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    Subject[PATCH] ARM: smp_scu: Enable standby mode
    Date
    Enable the SCU standby mode.
    From documentation:
    When set, SCU CLK is turned off when all processors are in WFI mode,
    there is no pending request on the ACP (if implemented), and there is
    no remaining activity in the SCU.

    When SCU CLK is off, ARREADYS, AWREADYS and WREADYS on the ACP are forced
    LOW. The clock is turned on when any processor leaves WFI mode, or if
    there is a new request on the ACP.

    Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
    ---
    Hi,

    I am working on some PM related patches for Zynq. One of them is
    enabling the SCU standby mode. I was wondering whether this is probably
    something that I should not do in platform specific code, but rather in
    the common code for everybody?

    Thanks,
    Sören
    ---
    arch/arm/kernel/smp_scu.c | 5 ++++-
    1 file changed, 4 insertions(+), 1 deletion(-)

    diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
    index 1aafa0d785eb..82548a76740d 100644
    --- a/arch/arm/kernel/smp_scu.c
    +++ b/arch/arm/kernel/smp_scu.c
    @@ -22,6 +22,9 @@
    #define SCU_INVALIDATE 0x0c
    #define SCU_FPGA_REVISION 0x10

    +#define SCU_CTRL_ENABLE BIT(0)
    +#define SCU_CTRL_STANDBY_ENABLE BIT(5)
    +
    #ifdef CONFIG_SMP
    /*
    * Get the number of CPU cores from the SCU configuration
    @@ -53,7 +56,7 @@ void scu_enable(void __iomem *scu_base)
    if (scu_ctrl & 1)
    return;

    - scu_ctrl |= 1;
    + scu_ctrl |= SCU_CTRL_ENABLE | SCU_CTRL_STANDBY_ENABLE;
    writel_relaxed(scu_ctrl, scu_base + SCU_CTRL);

    /*
    --
    2.0.1.1.gfbfc394
    --
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