From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754013AbdKMRHd (ORCPT ); Mon, 13 Nov 2017 12:07:33 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:30417 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753897AbdKMRHb (ORCPT ); Mon, 13 Nov 2017 12:07:31 -0500 Subject: Re: [PATCH v5 2/2] memory: ti-emif-sram: introduce relocatable suspend/resume handlers To: Russell King - ARM Linux Cc: Dave Gerlach , Tony Lindgren , Santosh Shilimkar , linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Keerthy J , Johan Hovold References: <20171013205915.9652-1-d-gerlach@ti.com> <20171013205915.9652-3-d-gerlach@ti.com> <19256977-40e1-a972-4de8-838a8da863cc@oracle.com> <20171110163922.GK28231@n2100.armlinux.org.uk> From: Santosh Shilimkar Organization: Oracle Corporation Message-ID: <2814bd15-d783-6e54-da0c-4b4ea0a31705@oracle.com> Date: Mon, 13 Nov 2017 09:07:33 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171110163922.GK28231@n2100.armlinux.org.uk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/10/2017 8:39 AM, Russell King - ARM Linux wrote: > On Mon, Oct 16, 2017 at 08:31:59AM -0700, Santosh Shilimkar wrote: >> Hi Russell, >> >> On 10/13/2017 1:59 PM, Dave Gerlach wrote: >>> Certain SoCs like Texas Instruments AM335x and AM437x require parts >>> of the EMIF PM code to run late in the suspend sequence from SRAM, >>> such as saving and restoring the EMIF context and placing the memory >>> into self-refresh. >>> >>> One requirement for these SoCs to suspend and enter its lowest power >>> mode, called DeepSleep0, is that the PER power domain must be shut off. >>> Because the EMIF (DDR Controller) resides within this power domain, it >>> will lose context during a suspend operation, so we must save it so we >>> can restore once we resume. However, we cannot execute this code from >>> external memory, as it is not available at this point, so the code must >>> be executed late in the suspend path from SRAM. >>> >>> This patch introduces a ti-emif-sram driver that includes several >>> functions written in ARM ASM that are relocatable so the PM SRAM >>> code can use them. It also allocates a region of writable SRAM to >>> be used by the code running in the executable region of SRAM to save >>> and restore the EMIF context. It can export a table containing the >>> absolute addresses of the available PM functions so that other SRAM >>> code can branch to them. This code is required for suspend/resume on >>> AM335x and AM437x to work. >>> >>> In addition to this, to be able to share data structures between C and >>> the ti-emif-sram-pm assembly code, we can automatically generate all of >>> the C struct member offsets and sizes as macros by processing >>> emif-asm-offsets.c into assembly code and then extracting the relevant >>> data as is done for the generated platform asm-offsets.h files. >>> >>> Signed-off-by: Dave Gerlach >>> --- >>> v4->v5: >>> * Simplify Makefile to generate include/generated/ti-emif-asm-offsets.h >>> >> If you are happy with this version from Dave, can I get your ack please? >> I can add this to the driver-soc then. > > Does it need my ack anymore? It doesn't touch anything in arch/arm. > If you still want it, then... notwithstanding the loss of type checking > that fncpy() gave and the new sram stuff messes up... > > Acked-by: Russell King > Thanks Russell !!