Re: [PATCH v5 00/21] PM / devferq: Add generic exynos bus frequency driver and new passive governor

[Chanwoo Choi]

Dear Anand and Tobias,

To Anand,
First of all, thanks to your test on previous patchset.
I removed the your tested-by tag from this version
because I modified the devfreq core using DEVFREQ_TRANSITION_NOTIFIER notifier.
I think that this patch-set need to test with this patchset.
If you possible, could you please test this patch-set? Thanks in advance.

To Tobias,
I fixed the following issues reported by you. Thanks your test and report.
- RCU locking issue
- debugfs error during kernel booting

Best Regards,
Chanwoo Choi

On 2016ë 03ì 24ì 13:25, Chanwoo Choi wrote:
> Dear all,
> 
> This patchset uses the DEVFREQ_TRANSITION_NOTIFIER notifier to connecth
> devfreq device using ondemand governor and devfreq device using passive
> governor. Also I fix the some issue reported by 'Tobias Jakobi' and add the
> detailed issue information. But, this patchset don't modify the anything of
> Device Tree patches (patch12 ~ patch21) which already got the reviewed-by
> from Exynos Soc Maintainer.
> 
> I tested it on exynos3250-rinato and exynos4412-odroidu3 board.
> 
> [Description]
> This patch-set includes the two features as following. The generic exynos bus
> frequency driver is able to support almost Exynos SoCs for bus frequency
> scaling. And the new passive governor is able to make the dependency on
> between devices for frequency/voltage scaling. I had posted the patch-set[1]
> with the similiar concept. This is is revised version for exynos bus frequency.
> - Generic exynos bus frequency driver
> - New passive governor of DEVFREQ framework
> [1] https://lkml.org/lkml/2015/1/7/872
> : [PATCHv3 0/8] devfreq: Add generic exynos memory-bus frequency driver
> 
> Changes from v4:
> (https://lkml.org/lkml/2015/12/14/43)
> - Add new DEVFREQ_TRANSITION_NOTIFIER notifier. The passive
>   devfreq device recevie the changed frequency of parent
>   devfreq device through DEVFREQ_TRANSITION_NOTIFIER.
> - Add governor type to identify thme using the defined constant
> - Modify the passive governor using the DEVFREQ_TRANSITION_NOTIFIER notifier.
> - Fix the RCU locking probrlm (Reported-by: Tobias Jakobi)
> - Fix the debugfs error during the kernel booting (Reported-by: Tobias Jakobi)
> 
> Changes from v3:
> (https://lkml.org/lkml/2015/12/11/75)
> - Add the reviewed-by tag from Krzysztof Kozlowski (patch2/3/13/14/15/16/17)
> - Fix typo of the description on patch14
> - Modify the subject and description of patch17
> - Reorder the 'bus_xxx' device tree node alphabetically in 
>   both exynos3250-rinato/monk.dts and exynos4412-trats/odroidu3
> 
> Changes from v2:
> (https://lkml.org/lkml/2015/12/8/869)
> - Fix typo on documentation
> - Modify the more appropriate sentence on patch description
> - Add the detailed description about both parent and passive bus device
> - Modify the DMC frequency for Exynos4x12 DMC bus (200MHz -> 267MHz)
> - Modify the voltage of 200MHz was included in Exynos3250 DMC bus (800mV -> 825mV)
> - Rename OPP nodes as 'opp@<opp-hz>'
> - Delete the duplicate 'opp-microvolt' property of passive devfreq device
> - Reorder the 'bus_xxx' device tree node alphabetically in exynos3250-rinato/monk.dts
> - Reorder the 'bus_xxx' device tree node alphabetically in exynos4412-trats/odroidu3
> - Add new exynos4412-ppmu-common.dtsi to remove the duplicate PPMU dt node
>   on rinato/monk/trats2/odroid-u3 board
> - Add the log message if bus device is registered to devfreq framework successfully
> - Add the reviewed-by tag from Krzysztof Kozlowski
> - Add the tested-by tag from Anand Moon on Odroid U3
> - Add 'SAMSUNG BUS FREQUENCY DRIVER' entry to MAINTAINERS
> 
> Changes from v1:
> (https://lkml.org/lkml/2015/11/26/260)
> - Check whether the instance of regulator is NULL or not
>   when executing regulator_disable() because of only parent
>   devfreq device has the regulator instance. After fixing it,
>   the wake-up from suspend state is well working. (patch1)
> - Fix bug which checks 'bus-clk' instead of 'bus->regulator'
>   after calling devm_clk_get() (on patch1)
> - Update the documentation to remove the description about
>   DEVFREQ-EVENT subsystem (on patch2)
> - Add the full name of DMC (Dynamic Memory Controller) (on patch2)
> - Modify the detailed correlation of buses for Exynos3250
