From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.trumtrar@pengutronix.de (Steffen Trumtrar) Date: Mon, 7 Jul 2014 18:16:57 +0200 Subject: [PATCH v4 2/2] ARM: i.MX53: globally disable supervisor protect In-Reply-To: <20140707140416.GT30239@dragon> References: <1404726087-2069-1-git-send-email-s.trumtrar@pengutronix.de> <1404726087-2069-2-git-send-email-s.trumtrar@pengutronix.de> <20140707140416.GT30239@dragon> Message-ID: <20140707161657.GA8178@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi! On Mon, Jul 07, 2014 at 10:04:18PM +0800, Shawn Guo wrote: > 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 > > --- > > 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. > I'm okay with that. I don't really have any preference here, so do as you like best. Thanks, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |