[PATCH v4 1/2] ARM: i.MX: allow disabling supervisor protect via DT

[PATCH v4 1/2] ARM: i.MX: allow disabling supervisor protect via DT

[Steffen Trumtrar]

The i.MX SoCs allow to setup fine grained access rights to peripherals on the
AIPS bus.
This is done via the Peripheral Access Register (PAR) in e.g. the i.MX21
or in later SoC versions the Off-Platform Peripheral Access Control Register
(OPACR), e.g. i.MX53.
Under certain circumstances this leads to problems in which bus masters are
not granted their access rights to peripherals.
To be able to disable these restrictions on DT platforms, add a helper function
that looks for AIPS nodes in the DT and disables them for every compatible node
it finds.
The compatible has to be declared in the mach-specific entry file, where this
helper function should then be called.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
Changes since v3:
	- use for_each_compatible_node

 arch/arm/mach-imx/common.h |  2 ++
 arch/arm/mach-imx/cpu.c    | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index 9ab785c..8c1a305 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -19,6 +19,7 @@ struct pt_regs;
 struct clk;
 struct device_node;
 enum mxc_cpu_pwr_mode;
+struct of_device_id;
 
 void mx1_map_io(void);
 void mx21_map_io(void);
@@ -77,6 +78,7 @@ void mxc_arch_reset_init(void __iomem *);
 void mxc_arch_reset_init_dt(void);
 int mx53_revision(void);
 void imx_set_aips(void __iomem *);
+void imx_aips_allow_unprivileged_access(const char *compat);
 int mxc_device_init(void);
 void imx_set_soc_revision(unsigned int rev);
 unsigned int imx_get_soc_revision(void);
diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
index bbe8ff1..df42c14 100644
--- a/arch/arm/mach-imx/cpu.c
+++ b/arch/arm/mach-imx/cpu.c
@@ -2,6 +2,7 @@
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
 
@@ -60,6 +61,18 @@ void __init imx_set_aips(void __iomem *base)
 	__raw_writel(reg, base + 0x50);
 }
 
+void __init imx_aips_allow_unprivileged_access(
+		const char *compat)
+{
+	void __iomem *aips_base_addr;
+	struct device_node *np;
+
+	for_each_compatible_node(np, NULL, compat) {
+		aips_base_addr = of_iomap(np, 0);
+		imx_set_aips(aips_base_addr);
+	}
+}
+
 struct device * __init imx_soc_device_init(void)
 {
 	struct soc_device_attribute *soc_dev_attr;
-- 
2.0.0

[PATCH v4 2/2] ARM: i.MX53: globally disable supervisor protect

[Steffen Trumtrar]

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";
+
 	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

[PATCH v4 2/2] ARM: i.MX53: globally disable supervisor protect

[Shawn Guo]

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
> 

[PATCH v4 2/2] ARM: i.MX53: globally disable supervisor protect

[Steffen Trumtrar]

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 <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.
> 

I'm okay with that. I don't really have any preference here, so
do as you like best.

Thanks,
Steffen

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