Hi Adam,
On Mon, May 17, 2021 at 2:50 PM Adam Ford <aford173@xxxxxxxxx> wrote:
> The bootloader/TF-A configuration we're using is based on the 4.19 CIP
> kernel that Renesas released. TF-A, we allocate some memory for the
Where can I find this BSP?
rcar-3.9.x is based on v4.14, and rcar-4.0.x on v5.4. I don't know about
BSPs using a kernel version in between.
> lossy compression and this memory is not available for Linux. I'd
> prefer to not have to use a special TF-A for the mainline Linux, but
> what appears to be happening is that Linux doesn't know about the
> reserved memory, so memory corruption happens.
>
> The Renesas CIP kernel uses the following to define the space
>
> /* device specific region for Lossy Decompression */
> lossy_decompress: linux,lossy_decompress@54000000 {
> no-map;
> reg = <0x00000000 0x54000000 0x0 0x03000000>;
> };
That is, inside a "reserved-memory" node.
> Then uses the following to carve it out so Linux doesn't think it can use it.
>
> mmngr {
> compatible = "renesas,mmngr";
> memory-region = <&mmp_reserved>, <&lossy_decompress>;
> };
>
> Unfortunately, renesas,mmngr doesn't exist upstream.
>
> I thought about changing the memory node to break it up, but it seems
> like a hack.
>
> What is the best suggestion for blocking this memory area from Linux
> while still appearing to show the full memory size?
I think "renesas,mmngr" is a red herring, as both rcar-3.9.x and
rcar-4.0.x use that compatible value in DTS files, but don't include
a driver.
Does it work if you manually add the reserved-memory node and the
relevant subnodes to your DTS file?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
