[PATCH 0/3] Update riscv's SYS_BOOTM_LEN to the most commonly used value.

[Tom Rini]

On Tue, Jul 15, 2025 at 06:35:17PM -0700, E Shattow wrote:
> 
> 
> On 7/15/25 04:27, Michal Simek wrote:
> > 
> > 
> > On 7/14/25 15:33, Martin Herren wrote:
> >>
> >> The most commonly used SYS_BOOTM_LEN for riscv is 0x4000000 which is
> >> used in 25 of the current defconfigs.
> >>
> >> The previous default config value of 0x800000 was only used in 8
> >> defconfigs.
> >>
> >> This patch sets the default to this value.
> >>
> >> Command used to get the stats of the used values on RISCV defconfigs:
> >>
> >> ```
> >> grep -l "CONFIG_RISCV=y" configs/* | \
> >>   xargs -I {} sh -c "grep -H CONFIG_SYS_BOOTM_LEN {} || echo
> >> {}:DEFAULT" | \
> >>   cut -d ':' -f 2 | sort | uniq -c
> >> ```
> >>
> >> Changes in v2:
> >> - Resubmit using another mail provider to prevent mangling and signature
> >>    attachement.
> >>
> >> Martin Herren (3):
> >>    riscv: Set SYS_BOOTM_LEN explicitly to 0x800000
> >>    riscv: Set SYS_BOOTM_LEN default to 0x4000000
> >>    riscv: Remove default SYS_BOOTM_LEN from defconfig
> >>
> >>   boot/Kconfig                            | 2 +-
> >>   configs/ae350_rv32_defconfig            | 1 -
> >>   configs/ae350_rv32_falcon_defconfig     | 1 -
> >>   configs/ae350_rv32_falcon_xip_defconfig | 1 -
> >>   configs/ae350_rv32_spl_defconfig        | 1 -
> >>   configs/ae350_rv32_spl_xip_defconfig    | 1 -
> >>   configs/ae350_rv32_xip_defconfig        | 1 -
> >>   configs/ae350_rv64_defconfig            | 1 -
> >>   configs/ae350_rv64_falcon_defconfig     | 1 -
> >>   configs/ae350_rv64_falcon_xip_defconfig | 1 -
> >>   configs/ae350_rv64_spl_defconfig        | 1 -
> >>   configs/ae350_rv64_spl_xip_defconfig    | 1 -
> >>   configs/ae350_rv64_xip_defconfig        | 1 -
> >>   configs/ibex-ast2700_defconfig          | 1 -
> >>   configs/k230_canmv_defconfig            | 1 +
> >>   configs/microchip_mpfs_icicle_defconfig | 1 +
> >>   configs/milkv_duo_defconfig             | 1 -
> >>   configs/qemu-riscv32_defconfig          | 1 -
> >>   configs/qemu-riscv32_smode_defconfig    | 1 -
> >>   configs/qemu-riscv32_spl_defconfig      | 1 -
> >>   configs/qemu-riscv64_defconfig          | 1 -
> >>   configs/qemu-riscv64_smode_defconfig    | 1 -
> >>   configs/qemu-riscv64_spl_defconfig      | 1 -
> >>   configs/sifive_unleashed_defconfig      | 1 -
> >>   configs/sifive_unmatched_defconfig      | 1 -
> >>   configs/sipeed_licheerv_nano_defconfig  | 1 -
> >>   configs/sipeed_maix_bitm_defconfig      | 1 +
> >>   configs/sipeed_maix_smode_defconfig     | 1 +
> >>   configs/starfive_visionfive2_defconfig  | 1 -
> >>   configs/th1520_lpi4a_defconfig          | 1 -
> >>   configs/xilinx_mbv32_defconfig          | 1 +
> >>   configs/xilinx_mbv32_smode_defconfig    | 1 +
> >>   configs/xilinx_mbv64_defconfig          | 1 +
> >>   configs/xilinx_mbv64_smode_defconfig    | 1 +
> >>   34 files changed, 9 insertions(+), 26 deletions(-)
> >>
> > 
> > I don't mind with these changes. It is just value which can be changed.
> > 
> > Acked-by; Michal Simek <michal.simek at amd.com> # xilinx_mbv
> > 
> > Thanks
> > Michal
> > 
> > 
> 
> Is there some reason for the value from documentation about the
> architecture? Or is it arbitrary?
> 
> I don't really see the sense in a default value which is simply popular
> but not founded in an architectural reasoning.
> 
> The values do not change often (ever?) so I miss why there is any
> default at all.

So, the default for SYS_BOOTM_LEN isn't so much arbitrary as just no
longer reflective of modern times. It's why there's larger defaults for
ARM64 for example. Likely RISCV should just also use that as the default
and platforms with very small amounts of RAM should stick with smaller.

-- 
Tom
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