From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756515AbcBXGWA (ORCPT ); Wed, 24 Feb 2016 01:22:00 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:34458 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750808AbcBXGV7 (ORCPT ); Wed, 24 Feb 2016 01:21:59 -0500 Subject: Re: [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset To: Paul Walmsley References: <1452780672-14339-1-git-send-email-kishon@ti.com> <1452780672-14339-4-git-send-email-kishon@ti.com> <20160127173104.GQ19432@atomide.com> <56A90971.4020409@ti.com> <20160127185649.GV19432@atomide.com> <56A94FB7.6020903@ti.com> <20160128183156.GH19432@atomide.com> <56B087AD.4000505@ti.com> <56B900E9.9040306@ti.com> <56BA2495.9020407@ti.com> <56BA958A.1020503@ti.com> <56BACCDB.2070507@ti.com> <56BD8091.4090007@ti.com> <56BE1454.3030002@ti.com> <56C5D377.50901@ti.com> <56CAA82D.6000507@ti.com> <56CADB23.8020202@ti.com> <56CC490F.3040301@ti.com> CC: Sekhar Nori , Suman Anna , , Tony Lindgren , Bjorn Helgaas , , Russell King , , , From: Kishon Vijay Abraham I Message-ID: <56CD4BE1.3010701@ti.com> Date: Wed, 24 Feb 2016 11:51:21 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: 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 Paul, On Tuesday 23 February 2016 11:58 PM, Paul Walmsley wrote: > Kishon > > On Tue, 23 Feb 2016, Kishon Vijay Abraham I wrote: > >> On Monday 22 February 2016 03:25 PM, Kishon Vijay Abraham I wrote: >>> On Monday 22 February 2016 12:01 PM, Paul Walmsley wrote: >>>> On Mon, 22 Feb 2016, Kishon Vijay Abraham I wrote: >>>>> On Thursday 18 February 2016 07:51 PM, Sekhar Nori wrote: >>>>>> On Friday 12 February 2016 10:50 PM, Suman Anna wrote: >>>>>>> Will you be following up with above suggestion since Kishon is gonna be out? >>>>>> >>>>>> Alright, noticed this action for me :) Went through the thread, and >>>>>> looks like this is what we want to see? >>>>>> >>>>>> Thanks, >>>>>> Sekhar >>>>>> >>>>>> ---8<--- >>>>>> From e3ba368f2235e1bf38a22ba8ea4e5c12aaafda19 Mon Sep 17 00:00:00 2001 >>>>>> Message-Id: >>>>>> From: Sekhar Nori >>>>>> Date: Thu, 18 Feb 2016 16:49:56 +0530 >>>>>> Subject: [PATCH 1/1] ARM: DRA7: hwmod: Add custom reset handler for PCIeSS >>>>>> >>>>>> Add a custom reset handler for DRA7x PCIeSS. This >>>>>> handler is required to deassert PCIe hardreset lines >>>>>> after they have been asserted. >>>>>> >>>>>> This enables the PCIe driver to access registers after >>>>>> PCIeSS has been runtime enabled without having to >>>>>> deassert hardreset lines itself. >>>>>> >>>>>> With this patch applied, used lspci to make sure >>>>>> connected PCIe device enumerates on DRA74x and DRA72x >>>>>> EVMs. >>>>>> >>>>>> Signed-off-by: Sekhar Nori >>>>>> --- >>>>>> Applies to tag for-v4.6/omap-hwmod-a of Paul W's tree. >>>>>> >>>>>> arch/arm/mach-omap2/omap_hwmod_7xx_data.c | 23 +++++++++++++++++++++++ >>>>>> 1 file changed, 23 insertions(+) >>>>>> >>>>>> diff --git a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c >>>>>> index b61355e2a771..252b74633e31 100644 >>>>>> --- a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c >>>>>> +++ b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c >>>>>> @@ -1526,8 +1526,31 @@ static struct omap_hwmod dra7xx_ocp2scp3_hwmod = { >>>>>> * >>>>>> */ >>>>>> >>>>>> +/* >>>>>> + * As noted in documentation for _reset() in omap_hwmod.c, the stock reset >>>>>> + * functionality of OMAP HWMOD layer does not deassert the hardreset lines >>>>>> + * associated with an IP automatically leaving the driver to handle that >>>>>> + * by itself. This does not work for PCIeSS which needs the reset lines >>>>>> + * deasserted for the driver to start accessing registers. >>>>>> + * >>>>>> + * We use a PCIeSS HWMOD class specific reset handler to deassert the hardreset >>>>>> + * lines after asserting them. >>>>>> + */ >>>>>> +static int dra7xx_pciess_reset(struct omap_hwmod *oh) >>>>>> +{ >>>>>> + int i; >>>>>> + >>>>>> + for (i = 0; i < oh->rst_lines_cnt; i++) { >>>>>> + omap_hwmod_assert_hardreset(oh, oh->rst_lines[i].name); >>>>>> + omap_hwmod_deassert_hardreset(oh, oh->rst_lines[i].name); >>>>>> + } >>>>>> + >>>>>> + return 0; >>>>>> +} >>>>>> + >>>>>> static struct omap_hwmod_class dra7xx_pciess_hwmod_class = { >>>>>> .name = "pcie", >>>>>> + .reset = dra7xx_pciess_reset, >>>>>> }; >>>>> >>>>> Thanks for the patch. >>>> >>>> Could you please test the bind/unbind functionality just to make sure it >>>> works? >>> >>> The pci-dra7xx driver neither expose the bind/unbind sysfs entry nor can be >>> built as module. >>> >>> However I hacked the pci-dra7xx driver to be built as module [and reverted >>> Commit 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe error >>> and driver unbind")] and I don't see an abort when the PCI registers are >>> accessed after rmmod/modprobe cycle (that was the issue that Sekhar's patch >>> tried to solve). However PCI as such doesn't work after rmmod/modprobe cycle >>> [1], but this is a different issue most likely in PCIe core and has to debugged. >>> >>> In summary, there are other issues in PCI across rmmod/modprobe cycle but the >>> reset of pci-dra7xx happens fine with this patch. >> >> Do you expect any other testing from me? > > No I think that's sufficient for the time being, thanks - but, two > questions: > > 1. Can I add your Tested-by: ? sure.. Tested-by: Kishon Vijay Abraham I > > 2. Are you going to follow up with these PCIe core issues with the PCIe > core developers? yeah, I see efforts have already started to convert the PCI drivers from built-in to module [1] and issues arising out of that will be debugged. Thanks Kishon [1] -> http://lkml.iu.edu/hypermail/linux/kernel/1602.0/06011.html > > > - Paul >