Messages in this thread | | | Date | Tue, 18 Oct 2022 15:58:38 +0200 | Subject | Re: [PATCH V2] dt-bindings: nvmem: u-boot,env: add Broadcom's variant binding | From | Rafał Miłecki <> |
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On 18.10.2022 12:19, Conor Dooley wrote: > On Fri, Oct 14, 2022 at 04:09:40PM -0500, Rob Herring wrote: >> On Fri, 30 Sep 2022 18:36:31 +0200, Rafał Miłecki wrote: >>> From: Rafał Miłecki <rafal@milecki.pl> >>> >>> Broadcom uses U-Boot for a lot of their bcmbca familiy chipsets. U-Boot >>> stores its configuration in an environment data block. >>> >>> Such blocks are usually stored on flash as a separated partition at >>> hardcoded address. Broadcom however decided to: >>> 1. Store env data block inside U-Boot partition >>> 2. Avoid sticking to hardcoded offsets >>> 3. Use custom header with "uEnv" magic and env data length >>> >>> Example (length 0x4000): >>> $ hexdump -n 32 -C -s 0x40000 /dev/mtdblock0 >>> 00040000 76 6e 45 75 00 40 00 00 34 89 7a 82 49 4d 41 47 |vnEu.@..4.z.IMAG| >>> 00040010 45 3d 4e 41 4e 44 3a 31 4d 2c 31 30 32 34 4d 00 |E=NAND:1M,1024M.| >>> (0x40000 offset is unit specific and can change) >>> >>> Starting with the commit 118f3fbe517f4 ("dt-bindings: mtd: partitions: >>> support label/name only partition") DT can describe partitions matching >>> them by a name (without specifying actual address). With that feature >>> and this binding change it's possible to: >>> 1. Specify DT node for Broadcom's U-Boot env data subpartition >>> 2. Add nodes for specific environment data variables >>> 3. Reference them as NVMEM cells >>> >>> This binding is unlikely to help Broadcom's U-Boot. U-Boot SPL needs to >>> find environment data early (before it accesses DTB) and it does that by >>> looking for an "uEnv" magic. Dirty way. >>> >>> This binding can however be used by operating systems. It allows >>> describing cleanly U-Boot, its env data and variables. It tells >>> operating system about Broadcom-specific env data so it can parse it. >>> >>> Signed-off-by: Rafał Miłecki <rafal@milecki.pl> >>> --- >>> V2: Work on better commit body & add example >>> --- >>> .../devicetree/bindings/nvmem/u-boot,env.yaml | 21 +++++++++++++++++++ >>> 1 file changed, 21 insertions(+) >>> >> >> Applied, thanks! > > Hey Rob, > Maybe my tooling is out of date or w/e but this is breaking > dt_binding_check for me. > > I applied the below to fix the build, which I was about to send, before > realising that you'd applied it and wondered if I was missing something.
Thanks for catching that and submitting a fix!
I guess I didn't run dt_binding_check this time or I did it before adding an example. Sorry for that!
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