[PATCH v8 00/20] PM / devferq: Add generic exynos bus frequency driver and new passive governor

Chanwoo Choi
2016-04-08T04:24:49Z

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 v7:
(https://lkml.org/lkml/2016/3/31/308)
- Use IS_ERR() instead of IS_ERR_OR_NULL() macro
- Add signed-off-by/acked-by tag of DEVFREQ maintainer
- Fix the comment in governor_passive.c

Changes from v6:
(https://lkml.org/lkml/2016/3/27/187)
- Patch1/2 add signed-off-by tag from DEVFREQ Maintainer (Myungjoo Ham)
- Drop patch5 (PM / devfreq: Add governer type with unique number)
- Add missing description about the transition_notifier_list in struct devfreq
- Remove the passive governor code from devfreq.c core driver. Instead, passive
governor uses the DEVFREQ_GOV_START/STOP signal to register/unregister the
DEVFREQ_TRANSITION_NOTIFIER between the parent devfreq device and passive
devfreq device.
- Add the author (myungjoo.ham at samsung.com) of passive governor
- Add 'struct devfreq_passive_data' to pass the devfreq instance of parent.

Changes from v5:
(https://lkml.org/lkml/2016/3/24/5)
- Rebase the patch-set on Linux v4.6-rc1
- Add Tested-by tag from Markus Reichl <m.reichl@fivetechno.de>
- Add Tested-by tag from Anand Moon <linux.amoon@gmail.com>

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)
- The Device Tree patches have got Reviewed-by tag from Exynos SoC Maintainer
(Krzysztof Kozlowski <k.kozlowski@samsung.com>)

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

[Description]
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
: 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 (20):
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 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 | 36 +-
drivers/devfreq/Makefile | 4 +-
drivers/devfreq/devfreq.c | 207 +++-
drivers/devfreq/exynos-bus.c | 570 +++++++++++
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_passive.c | 207 ++++
include/linux/devfreq.h | 99 ++
22 files changed, 2221 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

--
1.9.1