Subject: [PATCH v2 00/15] Krait clocks + Krait CPUfreq

From: [email-masked] (Stephen Boyd)
Date: Fri, 5 Sep 2014 15:47:19 -0700

These patches provide cpufreq scaling on devices with Krait CPUs.
In Krait CPU designs there's one PLL and two muxes per CPU, allowing
us to switch CPU frequencies independently.

				 secondary
	 +-----+                    +
	 | QSB |-------+------------|\
	 +-----+       |            | |-+
		       |    +-------|/  |
		       |    |       +   |
	 +-----+       |    |           |
	 | PLL |----+-------+           |   primary
	 +-----+    |  |                |     +
		    |  |                +-----|\       +------+
	 +-------+  |  |                      | \      |      |
	 | HFPLL |----------+-----------------|  |-----| CPU0 |
	 +-------+  |  |    |                 |  |     |      |
		    |  |    | +-----+         | /      +------+
		    |  |    +-| / 2 |---------|/
		    |  |      +-----+         +
		    |  |         secondary
		    |  |            +
		    |  +------------|\
		    |               | |-+
		    +---------------|/  |   primary
				    +   |     +
					+-----|\       +------+
	 +-------+                            | \      |      |
	 | HFPLL |----------------------------|  |-----| CPU1 |
	 +-------+          |                 |  |     |      |
			    | +-----+         | /      +------+
			    +-| / 2 |---------|/
			      +-----+         +

To support this in the common clock framework we model the muxes,
dividers, and PLLs as different clocks. CPUfreq only interacts
with the primary mux (farthest right in the diagram). When CPUfreq
sets a rate, the mux code finds the best parent that can provide the rate.
Due to the design, QSB and the top PLL are always a fixed rate and thus
only support one frequency each. These sources provide the lowest
frequencies for the CPUs. The HFPLLs are where we can make the CPU go
faster (GHz range). Sometimes we need to run the HFPLL twice as
fast and divide it by two to get a particular frequency.

When switching rates we can't leave the CPU clocked by the HFPLL because
we need to turn off the output of the PLL when changing its frequency.
This means we have to switch over to the secondary mux and use one of the
fixed sources. This is why we need something like the safe parent patch.

I plan to submit the DTS changes through arm-soc, but I've included everything
here to make it easier to pick things up for testing, etc. Please note
that these patches rely on the Krait L2 accessor patch I posted a while back
in another series[1]. This also relies on the cpufreq-generic patchset from
Viresh[2]. If anything can be picked up right now it would be better
to reduce the churn over time as other pieces settle. The series gets
progressively more controversial as it goes on, so I hope that things
near the beggining will be picked up earlier.

Changes since v1:
 * Added IPQ and APQ8064 support
 * Switched to cpufreq-generic
 * Added OPP parsing from DT (need to write binding though)
 * New patches to make clk-generic.c go away
  * Made mux and divider reusable for non-MMIO devices
  * Added a mux_determine_rate_closest (not sure if this is really needed)
  * Added unregistration of muxes
 * New patch to avoid sending high frequencies down to devices using clocks

TODO:
 * Add Krait regulator voltage scaling (not strictly necessary)
 * Document DT bindings
 * Use a new efuse/eeprom API instead of hardcoding the location in the driver
 * Add some thermal awareness

Stephen Boyd (15):
  clk: mux: Add unregistration API
  clk: mux: Split out register accessors for reuse
  clk: Add __clk_mux_determine_rate_closest
  clk: divider: Make generic for usage elsewhere
  clk: Add safe switch hook
  clk: Avoid sending high rates to downstream clocks during set_rate
  clk: qcom: Add support for High-Frequency PLLs (HFPLLs)
  clk: qcom: Add HFPLL driver
  clk: qcom: Add MSM8960/APQ8064's HFPLLs
  clk: qcom: Add IPQ806X's HFPLLs
  clk: qcom: Add support for Krait clocks
  clk: qcom: Add KPSS ACC/GCC driver
  clk: qcom: Add Krait clock controller driver
  cpufreq: Add module to register cpufreq on Krait CPUs
  ARM: dts: qcom: Add necessary DT data for Krait cpufreq

 arch/arm/boot/dts/qcom-apq8064.dtsi          | 230 +++++++++++++++++
 arch/arm/boot/dts/qcom-msm8960.dtsi          |  49 ++++
 arch/arm/boot/dts/qcom-msm8974.dtsi          | 311 ++++++++++++++++++++++-
 drivers/clk/clk-divider.c                    | 197 +++++++++------
 drivers/clk/clk-mux.c                        |  91 ++++---
 drivers/clk/clk.c                            | 133 +++++++---
 drivers/clk/qcom/Kconfig                     |  28 +++
 drivers/clk/qcom/Makefile                    |   5 +
 drivers/clk/qcom/clk-hfpll.c                 | 253 +++++++++++++++++++
 drivers/clk/qcom/clk-hfpll.h                 |  54 ++++
 drivers/clk/qcom/clk-krait.c                 | 166 +++++++++++++
 drivers/clk/qcom/clk-krait.h                 |  49 ++++
 drivers/clk/qcom/gcc-ipq806x.c               |  83 +++++++
 drivers/clk/qcom/gcc-msm8960.c               | 172 +++++++++++++
 drivers/clk/qcom/hfpll.c                     | 110 +++++++++
 drivers/clk/qcom/kpss-xcc.c                  |  94 +++++++
 drivers/clk/qcom/krait-cc.c                  | 357 +++++++++++++++++++++++++++
 drivers/cpufreq/Kconfig.arm                  |   9 +
 drivers/cpufreq/Makefile                     |   1 +
 drivers/cpufreq/qcom-cpufreq.c               | 199 +++++++++++++++
 include/dt-bindings/clock/qcom,gcc-msm8960.h |   2 +
 include/linux/clk-private.h                  |   2 +
 include/linux/clk-provider.h                 |  32 ++-
 23 files changed, 2486 insertions(+), 141 deletions(-)
 create mode 100644 drivers/clk/qcom/clk-hfpll.c
 create mode 100644 drivers/clk/qcom/clk-hfpll.h
 create mode 100644 drivers/clk/qcom/clk-krait.c
 create mode 100644 drivers/clk/qcom/clk-krait.h
 create mode 100644 drivers/clk/qcom/hfpll.c
 create mode 100644 drivers/clk/qcom/kpss-xcc.c
 create mode 100644 drivers/clk/qcom/krait-cc.c
 create mode 100644 drivers/cpufreq/qcom-cpufreq.c

[1] http://lkml.iu.edu/hypermail/linux/kernel/1404.0/02636.html
[2] git://git.linaro.org/people/viresh.kumar/linux cpufreq/cpu0-krait-v3
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