From: Arnd Bergmann <arnd@arndb.de>
To: Eli Billauer <eli.billauer@gmail.com>
Subject: Re: [PATCH 2/2] New driver: Xillybus generic interface for FPGA (programmable logic)
Date: Fri, 30 Nov 2012 17:32:27 +0000
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Cc: Greg KH <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org
References: <1354117293-13632-1-git-send-email-eli.billauer@gmail.com> <20121130163254.GB4478@kroah.com> <50B8E5A0.1020406@gmail.com>
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On Friday 30 November 2012, Eli Billauer wrote:
> The problem is if the page size smaller than 4kB. The buffers 
> allocated by the driver must not cross a 4kB boundary, and it's assumed 
> that anything returned by __get_free_pages() is 4 kB-aligned. Otherwise 
> the FPGA will generate illegal PCIe packets by crossing that boundary.
> 
> If the page boundary is bigger than 4k, the driver handles that well.
> 

That should be fine then. We don't really support running Linux on
systems with a page size smaller than 4KB anyway, and I think the
only ones that ever hard smaller hardware page sizes (iirc m68k
or vax) were emulating 4KB pages in software.

	Arnd
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