On Wed, Jul 10, 2024 at 02:50:42PM +0200, AngeloGioacchino Del Regno wrote: > 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. While I'd prefer "syscon" never existed in the first place, I don't care too much if it gets added here or not. U-boot's reasoning for wanting it isn't really much better or worse than Linux's. Though if u-boot has multiple drivers using it, seems like an abstraction is missing if Linux doesn't need that. Rob
