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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 CECF8C4360C for ; Tue, 8 Oct 2019 13:58:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B12542070B for ; Tue, 8 Oct 2019 13:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726293AbfJHN6k (ORCPT ); Tue, 8 Oct 2019 09:58:40 -0400 Received: from mga14.intel.com ([192.55.52.115]:2279 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725853AbfJHN6j (ORCPT ); Tue, 8 Oct 2019 09:58:39 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Oct 2019 06:58:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,270,1566889200"; d="scan'208";a="192581333" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga008.fm.intel.com with ESMTP; 08 Oct 2019 06:58:37 -0700 Received: from andy by smile with local (Exim 4.92.2) (envelope-from ) id 1iHq0a-0002EU-AO; Tue, 08 Oct 2019 16:58:36 +0300 Date: Tue, 8 Oct 2019 16:58:36 +0300 From: Andy Shevchenko To: Tuowen Zhao Cc: lee.jones@linaro.org, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com, acelan.kao@canonical.com, bhelgaas@google.com, kai.heng.feng@canonical.com, mcgrof@kernel.org Subject: Re: [PATCH v2] mfd: intel-lpss: use devm_ioremap_uc for MMIO Message-ID: <20191008135836.GL32742@smile.fi.intel.com> References: <20191007184231.13256-1-ztuowen@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191007184231.13256-1-ztuowen@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 07, 2019 at 12:42:31PM -0600, Tuowen Zhao wrote: > Some BIOS erroneously specifies write-combining BAR for intel-lpss-pci > in MTRR. This will cause the system to hang during boot. If possible, > this bug could be corrected with a firmware update. > > This patch adds devm_ioremap_uc as a new managed wrapper to ioremap_uc > and with it overwrite the MTRR settings to force the use of strongly > uncachable pages for intel-lpss. > > The BIOS bug is present on Dell XPS 13 7390 2-in-1: > > [ 0.001734] 5 base 4000000000 mask 6000000000 write-combining > > 4000000000-7fffffffff : PCI Bus 0000:00 > 4000000000-400fffffff : 0000:00:02.0 (i915) > 4010000000-4010000fff : 0000:00:15.0 (intel-lpss-pci) > Acked-by: Andy Shevchenko > Link: https://bugzilla.kernel.org/show_bug.cgi?id=203485 > Signed-off-by: Tuowen Zhao > --- > Changes from previous version: > > * changed commit message > > drivers/mfd/intel-lpss.c | 2 +- > include/linux/io.h | 2 ++ > lib/devres.c | 19 +++++++++++++++++++ > 3 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c > index bfe4ff337581..b0f0781a6b9c 100644 > --- a/drivers/mfd/intel-lpss.c > +++ b/drivers/mfd/intel-lpss.c > @@ -384,7 +384,7 @@ int intel_lpss_probe(struct device *dev, > if (!lpss) > return -ENOMEM; > > - lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET, > + lpss->priv = devm_ioremap_uc(dev, info->mem->start + LPSS_PRIV_OFFSET, > LPSS_PRIV_SIZE); > if (!lpss->priv) > return -ENOMEM; > diff --git a/include/linux/io.h b/include/linux/io.h > index accac822336a..a59834bc0a11 100644 > --- a/include/linux/io.h > +++ b/include/linux/io.h > @@ -64,6 +64,8 @@ static inline void devm_ioport_unmap(struct device *dev, void __iomem *addr) > > void __iomem *devm_ioremap(struct device *dev, resource_size_t offset, > resource_size_t size); > +void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset, > + resource_size_t size); > void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset, > resource_size_t size); > void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset, > diff --git a/lib/devres.c b/lib/devres.c > index 6a0e9bd6524a..beb0a064b891 100644 > --- a/lib/devres.c > +++ b/lib/devres.c > @@ -9,6 +9,7 @@ > enum devm_ioremap_type { > DEVM_IOREMAP = 0, > DEVM_IOREMAP_NC, > + DEVM_IOREMAP_UC, > DEVM_IOREMAP_WC, > }; > > @@ -39,6 +40,9 @@ static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset, > case DEVM_IOREMAP_NC: > addr = ioremap_nocache(offset, size); > break; > + case DEVM_IOREMAP_UC: > + addr = ioremap_uc(offset, size); > + break; > case DEVM_IOREMAP_WC: > addr = ioremap_wc(offset, size); > break; > @@ -68,6 +72,21 @@ void __iomem *devm_ioremap(struct device *dev, resource_size_t offset, > } > EXPORT_SYMBOL(devm_ioremap); > > +/** > + * devm_ioremap_uc - Managed ioremap_uc() > + * @dev: Generic device to remap IO address for > + * @offset: Resource address to map > + * @size: Size of map > + * > + * Managed ioremap_uc(). Map is automatically unmapped on driver detach. > + */ > +void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset, > + resource_size_t size) > +{ > + return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_UC); > +} > +EXPORT_SYMBOL(devm_ioremap_uc); > + > /** > * devm_ioremap_nocache - Managed ioremap_nocache() > * @dev: Generic device to remap IO address for > -- > 2.23.0 > -- With Best Regards, Andy Shevchenko