[PATCH] imx8m{m,n}_venice: update env memory layout

[Fabio Estevam]

Hi Tim,

[Adding Tom on Cc]

On Sat, Feb 26, 2022 at 6:37 PM Tim Harvey <tharvey at gateworks.com> wrote:
>
> On Sat, Feb 26, 2022 at 5:15 AM Fabio Estevam <festevam at gmail.com> wrote:
> >
> > Hi Tim,
> >
> > On Fri, Feb 18, 2022 at 8:20 PM Tim Harvey <tharvey at gateworks.com> wrote:
> > >
> > > Update distro config env memory layout:
> > >  - loadaddr=0x48200000 allows for 130MB area for uncompressing (ie FIT
> > >    images, kernel_comp_addr_r)
> > >  - fdt_addr_r = loadaddr + 128MB - allows for 128MB kernel
> > >  - scriptaddr = fdt_addr_r + 512KB - allows for 512KB fdt
> > >  - ramdisk_addr_r = scriptaddr + 512KB - allows for 512KB script
> > >
> > > Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> >
> > What about following the suggestion from Heiko at:
> > https://patchwork.ozlabs.org/project/uboot/patch/20220216122514.1659879-2-heiko.thiery@gmail.com/
>
> Fabio,
>
> I don't understand why include/configs/ti_armv7_common.h is always
> recommended when it comes to address maps. The comment there doesn't
> read that well and there are several addresses that I believe are
> outdated or uncommon (fdtaddr,rdaddr are outdated and it seems
> loadaddr could be used for dtboaddr)
>
> In my opinion what is relevant when choosing an addressing scheme is
> how much space you want to allow for kernel, fdt, scripts, ramdisk.
>
> ti_armv7_common.h allows for
> kernel/loadaddr:96M (too small in my opinion on modern boards)
> fdt:512M (makes sense)
> script:32M (excessive, and I don't understand why this is below
> loadaddr vs stacked on top of loadaddr like fdt)
> ramdisk: depends on mem size as its the highest addr (makes sense)
>
> For my more modern boards with typically 1-4GiB of dram, I wanted to
> allow for more than 96M for a kernel (kernel+ramdisk, fit image etc)
> as I commonly exceed 96M when using a buildroot kernel+rootfs that has
> something like gstreamer support for imx6/imx8 which is why I came up
> with a different scheme which I document well in the commit log as
>  - loadaddr=0x48200000 allows for 130MB area for uncompressing (ie FIT
>    images, kernel_comp_addr_r)
>  - fdt_addr_r = loadaddr + 128MB - allows for 128MB kernel
>  - scriptaddr = fdt_addr_r + 512KB - allows for 512KB fdt
>  - ramdisk_addr_r = scriptaddr + 512KB - allows for 512KB script

You bring good points and maybe we could use
include/configs/imx8mm_venice.h as a good standard to follow :-)

Reviewed-by: Fabio Estevam <festevam at denx.de>