From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30D3FC56202 for ; Tue, 27 Oct 2020 00:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D718020829 for ; Tue, 27 Oct 2020 00:46:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="P1tnxEX2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409073AbgJ0AoI (ORCPT ); Mon, 26 Oct 2020 20:44:08 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:44083 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436771AbgJ0AgM (ORCPT ); Mon, 26 Oct 2020 20:36:12 -0400 Received: by mail-pg1-f195.google.com with SMTP id o3so7013377pgr.11 for ; Mon, 26 Oct 2020 17:36:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to; bh=OOAZi1TGJloAiQqosVHHMdmpdn4GYar9ETx5k6SZ6WM=; b=P1tnxEX2oZ6ftzB4xTWL0DesBKun3QP1KD4pq/unAiUkWLFz0dXfz1SCEWHA41TSur g8AC0qQT/vLMI721uGerJby3lgRUzopA/olCkGKBoGbpFY+QKTKRGhI7U/OaZeLSRnz/ N6yYgJLgNrTQM6tHlcEUCrXnKJ3VzP+cuQhDM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to; bh=OOAZi1TGJloAiQqosVHHMdmpdn4GYar9ETx5k6SZ6WM=; b=KIzE3Jqz/I0rojKQub0VT4NTO3mtPe2bEalEmWTapodHxM81hUhoPfihWdbcie93RR 05to4BrdQUqDm/xpaH0Ho1u1AxX2pQaxnOyl4Mzrrh54k5M/cFZE+VOLDtFUAlDU1iy3 LHaKR3icO95MBMm7exDVg7VIeFoKYegSvomJAXNtAMAsyOng0UQvTFeJpxVJ4QGjJo71 ucxy6zAdwNu6bONEYyX1Vf/Wb3QW1vQ+3eGXxda15CxirXN6HMTpE9St9u69r2bZuK0s NyuePXao2b2L1OBsoTs766IelYolvWH93Y0Fu6DiMu/jlSovWurs/lmG+pxKHddO5st3 jNDg== X-Gm-Message-State: AOAM530xJUwJaYHLOI6+ZSkhvwtsh/ACtre8/IuyTEJZ+1h97m6Qdd3L cR5YH1YW41XldSRkKtfO9sFV6A== X-Google-Smtp-Source: ABdhPJx7iGUpRWW64X/vx9Y6gi5GRDWwfOF7mr/CiJOuOJxHJ7elouSf+EIHPqG7B4rj04zZrqnieA== X-Received: by 2002:a62:2b88:0:b029:163:c6fb:f2a with SMTP id r130-20020a622b880000b0290163c6fb0f2amr280260pfr.7.1603758971033; Mon, 26 Oct 2020 17:36:11 -0700 (PDT) Received: from [10.230.1.222] ([192.19.228.250]) by smtp.gmail.com with ESMTPSA id a11sm12698804pfn.125.2020.10.26.17.36.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Oct 2020 17:36:10 -0700 (PDT) Subject: Re: [PATCH v1 6/6] i2c: iproc: handle rx fifo full interrupt To: Rayagonda Kokatanur , Dhananjay Phadke Cc: Andy Shevchenko , BCM Kernel Feedback , Brendan Higgins , Florian Fainelli , linux-arm Mailing List , linux-i2c , Linux Kernel Mailing List , Lori Hikichi , Ray Jui , Scott Branden , Wolfram Sang References: <20201011182254.17776-7-rayagonda.kokatanur@broadcom.com> From: Ray Jui Message-ID: <94f8211d-1273-4c68-31e9-2f35f364e6c8@broadcom.com> Date: Mon, 26 Oct 2020 17:36:04 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="000000000000d0b4e405b29c3b54" Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --000000000000d0b4e405b29c3b54 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 10/26/2020 8:13 AM, Rayagonda Kokatanur wrote: > Hi Dhanajay, > > On Fri, Oct 23, 2020 at 11:12 PM Ray Jui wrote: >> >> >> >> On 10/12/2020 3:03 PM, Dhananjay Phadke wrote: >>> From: Rayagonda Kokatanur >>> >>> On Sun, 11 Oct 2020 23:52:54 +0530, Rayagonda Kokatanur wrote: >>>> Add code to handle IS_S_RX_FIFO_FULL_SHIFT interrupt to support >>>> master write request with >= 64 bytes. >>>> >>>> Iproc has a slave rx fifo size of 64 bytes. >>>> Rx fifo full interrupt (IS_S_RX_FIFO_FULL_SHIFT) will be generated >>>> when RX fifo becomes full. This can happen if master issues write >>>> request of more than 64 bytes. >>>> >>> >>> ARM cores run much faster than I2C bus, why would rx fifo go full when >>> rx interrupt is enabled and bytes are read out by bus driver isr? >>> Isn't fifo read pointer updated on these byte reads? >> >> Hi Rayagonda, >> >> Could you please reply on this question? For transactions > 64 bytes, do >> we batch until RX FIFO is full before we read out the data? > > Sorry I missed this question. > Yes with current design we are batching 64 bytes for translation > 64 bytes. > So we do batch the transfer and read them in one shot, and that's how the FIFO full interrupt is being utilized for. That sounds okay to me. Thanks, Ray > Best regards, > Rayagonda > > >> >> Thanks, >> >> Ray >> >>> Does controller stretch clock when rx fifo is full (e.g. kernel has >>> crashed, bus driver isn't draining fifo)? >>> --000000000000d0b4e405b29c3b54 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIIQMwYJKoZIhvcNAQcCoIIQJDCCECACAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg gg2IMIIE6DCCA9CgAwIBAgIOSBtqCRO9gCTKXSLwFPMwDQYJKoZIhvcNAQELBQAwTDEgMB4GA1UE CxMXR2xvYmFsU2lnbiBSb290IENBIC0gUjMxEzARBgNVBAoTCkdsb2JhbFNpZ24xEzARBgNVBAMT Ckdsb2JhbFNpZ24wHhcNMTYwNjE1MDAwMDAwWhcNMjQwNjE1MDAwMDAwWjBdMQswCQYDVQQGEwJC RTEZMBcGA1UEChMQR2xvYmFsU2lnbiBudi1zYTEzMDEGA1UEAxMqR2xvYmFsU2lnbiBQZXJzb25h bFNpZ24gMiBDQSAtIFNIQTI1NiAtIEczMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA tpZok2X9LAHsYqMNVL+Ly6RDkaKar7GD8rVtb9nw6tzPFnvXGeOEA4X5xh9wjx9sScVpGR5wkTg1 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