Re: [PATCH 3/3] ARM: i.MX6: load optee in PBL before barebox proper

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Dec 10, 2025 at 10:20:18AM +0100, Fabian Pflug wrote:
> Hey :)
> 
> On Wed, 2025-12-10 at 08:40 +0100, Sascha Hauer wrote:
> > On Mon, Dec 08, 2025 at 10:28:40AM +0100, Fabian Pflug wrote:
> > > This patch uses the space in the scratch memory to hand over to OP-TEE
> > > for device-tree overlays. If OP-TEE is configured with CFG_DT_ADDR=,
> > > then it will write its devicetree-overlay into the address and it will
> > > be picked up and applied by barebox.
> > > 
> > > This allows for generic OP-TEE loading for i.MX6 devices without changes
> > > to the board or lowlevel code.
> > > 
> > > Signed-off-by: Fabian Pflug <f.pflug@pengutronix.de>
> > > ---
> > >  arch/arm/mach-imx/esdctl.c | 49 +++++++++++++++++++++++++++++++++++++++++++---
> > >  common/Kconfig             |  1 +
> > >  firmware/Kconfig           |  8 ++++++++
> > >  firmware/Makefile          |  1 +
> > >  include/tee/optee.h        |  9 ++++++++-
> > >  5 files changed, 64 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
> > > index b9393fba4a..2434844c96 100644
> > > --- a/arch/arm/mach-imx/esdctl.c
> > > +++ b/arch/arm/mach-imx/esdctl.c
> > > @@ -6,6 +6,7 @@
> > >  #include <common.h>
> > >  #include <io.h>
> > >  #include <errno.h>
> > > +#include <firmware.h>
> > >  #include <linux/sizes.h>
> > >  #include <init.h>
> > >  #include <of.h>
> > > @@ -30,6 +31,7 @@
> > >  #include <mach/imx/imx7-regs.h>
> > >  #include <mach/imx/imx9-regs.h>
> > >  #include <mach/imx/scratch.h>
> > > +#include <mach/imx/tzasc.h>
> > >  #include <tee/optee.h>
> > >  
> > >  struct imx_esdctl_data {
> > > @@ -976,18 +978,59 @@ void __noreturn imx53_barebox_entry(void *boarddata)
> > >  static void __noreturn
> > >  imx6_barebox_entry(unsigned long membase, void *boarddata)
> > >  {
> > > -	barebox_arm_entry(membase,
> > > -			  imx6_mmdc_sdram_size(IOMEM(MX6_MMDC_P0_BASE_ADDR)),
> > > -			  boarddata);
> > > +	ulong memsize = imx6_mmdc_sdram_size(IOMEM(MX6_MMDC_P0_BASE_ADDR));
> > > +
> > > +	if (IS_ENABLED(CONFIG_FIRMWARE_IMX6_OPTEE) &&
> > > +	    IS_ENABLED(CONFIG_PBL_OPTEE) && imx6_can_access_tzasc()) {
> > > +		void *fdto;
> > > +		unsigned int fdto_size;
> > > +		int tee_size;
> > > +		void *tee;
> > > +
> > > +		get_builtin_firmware(imx6_optee_bin, &tee, &tee_size);
> > > +
> > > +		ulong endmem = arm_mem_barebox_image_end(membase + memsize);
> > > +		imx_init_scratch_space(endmem, 1);
> > > +		imx_scratch_get_optee_fdto(&fdto, &fdto_size);
> > > +		if (!fdto_size) {
> > > +			pr_warn("No space configured for OP-TEE devicetree\n");
> > > +			fdto = NULL;
> > > +		}
> > > +
> > > +		start_optee_early(fdto, tee);
> > > +		if (fdto_size)
> > > +			handoff_data_add(HANDOFF_DATA_BL32_DT_OVL, fdto,
> > > +					 fdto_size);
> > > +	}
> > > +
> > > +	barebox_arm_entry(membase, memsize, boarddata);
> > >  }
> > >  
> > >  void __noreturn imx6q_barebox_entry(void *boarddata)
> > >  {
> > > +	if (IS_ENABLED(CONFIG_FIRMWARE_IMX6_OPTEE) &&
> > > +	    IS_ENABLED(CONFIG_PBL_OPTEE) && imx6_can_access_tzasc()) {
> > > +		if (imx6q_tzc380_is_bypassed())
