From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>, Jason Cooper <jason@lakedaemon.net>,
Gregory Clement <gregory.clement@bootlin.com>,
kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: mvebu: how to determine the address of the internal register window
Date: Tue, 11 Dec 2018 10:37:06 +0100 [thread overview]
Message-ID: <20181211103657.79713087@windsurf> (raw)
In-Reply-To: <f54e8ca9-0ca5-ce03-aaf8-e837f68b3024@kleine-koenig.org>
Hello Uwe,
On Mon, 10 Dec 2018 18:09:38 +0100, Uwe Kleine-König wrote:
> using barebox on an mvebu machine the internal register window is moved
> from 0xd0000000 to 0xf1000000. Compared to U-Boot the PCI Express BAR0
> Internal Registers (on Armada 370: 0x40010 and 0x80010, on Armada XP a
> few more) are not fixed which makes accessing pci devices fail. Instead
> of letting barebox fix this up I'd like to make Linux ensure the
> register is configured correctly.
>
> I think the right place for that is mvebu_pcie_setup_wins which needs to do
>
> mvebu_writel(port, intregoffset, PCIE_BAR_LO_OFF(0));
>
> I wonder however how I should determine the actual value to write here.
> I didn't find a function that exports the offset of the internal
> register window. Do you have a hint for me?
The base address of the internal registers is available in the Device
Tree:
soc {
ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xf1000000 0x100000
See the 0xf1000000 here? That's the base address of the internal registers.
See also Documentation/devicetree/bindings/bus/mvebu-mbus.txt for more
details about this binding.
Alternatively, since the internal register window is always 1 MB large,
from the pci-mvebu driver, you can take the base address of any PCI
controller, do & ~0xFFFFF, and you get the base address of the internal
register window.
Does this helps?
Best regards
Thomas
--
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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prev parent reply other threads:[~2018-12-11 9:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-10 17:09 mvebu: how to determine the address of the internal register window Uwe Kleine-König
2018-12-11 9:37 ` Thomas Petazzoni [this message]
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