Message-ID: <55A53509.4060202@caviumnetworks.com>
Date: Tue, 14 Jul 2015 09:12:57 -0700
From: David Daney <ddaney@caviumnetworks.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7
MIME-Version: 1.0
To: Will Deacon <will.deacon@arm.com>
CC: David Daney <ddaney.cavm@gmail.com>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        Catalin Marinas <Catalin.Marinas@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Robert Richter <rrichter@cavium.com>,
        David Daney <david.daney@cavium.com>
Subject: Re: [PATCH] arm64: Define HAVE_ARCH_PIO_SIZE and related symbols.
References: <1436823096-24059-1-git-send-email-ddaney.cavm@gmail.com> <20150714110039.GC16213@arm.com>
In-Reply-To: <20150714110039.GC16213@arm.com>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
Content-Transfer-Encoding: 7bit
BY1PR0701MB1724: X-MS-Exchange-Organization-RulesExecuted
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Jul 2015 16:13:01.7982 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY1PR0701MB1724
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1294
Lines: 38

On 07/14/2015 04:00 AM, Will Deacon wrote:
> On Mon, Jul 13, 2015 at 10:31:36PM +0100, David Daney wrote:
>> From: David Daney <david.daney@cavium.com>
>>
>> Needed to make pci_iomap() work.
>
> Care to elaborate?
>

I should have explained what I am doing here a little better.

Systems based on the Cavium ThunderX processor may have up to 8 
independent PCIe root complexes.  The I/O space on each bus occupies an 
independent physical address window.

So, in order to be able to map all of these (semi) contiguously, we need 
a lot more virtual address space than is supplied by the default values 
for all these constants.

The option I chose here was to unconditionally expand the I/O ranges for 
all arm64 systems.  If you think this breaks existing systems/drivers, I 
will have to look for other options.

David Daney


> AFAICT, mapping an IO bar on arm64 just gives you back a VA into our
> PCI_IOBASE region and the ioreadX accessors will just call the readX
> macros, so there should be no need for further port adjustment.
>
> Will
>

--
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/