Re: [PATCH v2 1/3] io-64-nonatomic: add io{read|write}64[be] macros

From	Logan Gunthorpe <logang@deltatee.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 1/3] io-64-nonatomic: add io{read\|write}64[be] macros
Date	2017-06-28 18:10 +0200
Message-ID	<tXnHs-AC-21@gated-at.bofh.it> (permalink)
References	<tX7Ml-7kb-11@gated-at.bofh.it> <tX7Ml-7kb-9@gated-at.bofh.it> <tXieJ-5vN-1@gated-at.bofh.it>
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On 28/06/17 04:11 AM, Arnd Bergmann wrote:
> This is wrong since ioread* is not the same read* on x86 and other
> architectures that have native PCI PIO accessors, or that require
> additional barriers for those.
> 
> You have to copy hi_lo_readq() here, and call ioread32 twice instead
> of calling readl() twice. Same for iowrite64.
> 
>> +#ifndef ioread64be
>> +#define ioread64be(p) be64_to_cpu(ioread64(p))
>> +#endif
> 
> This has another problem: ioread64() is defined to access little-endian
> registers, just like readq(). This means that instead of be64_to_cpu()
> you need swab64() and always perform the byte swap, otherwise this
> would be broken on big-endian architectures.

Ah, ok, understood. I'll see if I can fix both these issues.

Thanks,

Logan

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[PATCH v2 1/3] io-64-nonatomic: add io{read|write}64[be] macros Logan Gunthorpe <logang@deltatee.com> - 2017-06-28 01:10 +0200
  Re: [PATCH v2 1/3] io-64-nonatomic: add io{read|write}64[be] macros Arnd Bergmann <arnd@arndb.de> - 2017-06-28 12:20 +0200
    Re: [PATCH v2 1/3] io-64-nonatomic: add io{read|write}64[be] macros Logan Gunthorpe <logang@deltatee.com> - 2017-06-28 18:10 +0200

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