From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C50D5ECDE44 for ; Tue, 30 Oct 2018 07:55:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99E5B2082D for ; Tue, 30 Oct 2018 07:55:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 99E5B2082D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726731AbeJ3Qri (ORCPT ); Tue, 30 Oct 2018 12:47:38 -0400 Received: from mga17.intel.com ([192.55.52.151]:43354 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726523AbeJ3Qri (ORCPT ); Tue, 30 Oct 2018 12:47:38 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Oct 2018 00:55:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,443,1534834800"; d="scan'208";a="275599471" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.130]) ([10.237.72.130]) by fmsmga005.fm.intel.com with ESMTP; 30 Oct 2018 00:55:12 -0700 Subject: Re: [PATCH v2] mmc: sdhci-pci: Try "cd" for card-detect lookup before using NULL To: Rajat Jain , Ulf Hansson , linux-mmc@vger.kernel.org, Linus Walleij , Rajat Jain , Linux Kernel Mailing List , Mika Westerberg , Andy Shevchenko , Dmitry Torokhov , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, Andy Shevchenko References: <20181029221701.51376-1-rajatja@google.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <79f9fb1f-9318-6265-d642-11d57719f287@intel.com> Date: Tue, 30 Oct 2018 09:53:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181029221701.51376-1-rajatja@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/10/18 12:17 AM, Rajat Jain wrote: > Problem: > > The card detect IRQ does not work with modern BIOS (that want > to use _DSD to provide the card detect GPIO to the driver). > > Details: > > The mmc core provides the mmc_gpiod_request_cd() API to let host drivers > request the gpio descriptor for the "card detect" pin. > This pin is specified in the ACPI for the SDHC device: > > * Either as a resource using _CRS. This is a method used by legacy BIOS. > (The driver needs to tell which resource index). > > * Or as a named property ("cd-gpios"/"cd-gpio") in _DSD (which internally > points to an entry in _CRS). This way, the driver can lookup using a > string. This is what modern BIOS prefer to use. > > This API finally results in a call to the following code: > > struct gpio_desc *acpi_find_gpio(..., const char *con_id,...) > { > ... > /* Lookup gpio (using "-gpio") in the _DSD */ > ... > if (!acpi_can_fallback_to_crs(adev, con_id)) > return ERR_PTR(-ENOENT); > ... > /* Falling back to _CRS is allowed, Lookup gpio in the _CRS */ > ... > } > > Note that this means that if the ACPI has _DSD properties, the kernel > will never use _CRS for the lookup (Because acpi_can_fallback_to_crs() > will always be false for any device hat has _DSD entries). > > The SDHCI driver is thus currently broken on a modern BIOS, even if > BIOS provides both _CRS (for index based lookup) and _DSD entries (for > string based lookup). Ironically, none of these will be used for the > lookup currently because: > > * Since the con_id is NULL, acpi_find_gpio() does not find a matching > entry in DSDT. (The _DSDT entry has the property name = "cd-gpios") > > * Because ACPI contains DSDT entries, thus acpi_can_fallback_to_crs() > returns false (because device properties have been populated from > _DSD), thus the _CRS is never used for the lookup. > > Fix: > > Try "cd" for lookup in the _DSD before falling back to using NULL so > as to try looking up in the _CRS. > > I've tested this patch successfully with both Legacy BIOS (that > provide only _CRS method) as well as modern BIOS (that provide both > _CRS and _DSD). Also the use of "cd" appears to be fairly consistent > across other users of this API (other MMC host controller drivers). > > Link: https://lkml.org/lkml/2018/9/25/1113 > Signed-off-by: Rajat Jain This is good enough for a fix. An ACPI GPIO mappings table can be done later. Acked-by: Adrian Hunter > --- > v2: Fix the commit log to take care of Andy's comments. > > drivers/mmc/host/sdhci-pci-core.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c > index 7bfd366d970d..e53333c695b3 100644 > --- a/drivers/mmc/host/sdhci-pci-core.c > +++ b/drivers/mmc/host/sdhci-pci-core.c > @@ -1762,8 +1762,13 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot( > device_init_wakeup(&pdev->dev, true); > > if (slot->cd_idx >= 0) { > - ret = mmc_gpiod_request_cd(host->mmc, NULL, slot->cd_idx, > + ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx, > slot->cd_override_level, 0, NULL); > + if (ret && ret != -EPROBE_DEFER) > + ret = mmc_gpiod_request_cd(host->mmc, NULL, > + slot->cd_idx, > + slot->cd_override_level, > + 0, NULL); > if (ret == -EPROBE_DEFER) > goto remove; > >