QCOM 8074 cpuidle driver

Add allowable C-States for each cpu using the cpu-idle-states node. ARM spec dictates WFI as the default idle state at 0. Support standalone power collapse (power down that does not affect any SoC idle states) for each cpu.

Signed-off-by Lina Iyer <[email protected]>

Add allowable C-States for each cpu using the cpu-idle-states node. ARM spec dictates WFI as the default idle state at 0. Support standalone power collapse (power down that does not affect any SoC idle states) for each cpu.

Signed-off-by Lina Iyer <[email protected]>

---
arch/arm/boot/dts/qcom-msm8974.dtsi | 20 ++++++++++++++++++++

1 file changed, 20 insertions(+)

arch/arm/boot/dts/qcom-msm8974.dtsi +4 -0

index 0580bc2..041c8b6 100644
@@ -21,6 +21,7 @@
 			reg = <0>;
 			next-level-cache = <&L2>;
 			qcom,acc = <&acc0>;
+			cpu-idle-states = <&CPU_WFI &CPU_SPC>;
 		};
 
 		CPU1: cpu at 1 {

@@ -30,6 +31,7 @@
 			reg = <1>;
 			next-level-cache = <&L2>;
 			qcom,acc = <&acc1>;
+			cpu-idle-states = <&CPU_WFI &CPU_SPC>;
 		};
 
 		CPU2: cpu at 2 {

@@ -39,6 +41,7 @@
 			reg = <2>;
 			next-level-cache = <&L2>;
 			qcom,acc = <&acc2>;
+			cpu-idle-states = <&CPU_WFI &CPU_SPC>;
 		};
 
 		CPU3: cpu at 3 {

@@ -48,6 +51,7 @@
 			reg = <3>;
 			next-level-cache = <&L2>;
 			qcom,acc = <&acc3>;
+			cpu-idle-states = <&CPU_WFI &CPU_SPC>;
 		};
 
 		L2: l2-cache {

arch/arm/boot/dts/qcom-msm8974.dtsi +13 -0

+				compatible = "qcom,idle-state-wfi", "arm,idle-state";
+				entry-latency-us = <1>;
+				exit-latency-us = <1>;
+				min-residency-us = <2>;
+			};
+
+			CPU_SPC: cpu-idle-state-1 {
+				compatible = "qcom,idle-state-spc", "arm,idle-state";
+				entry-latency-us = <150>;
+				exit-latency-us = <200>;
+				min-residency-us = <2000>;
+			};
+		};
 	};
 
 	cpu-pmu {

Signature · 1 line

1.9.1

Changes since v4:
[ https://www.mail-archive.com/[email protected]/msg10327.html ]
- Update to the v8 of ARM generic idle states patches
- Use platform device model for cpuidle-qcom
- Clean up msm-pm.c to remove unnecessary include files and functions
- Update commit text and documentation for all idle states
- Remove scm-boot relocate patch from this series, submitted earlier [ https://www.mail-archive.com/[email protected]/msg10518.html ]

Changes since v3:
[ https://www.mail-archive.com/[email protected]/msg10288.html ]
- Fix CONFIG_QCOM_PM Kconfig as bool
- More clean ups in spm.c and spm-devices.c
- Removed and re-organized data structures to make initialization simple
- Remove export of sequence flush functions
- Updated commit text
- Comments for use of barriers.
- Rebase on top of 3.17-rc1

Changes since v2:
[ https://www.mail-archive.com/[email protected]/msg10148.html ]
- Prune all the drivers to support basic WFI and power down cpuidle functionality. Remove debug code.
- Integrate KConfig changes into the drivers' patches.
- Use Lorenzo's ARM idle-states patches as the basis for reading cpuidle c-states from DT.
[ http://marc.info/?l=linux-pm&m=140794514812383&w=2 ]
- Incorporate review comments
- Rebase on top of 3.16

Changes since v1/RFC:
[ https://www.mail-archive.com/[email protected]/msg10065.html ]
- Remove hotplug from the patch series. Will submit it separately.
- Fix SPM drivers per the review comments
- Modify patch sequence to compile SPM drivers independent of msm-pm, so as to allow wfi() calls to use SPM even without SoC interface driver.

