Re: [PATCH v2] arm: spl: Ensure 8 byte alignment of appended DTB without separate BSS

[Tom Rini <trini@konsulko.com>]

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On Fri, Feb 06, 2026 at 07:02:07PM -0500, Greg Malysa wrote:
> Hi Tom,
> 
> On Thu, Feb 5, 2026 at 6:42 PM Tom Rini <trini@konsulko.com> wrote:
> >
> > Which means second, 64bit ARM platforms. With the exception of:
> > socfpga_agilex7m socfpga_n5x_atf socfpga_n5x_vab socfpga_stratix10_atf
> > all ARM64 SPL_FRAMEWORK using platforms use the
> > arch/arm/cpu/armv8/u-boot-spl.lds explicitly. These other ones set
> > CONFIG_SPL_LDSCRIPT to a non-existant file and then fall back to using
> > arch/arm/cpu/armv8/u-boot-spl.lds. There are only 4 platforms which
> > don't use a separate BSS section and so could trip up the above as well:
> > r8a779g0_whitehawk r8a779g3_sparrowhawk sc598-som-ezkit-spl sc598-som-ezlite-spl
> > I have inspected the Renesas platforms manually, and I'm a little unsure
> > how this case works on the two sc598 platforms.
> 
> Do you recommend using SPL_SEPARATE_BSS on our platform? After power
> on, the sc598 has 2 MB of SRAM available starting at 0x20000000 which
> we treat as just a single block of memory to use for all of SPL
> operation, so we don't have any requirement to do something like a
> bare bones DDR initialization before using it as our main memory for
> SPL, so it didn't seem necessary to enable. The boot ROM has some
> guidelines on where it will place its stack, so we restrict SPL to the
> first 192 KB currently but this can easily be expanded. I'm not sure
> if I should admit to it, but some decisions on Kconfigs were made 4
> years ago as an arbitrary choice during our initial bringup and then
> were not reviewed because things were working.
> 
> Either way, works for me on the sc598 + ezkit. There's no reason for
> it to fail on the ezlite in that case either.

So SPL_SEPARATE_BSS is for when the BSS can be easily put in SDRAM
instead. It's not better or worse than SRAM, it just depends on the
system constraints. I only called these two platforms out because I
don't actually see where the dtb comes from and so couldn't check the
alignment and location matched.

-- 
Tom

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