From f4d1414a9385e3375d9107b29eeb75d27daf2147 Mon Sep 17 00:00:00 2001 From: Stafford Horne Date: Mon, 24 Apr 2017 06:07:42 +0900 Subject: target/openrisc: Support non-busy idle state using PMR SPR The OpenRISC architecture has the Power Management Register (PMR) special purpose register to manage cpu power states. The interesting modes are: * Doze Mode (DME) - Stop cpu except timer & pic - wake on interrupt * Sleep Mode (SME) - Stop cpu and all units - wake on interrupt * Suspend Model (SUME) - Stop cpu and all units - wake on reset The linux kernel will set DME when idle. This patch implements the PMR SPR and halts the qemu cpu when there is a change to DME or SME. This means that openrisc qemu in no longer peggs a host cpu at 100%. In order for this to work we need to kick the CPU when timers are expired. Update the cpu timer to kick the cpu upon each timer event. Reviewed-by: Richard Henderson Signed-off-by: Stafford Horne --- target/openrisc/cpu.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'target/openrisc/cpu.h') diff --git a/target/openrisc/cpu.h b/target/openrisc/cpu.h index 938ccc3863..2721432c4f 100644 --- a/target/openrisc/cpu.h +++ b/target/openrisc/cpu.h @@ -140,6 +140,15 @@ enum { IMMUCFGR_HTR = (1 << 11), }; +/* Power management register */ +enum { + PMR_SDF = (15 << 0), + PMR_DME = (1 << 4), + PMR_SME = (1 << 5), + PMR_DCGE = (1 << 6), + PMR_SUME = (1 << 7), +}; + /* Float point control status register */ enum { FPCSR_FPEE = 1, @@ -284,6 +293,7 @@ typedef struct CPUOpenRISCState { uint32_t immucfgr; /* IMMU configure register */ uint32_t esr; /* Exception supervisor register */ uint32_t evbar; /* Exception vector base address register */ + uint32_t pmr; /* Power Management Register */ uint32_t fpcsr; /* Float register */ float_status fp_status; -- cgit v1.2.3