[PATCH v2] arm: dts: k3-am625-beagleplay: Package TIFS Stub

[Dhruva Gole]

Nishanth,

On Jun 19, 2024 at 13:47:36 -0500, Nishanth Menon wrote:
> On 10:26-20240618, Dhruva Gole wrote:
> > Add support for packaging the TIFS Stub as it's required for basic Low
> > Power Modes like Deep Sleep.
> 
> What the heck is tifs stub?
> https://docs.u-boot.org/en/latest/search.html?q=tifs&check_keywords=yes&area=default
> I see no mention of the same?

I agree, documentation is lacking, will be sure to add that.

> > 
> > Acked-by: Neha Malcom Francis <n-francis at ti.com>
> > Signed-off-by: Dhruva Gole <d-gole at ti.com>
> > ---
> > 
> > No changes from v1, just picked Neha's ack and rebased on master again.
> > Link to v1:
> > https://lore.kernel.org/u-boot/20240612062351.3690091-1-d-gole@ti.com/
> > 
> >  arch/arm/dts/k3-am625-beagleplay-u-boot.dtsi | 33 +++++++++++++++++++-
> >  1 file changed, 32 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/dts/k3-am625-beagleplay-u-boot.dtsi b/arch/arm/dts/k3-am625-beagleplay-u-boot.dtsi
> > index fb2032068d1c..5e2248a4a668 100644
> > --- a/arch/arm/dts/k3-am625-beagleplay-u-boot.dtsi
> > +++ b/arch/arm/dts/k3-am625-beagleplay-u-boot.dtsi
> > @@ -69,6 +69,23 @@
> >  		};
> >  	};
> >  
> > +	tifsstub-gp {
> > +		filename = "tifsstub.bin_gp";
> > +		ti-secure-rom {
> > +			content = <&tifsstub_gp>;
> > +			core = "secure";
> > +			load = <0x60000>;
> > +			sw-rev = <CONFIG_K3_X509_SWRV>;
> > +			keyfile = "ti-degenerate-key.pem";
> > +			tifsstub;
> > +		};
> > +		tifsstub_gp: tifsstub-gp.bin {
> > +			filename = "ti-sysfw/ti-fs-stub-firmware-am62x-gp.bin";
> > +			type = "blob-ext";
> > +			optional;
> > +		};
> > +	};
> > +
> >  	ti-spl_unsigned {
> >  		filename = "tispl.bin_unsigned";
> >  		pad-byte = <0xff>;
> > @@ -105,6 +122,19 @@
> >  					};
> >  				};
> >  
> > +				tifsstub-gp {
> > +					description = "tifsstub";
> > +					type = "firmware";
> > +					arch = "arm32";
> > +					compression = "none";
> > +					os = "tifsstub-gp";
> > +					load = <0x9dc00000>;
> > +					entry = <0x9dc00000>;
> 
> two issues with this:
> a) if the tifsstub-gp is not automatically consumed by tifs by the time
> u-boot is up or kernel is up, this is going to get clobbered by OS
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/ti/k3-am625-beagleplay.dts#n78
> Should be updated before this is done.

This won't be much of a concern, the TIFS Stub is loaded into the R5 ATCM as
soon as the DM R5 core comes up [0] : See the Deep Sleep Exit part, it
talks about this stub.

[0] https://software-dl.ti.com/processor-sdk-linux/esd/AM62AX/09_01_00/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Power_Management/pm_sw_arch.html

> b) Documentation update - please always make sure you update
>   documentation when doing this kind of change
> https://docs.u-boot.org/en/latest/board/beagle/am62x_beagleplay.html#image-formats

Will do.

-- 
Best regards,
Dhruva Gole <d-gole at ti.com>