On Mon, 24 Oct 2022 05:39:20 +0100, Hector Martin <marcan@xxxxxxxxx> wrote: > > Hi folks, > > Third time's the charm? Here's v3 of the cpufreq driver for Apple SoCs. > This version takes a page from both v1 and v2, keeping the dedicated > cpufreq style (instead of pretending to be a clock controller) but using > dedicated DT nodes for each cluster, which accurately represents the > hardware. In particular, this makes supporting t6002 (M1 Ultra) a lot > more reasonable on the DT side. > > This version also switches to the standard performance-domains binding, > so we don't need any more vendor-specific properties. In order to > support this, I had to make the performance-domains parsing code more > generic. This required a minor change to the only consumer > (mediatek-cpufreq-hw). > > The Linux driver probes based on platform compatible, and then attempts > to locate the cluster nodes by following the performance-domains links > from CPU nodes (this will then fail for any incompatible nodes, e.g. if > a future SoC needs a new compatible and can't fall back). This approach > was suggested by robh as the right way to handle the impedance mismatch > between the hardware, which has separate controllers per cluster, and > the Linux model where there can only be one CPUFreq driver instance. > > Functionality-wise, there are no significant changes from v2. The only > notable difference is support for t8112 (M2). This works largely the > same as the other SoCs, but they ran out of bits in the current PState > register, so that needs a SoC-specific quirk. Since that register is > not used by macOS (it was discovered experimentally) and is not critical > for functionality (it just allows accurately reporting the current > frequency to userspace, given boost clock limitations), I've decided to > only use it when a SoC-specific compatible is present. The default > fallback code will simply report the requested frequency as actual. > I expect this will work for future SoCs. > > As usual, MAINTAINERS and DT changes are split. I expect patches #2~#4 > to go through the cpufreq tree, and we'll take care of #1 and #5 via > the asahi-soc tree. > > Hector Martin (5): > MAINTAINERS: Add entries for Apple SoC cpufreq driver > dt-bindings: cpufreq: apple,soc-cpufreq: Add binding for Apple SoC > cpufreq > cpufreq: Generalize of_perf_domain_get_sharing_cpumask phandle format > cpufreq: apple-soc: Add new driver to control Apple SoC CPU P-states > arm64: dts: apple: Add CPU topology & cpufreq nodes for t8103 > > .../cpufreq/apple,cluster-cpufreq.yaml | 119 ++++++ > MAINTAINERS | 2 + > arch/arm64/boot/dts/apple/t8103.dtsi | 206 +++++++++- > drivers/cpufreq/Kconfig.arm | 9 + > drivers/cpufreq/Makefile | 1 + > drivers/cpufreq/apple-soc-cpufreq.c | 352 ++++++++++++++++++ > drivers/cpufreq/cpufreq-dt-platdev.c | 2 + > drivers/cpufreq/mediatek-cpufreq-hw.c | 14 +- > include/linux/cpufreq.h | 28 +- > 9 files changed, 706 insertions(+), 27 deletions(-) > create mode 100644 Documentation/devicetree/bindings/cpufreq/apple,cluster-cpufreq.yaml > create mode 100644 drivers/cpufreq/apple-soc-cpufreq.c FWIW, and for the whole series: Acked-by: Marc Zyngier <maz@xxxxxxxxxx> M. -- Without deviation from the norm, progress is not possible.
