On Tue, Mar 10 2015 at 11:26 -0600, Kumar Gala wrote:

On Mar 9, 2015, at 10:16 AM, Lina Iyer [off-list ref] wrote:

quoted

SPM is a hardware block that controls the peripheral logic surrounding
the application cores (cpu/l$). When the core executes WFI instruction,
the SPM takes over the putting the core in low power state as
configured. The wake up for the SPM is an interrupt at the GIC, which
then completes the rest of low power mode sequence and brings the core
out of low power mode.

The SPM has a set of control registers that configure the SPMs
individually based on the type of the core and the runtime conditions.
SPM is a finite state machine block to which a sequence is provided and
it interprets the bytes and executes them in sequence. Each low power
mode that the core can enter into is provided to the SPM as a sequence.

Configure the SPM to set the core (cpu or L2) into its low power mode,
the index of the first command in the sequence is set in the SPM_CTL
register. When the core executes ARM wfi instruction, it triggers the
SPM state machine to start executing from that index. The SPM state
machine waits until the interrupt occurs and starts executing the rest
of the sequence until it hits the end of the sequence. The end of the
sequence jumps the core out of its low power mode.

Add support for an idle driver to set up the SPM to place the core in
Standby or Standalone power collapse mode when the core is idle.

Based on work by: Mahesh Sivasubramanian [off-list ref],
Ai Li [off-list ref], Praveen Chidambaram [off-list ref]
Original tree available at -
git://codeaurora.org/quic/la/kernel/msm-3.10.git

Cc: Stephen Boyd <redacted>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kevin Hilman <redacted>
Cc: Daniel Lezcano <redacted>
Signed-off-by: Lina Iyer <redacted>
---
.../devicetree/bindings/arm/msm/qcom,saw2.txt      |  31 +-
drivers/soc/qcom/Kconfig                           |   7 +
drivers/soc/qcom/Makefile                          |   1 +
drivers/soc/qcom/spm.c                             | 422 +++++++++++++++++++++
4 files changed, 455 insertions(+), 6 deletions(-)
create mode 100644 drivers/soc/qcom/spm.c

diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
index 1505fb8..690c3c0 100644
--- a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt

@@ -2,11 +2,20 @@ SPM AVS Wrapper 2 (SAW2)

The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
-micro-controller that transitions a piece of hardware (like a processor or
+power-controller that transitions a piece of hardware (like a processor or
subsystem) into and out of low power modes via a direct connection to
the PMIC. It can also be wired up to interact with other processors in the
system, notifying them when a low power state is entered or exited.

+Multiple revisions of the SAW hardware are supported using these Device Nodes.
+SAW2 revisions differ in the register offset and configuration data. Also, the
+same revision of the SAW in different SoCs may have different configuration
+data due the the differences in hardware capabilities. Hence the SoC name, the
+version of the SAW hardware in that SoC and the distinction between cpu (big
+or Little) or cache, may be needed to uniquely identify the SAW register
+configuration and initialization data. The compatible string is used to
+indicate this parameter.
+
PROPERTIES

- compatible:

@@ -14,10 +23,13 @@ PROPERTIES

	Value type: <string>
	Definition: shall contain "qcom,saw2". A more specific value should be
		    one of:
-			 "qcom,saw2-v1"
-			 "qcom,saw2-v1.1"
-			 "qcom,saw2-v2"
-			 "qcom,saw2-v2.1"
+			"qcom,saw2-v1"
+			"qcom,saw2-v1.1"
+			"qcom,saw2-v2"
+			"qcom,saw2-v2.1"
+			"qcom,apq8064-saw2-v1.1-cpu"
+			"qcom,msm8974-saw2-v2.1-cpu"
+			"qcom,apq8084-saw2-v2.1-cpu”

We don’t seem to use the "qcom,saw2-v1*” variants so should we just drop them?

Sure. Will fix in the next.

quoted

- reg:
	Usage: required

@@ -26,10 +38,17 @@ PROPERTIES

		    the register region. An optional second element specifies
		    the base address and size of the alias register region.

+- regulator:
+	Usage: optional
+	Value type: boolean
+	Definition: Indicates that this SPM device acts as a regulator device
+			device for the core (CPU or Cache) the SPM is attached
+			to.

Example:

-	regulator@2099000 {
+	power-controller@2099000 {
		compatible = "qcom,saw2";
		reg = <0x02099000 0x1000>, <0x02009000 0x1000>;
+		regulator;
	};

- k

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