linux-kernel - Re: [PATCH 0/2] ARM: zynq: address silent L2 cache corruption

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Message-ID: <56B9AF14.3070706@xilinx.com>
Date:	Tue, 9 Feb 2016 10:19:16 +0100
From:	Michal Simek <michal.simek@...inx.com>
To:	Josh Cartwright <joshc@...com>,
	Michal Simek <michal.simek@...inx.com>,
	Sören Brinkmann <soren.brinkmann@...inx.com>
CC:	Russell King <linux@....linux.org.uk>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>,
	Gratian Crisan <gratian.crisan@...com>
Subject: Re: [PATCH 0/2] ARM: zynq: address silent L2 cache corruption

On 3.2.2016 03:30, Josh Cartwright wrote:
> The Zynq has a bug where the L2 cache will return invalid data in some
> circumstances unless the L2C_RAM register is set to 0x20202 before the first
> enabling of the L2 cache.
> 
> The Xilinx-recommended solution to this problem is to ensure that early one of
> the earlier bootstages correctly initialize L2C_RAM, however, this issue wasn't
> discovered and fixed until after their EDK/SDK 14.4 release.  For systems built
> prior to that, and which lack field-upgradable bootloaders, this issue still
> exists and silent data corruption can be seen in the wild.
> 
> Fix these systems by ensuring L2C_RAM is properly initialized at the
> earliest convenient moment prior to the L2 being brought up, which is
> when the SLCR is first mapped.
> 
> Unfortunately, there isn't much public documentation on exactly what the
> L2C_RAM register is for, or how it is used, only that software is responsible
> for initializing it to the proper value prior to bringing up L2.
> 
> You can find more information about this bug in AR#54190[1].
> 
> 1: http://www.xilinx.com/support/answers/54190.html
> 
> Josh Cartwright (2):
>   ARM: zynq: initialize slcr mapping earlier
>   ARM: zynq: address L2 cache data corruption
> 
>  arch/arm/mach-zynq/common.c | 3 +--
>  arch/arm/mach-zynq/slcr.c   | 4 ++++
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 

Applied both.

Thanks,
Michal