Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752206Ab2JANzq (ORCPT ); Mon, 1 Oct 2012 09:55:46 -0400 Received: from mail-ie0-f174.google.com ([209.85.223.174]:49419 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751694Ab2JANzo (ORCPT ); Mon, 1 Oct 2012 09:55:44 -0400 Date: Mon, 1 Oct 2012 09:56:03 -0400 From: Matt Porter To: Sekhar Nori Cc: Linux DaVinci Kernel List , Paul Walmsley , Russell King , Benoit Cousson , Tony Lindgren , Greg Kroah-Hartman , Linux Kernel Mailing List , "Hans J. Koch" , Linux OMAP List , Linux ARM Kernel List Subject: Re: [PATCH v2 4/7] ARM: davinci: Add support for an L3RAM gen_pool Message-ID: <20121001135603.GM5641@beef> References: <1348861072-14507-1-git-send-email-mporter@ti.com> <1348861072-14507-5-git-send-email-mporter@ti.com> <506986B2.1030000@ti.com> <20121001123242.GJ5641@beef> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121001123242.GJ5641@beef> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2807 Lines: 55 On Mon, Oct 01, 2012 at 08:32:42AM -0400, Matt Porter wrote: > On Mon, Oct 01, 2012 at 05:34:02PM +0530, Sekhar Nori wrote: > > Hi Matt, > > > > On 9/29/2012 1:07 AM, Matt Porter wrote: > > > L3RAM (shared SRAM) is needed for use by several drivers. > > > This creates a genalloc pool and a hook for the platform code > > > to provide the struct gen_pool * in platform data. > > > > > > Signed-off-by: Matt Porter > > > > I am not sure if any of the DaVinci devices have a need to allocate from > > *both* ARM RAM and shared RAM. Shared RAM is not present on all DaVinci > > devices AFAIR, and on DA850, there is just 8KB ARM RAM so I am not sure > > if there is much point in trying to allocate from there. > > > > Can you instead see if Ben's earlier patch[1] to use shared RAM for SRAM > > allocation on DA850 makes sense for your case? If yes, can you repost > > with Ben's patch included in your series instead of this patch? I would > > prefer that over creating a new pool for shared RAM. > > Hrm, I did look at Ben's earlier patch. The reason I added a separate > pool mostly was so I didn't have to touch the PM code at all. That can > continue using the private SRAM API with the ARM RAM as it is now. The > idea here was to allow that to be separate since no other bus masters > can access the ARM RAM anyway and do something that didn't require > regression testing PM. Also, I figured there's really no reason to use > even a tiny bit of the shared SRAM on PM if we have that ARM RAM there > and working fine for that use case. > > The other thing is that Ben's patch needs to be rewritten to at least > have the hook I added so we can provide the gen_pool in platform data. > If you prefer this path still, I can add the needed hook on top of his > original patch. Ultimately, I only *need* genalloc support for the > shared sram so I can remove the private SRAM API from uio_pruss...so I'm > happy with any way to get at it. > > Oh, and to be honest...it's not just for uio_pruss, but also to cleanly > remove the private SRAM API usage from the davinci ASoC driver too. [and replying to myself :)] Looking at the older parts (DM355/365/DM64xx) in more detail now, I see that to get rid of SRAM API in davinci ASoC, we'll have a similar hook to get the local ARM RAM gen_pool pointer necessary to support ping-pong to that pool since that's able to be accessed from EDMA on those parts. Ultimately, the approach is the same, it's just a matter of if we want to fully leverage both SRAM pools on DA850 and friends. -Matt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/