From mboxrd@z Thu Jan  1 00:00:00 1970
From: sebastian.hesselbarth@gmail.com (Sebastian Hesselbarth)
Date: Tue, 18 Jun 2013 16:00:09 +0200
Subject: Marvell SoCs: is register remapping to 0xf1NNNNNN safe?
In-Reply-To: <20130618134220.GY2718@n2100.arm.linux.org.uk>
References: <20130618134220.GY2718@n2100.arm.linux.org.uk>
Message-ID: <51C067E9.5060607@gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 06/18/13 15:42, Russell King - ARM Linux wrote:
> On the Armada 510, like most mvebu platforms, the registers are remapped
> to 0xf1NNNNNN.  This means things like the ATA interfaces are at
> 0xf10a0000, SPI at 0xf1010600 etc.
>
> It also means that the global config 1 register is at 0xf10e802c.  Other
> registers live at 0xf10e0000, 0xf10e4000, etc.
>
> Now, if I access any register in the 0xf10eNNNN, whether it be the global
> configuration register, a GPIO register, AC'97 register, the result is an
> instant and solid hang - presumably the bus locks up.  It doesn't matter
> if it is accessed in an interrupt-protected region, preempt-disabled
> region, or via a userspace mapping of that memory, the result is always
> the same, and things like sysrq don't work.
>
> Only a watchdog or power cycle recovers the SoC (presumably also a hardware
> reset too, but I can't test that.)
>
> Any ideas?  Can this behaviour be replicated on any other of these SoCs?

Russell,

just to make sure: Is pdma clock enabled, i.e. ungated? Usually, Dove
only hangs if corresponding clocks are not enabled.

Sebastian