8074 like any ARM SoC can do architectural clock gating, that helps save on power, but not enough of leakage power. Leakage power of the SoC can be further reduced by turning off power to the core. To aid this, every core (cpu and L2) is accompanied by a Sub-system Power Manager (SPM), that can be configured to indicate the low power mode, the core would be put into and the SPM programs the peripheral h/w accordingly to enter low power and turn off the power rail to the core.

The idle invocation hierarchy -

	CPUIDLE
	|
	cpuidle-qcom.c [CPUIdle driver]
	|
	------>	msm-pm.c [SoC Interface layer for QCOM chipsets]
		|
		------> spm-devices.c [SPM devices manager]
		|	|
		|	------>	spm.c [SPM h/w driver]
		|
		------> scm-boot.c [SCM interface layer]		
			|
------------------------|--------------------------
(EL)			Secure Monitor Code
			|
			|
			wfi(); 
------------------------|--------------------------
(HW)			[CPU] {clock gate}
			|
			-----> [SPM] {statemachine}

The patchset does the following -

- Add new Secure Monitor flags to support warmboot of a quad core system.

- Introduce the SPM driver to control power to the core. The SPM h/w IP works in conjunction with the Krait CPU/L2. When the core executes WFI instruction, the core is clockgated and the SPM state machine takes over and powers the core down. An interrupt from GIC, resumes the SPM state machine which brings the cpu out of the low power mode.

- Add a SPM device manager to configure multiple SPM devices.

- Add the device tree configuration for each of the SPM nodes. There is one for each cpu. There is one for each cpu.

- Introduce the SoC driver interface layer to configure SPM per the core's idle state. To power down the cpu core, the SPM h/w needs to be set up correctly
to power down the core, when the core executes WFI. Linux is expected to call into Secure Monitor to power down the core. At reset, the core will start in seure mode and will be returned back to Linux.

- Add CPUIDLE driver for QCOM cpus. The cpuidle driver uses the SoC interface layer to configure the SPM to allow Krait to be powered down. The cpuidle driver is based on ARM idle-state framework for cpuidle drivers.

- Provide device configuration for 8074 SoC. Current support is for WFI and standalone power collapse, which powers only the core independent of the other cores and caches.

Thanks,
Lina

Lina Iyer (7):
msm: scm: Add SCM warmboot flags for quad core targets.
qcom: spm: Add Subsystem Power Manager driver (SAW2)
qcom: spm-devices: Add SPM device manager for the SoC
arm: dts: qcom: Add SPM device bindings for 8974
qcom: msm-pm: Add cpu low power mode functions
qcom: cpuidle: Add cpuidle driver for QCOM cpus
arm: dts: qcom: Add idle states device nodes for 8974

 .../bindings/arm/msm/qcom,idle-state.txt           |  72 ++++++++
 Documentation/devicetree/bindings/arm/msm/spm.txt  |  47 +++++
 arch/arm/boot/dts/qcom-msm8974-pm.dtsi             |  69 +++++++
 arch/arm/boot/dts/qcom-msm8974.dtsi                |  30 +++-
 drivers/cpuidle/Kconfig.arm                        |   7 +
 drivers/cpuidle/Makefile                           |   1 +
 drivers/cpuidle/cpuidle-qcom.c                     |  87 +++++++++
 drivers/soc/qcom/Kconfig                           |   8 +
 drivers/soc/qcom/Makefile                          |   1 +
 drivers/soc/qcom/msm-pm.c                          | 106 +++++++++++
 drivers/soc/qcom/spm-devices.c                     | 198 +++++++++++++++++++++
 drivers/soc/qcom/spm-drv.h                         |  69 +++++++
 drivers/soc/qcom/spm.c                             | 192 ++++++++++++++++++++
 include/soc/qcom/pm.h                              |  31 ++++
 include/soc/qcom/scm-boot.h                        |   2 +
 include/soc/qcom/spm.h                             |  38 ++++
 16 files changed, 954 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt
 create mode 100644 Documentation/devicetree/bindings/arm/msm/spm.txt
 create mode 100644 arch/arm/boot/dts/qcom-msm8974-pm.dtsi
 create mode 100644 drivers/cpuidle/cpuidle-qcom.c
 create mode 100644 drivers/soc/qcom/msm-pm.c
 create mode 100644 drivers/soc/qcom/spm-devices.c
 create mode 100644 drivers/soc/qcom/spm-drv.h
 create mode 100644 drivers/soc/qcom/spm.c
 create mode 100644 include/soc/qcom/pm.h
 create mode 100644 include/soc/qcom/spm.h

