From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from co9outboundpool.messaging.microsoft.com (co9ehsobe004.messaging.microsoft.com [207.46.163.27]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 649232C013A for ; Tue, 16 Jul 2013 08:16:11 +1000 (EST) Date: Mon, 15 Jul 2013 17:15:58 -0500 From: Scott Wood Subject: Re: [PATCH] powerpc/fsl-booke: Work around erratum A-006958 To: Scott Wood References: <1373907234.8183.297@snotra> In-Reply-To: <1373907234.8183.297@snotra> (from scottwood@freescale.com on Mon Jul 15 11:53:54 2013) Message-ID: <1373926558.8183.317@snotra> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Cc: David Laight , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/15/2013 11:53:54 AM, Scott Wood wrote: > On 07/15/2013 03:45:36 AM, David Laight wrote: >> Also, if the high word changes, there is no need to loop. >> Just return the second value with a low word of zero >> (the returned count happened while the function was active). >=20 > That would be more complicated than looping. That said, it's since been confirmed internally that the low word =20 should always be zero when this happens, so we could share the Cell =20 workaround code -- as long as we do something special in the timebase =20 sync code so that we don't get stuck if the timebase happens to be =20 frozen with TBL=3D=3D0. This would avoid the need for scratch registers =20 (other than CR0). -Scott=