Il 10/07/24 13:34, Frank Wunderlich ha scritto:
Hi
Gesendet: Mittwoch, 10. Juli 2024 um 12:45 Uhr
Von: "AngeloGioacchino Del Regno" <angelogioacchino.delregno@xxxxxxxxxxxxx>
Betreff: Re: [PATCH v1 0/4] add syscon requirement for mt7988
Il 09/07/24 12:13, Frank Wunderlich ha scritto:
From: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx>
Some nodes require the syscon fallback at least in u-boot when using
OF_UPSTREAM.
This is because uboot driver uses syscon_node_to_regmap in mtk_eth.c for
"mediatek,toprgu", "mediatek,xfi_pll" and reset pointing to watchdog-node.
I wonder what's the major blocker here to modify the u-boot driver to take
the upstream devicetree as-is, instead of using syscon_node_to_regmap?
in uboot there is no driver for all syscon and to handle parallel access this is done with the syscon fallback.
The syscon uclass is a small driver which is generic and only handle the regmap in global context.
In theory it could be possible that regmap is aquired twice when used from 2+ other drivers...to prevent this without
adding the syscon fallback each syscon needs a dedicated driver like in linux which does only syscon stuff (code
duplication at its best :) ).
of course i can use regmap_init_mem in the uboot ethernet driver
https://elixir.bootlin.com/u-boot/latest/source/drivers/core/regmap.c#L242
like it's done once for syscon-uclass.
but i will cause issues when a second device tries to access this regmap. So it was be much easier (for me) to add this
fallback and not writing 3 device-drivers in uboot doing the exactly same as syscon.
if you have a better idea how to handle it, let me know :)
I see. The problem is that, from your description, it looks like u-boot
uses that as a kind of workaround for concurrent access to MMIO...
...looks like a good topic to discuss in the u-boot mailing lists.
Definitely, the TOPRGU and the XFI PLL are not system controllers, so the actual
"syscon" definition would be wrong for these, that's it.
Cheers
regards Frank
Regards,
Angelo
