| Message ID | 20240709101328.102969-1-linux@fw-web.de (mailing list archive) |
|---|---|
| Headers | show |
| Series | add syscon requirement for mt7988 | expand |
Il 09/07/24 12:13, Frank Wunderlich ha scritto: > From: Frank Wunderlich <frank-w@public-files.de> > > 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? Regards, Angelo > Frank Wunderlich (4): > dt-bindings: watchdog: mediatek,mtk-wdt: add MT7988 syscon requirement > dt-bindings: clock: mediatek: add syscon requirement for mt7988 > xfi-pll > dt-bindings: clock: mediatek: add syscon requirement for mt7988 > ethwarp > arm64: dts: mediatek: mt7988: add syscon for watchdog, xfi-pll and > ethwarp > > .../devicetree/bindings/clock/mediatek,mt7988-ethwarp.yaml | 6 ++++-- > .../devicetree/bindings/clock/mediatek,mt7988-xfi-pll.yaml | 7 +++++-- > .../devicetree/bindings/watchdog/mediatek,mtk-wdt.yaml | 5 ++++- > arch/arm64/boot/dts/mediatek/mt7988a.dtsi | 6 +++--- > 4 files changed, 16 insertions(+), 8 deletions(-) >
Hi > Gesendet: Mittwoch, 10. Juli 2024 um 12:45 Uhr > Von: "AngeloGioacchino Del Regno" <angelogioacchino.delregno@collabora.com> > 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@public-files.de> > > > > 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 :) regards Frank > Regards, > Angelo
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@collabora.com> >> 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@public-files.de> >>> >>> 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 >
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@collabora.com> > > > 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@public-files.de> > > > > > > > > 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
From: Frank Wunderlich <frank-w@public-files.de> 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. Frank Wunderlich (4): dt-bindings: watchdog: mediatek,mtk-wdt: add MT7988 syscon requirement dt-bindings: clock: mediatek: add syscon requirement for mt7988 xfi-pll dt-bindings: clock: mediatek: add syscon requirement for mt7988 ethwarp arm64: dts: mediatek: mt7988: add syscon for watchdog, xfi-pll and ethwarp .../devicetree/bindings/clock/mediatek,mt7988-ethwarp.yaml | 6 ++++-- .../devicetree/bindings/clock/mediatek,mt7988-xfi-pll.yaml | 7 +++++-- .../devicetree/bindings/watchdog/mediatek,mtk-wdt.yaml | 5 ++++- arch/arm64/boot/dts/mediatek/mt7988a.dtsi | 6 +++--- 4 files changed, 16 insertions(+), 8 deletions(-)