Re: [PATCH 00/36] clk: port Linux Common Clock Framework to U-Boot
Neil Armstrong <[email protected]>
| Newsgroups | gmane.comp.boot-loaders.u-boot |
|---|---|
| Organization | Linaro |
| Message-ID | <[email protected]> |
Hi, On 7/20/26 18:40, Casey Connolly wrote: > This series introduces support for the Linux Common Clock framework in > U-Boot, when enabled it replaces UCLASS_CLK entirely, instead offering > the typical clock provider API from Linux. This has the significant > advantage of allowing one "udevice" to provide an arbitrary number > of clocks without the need to populate U-Boot driver model with dummy > devices. > > Historically, U-Boots clock support has focused on being small and > simple, allowing platforms to configure the clocks they need to boot. > But as we support more modern SoCs it's become clear that the existing > API doesn't scale as we need to be able to calculate clock rates, handle > reparenting, and other more complicated configurations. Rather than > trying to re-invent the wheel here (which would likely never leave us > with a truly satisfactory solution) adopting the Linux API solves a > whole host of problems in U-Boot. > > With the Linux CCF, complicated Linux clock drivers can now be adopted > with relative ease rather than having to painfully rewrite them to work > in U-Boots limited clock model. This also drastically simplifies the > bringup process for new platforms. > > To offer an example, the DSI PHY devices on most Qualcomm platforms > have their own VCO, PLL, dividers, and muxes which are programmed > based on the pixel clock of the display, if it's using D-phy or > C-phy, display stream compression, etc. This isn't directly modelled > in devicetree though since the PHY clock outputs are routed into the > "dispcc" block which is what the DSI controller itself sees. Modelling > the relationship between the pixel/byte clocks in dispcc and their > parents in the phy must be handled by the clock framework and though > assigned-clock-parents, something that U-Boots existing clock framework > simply doesn't support. Additionally, dual-DSI panels are even more > annoying since both sets of pixel/byte clocks are sourced from only one > of the PHYs. > > U-Boot did already have some very limited support for "CCF", however > this is essentially just using the driver model to maintain the clock > tree and registering a device for each clock. This simply doesn't > scale well for the huge number of clocks on modern platforms and still > requires significant effort to port drivers from Linux. > > There is one notable limitation with the full CCF port, since it > requires the entire clock tree to be modelled before it can actually > manage any clocks it isn't feasible to run pre-relocation making it > unsuitable for platforms that require clocks at this point. My hope is > that we can continue to reduce the complexity of U-Boots pre-relocation > stage to mitigate this issue, but since some platforms are already using > CONFIG_SKIP_EARLY_DM I hope this won't be a blocking issue. > > When it comes to U-Boot SPL, it likely doesn't make sense to expect to > use CCF in that environment. Since the scope of SPL is so much smaller > it should still be acceptable to use UCLASS_CLK here and only build with > CCF for full U-Boot images. > > -- Overview -- > > This series contains a few preparatory patches to align U-Boots > existing clock API with upstream and rename clk_ops to clk_ops_uboot to > differentiate UCLASS_CLK ops. > > The generic CCF mux/div/fixed clock drivers are in drivers/clk/ccf along > with the CCF core. > > Sandbox also gets CCF_FULL support for the purposes of testing. > > Lastly, the Qualcomm clock drivers from Linux are ported over with > minimal changes to enable CCF support on the SM8650 platform, this will > be expanded in the future to other Qualcomm platforms. This demonstrates > the ease of porting Linux drivers and acts as a template that others > can follow. > > -- Architecture -- > > The CCF port is fairly straightforward, clk-uclass.c has some its common > API split out into clk-common.c which either calls into clk-uclass or > ccf/clk.c based on the configuration. To keep things simple, CLK_UCLASS > is completely unsupported when CCF is enabled, by not building > clk-uclass.c we don't provide any support for non-CCF clocks and they > won't show up in the device model at runtime. > > Devices that provide clocks can be of any uclass, they will be probed > via ofnode lookup and should register their clocks with CCF (via the > typical clk_register helpers) during probe. > > Clock consumers still work the same way, although internal API > differences may require changes to some drivers such as the UFS fixes in > this series. Notably it may be necessary to actually call clk_set_rate() > with a suitable rate, I think it's safe to say these calls being > missing and relying on the clock driver to pick a suitable rate is a bug > regardless of CCF. > > -- Merging and maintenance -- > > Given the scope and complexity of this change and that it's entirely > opt-in, I'm hopeful that we can focus on issues that are important to > solve before this can be merged, and focus on improving any rough edges > after the fact. This will also make it easier for others to try it out > and investigate using CCF_FULL for their platforms. > > In the short-medium term I'm happy to maintain this port and help others > who are interested in using it. However I very much invite anyone with > an interest in this to co-maintain it or take it over in the future. > > I previously sent an RFC for this which can be found below, it has gone > through some significant rework since then and quite a bit of testing > locally as I've used this as the basis for Qualcomm display bringup. > > https://lore.kernel.org/u-boot/[email protected]/ > > --- > Casey Connolly (36): > clk: move U-Boot CCF to clk/uccf > clk: rename clk_ops to clk_ops_uboot > clk: move fixed clocks to clk/basic > clk: make clk_set_rate() return signed long > clk: make clk_get_parent_rate return signed long > clk: compat: add clk (un)prepare and associated functions > dm: ofnode: fix parse_phandle_with_args API > clk: import full CCF from Linux > clk: move clock flags to common