[PATCH 2/2] riscv: Enable CONFIG_OF_BOARD_FIXUP by default

[Bin Meng]

Hi Rick,

On Thu, May 28, 2020 at 4:17 PM Rick Chen <rickchen36 at gmail.com> wrote:
>
> Hi Bin
>
> > From: Bin Meng [mailto:bmeng.cn at gmail.com]
> > Sent: Wednesday, May 20, 2020 3:40 PM
> > To: Rick Jian-Zhi Chen(陳建志); U-Boot Mailing List
> > Cc: Bin Meng
> > Subject: [PATCH 2/2] riscv: Enable CONFIG_OF_BOARD_FIXUP by default
> >
> > From: Bin Meng <bin.meng at windriver.com>
> >
> > Starting from OpenSBI v0.7, the SBI firmware inserts/fixes up the reserved memory node for PMP protected memory regions. All RISC-V boards needs to copy the reserved memory node from the device tree provided by the firmware to the device tree used by U-Boot.
> >
> > Turn on CONFIG_OF_BOARD_FIXUP by default.
> >
> > Signed-off-by: Bin Meng <bin.meng at windriver.com>
> > ---
> >
> >  arch/riscv/Kconfig             | 3 +++
> >  configs/sifive_fu540_defconfig | 1 -
> >  2 files changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index fb5fe5a..5176b35 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -272,4 +272,7 @@ config STACK_SIZE_SHIFT
> >         int
> >         default 14
> >
> > +config OF_BOARD_FIXUP
> > +       default y
>
> I think it shall invoke by individual board, just like the description
> of riscv_fdt_copy_resv_mem_node function.

I believe we should turn on this feature by default for every RISC-V
board, because SBI firmware used memory must be marked as reserved
otherwise OS might use it and get crashed. For boards which don't want
to enable this, they can unset the option in their board defconfig
files. This is to reduce some maintenance effort.

>
> In [PATCH 1/2] if source and destination are the same place, it represent that
> OF_BOARD_FIXUP is unnecessary.
>
> BTW when I try OF_SEPARATE and OF_BOARD_FIXUP both are enabled, it hit
> the problem as below:
>
> U-Boot SPL 2020.07-rc3-16981-g4332225-dirty (May 28 2020 - 14:48:18 +0800)
> Trying to boot from RAM
>
>
> U-Boot 2020.07-rc3-16981-g4332225-dirty (May 28 2020 - 14:48:18 +0800)
>
> DRAM:  1 GiB
> failed to add reserved memory: -3

-3 means FDT_ERR_NOSPACE.

The FDT does not have enough space to add reserved memory node. Could
you please check your FDT blob?

> failed to fixup DT for reserved memory: -3
> initcall sequence 0000000001253c20 failed at call 000000000120b8e0 (err=-3)
> ### ERROR ### Please RESET the board ###
>
> I will dig in and figure out what is going on here ?
> Maybe there exist a potential issue somehow!
>

Regards,
Bin