From mboxrd@z Thu Jan  1 00:00:00 1970
From: shawn.guo@freescale.com (Shawn Guo)
Date: Mon, 7 Jul 2014 22:04:18 +0800
Subject: [PATCH v4 2/2] ARM: i.MX53: globally disable supervisor protect
In-Reply-To: <1404726087-2069-2-git-send-email-s.trumtrar@pengutronix.de>
References: <1404726087-2069-1-git-send-email-s.trumtrar@pengutronix.de>
 <1404726087-2069-2-git-send-email-s.trumtrar@pengutronix.de>
Message-ID: <20140707140416.GT30239@dragon>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Jul 07, 2014 at 11:41:27AM +0200, Steffen Trumtrar wrote:
> Most peripherals on the i.MX53 have an
>   Off-Platform Peripheral Access Control Register (OPACR)
> in which the access rights (together with the MPROT registers) can be declared.
> However, this does not seem to work for example for SSI1+SDMA, because the
> supervisor bit is not set for the SDMA unit.
> It does work for SSI2, the QSB for example uses SSI2 for its audio. But SSI2 only
> works because it does NOT have an OPACR.
> 
> The right solution would be to fix the access rights for the SDMA, but the unit
> responsible for this is the Central Security Unit (CSU), which of course is NOT
> documented. So, until documentation for this is openly available, turn off the
> supervisor protection because it cripples the hardware.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
> ---
>  arch/arm/mach-imx/mach-imx53.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/mach-imx53.c b/arch/arm/mach-imx/mach-imx53.c
> index 2bad387..1fbd77d 100644
> --- a/arch/arm/mach-imx/mach-imx53.c
> +++ b/arch/arm/mach-imx/mach-imx53.c
> @@ -26,9 +26,13 @@
>  
>  static void __init imx53_dt_init(void)
>  {
> +	const char *aips_compatible = "fsl,imx53-aipstz";
> +

The variable is not really necessary, since we can just do:

	imx_aips_allow_unprivileged_access("fsl,imx53-aipstz");

I'm going to fix it up and apply both patches.  Let me know if you have
concern with that.

Shawn

>  	mxc_arch_reset_init_dt();
>  
>  	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> +
> +	imx_aips_allow_unprivileged_access(aips_compatible);
>  }
>  
>  static const char *imx53_dt_board_compat[] __initconst = {
> -- 
> 2.0.0
>