[PATCH v18 01/11] ARM: qcom: Add Subsystem Power Manager (SPM) driver

[Lina Iyer]

On Fri, Apr 03 2015 at 15:54 -0600, Kevin Hilman wrote:
>Lina Iyer <lina.iyer at linaro.org> writes:
>
>> 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 at codeaurora.org>,
>> Ai Li <ali at codeaurora.org>, Praveen Chidambaram <pchidamb at codeaurora.org>
>> Original tree available at -
>> git://codeaurora.org/quic/la/kernel/msm-3.10.git
>>
>> Cc: Stephen Boyd <sboyd at codeaurora.org>
>> Cc: Arnd Bergmann <arnd at arndb.de>
>> Cc: Kevin Hilman <khilman at linaro.org>
>> Cc: Daniel Lezcano <daniel.lezcano at linaro.org>
>> Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
>
>Acked-by: Kevin Hilman <khilman at linaro.org>
>
>and also tested on qcom-apq8064-ifc6410 and
>qcom-msm8974-sony-xperia-honami and saw the various states being entered
>on all CPUs.

Thanks Kevin.


>
>Tested-by: Kevin Hilman <khilman at linaro.org>
>
>Kevin