[PATCH 11/12] ARM: dts: add support for Vybrid running on Cortex-M4

Arnd Bergmann
2014-12-17T12:31:48Z

On Wednesday 17 December 2014 00:41:33 Stefan Agner wrote:
> On 2014-12-03 12:03, Arnd Bergmann wrote:
> > On Wednesday 03 December 2014 01:12:10 Stefan Agner wrote:
> >> diff --git a/arch/arm/boot/dts/vf610m4-colibri.dts b/arch/arm/boot/dts/vf610m4-colibri.dts
> >> new file mode 100644
> >> index 0000000..051ee0f
> >> --- /dev/null
> >> +++ b/arch/arm/boot/dts/vf610m4-colibri.dts
> >> @@ -0,0 +1,52 @@
> >> +/*
> >> + * Device tree for Colibri VF61 Cortex-M4 support
> >> + *
> >> + * Copyright 2014 Stefan Agner
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License as published by
> >> + * the Free Software Foundation; either version 2 of the License, or
> >> + * (at your option) any later version.
> >> + */
> >> +
> >> +/dts-v1/;
> >> +#include "vf610m4.dtsi"
> >> +
> >> +/ {
> >> + model = "VF610 Cortex-M4";
> >> + compatible = "fsl,vf610m4";
> >> +
> >> + chosen {
> >> + bootargs = "console=ttyLP2,115200 ihash_entries=64 dhash_entries=64 earlyprintk clk_ignore_unused init=/linuxrc rw";
> >> + };
> >> +
> >
> > Starting with v3.19, you should be able to use the earlycon framework on
> > arm32, so it would be better to replace earlyprintk with earlycon here
> > and add a stdout-path property in chosen that points to the console
> > uart.
>
> I started to implement earlycon support, but something currently fails
> when earlycon tries to map the UART registers:
> [ 0.000000] earlycon_map: Couldn't map 0x40027000
>
> I traced the issue a bit further down and found that get_vm_area_caller
> returns NULL (in __arm_ioremap_pfn_caller). This happend on Linus master
> as of today (2dbfca5a181973558277b28b1f4c36362291f5e0). Do I miss
> something here?

Hmm, I fear the arm32 FIX_EARLYCON_MEM support ended up not making it
into 3.19 after all. :(

Rob, is this something you are still working on?

Arnd