clk-provider.h > clk/ccf: adapt clk-conf for U-Boot > clk/ccf: adapt CCF core for U-Boot > clk/ccf: adapt CCF generic clocks for U-Boot > clk: split clk-uclass.c into clk-common.c > clk/common: add CCF_FULL support > clk/ccf: optimise orphan clock handling > clk/ccf: debug log enable/disable calls > cmd/clk: add CCF_FULL support > doc: describe Common Clock Framework > clk/sandbox: add a CCF_FULL port of clk_sandbox > clk: sandbox: fix set_rate and move to clk/basic > clk/ccf: add CCF_FULL port of clk_sandbox > test: dm: adjust clk tests for CCF_FULL > configs: add sandbox CCF_FULL defconfig > CI: add sandbox64_ccf_full > MAINTAINERS: add entry for CCF port > clk/qcom: move existing clock drivers to clk/qcom/basic > clk/qcom: drop in Linux Qualcomm CCF drivers > clk/qcom/ccf: drop in Linux rpmh clock driver > clk/qcom/ccf: add sm8650 GCC, dispcc and tcsrcc. > clk/qcom/ccf: add uboot common code > clk/qcom/ccf: adapt common, gdsc, and reset code for U-Boot > clk/qcom/ccf: adapt clocks for U-Boot > clk/qcom/ccf: adapt sm8650 clock drivers for U-Boot > ufs: qcom: use clk_prepare_enable_bulk() > qcom_sm8650_defconfig: enable CCF_FULL > ufs: qcom: fix core clk max rate setting I tried to apply it to v2026.10-rc1 but it doesn't apply cleanly, what are the dependencies ? I'll probably try to port the Linux Amlogic clock drivers with the CCF FULL, it should probably work 1:1 since we mimic the Linux behviour with the basic U-Boot clock driver. Also please share a branch from where to pull the changes for such large patchsets. Thanks, Neil > > .gitlab-ci.yml | 5 + > MAINTAINERS | 7 + > arch/arm/cpu/armv7/bcm281xx/clk-core.c | 8 +- > arch/arm/cpu/armv7/bcm281xx/clk-core.h | 14 +- > arch/sandbox/dts/test.dts | 4 +- > arch/sandbox/include/asm/clk.h | 2 +- > cmd/clk.c | 21 +- > configs/qcom_sm8650_defconfig | 1 + > configs/sandbox64_ccf_full_defconfig | 5 + > doc/api/clk.rst | 25 + > doc/develop/ccf.rst | 35 + > doc/develop/index.rst | 1 + > drivers/clk/Kconfig | 54 +- > drivers/clk/Makefile | 21 +- > drivers/clk/adi/clk-adi-pll.c | 2 +- > drivers/clk/adi/clk-shared.c | 4 +- > drivers/clk/adi/clk.h | 2 +- > drivers/clk/airoha/clk-airoha.c | 4 +- > drivers/clk/altera/clk-agilex.c | 2 +- > drivers/clk/altera/clk-agilex5.c | 2 +- > drivers/clk/altera/clk-arria10.c | 2 +- > drivers/clk/altera/clk-mem-n5x.c | 2 +- > drivers/clk/altera/clk-n5x.c | 2 +- > drivers/clk/aspeed/clk_ast2500.c | 4 +- > drivers/clk/aspeed/clk_ast2600.c | 4 +- > drivers/clk/aspeed/clk_ast2700.c | 4 +- > drivers/clk/at91/clk-generic.c | 4 +- > drivers/clk/at91/clk-main.c | 8 +- > drivers/clk/at91/clk-master.c | 8 +- > drivers/clk/at91/clk-peripheral.c | 6 +- > drivers/clk/at91/clk-programmable.c | 4 +- > drivers/clk/at91/clk-sam9x60-pll.c | 10 +- > drivers/clk/at91/clk-sam9x60-usb.c | 4 +- > drivers/clk/at91/clk-system.c | 2 +- > drivers/clk/at91/clk-utmi.c | 4 +- > drivers/clk/at91/compat.c | 30 +- > drivers/clk/at91/pmc.c | 2 +- > drivers/clk/at91/pmc.h | 2 +- > drivers/clk/at91/sckc.c | 4 +- > drivers/clk/basic/Makefile | 8 + > drivers/clk/{ => basic}/clk_fixed_factor.c | 2 +- > drivers/clk/{ => basic}/clk_fixed_rate.c | 4 +- > drivers/clk/{ => basic}/clk_sandbox.c | 12 +- > drivers/clk/ccf/Kconfig | 8 + > drivers/clk/ccf/Makefile | 19 + > drivers/clk/ccf/clk-composite.c | 495 +++ > drivers/clk/ccf/clk-conf.c | 189 + > drivers/clk/ccf/clk-divider.c | 663 ++++ > drivers/clk/ccf/clk-fixed-factor.c | 409 +++ > drivers/clk/ccf/clk-fixed-rate.c | 217 ++ > drivers/clk/ccf/clk-gate.c | 260 ++ > drivers/clk/ccf/clk-mux.c | 282 ++ > drivers/clk/ccf/clk.c | 3250 +++++++++++++++++ > drivers/clk/ccf/clk.h | 53 + > drivers/clk/ccf/clk_sandbox.c | 281 ++ > drivers/clk/ccf/clk_sandbox_ccf_full.c | 220 ++ > drivers/clk/clk-cdce9xx.c | 4 +- > drivers/clk/clk-common.c | 255 ++ > drivers/clk/clk-common.h | 45 + > drivers/clk/clk-gpio.c | 2 +- > drivers/clk/clk-hsdk-cgu.c | 4 +- > drivers/clk/clk-stub.c | 4 +- > drivers/clk/clk-uclass.c | 202 +- > drivers/clk/clk-xlnx-clock-wizard.c | 4 +- > drivers/clk/clk_bcm6345.c | 2 +- > drivers/clk/clk_boston.c | 2 +- > drivers/clk/clk_k210.c | 8 +- > drivers/clk/clk_octeon.c | 2 +- > drivers/clk/clk_pic32.c | 4 +- > drivers/clk/clk_sandbox_test.c | 2 +- > drivers/clk/clk_scmi.c | 6 +- > drivers/clk/clk_versaclock.c | 22 +- > drivers/clk/clk_versal.c | 4 +- > drivers/clk/clk_vexpress_osc.c | 4 +- > drivers/clk/clk_zynq.c | 8 +- > drivers/clk/clk_zynqmp.c | 6 +- > drivers/clk/exynos/clk-exynos7420.c | 6 +- > drivers/clk/exynos/clk-pll.c | 4 +- > drivers/clk/exynos/clk.h | 2 +- > drivers/clk/ics8n3qv01.c | 4 +- > drivers/clk/imx/clk-composite-8m.c | 6 +- > drivers/clk/imx/clk-composite-93.c | 2 +- > drivers/clk/imx/clk-fracn-gppll.c | 4 +- > drivers/clk/imx/clk-gate-93.c | 4 +- > drivers/clk/imx/clk-gate2.c | 4 +- > drivers/clk/imx/clk-imx6q.c | 2 +- > drivers/clk/imx/clk-imx6ul.c | 2 +- > drivers/clk/imx/clk-imx8.c | 4 +- > drivers/clk/imx/clk-imx8.h | 2 +- > drivers/clk/imx/clk-imx8qm.c | 2 +- > drivers/clk/imx/clk-imx8qxp.c | 2 +- > drivers/clk/imx/clk-imxrt1020.c | 2 +- > drivers/clk/imx/clk-imxrt1170.c | 4 +- > drivers/clk/imx/clk-pfd.c | 4 +- > drivers/clk/imx/clk-pll14xx.c | 8 +- > drivers/clk/imx/clk-pllv3.c | 18 +- > drivers/clk/intel/clk_intel.c | 2 +- > drivers/clk/mediatek/clk-mtk.c | 14 +- > drivers/clk/mediatek/clk-mtk.h | 10 +- > drivers/clk/meson/a1.c | 8 +- > drivers/clk/meson/axg-ao.c | 2 +- > drivers/clk/meson/axg.c | 2 +- > drivers/clk/meson/clk-measure.c | 2 +- > drivers/clk/meson/g12a-ao.c | 2 +- > drivers/clk/meson/g12a.c | 10 +- > drivers/clk/meson/gxbb.c | 8 +- > drivers/clk/microchip/mpfs_clk_cfg.c | 4 +- > drivers/clk/microchip/mpfs_clk_msspll.c | 2 +- > drivers/clk/microchip/mpfs_clk_periph.c | 2 +- > drivers/clk/mpc83xx_clk.c | 2 +- > drivers/clk/mtmips/clk-mt7620.c | 2 +- > drivers/clk/mtmips/clk-mt7621.c | 2 +- > drivers/clk/mtmips/clk-mt7628.c | 2 +- > drivers/clk/mvebu/armada-37xx-periph.c | 4 +- > drivers/clk/mvebu/armada-37xx-tbg.c | 2 +- > drivers/clk/nuvoton/clk_npcm.c | 4 +- > drivers/clk/nuvoton/clk_npcm.h | 2 +- > drivers/clk/owl/clk_owl.c | 6 +- > drivers/clk/qcom/Kconfig | 1 + > drivers/clk/qcom/Makefile | 31 +- > drivers/clk/qcom/basic/Makefile | 28 + > drivers/clk/qcom/{ => basic}/clock-apq8016.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-apq8096.