Re: [PATCH 1/6] arch: riscv: add support for building DTB files from DT source data

[Paul Walmsley]

On Thu, 11 Apr 2019, Christoph Hellwig wrote:

> On Thu, Apr 11, 2019 at 01:42:59AM -0700, Paul Walmsley wrote:
> > Similar to ARM64, add support for building DTB files from DT source
> > data for RISC-V boards.
> > 
> > This patch starts with the infrastructure needed for SiFive boards.
> > Boards from other vendors would add support here in a similar form.
> 
> What do we build it for?  We'd really need something like this:
> 
> http://git.infradead.org/users/hch/misc.git/commitdiff/d6242aa147baf57e05e2932199c74d8d24b9926e
> http://git.infradead.org/users/hch/misc.git/commitdiff/0cd5413c8094ab57b68e0629dacfed695f4c1ef1
> 
> To actually use the DT files.

Those patches might be useful - I have not reviewed them closely - but 
they are not necessary. 

The FSBL already supplies a DTB to Linux.  I assume the U-boot port works 
the same way.

I haven't switched to U-boot yet for these driver tests, so I personally 
have been using the open-source FSBL (freedom-u540-c000-bootloader) with 
the following trivial patches applied:

https://github.com/sifive/freedom-u540-c000-bootloader/tree/dev/paulw/supply-fsbl-dtb-v5.1-rc4

The fsbl/ux00_fsbl.dtb file can be symlinked to the kernel DTB output, 
e.g., ~/linux/arch/riscv/boot/dts/sifive/hifive-unleashed-a00-fu540.dtb.


- Paul