Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933857AbbBCLiK (ORCPT ); Tue, 3 Feb 2015 06:38:10 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:40788 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932312AbbBCLiD (ORCPT ); Tue, 3 Feb 2015 06:38:03 -0500 Date: Tue, 3 Feb 2015 11:37:44 +0000 From: Catalin Marinas To: "hanjun.guo@linaro.org" Cc: "Rafael J. Wysocki" , Olof Johansson , Arnd Bergmann , Mark Rutland , "grant.likely@linaro.org" , Will Deacon , Lorenzo Pieralisi , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , Ashwin Chaugule , "suravee.suthikulpanit@amd.com" , Mark Langsdorf , "wangyijing@huawei.com" , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" , "msalter@redhat.com" Subject: Re: [PATCH v8 02/21] acpi: fix acpi_os_ioremap for arm64 Message-ID: <20150203113744.GA3677@e104818-lin.cambridge.arm.com> References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-3-git-send-email-hanjun.guo@linaro.org> <2422968.Es7R0p3loO@vostro.rjw.lan> <54D0901A.2080406@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <54D0901A.2080406@linaro.org> Thread-Topic: [PATCH v8 02/21] acpi: fix acpi_os_ioremap for arm64 Accept-Language: en-GB, en-US Content-Language: en-US User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2591 Lines: 68 On Tue, Feb 03, 2015 at 09:08:42AM +0000, Hanjun Guo wrote: > On 2015年02月03日 06:14, Rafael J. Wysocki wrote: > > On Monday, February 02, 2015 08:45:30 PM Hanjun Guo wrote: > >> From: Mark Salter > >> > >> The acpi_os_ioremap() function may be used to map normal RAM or IO > >> regions. The current implementation simply uses ioremap_cache(). This > >> will work for some architectures, but arm64 ioremap_cache() cannot be > >> used to map IO regions which don't support caching. So for arm64, use > >> ioremap() for non-RAM regions. > >> > >> CC: Rafael J Wysocki > >> Signed-off-by: Mark Salter > >> Signed-off-by: Hanjun Guo > >> --- > >> include/acpi/acpi_io.h | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/include/acpi/acpi_io.h b/include/acpi/acpi_io.h > >> index 444671e..9d573db 100644 > >> --- a/include/acpi/acpi_io.h > >> +++ b/include/acpi/acpi_io.h > >> @@ -1,11 +1,17 @@ > >> #ifndef _ACPI_IO_H_ > >> #define _ACPI_IO_H_ > >> > >> +#include > >> #include > >> > >> static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys, > >> acpi_size size) > >> { > >> +#ifdef CONFIG_ARM64 > >> + if (!page_is_ram(phys >> PAGE_SHIFT)) > >> + return ioremap(phys, size); > >> +#endif > > > > I don't want to see #ifdef CONFIG_ARM64 in this file. > > > > There are multiple examples of how things like this are done. Generally, > > the logic is "If the architecture provides its own function for this, use > > that one, or use the generic one provided here otherwise." > > OK. I think weak function would work. Probably not in a header file. It's better to define acpi_os_ioremap() in an arm64 kernel file, together with something like: #define ARCH_HAS_ACPI_OS_IOREMAP and the corresponding #ifdef's in the acpi_io.h file. On arm64 could we make this function call iorema (nocache) all the time? We need to clarify the contexts where this is used in the core ACPI code. The acpi_map() function for example checks if the page is ram and does a kmap(). Do we need to handle the NVS on arm64? AFAICT, we don't even compile drivers/acpi/sleep.c in. Are there other cases where acpi_os_ioremap() is called directly and it needs a cacheable mapping? -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/