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

From: [email-masked] (Tobias Jakobi)
Date: Thu, 24 Mar 2016 14:52:30 +0100

Hello everybody,

Markus Reichl wrote:
> Hi Chanwoo,
> 
> Am 24.03.2016 um 05:30 schrieb 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
> 
> This set works fine on odroid U3 but gives the following with dmesg |grep devfreq:
> 
> [    2.066890] devfreq bus_dmc: Couldn't update frequency transition information.
> [    2.190238] devfreq bus_leftbus: Couldn't update frequency transition information.
I have yet to test this new iteration of the patchset, but this message
looks familiar. I already encountered it with the older version applied
to vanilla-4.5.y.

The messages happen when devfreq_update_status() (in
drivers/devfreq/devfreq.c) encounters a uninitialized (zero)
previous_freq. I have currently fixed this in my local tree by just
skipping (goto out) devfreq_update_status() in that case.

Maybe it would be more elegant to set previous_freq to something sane on
probe. IIRC then it is set from initial_freq on probe, but the exynos
code doesn't set this one.

Maybe this info is helpful?

With best wishes,
Tobias

> 
> Thanks,
> --
> Markus Reichl
> 
>>
>> On 2016? 03? 24? 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 at 50000000 {
>>> 			opp-hz = /bits/ 64 <50000000>;
>>> 			opp-microvolt = <800000>;
>>> 		};
>>> 		opp at 100000000 {
>>> 			opp-hz = /bits/ 64 <100000000>;
>>> 			opp-microvolt = <800000>;
>>> 		};
>>> 		opp at 134000000 {
>>> 			opp-hz = /bits/ 64 <134000000>;
>>> 			opp-microvolt = <800000>;
>>> 		};
>>> 		opp at 200000000 {
>>> 			opp-hz = /bits/ 64 <200000000>;
>>> 			opp-microvolt = <825000>;
>>> 		};
>>> 		opp at 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
>>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
>> the body of a message to majordomo at vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>