From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Tue, 25 Mar 2014 19:42:42 +0100
Subject: [PATCH v5 6/9] ARM: shmobile: Add PCIe device tree nodes for
 R8A7790
In-Reply-To: <1395766604-30926-7-git-send-email-phil.edworthy@renesas.com>
References: <1395766604-30926-1-git-send-email-phil.edworthy@renesas.com>
 <1395766604-30926-7-git-send-email-phil.edworthy@renesas.com>
Message-ID: <14997425.EPjrKhVy10@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tuesday 25 March 2014 16:56:41 Phil Edworthy wrote:
> +               /* Map all possible DDR as inbound ranges */
> +               dma-ranges = <0x42000000 0 0x40000000 0 0x40000000 0 0x80000000
> +                             0x43000000 1 0x80000000 1 0x80000000 0 0x80000000>;

Typo: 0x43000000 should be 0x42000000 I guess.

Since you control the mapping, I wonder if you could also do this as

               dma-ranges = <0x42000000 0 0x00000000 0 0x40000000 0 0x80000000
                             0x43000000 0 0x80000000 1 0x80000000 0 0x80000000>;

i.e. map all the RAM into PCI bus addresses below the 32-bit boundary.
This would be really nice from the perspective that now all PCI
devices could access all of RAM without using an IOMMU or the
relying on 64-bit master capability.

The downside of this is that you'd probably need a custom dma_map_ops
wrapper.

	Arnd