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-ipq4019.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-ipq5424.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-ipq9574.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-milos.c | 4 +- > drivers/clk/qcom/{ => basic}/clock-qcm2290.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-qcom.c | 4 +- > drivers/clk/qcom/{ => basic}/clock-qcom.h | 2 +- > drivers/clk/qcom/{ => basic}/clock-qcs404.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-qcs615.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-qcs8300.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sa8775p.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sc7280.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sdm845.c | 4 +- > drivers/clk/qcom/{ => basic}/clock-sm6115.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm6125.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm6350.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm7150.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm8150.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm8250.c | 2 +- > drivers/clk/qcom/{ => basic}/clock-sm8550.c | 4 +- > drivers/clk/qcom/{ => basic}/clock-sm8650.c | 4 +- > drivers/clk/qcom/{ => basic}/clock-x1e80100.c | 4 +- > drivers/clk/qcom/ccf/Makefile | 21 + > drivers/clk/qcom/ccf/clk-alpha-pll.c | 3196 ++++++++++++++++ > drivers/clk/qcom/ccf/clk-alpha-pll.h | 251 ++ > drivers/clk/qcom/ccf/clk-branch.c | 203 ++ > drivers/clk/qcom/ccf/clk-branch.h | 125 + > drivers/clk/qcom/ccf/clk-rcg.h | 217 ++ > drivers/clk/qcom/ccf/clk-rcg2.c | 1765 +++++++++ > drivers/clk/qcom/ccf/clk-regmap-divider.c | 90 + > drivers/clk/qcom/ccf/clk-regmap-divider.h | 22 + > drivers/clk/qcom/ccf/clk-regmap-mux-div.c | 232 ++ > drivers/clk/qcom/ccf/clk-regmap-mux-div.h | 44 + > drivers/clk/qcom/ccf/clk-regmap-mux.c | 57 + > drivers/clk/qcom/ccf/clk-regmap-mux.h | 23 + > drivers/clk/qcom/ccf/clk-regmap-phy-mux.c | 62 + > drivers/clk/qcom/ccf/clk-regmap-phy-mux.h | 33 + > drivers/clk/qcom/ccf/clk-regmap.c | 104 + > drivers/clk/qcom/ccf/clk-regmap.h | 38 + > drivers/clk/qcom/ccf/clk-rpmh.c | 1030 ++++++ > drivers/clk/qcom/ccf/common-uboot.c | 188 + > drivers/clk/qcom/ccf/common-uboot.h | 34 + > drivers/clk/qcom/ccf/common.c | 248 ++ > drivers/clk/qcom/ccf/common.h | 106 + > drivers/clk/qcom/ccf/dispcc-sm8550.c | 1825 ++++++++++ > drivers/clk/qcom/ccf/gcc-sm8650.c | 3846 ++++++++++++++++++++ > drivers/clk/qcom/ccf/gdsc.c | 545 +++ > drivers/clk/qcom/ccf/gdsc.h | 103 + > drivers/clk/qcom/ccf/reset.c | 112 + > drivers/clk/qcom/ccf/reset.h | 29 + > drivers/clk/qcom/ccf/tcsrcc-sm8650.c | 174 + > drivers/clk/qcom/clock-sc7180.c | 2 +- > drivers/clk/renesas/clk-rcar-gen2.c | 4 +- > drivers/clk/renesas/clk-rcar-gen3.c | 4 +- > drivers/clk/renesas/compound-clock.c | 4 +- > drivers/clk/renesas/r8a78000-cpg.c | 6 +- > drivers/clk/renesas/r9a06g032-clocks.c | 6 +- > drivers/clk/renesas/rcar-gen2-cpg.h | 2 +- > drivers/clk/renesas/rcar-gen3-cpg.h | 2 +- > drivers/clk/renesas/rzg2l-cpg.c | 8 +- > drivers/clk/rockchip/clk_px30.c | 12 +- > drivers/clk/rockchip/clk_rk3036.c | 4 +- > drivers/clk/rockchip/clk_rk3066.c | 4 +- > drivers/clk/rockchip/clk_rk3128.c | 4 +- > drivers/clk/rockchip/clk_rk3188.c | 4 +- > drivers/clk/rockchip/clk_rk322x.c | 4 +- > drivers/clk/rockchip/clk_rk3288.c | 4 +- > drivers/clk/rockchip/clk_rk3308.c | 4 +- > drivers/clk/rockchip/clk_rk3328.c | 4 +- > drivers/clk/rockchip/clk_rk3368.c | 4 +- > drivers/clk/rockchip/clk_rk3399.c | 8 +- > drivers/clk/rockchip/clk_rk3506.c | 4 +- > drivers/clk/rockchip/clk_rk3528.c | 10 +- > drivers/clk/rockchip/clk_rk3568.c | 14 +- > drivers/clk/rockchip/clk_rk3576.c | 8 +- > drivers/clk/rockchip/clk_rk3588.c | 12 +- > drivers/clk/rockchip/clk_rv1108.c | 4 +- > drivers/clk/rockchip/clk_rv1126.c | 12 +- > drivers/clk/sifive/sifive-prci.c | 4 +- > drivers/clk/sophgo/clk-cv1800b.c | 4 +- > drivers/clk/sophgo/clk-ip.c | 30 +- > drivers/clk/sophgo/clk-ip.h | 18 +- > drivers/clk/sophgo/clk-pll.c | 8 +- > drivers/clk/sophgo/clk-pll.h | 4 +- > drivers/clk/starfive/clk-jh7110-pll.c | 4 +- > drivers/clk/starfive/clk.h | 2 +- > drivers/clk/stm32/clk-stm32-core.c | 22 +- > drivers/clk/stm32/clk-stm32-core.h | 2 +- > drivers/clk/stm32/clk-stm32f.c | 4 +- > drivers/clk/stm32/clk-stm32h7.c | 2 +- > drivers/clk/stm32/clk-stm32mp1.c | 4 +- > drivers/clk/sunxi/clk_sun6i_rtc.c | 2 +- > drivers/clk/sunxi/clk_sunxi.c | 2 +- > drivers/clk/tegra/tegra-car-clk.c | 4 +- > drivers/clk/tegra/tegra186-clk.c | 4 +- > drivers/clk/thead/clk-th1520-ap.c | 8 +- > drivers/clk/ti/clk-am3-dpll-x2.c | 2 +- > drivers/clk/ti/clk-am3-dpll.c | 4 +- > drivers/clk/ti/clk-ctrl.c | 2 +- > drivers/clk/ti/clk-divider.c | 4 +- > drivers/clk/ti/clk-gate.c | 2 +- > drivers/clk/ti/clk-k3-pll.c | 4 +- > drivers/clk/ti/clk-k3.c | 6 +- > drivers/clk/ti/clk-mux.c | 4 +- > drivers/clk/ti/clk-sci.c | 4 +- > drivers/clk/uccf/Kconfig | 22 + > drivers/clk/uccf/Makefile | 11 + > drivers/clk/{ => uccf}/clk-composite.c | 20 +- > drivers/clk/{ => uccf}/clk-divider.c | 4 +- > drivers/clk/{ => uccf}/clk-fixed-factor.c | 2 +- > drivers/clk/{ => uccf}/clk-gate.c | 2 +- > drivers/clk/{ => uccf}/clk-mux.c | 2 +- > drivers/clk/{ => uccf}/clk.c | 4 +- > .../{clk_sandbox_ccf.c => uccf/clk_sandbox_uccf.c} | 12 +- > drivers/clk/uniphier/clk-uniphier-core.c | 6 +- > drivers/core/ofnode.c | 4 +- > drivers/phy/cadence/phy-cadence-sierra.c | 2 +- > drivers/phy/cadence/phy-cadence-torrent.c | 2 +- > drivers/phy/phy-stm32-usbphyc.c | 2 +- > drivers/phy/phy-ti-am654.c | 2 +- > drivers/phy/rockchip/phy-rockchip-inno-usb2.c | 2 +- > drivers/phy/ti/phy-j721e-wiz.c | 6 +- > drivers/power/domain/imx8mp-hsiomix.c | 2 +- > drivers/ufs/ufs-qcom.c | 31 +- > include/clk-uclass.h | 6 +- > include/clk.h | 102 +- > include/linux/clk-provider-ccf_full.h | 1461 ++++++++ > include/linux/clk-provider-uccf.h | 256 ++ > include/linux/clk-provider.h | 253 +- > include/linux/clk/clk-conf.h | 22 + > include/sandbox-clk.h | 5 +- > test/dm/Makefile | 3 +- > test/dm/clk.c | 32 +- > test/dm/clk_ccf.c | 117 +- > test/test-main.c | 6 + > 258 files changed, 24032 insertions(+), 997 deletions(-) > --- > base-commit: e0ef25054db31fee49d031ac337099b12c67e5b8 > > Casey Connolly <[email protected]> >