>   on documentation (patch2)
> - Add the MFC bus node for Exynos3250 (on patch11, patch12)
> - Fix the duplicate frequency of bus_display on Exynos4x12.dtsi
> - Add the PPMU node for exynos4412-odroidu3
> - Add the support of bus frequency for exynos4412-odroidu3
> 
> Detailed descirption for patch-set:
> 1. Add generic exynos bus frequency driver
> : This patch-set adds the generic exynos bus frequency driver for AXI bus
> of sub-blocks in exynos SoC. The Samsung Exynos SoC have the common
> architecture for bus between DRAM and sub-blocks in SoC.
> 
>  There are the different buses according to Exynos SoC because Exynos SoC
> has the differnt sub-blocks and bus speed. In spite of this difference
> among Exynos SoCs, this driver is able to support almost Exynos SoC by adding
> unique data of each bus in the devicetree file.
> 
>  In devicetree, each bus node has a bus clock, regulator, operation-point
> and devfreq-event devices which measure the utilization of each bus block.
> 
> For example,
> - The bus of DMC block in exynos3250.dtsi are listed below:
> 
> 	bus_dmc: bus_dmc {
> 		compatible = "samsung,exynos-bus";
> 		clocks = <&cmu_dmc CLK_DIV_DMC>;
> 		clock-names = "bus";
> 		operating-points-v2 = <&bus_dmc_opp_table>;
> 		status = "disabled";
> 	};
> 
> 	bus_dmc_opp_table: opp_table1 {
> 		compatible = "operating-points-v2";
> 		opp-shared;
> 
> 		opp@50000000 {
> 			opp-hz = /bits/ 64 <50000000>;
> 			opp-microvolt = <800000>;
> 		};
> 		opp@100000000 {
> 			opp-hz = /bits/ 64 <100000000>;
> 			opp-microvolt = <800000>;
> 		};
> 		opp@134000000 {
> 			opp-hz = /bits/ 64 <134000000>;
> 			opp-microvolt = <800000>;
> 		};
> 		opp@200000000 {
> 			opp-hz = /bits/ 64 <200000000>;
> 			opp-microvolt = <825000>;
> 		};
> 		opp@400000000 {
> 			opp-hz = /bits/ 64 <400000000>;
> 			opp-microvolt = <875000>;
> 		};
> 	};
> 
> - Usage case to handle the frequency and voltage of bus on runtime
>   in exynos3250-rinato.dts are listed below:
> 
> 	&bus_dmc {
> 		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
> 		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
> 		status = "okay";
> 	};
> 
> 2. Add new passive governor of DEVFREQ framework (patch5-patch7)
> : This patch-set add the new passive governor for DEVFREQ framework.
> The existing governors (ondemand, performance and so on) are used for DVFS
> (Dynamic Voltage and Frequency Scaling) drivers. The existing governors
> are independently used for specific device driver which don't give the
> influence to other device drviers and also don't receive the effect from
> other device drivers.
> 
>  The passive governor depends on operation of parent driver with existing
> governors(ondemand, performance and so on) extremely and is not able to
> decide the new frequency by oneself. According to the decided new frequency
> of parent driver with governor, the passive governor uses it to decide
> the appropriate frequency for own device driver. The passive governor
> must need the following information from device tree:
> 
> For exameple,
>  There are one more bus device drivers in Exynos3250 which need to
> change their source clock according to their utilization on runtime.
> But, they share the same power line (e.g., regulator). So, LEFTBUS bus
> driver is operated as parent with ondemand governor and then the rest
> device driver with passive governor.
> 
>  The buses of Internal block in exynos3250.dtsi are listed below:
> When LEFTBUS bus driver (parent) changes the bus frequency with
> ondemand governor on runtime, the rest bus devices which sharing
> the same power line (VDD_INT) will change the each bus frequency
> according to the decision of LEFTBUS bus driver (parent).
> 
> - INT (Internal) block
> 	: VDD_INT |--- LEFTBUS
> 		  |--- PERIL
> 		  |--- MFC
> 		  |--- G3D
> 		  |--- RIGHTBUS
> 		  |--- FSYS
> 		  |--- LCD0
> 		  |--- PERIR
> 		  |--- ISP
> 		  |--- CAM
> 
> - The buss of INT block in exynos3250.dtsi are listed below:
> 	bus_leftbus: bus_leftbus {
> 		compatible = "samsung,exynos-bus";
> 		clocks = <&cmu CLK_DIV_GDL>;
> 		clock-names = "bus";
> 		operating-points-v2 = <&bus_leftbus_opp_table>;
> 		status = "disabled";
> 	};
> 
> 	bus_rightbus: bus_rightbus {
> 		compatible = "samsung,exynos-bus";
> 		clocks = <&cmu CLK_DIV_GDR>;
> 		clock-names = "bus";
> 		operating-points-v2 = <&bus_leftbus_opp_table>;
> 		status = "disabled";
