Re: [PATCH v8 02/21] acpi: fix acpi_os_ioremap for arm64

From: Hanjun Guo <hanjun.guo@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>,
	Mark Rutland <mark.rutland@arm.com>,
	Grant Likely <grant.likely@linaro.org>,
	Will Deacon <will.deacon@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Graeme Gregory <graeme.gregory@linaro.org>,
	Sudeep Holla <Sudeep.Holla@arm.com>, Jon Masters <jcm@redhat.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Mark Brown <broonie@kernel.org>, Rob Herring <robh@kernel.org>,
	Robert Richter <rric@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Charles.Garcia-Tobin@arm.com, phoenix.liyi@huawei.com,
	Timur Tabi <timur@codeaurora.org>,
	Ashwin Chaugule <ashwinc@codeaurora.org>,
	suravee.suthikulpanit@amd.com,
	Mark Langsdorf <mlangsdo@redhat.com>,
	wangyijing@huawei.com, linux-acpi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org,
	Mark Salter <msalter@redhat.com>
Subject: Re: [PATCH v8 02/21] acpi: fix acpi_os_ioremap for arm64
Date: Tue, 03 Feb 2015 17:08:42 +0800	[thread overview]
Message-ID: <54D0901A.2080406@linaro.org> (raw)
In-Reply-To: <2422968.Es7R0p3loO@vostro.rjw.lan>

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 <msalter@redhat.com>
>>
>> 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 <rjw@rjwysocki.net>
>> Signed-off-by: Mark Salter <msalter@redhat.com>
>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
>> ---
>>   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 <linux/mm.h>
>>   #include <linux/io.h>
>>
>>   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.

Thanks
Hanjun