Subject: [PATCH v3 1/2] ARM: i.MX: allow disabling supervisor protect via DT

From: [email-masked] (Shawn Guo)
Date: Wed, 2 Jul 2014 12:45:37 +0800

On Tue, Jul 01, 2014 at 10:27:47AM +0200, Steffen Trumtrar wrote:
> 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 match it finds.
> The match table has to be declared in the mach-specific entry file, where this
> helper function should then be called.
> 
> Signed-off-by: Steffen Trumtrar <[email-masked]>
> ---
>  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..9f6e778 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 struct of_device_id *of_matches);
>  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..7f66d77 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 struct of_device_id *of_matches)
> +{
> +	void __iomem *aips_base_addr;
> +	struct device_node *np;
> +
> +	for_each_matching_node(np, of_matches) {

Can we use for_each_compatible_node() here, so that the caller only
needs to pass a compatible string instead of a match table?

Shawn

> +		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
>