> 	};
> 
> 	(Omit the rest bus dt node)
> 
> - Usage case to handle the frequency and voltage of bus on runtime
>   in exynos3250-rinato.dts are listed below:
> 	/* Parent bus device of VDD_INT */
> 	&bus_leftbus {
> 		devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
> 		vdd-supply = <&buck3_reg>;
> 		status = "okay";
> 	};
> 
> 	/* Passive bus device depend on LEFTBUS bus. */
> 	&bus_rightbus {
> 		devfreq = <&bus_leftbus>; /* 'devfreq' property indicates
> 					     the phandle of parent device. */
> 		status = "okay";
> 	};
> 
> 	(Omit the rest bus dt node)
> 
> Chanwoo Choi (21):
>   PM / devfreq: exynos: Add generic exynos bus frequency driver
>   PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver
>   PM / devfreq: Add devfreq_get_devfreq_by_phandle()
>   PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier
>   PM / devfreq: Add governer type with unique number
>   PM / devfreq: Add new passive governor
>   PM / devfreq: exynos: Add support of bus frequency of sub-blocks using passive governor
>   PM / devfreq: exynos: Update documentation for bus devices using passive governor
>   PM / devfreq: exynos: Add the detailed correlation between sub-blocks and power line
>   PM / devfreq: exynos: Remove unused exynos4/5 busfreq driver
>   MAINTAINERS: Add samsung bus frequency driver entry
>   ARM: dts: Add DMC bus node for Exynos3250
>   ARM: dts: Add DMC bus frequency for exynos3250-rinato/monk
>   ARM: dts: Add bus nodes using VDD_INT for Exynos3250
>   ARM: dts: Add bus nodes using VDD_MIF for Exynos4x12
>   ARM: dts: Add bus nodes using VDD_INT for Exynos4x12
>   ARM: dts: Add bus nodes using VDD_MIF for Exynos4210
>   ARM: dts: Add exynos4412-ppmu-common dtsi to delete duplicate PPMU nodes
>   ARM: dts: Add support of bus frequency using VDD_INT for exynos3250-rinato
>   ARM: dts: Expand the voltage range of buck1/3 regulator for exynos4412-odroidu3
>   ARM: dts: Add support of bus frequency for exynos4412-trats/odroidu3
> 
>  .../devicetree/bindings/devfreq/exynos-bus.txt     |  390 ++++++++
>  MAINTAINERS                                        |    9 +
>  arch/arm/boot/dts/exynos3250-monk.dts              |   47 +-
>  arch/arm/boot/dts/exynos3250-rinato.dts            |   88 +-
>  arch/arm/boot/dts/exynos3250.dtsi                  |  181 ++++
>  arch/arm/boot/dts/exynos4210.dtsi                  |  159 +++
>  arch/arm/boot/dts/exynos4412-odroid-common.dtsi    |   56 +-
>  arch/arm/boot/dts/exynos4412-ppmu-common.dtsi      |   50 +
>  arch/arm/boot/dts/exynos4412-trats2.dts            |   88 +-
>  arch/arm/boot/dts/exynos4x12.dtsi                  |  174 ++++
>  drivers/devfreq/Kconfig                            |   35 +-
>  drivers/devfreq/Makefile                           |    4 +-
>  drivers/devfreq/devfreq.c                          |  224 ++++-
>  drivers/devfreq/exynos-bus.c                       |  561 +++++++++++
>  drivers/devfreq/exynos/Makefile                    |    3 -
>  drivers/devfreq/exynos/exynos4_bus.c               | 1055 --------------------
>  drivers/devfreq/exynos/exynos4_bus.h               |  110 --
>  drivers/devfreq/exynos/exynos5_bus.c               |  431 --------
>  drivers/devfreq/exynos/exynos_ppmu.c               |  119 ---
>  drivers/devfreq/exynos/exynos_ppmu.h               |   86 --
>  drivers/devfreq/governor.h                         |   21 +
>  drivers/devfreq/governor_passive.c                 |  192 ++++
>  drivers/devfreq/governor_performance.c             |    1 +
>  drivers/devfreq/governor_powersave.c               |    1 +
>  drivers/devfreq/governor_simpleondemand.c          |    1 +
>  drivers/devfreq/governor_userspace.c               |    1 +
>  include/linux/devfreq.h                            |   70 ++
>  27 files changed, 2209 insertions(+), 1948 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>  create mode 100644 arch/arm/boot/dts/exynos4412-ppmu-common.dtsi
>  create mode 100644 drivers/devfreq/exynos-bus.c
>  delete mode 100644 drivers/devfreq/exynos/Makefile
>  delete mode 100644 drivers/devfreq/exynos/exynos4_bus.c
>  delete mode 100644 drivers/devfreq/exynos/exynos4_bus.h
>  delete mode 100644 drivers/devfreq/exynos/exynos5_bus.c
>  delete mode 100644 drivers/devfreq/exynos/exynos_ppmu.c
>  delete mode 100644 drivers/devfreq/exynos/exynos_ppmu.h
>  create mode 100644 drivers/devfreq/governor_passive.c
>