From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753053AbcEWGXD (ORCPT ); Mon, 23 May 2016 02:23:03 -0400 Received: from arroyo.ext.ti.com ([198.47.19.12]:39308 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752879AbcEWGXA (ORCPT ); Mon, 23 May 2016 02:23:00 -0400 Subject: Re: [RFC PATCH 2/3] mmc: host: omap_hsmmc: Enable ADMA2 To: Felipe Balbi , Tony Lindgren , Peter Ujfalusi References: <1463561115-31798-1-git-send-email-kishon@ti.com> <1463561115-31798-3-git-send-email-kishon@ti.com> <20160518193028.GT5995@atomide.com> <0d463add-9fa5-a768-2ba6-34c4126c7817@ti.com> <20160519145745.GU5995@atomide.com> <87shxdlws6.fsf@linux.intel.com> CC: , , , , , , , , , , , , , , From: Kishon Vijay Abraham I Message-ID: <5742A189.4060803@ti.com> Date: Mon, 23 May 2016 11:52:01 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <87shxdlws6.fsf@linux.intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Felipe, On Friday 20 May 2016 12:06 AM, Felipe Balbi wrote: > > Hi, > > Tony Lindgren writes: >> * Peter Ujfalusi [160519 01:10]: >>> On 05/18/2016 10:30 PM, Tony Lindgren wrote: >>>> Ideally the adma support would be a separate loadable module, >>>> similar how the cppi41dma is a child of the OTG controller. >>> >>> The Master DMA is part of the hsmmc IP block. If the same ADMA module is >>> present on other IPs it might be beneficial to have a helper library to handle >>> it (allocating the descriptor pool, wrinting, updating descriptors, etc). >> >> OK. Yeah if it's part of the MMC controller it makes no sense to >> separate it. So then the conecrns are using alternate DMA >> implementations and keeping PM runtime working :) >> >> BTW, Felipe mentioned that the best thing to do in the long run would >> be to set up sdhci-omap.c operating in ADMA mode. >> >> Felipe, care to summarize what you had in mind? > > yeah, just write a new sdhci-omap.c to start moving away from > omap-hsmmc.c, just like it was done for 8250-omap. > > At the beginning, it could be just the bare minimum to get it working > and slowly move over stuff like pm runtime, dmaengine, PIO. Move more > platforms over to that driver and, eventually, get rid of omap-hsmmc.c > altogether. > > That way, development can be focussed on generic layers (SDHCI) to which > OMAP MMC controller is compliant (apart from the VERSION register > quirk). About an year back, when I tried using SDHCI for OMAP I ran into issues and was not able to get it working. IIRC SDHCI_PRESENT_STATE (or OMAP_HSMMC_PSTATE) was not showing the correct state for card present and is unable to raise an interrupt when a card is inserted. I didn't debug this further. It also kept me wondering why gpio interrupt was always used for card detect instead of using mmci_sdcd line of the controller. Thanks Kishon