Re: [PATCH] arm: boards: Add support for MYIR MYD-AM335X Development Board

[Sascha Hauer <sha@pengutronix.de>]

On Thu, Apr 21, 2022 at 10:57:33AM +0300, Alexander Shiyan wrote:
> чт, 21 апр. 2022 г. в 10:35, Sascha Hauer <sha@pengutronix.de>:
> >
> > On Wed, Apr 20, 2022 at 12:53:22PM +0300, Alexander Shiyan wrote:
> > > The MYD-AM335X Development Board designed by MYIR is a high-performance
> > > ARM Evaluation Module (EVM) using the MYC-AM335X CPU module as the core
> > > controller board. It is based on up to 1GHz Texas Instruments (TI)
> > > Sitara AM335x family of ARM Cortex-A8 Microprocessors (MPUs) that deliver
> > > high DMIPs at a low cost while also delivering optional 3D graphics
> > > acceleration and key peripherals.
> > >
> > > Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
> ...
> > > +static struct omap_barebox_part myir_barebox_part = {
> > > +     .nand_offset = SZ_128K,
> > > +     .nand_size = SZ_512K,
> > > +};
> >
> > Isn't this a bit too small? Putting a barebox into 128k seems very
> > ambicous.
> 
> The boot image (MLO) should not exceed 128 KB in size,
> so I think this should be enough.
> In any case this size is already specified for the boot partition
> in kernel DTS for this board. :)

Oh, I accidently misread nand_size as SZ_128K. Indeed it's SZ_512K which
is small, but sufficient. Anyway, the BBU code assumes 4 eraseblocks for
the four MLO images. That would be a nand_offset of SZ_512K also, which
would then also match the upstream device tree for the board:

&nand0 {
        partition@0 {
                label = "MLO";
                reg = <0x00000 0x20000>;
        };

        partition@20000 {
                label = "boot";
                reg = <0x20000 0x80000>;
        };
};

512k is still very small nowadays. The images built with omap_defconfig
are just a bit smaller than that.

Sascha

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