From owner-freebsd-arm@freebsd.org Wed Sep 30 22:40:12 2020 Return-Path: Delivered-To: freebsd-arm@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C9294432B0F for ; Wed, 30 Sep 2020 22:40:12 +0000 (UTC) (envelope-from marklmi@yahoo.com) Received: from sonic303-25.consmr.mail.gq1.yahoo.com (sonic303-25.consmr.mail.gq1.yahoo.com [98.137.64.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4C1rmq6PkFz3d4w for ; Wed, 30 Sep 2020 22:40:11 +0000 (UTC) (envelope-from marklmi@yahoo.com) X-YMail-OSG: RiZbZswVM1kqYZpqFPhhDKN1gxC8UCuj31_crPr7AciRa0rGhimaLynmi0SLpu3 SJpjONPNdbo0d4kKC8y_tEGccnuVkTjG8ldr8nd1dZ0u6pVn1kwekQwTBVzWnX9yhE3c8zeD49K3 tnErHEvsax9VO4GX7dEMBoYYY1YkOhEn7_nkiutQMetD8GtCybEwLWvwchKfpGCFpKF5Ro3xbvLg LrlhsUDty_YMgtZ9Byi1IfswUlmJm3G_n4OBlB3HCSjgceQ3GhzKG8T5N2XpZ2Z6LrXhF_Zz1RBW H4HIpffNgV6HDgp0KWTLHtsixvrja61c6od33TfUYEn3kZ3TraIoPKAr4nuSo1fMZWf2bSL7F0EB UsbnHC5AmQIPF4P7EZJgU6WX882sC_GPgffy6EW8okJLn9WXyfN6nE5P8oB09HYNBeDEbn5Q0775 pK7G0wy.NGSSKw72h4xP8tX0ctZoZu9YG0RbpEOvK0SFJU_CYvxzuoBUCl3CErqMW8VVcQY_xDWM DRZLTY3pv5QlylJt_jkMoFwt8fQN_3UEGpm5pLr0OQmUuAS7ptmrh4HEmCcomQxPOjzBJEas8OoB 8ErJRy5w1d9Vn7YBhWZy2b664IgYm6PEUKvyC_IZl1npbi0BHZSjX6eUYiLv8qbA7svIxpXUnw.v zp6AYvfCVDe.NctRWcWH7NTH7aOZbj8ywR.mzjsCc70DEiL9.smTZ9qS98rCBbHqkorCpnjTjKoR FbYWybv1.5WL1ZH4nt4q1Qn8QqoWrZbbGTJ.umB9Sxm_EE1WNW489HhbiAVsYpyj6eHtUGv_kCTW VaY3daPCqLoR2q8EMmOG0QKp4woi3qELm8jDR0KxJVN90TK.Biy9yh5z57xagIS8PQdVYffbOpUu 3GkiPEUg2kgOOo2Q5h.nZS40mCrJuFHBI8bwn.ngFpxY8ZYIikfX2p8ZUR1o3Trn950S6MbyVTR9 EvPn0zUbox.i3sacHgHHh89k7SDUF3ZmUtmexdH2nMhFDZDe815DUDIqE.sv640pXHjP.AJFp_ga U9gXqsIQoYAQKN7c1IFbOWwi8PDu4FlL7QYqopZ2RILJTwcwPgTuYfWDlWN7cfwoGe4360Yd.ge2 7Rq7ij5XhhnEhMHt14X_6UtzErPXM6q9T3QzlO1AYHa45eVuPX137zoECPHNg24CPfPgc2rIF_Ep tczCD.KZnSNhlPW5oZMQdGekFrJGYoyqmf2Q3LQRVpS213gzGeNh2Exf.wsPB8OC6v.8jr65eHJ3 ugzrqvz71CVH5C4lp8Hl3eiEvQRMAtOQLCMEdeLMQyB.MEnzp0FKJinf3QQGm3tZ6aK_6uL1u8fM FGwyxxslcVPzAl72eIdwOUB.g2vKxz7f6i.y_qTZQDnYPggofkPcJklt0uxYjX3mfA9PQ4A7Ddjd 3F_f0GlsTO.T9Rhfu9dXiFv19dMbmuI9itSjdC9bpT11LG8PtHATSzPXoUTiJSHL.heatfVpRgux dJAcE58ZVNCaDJkoOtn_uY3YgNCYrdmF9syiyegRLHYY_qxtmsPfLIWe3XuJeOU5P2FlqsNv7NlG QVYr3PWgYaU4KkZwBLbsnKzmRW678Gd8BdPtT Received: from sonic.gate.mail.ne1.yahoo.com by sonic303.consmr.mail.gq1.yahoo.com with HTTP; Wed, 30 Sep 2020 22:40:10 +0000 Received: by smtp407.mail.bf1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 87a43b783f74bd1860a62052778f512d; Wed, 30 Sep 2020 22:40:07 +0000 (UTC) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.1\)) Subject: Re: RPi4B's DMA11 (DMA4 engine example) vs. xHCI/pcie From: Mark Millard In-Reply-To: Date: Wed, 30 Sep 2020 15:40:06 -0700 Cc: freebsd-arm Content-Transfer-Encoding: quoted-printable Message-Id: <93A90975-39F1-4DA3-87E0-89E07505108A@yahoo.com> References: <8C6DE44F-6CE2-4C74-8748-3BBFB54AE183@yahoo.com> <0FE382AB-8DE3-4467-9CB0-E8582AC70EA2@yahoo.com> <85FEDC51-B5B0-4ED4-A5ED-62B63EF9D5A8@yahoo.com> <903FE769-ED46-4FBC-A272-4D2C89A9CD7A@yahoo.com> To: Robert Crowston X-Mailer: Apple Mail (2.3608.120.23.2.1) X-Rspamd-Queue-Id: 4C1rmq6PkFz3d4w X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.28 / 15.00]; FREEMAIL_FROM(0.00)[yahoo.com]; MV_CASE(0.50)[]; R_SPF_ALLOW(-0.20)[+ptr:yahoo.com]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[yahoo.com:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[yahoo.com,reject]; NEURAL_HAM_SHORT(-0.74)[-0.745]; FREEMAIL_TO(0.00)[protonmail.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[yahoo.com]; ASN(0.00)[asn:36647, ipnet:98.137.64.0/20, country:US]; MID_RHS_MATCH_FROM(0.00)[]; DWL_DNSWL_NONE(0.00)[yahoo.com:dkim]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.03)[-1.025]; R_DKIM_ALLOW(-0.20)[yahoo.com:s=s2048]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.01)[-1.011]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[98.137.64.206:from]; RWL_MAILSPIKE_POSSIBLE(0.00)[98.137.64.206:from]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[freebsd-arm] X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Sep 2020 22:40:12 -0000 On 2020-Sep-30, at 14:15, Robert Crowston = wrote: > Very interesting analysis. Certainly uncovered a few things I wasn't = aware of. >=20 > By default sc->sc_bus.dma_bits in xhci_init is 64 bits; I toggle it = back to 32 bits in the xhci shim I wrote for the Pi 4. You can see that = output in a verbose dmesg. >=20 My biggest worry from all that material, for things as they currently are, is that it appears that FreeBSD could try to use a RPi4B DMA LITE engine but not follow its limitations when doing so. For example, ending up using a smaller size DMA transfer than intended (just 16 bits for size). (Other RPi's might have the same issue?) =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)