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

[Pramod Gurav <pramod.gurav@smartplayin.com>]

Hi Stephen,
Looks like one patch is missing from v1. Is this removed from v2
patchset from some reason?
	ARM: Add Krait L2 register accessor functions

But there are references to this in v2 set and build fails while
compiling drivers/clk/qcom/clk-krait.c.

Thanks and Regards
Pramod

On Saturday 06 September 2014 04:17 AM, Stephen Boyd wrote:
> 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
>