[PATCH 14/23] ARM: i.MX: scratch: add OP-TEE FDTO support

[Marco Felsch]

Hi Ahmad,

On 26-01-15, Ahmad Fatoum wrote:
> Hello Marco,
> 
> On 11/10/25 9:34 PM, Marco Felsch wrote:
> > OP-TEE has the support to write DTB overlay fragments if enabled via
> > OP-TEE config switch CFG_EXTERNAL_DTB_OVERLAY.
> > 
> > The overlay fragments are added to the exisiting DTB if OP-TEE was
> > started with a DTB provided via arg2 or written to a stand-alone DTB
> > overlay.
> > 
> > This adds a dedicated storage slot which can be passed to OP-TEE or be
> > used by barebox to extract the added overlay fragment into it.
> > 
> > Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
> > ---
> 
> 
> > +config SCRATCH_FDTO_SIZE
> > +	hex
> > +	default 0x0
> > +	default 0x4000 if PBL_EARLY_FDT_LOAD
> > +	prompt "Scratch FDTO size"
> > +	help
> > +	  The size of possible FDT overlay areas used by BL3x binaries to store
> > +	  runtime generated overlays. Can be 0x0 if early FDT support is not
> > +	  requied e.g. during BL31 and BL32 stage.
> 
> I understand the need, but I dislike that we add such fine-grained
> Kconfig symbols here. With Sascha's series to make barebox proper an
> ELF, PBL will have more insight about how much space barebox proper
> occupies and I intend to send a series after it to allow easier
> allocation for hand-off data.

Don't get me wrong I don't like it either. To be honest, I really
don't like the current firmware handling since it doesn't scale for
multi-images.

> I will include provisions for passing around the device tree and an
> overlay with that series, so please hold off sending your v2 until then.

This series is on the list since quite a while. Unfortunately I didn't
had the time to ping the ML since I was busy with other projects and
also tried in the mean time to get the missing OP-TEE part mainline.

However, I would like to get this mainline. Not sure how Sascha is going
to pick the patchsets but for the purpose of converting behaviours I
used a generic name like SCRATCH_FDTO_SIZE, instead of going the
Rockchip way which defined a Rockchip specific variable (unfortunately).

However, I would like to get this series mainline ASAP since my customer
is going to rely on the mechanism we implemented here. Furthermore it
improves the situation for i.MX6/i.MX7 by a lot (with Fabians patchset).

Regards,
  Marco


> 
> Thanks,
> Ahmad
> 
> 
> > +
> >  config MALLOC_ALIGNMENT
> >  	hex
> >  	default 8
> > diff --git a/include/mach/imx/scratch.h b/include/mach/imx/scratch.h
> > index 43bf55de48099f1662cd4331620a93303d4dd710..a9745a95732dd961dcae83ec46c3eaa078d62a16 100644
> > --- a/include/mach/imx/scratch.h
> > +++ b/include/mach/imx/scratch.h
> > @@ -15,6 +15,7 @@ const struct optee_header *imx_scratch_get_optee_hdr(void);
> >  void imx_scratch_save_optee_hdr(const struct optee_header *hdr);
> >  
> >  void imx_scratch_get_fdt(void **fdt, unsigned int *fdt_sz);
> > +void imx_scratch_get_optee_fdto(void **fdto, unsigned int *fdto_sz);
> >  
> >  #define imx8mq_init_scratch_space() imx8m_init_scratch_space(32, true)
> >  #define imx8mm_init_scratch_space() imx8m_init_scratch_space(32, true)
> > 
> 
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> 

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