Hi Lina,

With your patchset on top of 3.17-rc4 with v9 of ARM generic idle states patches from Lorenzo I have tested cpuidle on dragonboard8974 with Linaro test suites. All testcases report pass. Also verified manually through sysfs to see changes in usage count and other details about each state on all cpus.

So,

Tested-by Pramod Gurav <[email protected]>

I have a comment/observation only on name entry for each state which reflects only "cpu-idle-state-" as Lorenzo dt-idle driver limits CPUIDLE_NAME_LEN to 16.

Thanks
Pramod.

Quoted 141 lines · Lina Iyer

Changes since v4:
[ https://www.mail-archive.com/linux-arm-msm at vger.kernel.org/msg10327.html ]
- Update to the v8 of ARM generic idle states patches
- Use platform device model for cpuidle-qcom
- Clean up msm-pm.c to remove unnecessary include files and functions
- Update commit text and documentation for all idle states
- Remove scm-boot relocate patch from this series, submitted earlier [ https://www.mail-archive.com/linux-arm-msm at vger.kernel.org/msg10518.html ]

Changes since v3:
[ https://www.mail-archive.com/linux-arm-msm at vger.kernel.org/msg10288.html ]
- Fix CONFIG_QCOM_PM Kconfig as bool
- More clean ups in spm.c and spm-devices.c
- Removed and re-organized data structures to make initialization simple
- Remove export of sequence flush functions
- Updated commit text
- Comments for use of barriers.
- Rebase on top of 3.17-rc1

Changes since v2:
[ https://www.mail-archive.com/linux-arm-msm at vger.kernel.org/msg10148.html ]
- Prune all the drivers to support basic WFI and power down cpuidle functionality. Remove debug code.
- Integrate KConfig changes into the drivers' patches.
- Use Lorenzo's ARM idle-states patches as the basis for reading cpuidle c-states from DT.
[ http://marc.info/?l=linux-pm&m=140794514812383&w=2 ]
- Incorporate review comments
- Rebase on top of 3.16

Changes since v1/RFC:
[ https://www.mail-archive.com/linux-arm-msm at vger.kernel.org/msg10065.html ]
- Remove hotplug from the patch series. Will submit it separately.
- Fix SPM drivers per the review comments
- Modify patch sequence to compile SPM drivers independent of msm-pm, so as to allow wfi() calls to use SPM even without SoC interface driver.

8074 like any ARM SoC can do architectural clock gating, that helps save on power, but not enough of leakage power. Leakage power of the SoC can be further reduced by turning off power to the core. To aid this, every core (cpu and L2) is accompanied by a Sub-system Power Manager (SPM), that can be configured to indicate the low power mode, the core would be put into and the SPM programs the peripheral h/w accordingly to enter low power and turn off the power rail to the core.

