On Mar 9, 2015, at 10:16 AM, Lina Iyer <lina.iyer@xxxxxxxxxx> wrote:
> 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 <msivasub@xxxxxxxxxxxxxx>,
> Ai Li <ali@xxxxxxxxxxxxxx>, Praveen Chidambaram <pchidamb@xxxxxxxxxxxxxx>
> Original tree available at -
> git://codeaurora.org/quic/la/kernel/msm-3.10.git
>
> Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
> Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> ---
> .../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?
> - 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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