From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752016AbeDEN1K (ORCPT ); Thu, 5 Apr 2018 09:27:10 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:53568 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751233AbeDEN1F (ORCPT ); Thu, 5 Apr 2018 09:27:05 -0400 X-Google-Smtp-Source: AIpwx4/G52uu2CM+0kdcW3gpgf75Cpx/iGNqoB9r8eu49IRR5hEFYDU6eN5VOjxa9e/agxcsj+VJAw== Subject: Re: [PATCH] ata: ahci-platform: add reset control support To: Patrice CHOTARD , Thierry Reding , Kunihiko Hayashi , Tejun Heo , Matthias Brugger Cc: Rob Herring , Mark Rutland , "linux-ide@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mediatek@lists.infradead.org" References: <1521768653-11824-1-git-send-email-hayashi.kunihiko@socionext.com> <20180405095429.GA7506@ulmo> From: Hans de Goede Message-ID: <1f7d0738-1963-21c5-c293-e46fb0214ecf@redhat.com> Date: Thu, 5 Apr 2018 15:27:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 05-04-18 15:17, Patrice CHOTARD wrote: > Hi Thierry > > On 04/05/2018 11:54 AM, Thierry Reding wrote: >> On Fri, Mar 23, 2018 at 10:30:53AM +0900, Kunihiko Hayashi wrote: >>> Add support to get and control a list of resets for the device >>> as optional and shared. These resets must be kept de-asserted until >>> the device is enabled. >>> >>> This is specified as shared because some SoCs like UniPhier series >>> have common reset controls with all ahci controller instances. >>> >>> Signed-off-by: Kunihiko Hayashi >>> --- >>> .../devicetree/bindings/ata/ahci-platform.txt | 1 + >>> drivers/ata/ahci.h | 1 + >>> drivers/ata/libahci_platform.c | 24 +++++++++++++++++++--- >>> 3 files changed, 23 insertions(+), 3 deletions(-) >> >> This causes a regression on Tegra because we explicitly request the >> resets after the call to ahci_platform_get_resources(). > > I confirm, we got exactly the same behavior on STi platform. > >> >> From a quick look, ahci_mtk and ahci_st are in the same boat, adding the >> corresponding maintainers to Cc. >> >> Patrice, Matthias: does SATA still work for you after this patch? This >> has been in linux-next since next-20180327. > > SATA is still working after this patch, but a kernel warning is > triggered due to the fact that resets are both requested by > libahci_platform and by ahci_st driver. So in your case you might be able to remove the reset handling from the ahci_st driver and rely on the new libahci_platform handling instead? If that works that seems like a win to me. As said elsewhere in this thread I think it makes sense to keep (or re-add after a revert) the libahci_platform reset code, but make it conditional on a flag passed to ahci_platform_get_resources(). This way we get the shared code for most cases and platforms which need special handling can opt-out. Regards, Hans > > Patrice > >> >> Given how this is one of the more hardware-specific bits, perhaps a >> better way to do this is to move reset handling into a Uniphier driver >> much like Tegra, Mediatek and ST? >> >> That said, I don't see SATA support for any of the Socionext hardware >> either in the DT bindings or drivers/ata, so perhaps it'd be best to >> back this out again until we have something that's more well tested? >> >> Thierry