The idle invocation hierarchy -

	CPUIDLE
	|
	cpuidle-qcom.c [CPUIdle driver]
	|
	------>	msm-pm.c [SoC Interface layer for QCOM chipsets]
		|
		------> spm-devices.c [SPM devices manager]
		|	|
		|	------>	spm.c [SPM h/w driver]
		|
		------> scm-boot.c [SCM interface layer]		
			|
------------------------|--------------------------
(EL)			Secure Monitor Code
			|
			|
			wfi();
------------------------|--------------------------
(HW)			[CPU] {clock gate}
			|
			-----> [SPM] {statemachine}

The patchset does the following -

- Add new Secure Monitor flags to support warmboot of a quad core system.

- Introduce the SPM driver to control power to the core. The SPM h/w IP works in conjunction with the Krait CPU/L2. When the core executes WFI instruction, the core is clockgated and the SPM state machine takes over and powers the core down. An interrupt from GIC, resumes the SPM state machine which brings the cpu out of the low power mode.

- Add a SPM device manager to configure multiple SPM devices.

- Add the device tree configuration for each of the SPM nodes. There is one for each cpu. There is one for each cpu.

- Introduce the SoC driver interface layer to configure SPM per the core's idle state. To power down the cpu core, the SPM h/w needs to be set up correctly
to power down the core, when the core executes WFI. Linux is expected to call into Secure Monitor to power down the core. At reset, the core will start in seure mode and will be returned back to Linux.

- Add CPUIDLE driver for QCOM cpus. The cpuidle driver uses the SoC interface layer to configure the SPM to allow Krait to be powered down. The cpuidle driver is based on ARM idle-state framework for cpuidle drivers.

- Provide device configuration for 8074 SoC. Current support is for WFI and standalone power collapse, which powers only the core independent of the other cores and caches.

Thanks,
Lina

Lina Iyer (7):
msm: scm: Add SCM warmboot flags for quad core targets.
qcom: spm: Add Subsystem Power Manager driver (SAW2)
qcom: spm-devices: Add SPM device manager for the SoC
arm: dts: qcom: Add SPM device bindings for 8974
qcom: msm-pm: Add cpu low power mode functions
qcom: cpuidle: Add cpuidle driver for QCOM cpus
arm: dts: qcom: Add idle states device nodes for 8974

 .../bindings/arm/msm/qcom,idle-state.txt           |  72 ++++++++
 Documentation/devicetree/bindings/arm/msm/spm.txt  |  47 +++++
 arch/arm/boot/dts/qcom-msm8974-pm.dtsi             |  69 +++++++
 arch/arm/boot/dts/qcom-msm8974.dtsi                |  30 +++-
 drivers/cpuidle/Kconfig.arm                        |   7 +
 drivers/cpuidle/Makefile                           |   1 +
 drivers/cpuidle/cpuidle-qcom.c                     |  87 +++++++++
 drivers/soc/qcom/Kconfig                           |   8 +
 drivers/soc/qcom/Makefile                          |   1 +
 drivers/soc/qcom/msm-pm.c                          | 106 +++++++++++
 drivers/soc/qcom/spm-devices.c                     | 198 +++++++++++++++++++++
 drivers/soc/qcom/spm-drv.h                         |  69 +++++++
 drivers/soc/qcom/spm.c                             | 192 ++++++++++++++++++++
 include/soc/qcom/pm.h                              |  31 ++++
 include/soc/qcom/scm-boot.h                        |   2 +
 include/soc/qcom/spm.h                             |  38 ++++
 16 files changed, 954 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt
 create mode 100644 Documentation/devicetree/bindings/arm/msm/spm.txt
 create mode 100644 arch/arm/boot/dts/qcom-msm8974-pm.dtsi
 create mode 100644 drivers/cpuidle/cpuidle-qcom.c
 create mode 100644 drivers/soc/qcom/msm-pm.c
 create mode 100644 drivers/soc/qcom/spm-devices.c
 create mode 100644 drivers/soc/qcom/spm-drv.h
 create mode 100644 drivers/soc/qcom/spm.c
 create mode 100644 include/soc/qcom/pm.h
 create mode 100644 include/soc/qcom/spm.h