From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1426806AbcBRS2k (ORCPT ); Thu, 18 Feb 2016 13:28:40 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:47738 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423425AbcBRS2i (ORCPT ); Thu, 18 Feb 2016 13:28:38 -0500 Subject: Re: [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset To: Paul Walmsley , Sekhar Nori , Kishon Vijay Abraham I , 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> CC: Tony Lindgren , Bjorn Helgaas , , Russell King , , , From: Suman Anna Message-ID: <56C60D2D.2060108@ti.com> Date: Thu, 18 Feb 2016 12:27:57 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 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 On 02/18/2016 11:23 AM, Paul Walmsley wrote: > > On Thu, 18 Feb 2016, Sekhar Nori wrote: > >> On Friday 12 February 2016 10:50 PM, Suman Anna wrote: >>> Sekhar, >>> 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. Did you try the driver unbind/bind sequence a few times to > ensure that works, per Suman's earlier E-mail? Should work since the assert/deassert is now out of the driver probe/remove path and is done only at init time, but will let Sekhar confirm this. > > Suman, is there any further testing that you are planning to do on this > patch? No, nothing on my side, since this is now localized to PCIe and only on DRA7xx. I will relook at your custom flags solution when I consolidate the reset for OMAP IOMMUs and remoteprocs, that looks promising to remove the pdata quirks for resets or dependencies in drivers against a reset API. > > - Paul > > >> >> 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. Yep, this is what I had in mind. Glad that it resolves the issue. >> >> 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); Hmm, ignoring return values?? regards Suman >> + } >> + >> + return 0; >> +} >> + >> static struct omap_hwmod_class dra7xx_pciess_hwmod_class = { >> .name = "pcie", >> + .reset = dra7xx_pciess_reset, >> }; >> >> /* pcie1 */ >> -- >> 2.6.3 >> >> > > > - Paul >