From owner-freebsd-mips@FreeBSD.ORG Sun Oct 6 04:15:38 2013 Return-Path: Delivered-To: freebsd-mips@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 838FE649 for ; Sun, 6 Oct 2013 04:15:38 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-ie0-f179.google.com (mail-ie0-f179.google.com [209.85.223.179]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 44B9D25A1 for ; Sun, 6 Oct 2013 04:15:37 +0000 (UTC) Received: by mail-ie0-f179.google.com with SMTP id e14so12275435iej.24 for ; Sat, 05 Oct 2013 21:15:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=HThZfqvNLVRoG+TzEW2KeGGGbkJCettBc6uvmn/KHeQ=; b=ge1wZxf+c9KvqbY0psCml2ANUSPFVlKunE7AC5nwy6MCg2sDkDIt786Q0PKjS6JOEL dNr3YuNrnsGBZUJppJW2tR9a6IkWKeJWxUxKNpTjzFEz2DITe+VRkEtvl+Rah6MvQg0X M3EQlrav5tbPxihBHpxYGj3/i2zJPCgOCUQmyHNH4Npml57ugcA6LBZt6hQMYm/gX6D3 pZE+rTx4soG7kOhEsiBDFXOhp79hs6BQa6bq7jXmqmQhN7mtFwuHMC1pwjueT/uX0E4d hQp3vyQtoT+eAKzdFp1F3lOkIScT5fgUrxA9rCtf4PQv4rVScYTZ57/ZMqTHk7RWH4Kf N17A== X-Gm-Message-State: ALoCoQkeXwyLd28bM+GuKu8xWorScMfbxsJ4v1Ovqx35dllOf3sl9XE4d8aZPgF/7ApGYb7fR0aP X-Received: by 10.50.26.36 with SMTP id i4mr12143551igg.33.1381032931222; Sat, 05 Oct 2013 21:15:31 -0700 (PDT) Received: from 53.imp.bsdimp.com (50-78-194-198-static.hfc.comcastbusiness.net. [50.78.194.198]) by mx.google.com with ESMTPSA id p7sm18251725iga.3.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 05 Oct 2013 21:15:30 -0700 (PDT) Sender: Warner Losh Subject: Re: How's bus-space stuff supposed to work with superscalar MIPS? Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Warner Losh In-Reply-To: Date: Sat, 5 Oct 2013 22:15:29 -0600 Content-Transfer-Encoding: quoted-printable Message-Id: <0ED4F6A1-458A-474F-97F1-488336AB9A4D@bsdimp.com> References: To: Adrian Chadd X-Mailer: Apple Mail (2.1085) Cc: "freebsd-mips@freebsd.org" X-BeenThere: freebsd-mips@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to MIPS List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Oct 2013 04:15:38 -0000 On Oct 5, 2013, at 11:18 AM, Adrian Chadd wrote: > Hi all, >=20 > I've been bringing up the AR9344 PHY and after a lot of digging, I > discovered that I can fix things by changing ARGE_WRITE() (ie, write = to the > ethernet space registers) to: >=20 > bus_write_4(); > bus_read_4(); >=20 > .. to (what I'm guessing here) flush the write out before the next > instruction is run. read after write ensures that the write is flushed by definition. > So, given this particular hilarity has shown up, what's the story with > doing IO accesses on a superscalar MIPS CPU? If it's going to kseg1, = is it > somehow going to magically enforce ordering? Or am I right in thinking = we > will need explicit barriers here? If you are on a super-scalor architecture, then you'll need memory = barriers. It doesn't look like we've implemented them just yet. > I'd like to sneak this into the initial mips74k bringup support that = I'm > going to commit to -HEAD soon. Sneak what in? Warner > Thanks, >=20 >=20 > -adrian > _______________________________________________ > freebsd-mips@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-mips > To unsubscribe, send any mail to = "freebsd-mips-unsubscribe@freebsd.org"