depth = 3 is required for an EP that supports bursting. Otherwise, there may be frequent occurences of bursts ending. For high bandwidth functions, such as data tethering (protocols that support data aggregation), mass storage, and media transfer protocol (over FFS), the bMaxBurst value can be large, and a bigger TXFIFO depth may prove to be beneficial in terms of USB throughput. (which can be associated to system access latency, etc...) It allows for a more consistent burst of traffic, w/o any interruptions, as data is readily available in the FIFO. With testing done using the mass storage function driver, the results show that with a larger TXFIFO depth, the bandwidth increased significantly. Test Parameters: - Platform: Qualcomm SM8150 - bMaxBurst = 6 - USB req size = 256kB - Num of USB reqs = 16 - USB Speed = Super-Speed - Function Driver: Mass Storage (w/ ramdisk) - Test Application: CrystalDiskMark Results: TXFIFO Depth = 3 max packets Test Case | Data Size | AVG tput (in MB/s) ------------------------------------------- Sequential|1 GB x | Read |9 loops | 193.60 | | 195.86 | | 184.77 | | 193.60 ------------------------------------------- TXFIFO Depth = 6 max packets Test Case | Data Size | AVG tput (in MB/s) ------------------------------------------- Sequential|1 GB x | Read |9 loops | 287.35 | | 304.94 | | 289.64 | | 293.61 ------------------------------------------- Wesley Cheng (3): usb: dwc3: Resize TX FIFOs to meet EP bursting requirements arm64: boot: dts: qcom: sm8150: Enable dynamic TX FIFO resize logic dt-bindings: usb: dwc3: Add entry for tx-fifo-resize Documentation/devicetree/bindings/usb/dwc3.txt | 2 +- arch/arm64/boot/dts/qcom/sm8150.dtsi | 1 + drivers/usb/dwc3/core.c | 2 + drivers/usb/dwc3/core.h | 8 ++ drivers/usb/dwc3/ep0.c | 37 +++++++- drivers/usb/dwc3/gadget.c | 115 +++++++++++++++++++++++++ 6 files changed, 163 insertions(+), 2 deletions(-)