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Date:   Sat, 19 Feb 2022 12:34:45 +0100
From:   Marek =?UTF-8?B?QmVow7pu?= <kabel@kernel.org>
To:     Pali =?UTF-8?B?Um9ow6Fy?= <pali@kernel.org>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Gregory Clement <gregory.clement@bootlin.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: dts: marvell: armada-37xx: Remap IO space to bus
 address 0x0
Message-ID: <20220219123445.14940a12@thinkpad>
In-Reply-To: <20220218212526.16021-1-pali@kernel.org>
References: <20220218212526.16021-1-pali@kernel.org>
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On Fri, 18 Feb 2022 22:25:26 +0100
Pali Roh=C3=A1r <pali@kernel.org> wrote:

> Remap PCI I/O space to the bus address 0x0 in the Armada 37xx
> device-tree in order to support legacy I/O port based cards which have
> hardcoded I/O ports in low address space.
>=20
> Some legacy PCI I/O based cards do not support 32-bit I/O addressing.
>=20
> Since commit 64f160e19e92 ("PCI: aardvark: Configure PCIe resources from
> 'ranges' DT property") this driver can work with I/O windows which have
> a different address for CPU than for PCI bus (unless there is some
> conflict with other A37xx mapping), without needing additional support
> for this in the firmware.
>=20
> Note that DDR on A37xx is mapped to bus address 0x0 and that mapping of
> I/O space can be set to address 0x0 too because MEM space and I/O space
> are separate and so they do not conflict.
>=20
> Signed-off-by: Pali Roh=C3=A1r <pali@kernel.org>
> Reported-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Marek Beh=C3=BAn <kabel@kernel.org>