> > > +			panic("TZC380 is bypassed, abort OP-TEE loading\n");
> > > +
> > > +		/* Add early non-secure TZASC region1 to pass DTO */
> > > +		imx6q_tzc380_early_ns_region1();
> > > +	}
> > > +
> > >  	imx6_barebox_entry(MX6_MMDC_PORT01_BASE_ADDR, boarddata);
> > >  }
> > >  
> > >  void __noreturn imx6ul_barebox_entry(void *boarddata)
> > >  {
> > > +	if (IS_ENABLED(CONFIG_FIRMWARE_IMX6_OPTEE) &&
> > > +	    IS_ENABLED(CONFIG_PBL_OPTEE) && imx6_can_access_tzasc()) {
> > > +		if (imx6ul_tzc380_is_bypassed())
> > > +			panic("TZC380 is bypassed, abort OP-TEE loading\n");
> > > +
> > > +		/* Add early non-secure TZASC region1 to pass DTO */
> > > +		imx6ul_tzc380_early_ns_region1();
> > > +	}
> > > +
> > >  	imx6_barebox_entry(MX6_MMDC_PORT0_BASE_ADDR, boarddata);
> > >  }
> > >  
> > > diff --git a/common/Kconfig b/common/Kconfig
> > > index c42dc88ccf..20012cdc2c 100644
> > > --- a/common/Kconfig
> > > +++ b/common/Kconfig
> > > @@ -322,6 +322,7 @@ config SCRATCH_FDTO_SIZE
> > >  	hex
> > >  	default 0x0
> > >  	default 0x4000 if PBL_EARLY_FDT_LOAD
> > > +	default 0x4000 if FIRMWARE_IMX6_OPTEE
> > >  	prompt "Scratch FDTO size"
> > >  	help
> > >  	  The size of possible FDT overlay areas used by BL3x binaries to store
> > > diff --git a/firmware/Kconfig b/firmware/Kconfig
> > > index a97a1e0dd3..3e4245989c 100644
> > > --- a/firmware/Kconfig
> > > +++ b/firmware/Kconfig
> > > @@ -49,6 +49,14 @@ config FIRMWARE_IMX93_ATF
> > >  config FIRMWARE_AGILEX5_ATF
> > >  	bool
> > >  
> > > +config FIRMWARE_IMX6_OPTEE
> > > +	bool "install OP-TEE on i.MX6 boards"
> > > +	depends on PBL_OPTEE
> > > +	help
> > > +	  This enables OP-TEE loading and starting on i.MX6. Place the OP-TEE binary
> > > +	  in CONFIG_EXTRA_FIRMWARE_DIR/imx6-optee.bin. If this is enabled, then
> > > +	  the OP-TEE will automagically be loaded during boot.
> > 
> > automatically please.
> > 
> > > -int start_optee_early(void* fdt, void* tee);
> > > +int start_optee_early(void *fdt, void *tee);
> > >  int imx6q_start_optee_early(void *fdt, void *tee, void *data_location,
> > >  			    unsigned int data_location_size);
> > >  int imx6ul_start_optee_early(void *fdt, void *tee, void *data_location,
> > >  			     unsigned int data_location_size);
> > >  
> > > +#else
> > > +
> > > +static inline int start_optee_early(void *fdt, void *tee)
> > > +{
> > > +	return -ENOSYS;
> > > +}
> > 
> > Is this needed?
> 
> 
> Without it, I get
> | /patch/to/barebox/arch/arm/mach-imx/esdctl.c: In function 'imx6_barebox_entry':
> | /patch/to/barebox/arch/arm/mach-imx/esdctl.c:1000:17: error: implicit declaration of function 'start_optee_early' [-
> Werror=implicit-function-declaration]
> |  1000 |                 start_optee_early(fdto, tee);
> |       |                 ^~~~~~~~~~~~~~~~~
> 
> during compile.
> 
> That leaves three choices:
> * Add a -ENOSYS to header
> * disable compiling esdctl.c for barebox
> * wrap call to start_optee_early in esdctl.c with #ifdef
> 
> Is there an error with esdctl being compiled for non-PBL?

esdctl.c is needed for non-PBL. Keep it like it is with returning
-ENOSYS. I was just curious.

Sascha

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