ARM: i.MX: allow disabling supervisor protect via DT
Subsystems (3)
PATCH v4 1/2 ARM: i.MX: allow disabling supervisor protect via DT
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.
---
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(+)
arch/arm/mach-imx/common.h +2 -0
@@ -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 );
arch/arm/mach-imx/cpu.c +13 -0
@@ -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;
Signature · 1 line
2.0.0
PATCH v4 2/2 ARM: i.MX53: globally disable supervisor protect
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.
--- arch/arm/mach-imx/mach-imx53.c | 4 ++++ 1 file changed, 4 insertions(+)
arch/arm/mach-imx/mach-imx53.c +4 -0
@@ -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 = {
Signature · 1 line
2.0.0
PATCH v4 2/2 ARM: i.MX53: globally disable supervisor protect
Quoted 23 lines · 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 <[email protected]>--- arch/arm/mach-imx/mach-imx53.c | 4 ++++ 1 file changed, 4 insertions(+)arch/arm/mach-imx/mach-imx53.c +0
-0
arch/arm/mach-imx/mach-imx53.c line 30
Quoted 5 lines
arch/arm/mach-imx/mach-imx53.c +2
-0@@ -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
Quoted 11 lines
arch/arm/mach-imx/mach-imx53.c +2
-0mxc_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 = {Signature · 1 line
2.0.0
PATCH v4 2/2 ARM: i.MX53: globally disable supervisor protect
Hi!
Quoted 32 lines · Shawn Guo
Quoted 23 lines · 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 <[email protected]>--- arch/arm/mach-imx/mach-imx53.c | 4 ++++ 1 file changed, 4 insertions(+)arch/arm/mach-imx/mach-imx53.c +0
-0arch/arm/mach-imx/mach-imx53.c line 30
Quoted 5 lines
arch/arm/mach-imx/mach-imx53.c +2
-0@@ -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:
Quoted 5 lines
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
Signature · 4 lines
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