From mboxrd@z Thu Jan 1 00:00:00 1970 From: Govindraj Subject: Re: [PM][PATCH v3 2/4] OMAP3: Serial: Errata i202: fix for MDR1 access Date: Thu, 6 May 2010 15:24:43 +0530 Message-ID: References: <1271097933-22981-1-git-send-email-nm@ti.com> <87d3x9ykdf.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-qy0-f189.google.com ([209.85.221.189]:51072 "EHLO mail-qy0-f189.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757397Ab0EFJyo convert rfc822-to-8bit (ORCPT ); Thu, 6 May 2010 05:54:44 -0400 Received: by qyk27 with SMTP id 27so12037073qyk.23 for ; Thu, 06 May 2010 02:54:43 -0700 (PDT) In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Kattungal, Deepak" Cc: Kevin Hilman , "Menon, Nishanth" , linux-omap , "Raja, Govindraj" , Tero Kristo On Thu, May 6, 2010 at 5:49 AM, Kattungal, Deepak wro= te: > Hi Kevin, > > My Comments as below. > > Regards > Deepak > > -----Original Message----- > From: Kevin Hilman [mailto:khilman@deeprootsystems.com] > Sent: Wednesday, May 05, 2010 6:55 PM > To: Menon, Nishanth > Cc: linux-omap; Kattungal, Deepak; Raja, Govindraj; Tero Kristo > Subject: Re: [PM][PATCH v3 2/4] OMAP3: Serial: Errata i202: fix for M= DR1 access > > Nishanth Menon writes: > >> From: Deepak K >> >> Original patch: >> http://git.omapzoom.org/?p=3Dkernel/omap.git;a=3Dcommitdiff;h=3D42d4= a342c009bd9727c100abc8a4bc3063c22f0c >> >> Errata i202 (OMAP3430 - 1.12, OMAP3630 - 1.6): > > This workaround is currently done for all OMAPs. > > Presumably, this errata will eventually be fixed. =A0So, as with othe= r > errata fixes, we need some sort of SoC-rev based flag and the errata > workaround done based on that flag. > > Deepak : This would be a good fix, thanks for the suggestion. > > Also, shouldn't there be a fix for this in the 8250 and omap-serial > drivers too? > > > Deepak : The 8250 is not using the MDR Register. This would be needed= only by the omap-serial. The 8250 being a general driver we may not re= quire the access to MDR1 register. Hence the fix not required for 8250. > Why do you say this fix is not necessary for 8250? Isn't the omap_uart_reset configuring uart for 16x mode? Context save and restore is an common for whether it is 8250 or omap-se= rial.c The only difference here wrt to MDR and 8250 is -> MDR though not accesed by 8250 currently serial.c sets it to uart16x= mode. In omap-serial.c we configure MDR based on baudrate as we have an uart1= 3x mode which is ignored in 8250 and thus 8250 may not support 13x baud's corre= ctly which is taken care in omap-serial. I think this patch is fine and only concern is to make it applicable to appropriate socs as kevin said. --- Regards, Govindraj.R -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html