From owner-freebsd-arm@FreeBSD.ORG Mon Dec 3 16:17:43 2012 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id E5198446 for ; Mon, 3 Dec 2012 16:17:42 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-ia0-f169.google.com (mail-ia0-f169.google.com [209.85.210.169]) by mx1.freebsd.org (Postfix) with ESMTP id 9838A8FC08 for ; Mon, 3 Dec 2012 16:17:42 +0000 (UTC) Received: by mail-ia0-f169.google.com with SMTP id r4so2679510iaj.14 for ; Mon, 03 Dec 2012 08:17:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=sender:subject:mime-version:content-type:from:x-priority :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to:x-mailer:x-gm-message-state; bh=wm/hFb74cxc1oWXCTWhJYC3+N8rW6ObPO31csB/+CoQ=; b=jiG7ebMI95K6pEn6gTRZU5oKJtl3R9lNoVl+OiVsQTtbS6UGaai5ahm+TobodTlG4e Jwr1SEYSQAtrI/d2WwsKOxevOQEha7H+nChEJVQYYjsAP+aSi461pPlAyPknhUVc3kdJ jOHffmsyARZlo9V2IW/09Omvv0/2Q3iQRIdG79JX75qmyOAvB1NvckLZjf2E5/cHk5sJ E8J+WAfDsOY85jvMHEGrZ7JT5yLdXpZAGGWQjmGvSGHXe12MSP+nFVkWft1bQkbJ+W6V YEvMKV+MIAqOd+V4T386kuW6AVZoGkNSMxzgRmpHzlW9jFeIgtNNtW5cS2uFL4Xukdnf rTUg== Received: by 10.50.150.175 with SMTP id uj15mr6593163igb.52.1354551456201; Mon, 03 Dec 2012 08:17:36 -0800 (PST) Received: from 53.imp.bsdimp.com (50-78-194-198-static.hfc.comcastbusiness.net. [50.78.194.198]) by mx.google.com with ESMTPS id 10sm7364613ign.5.2012.12.03.08.17.33 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 03 Dec 2012 08:17:34 -0800 (PST) Sender: Warner Losh Subject: Re: FreeBSD on Raspberry Pi 512MB (with U-Boot + ubldr) Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Warner Losh X-Priority: 3 In-Reply-To: Date: Mon, 3 Dec 2012 09:17:31 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: <18DB98C9-66D9-4B00-989A-156F21E9981C@bsdimp.com> References: <3988C1622A974F19A9D3888F0334FF10@ad.peach.ne.jp> <50B8058C.9030909@bluezbox.com> To: "Daisuke Aoyama" X-Mailer: Apple Mail (2.1085) X-Gm-Message-State: ALoCoQmwd7X2nW2x8RqiaJViAp4jtG+9Mnp+T9x2SqGwRxcs0LlHK7LFuKv4P+TtFaeoUVyuORmS Cc: freebsd-arm@freebsd.org, Ralf.Wenk@hs-karlsruhe.de X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Dec 2012 16:17:43 -0000 On Dec 3, 2012, at 7:51 AM, Daisuke Aoyama wrote: >>>> BTW, SDHCI is not yet stable? >>>=20 >>> There is one issue with setting SDHCI clock. I'll commit fix later = today. >>=20 >>=20 >> I like to share some information about the SD card reading speed. >>=20 >> While exchanging the old boot sequence with then new one I once = booted >> with the new boot sequence but without an /boot/loader.rc file. >>=20 >> The reading speed achieved with >> dd if=3D/dev/mmcsd0 of=3D/dev/null bs=3D1m count=3D100 >> from the SD card was 10 Mbyte/sec. >>=20 >> After creating the file with "echo 'fdt addr 0x100' > = /boot/loader.rc" >> and rebooting the reading speed achieved from the SD card was down to >> 2.8 Mbyte/sec. >>=20 >> Although the SDHCI frequency was shown on the second boot as double = high as >> on the first (100MHz versus 50MHz) the reading speed was much lower. >> I think the cause was the mmcsd bus bit width which was reported as 4 = at >> the first and as 1 at the second boot. >=20 > At this time, it must be 50. if use 100MHz, some cards cant be used = anymore. > Howerver, probably 4bit transfer is OK. 33MHz is the top speed for SD cards. There's an extension to make them = go as fast as 50MHz. Most SD cards cope at 50MHz without enabling the = extension and even more when enabled. The current common code tries to = enable things properly, but relies on the host bridge adapter driver to = set the clock properly... There may be some cruft here left over from = the early Atmel legacy where the datasheet gave somewhat aggressive = advise.. 100MHz at one bit is 100Mbps. 50MHz 4 bit is 200Mbps. I gotta get a pi to play around with this :) Warner=