From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCHv3 4/9] ARM: OMAP2+: AM33XX: Reserve memory to comply with EMIF spec Date: Thu, 08 Aug 2013 11:16:44 -0700 Message-ID: <87fvukhwtv.fsf@kernel.org> References: <1375811376-49985-1-git-send-email-d-gerlach@ti.com> <1375811376-49985-5-git-send-email-d-gerlach@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-pb0-f41.google.com ([209.85.160.41]:53100 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758083Ab3HHSQs (ORCPT ); Thu, 8 Aug 2013 14:16:48 -0400 Received: by mail-pb0-f41.google.com with SMTP id rp2so3653056pbb.28 for ; Thu, 08 Aug 2013 11:16:48 -0700 (PDT) In-Reply-To: <1375811376-49985-5-git-send-email-d-gerlach@ti.com> (Dave Gerlach's message of "Tue, 6 Aug 2013 12:49:31 -0500") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Dave Gerlach Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, Paul Walmsley , Vaibhav Bedia Dave Gerlach writes: > From: Vaibhav Bedia > > SDRAM controller on AM33XX requires that a modification of certain > bit-fields in PWR_MGMT_CTRL register (ref. section 7.3.5.13 in > AM335x-Rev H) is followed by a dummy read access to SDRAM. This > scenario arises when entering a low power state like DeepSleep. > To ensure that the read is not from a cached region we reserve > some memory during bootup using the arm_memblock_steal() API. Hmm, sounds to me an awful lot like the existing omap_bus_sync() ? However, you remove that feature when you remove omap_reserve() here becasue omap_reserve() ss not called from your new reserve function. Are you *really* sure you don't need the functions called there? This is a pretty big change that's not mentioned anywhere in the changelog. Kevin From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@linaro.org (Kevin Hilman) Date: Thu, 08 Aug 2013 11:16:44 -0700 Subject: [PATCHv3 4/9] ARM: OMAP2+: AM33XX: Reserve memory to comply with EMIF spec In-Reply-To: <1375811376-49985-5-git-send-email-d-gerlach@ti.com> (Dave Gerlach's message of "Tue, 6 Aug 2013 12:49:31 -0500") References: <1375811376-49985-1-git-send-email-d-gerlach@ti.com> <1375811376-49985-5-git-send-email-d-gerlach@ti.com> Message-ID: <87fvukhwtv.fsf@kernel.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Dave Gerlach writes: > From: Vaibhav Bedia > > SDRAM controller on AM33XX requires that a modification of certain > bit-fields in PWR_MGMT_CTRL register (ref. section 7.3.5.13 in > AM335x-Rev H) is followed by a dummy read access to SDRAM. This > scenario arises when entering a low power state like DeepSleep. > To ensure that the read is not from a cached region we reserve > some memory during bootup using the arm_memblock_steal() API. Hmm, sounds to me an awful lot like the existing omap_bus_sync() ? However, you remove that feature when you remove omap_reserve() here becasue omap_reserve() ss not called from your new reserve function. Are you *really* sure you don't need the functions called there? This is a pretty big change that's not mentioned anywhere in the changelog. Kevin