Commit f4d1414a authored by Stafford Horne's avatar Stafford Horne

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: 's avatarRichard Henderson <rth@twiddle.net>
Signed-off-by: 's avatarStafford Horne <shorne@gmail.com>
parent 48a1b62b
......@@ -61,6 +61,7 @@ void cpu_openrisc_timer_update(OpenRISCCPU *cpu)
}
next = now + (uint64_t)wait * TIMER_PERIOD;
timer_mod(cpu->env.timer, next);
qemu_cpu_kick(CPU(cpu));
}
void cpu_openrisc_count_start(OpenRISCCPU *cpu)
......
......@@ -51,7 +51,8 @@ static void openrisc_cpu_reset(CPUState *s)
cpu->env.lock_addr = -1;
s->exception_index = -1;
cpu->env.upr = UPR_UP | UPR_DMP | UPR_IMP | UPR_PICP | UPR_TTP;
cpu->env.upr = UPR_UP | UPR_DMP | UPR_IMP | UPR_PICP | UPR_TTP |
UPR_PMP;
cpu->env.dmmucfgr = (DMMUCFGR_NTW & (0 << 2)) | (DMMUCFGR_NTS & (6 << 2));
cpu->env.immucfgr = (IMMUCFGR_NTW & (0 << 2)) | (IMMUCFGR_NTS & (6 << 2));
......
......@@ -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;
......
......@@ -60,6 +60,8 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
env->sr |= SR_SM;
env->sr &= ~SR_IEE;
env->sr &= ~SR_TEE;
env->pmr &= ~PMR_DME;
env->pmr &= ~PMR_SME;
env->tlb->cpu_openrisc_map_address_data = &cpu_openrisc_get_phys_nommu;
env->tlb->cpu_openrisc_map_address_code = &cpu_openrisc_get_phys_nommu;
env->lock_addr = -1;
......
......@@ -138,6 +138,7 @@ static const VMStateDescription vmstate_env = {
VMSTATE_UINT32(dmmucfgr, CPUOpenRISCState),
VMSTATE_UINT32(immucfgr, CPUOpenRISCState),
VMSTATE_UINT32(evbar, CPUOpenRISCState),
VMSTATE_UINT32(pmr, CPUOpenRISCState),
VMSTATE_UINT32(esr, CPUOpenRISCState),
VMSTATE_UINT32(fpcsr, CPUOpenRISCState),
VMSTATE_UINT64(mac, CPUOpenRISCState),
......
......@@ -22,6 +22,7 @@
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "exception.h"
#define TO_SPR(group, number) (((group) << 11) + (number))
......@@ -141,6 +142,15 @@ void HELPER(mtspr)(CPUOpenRISCState *env,
case TO_SPR(5, 2): /* MACHI */
env->mac = deposit64(env->mac, 32, 32, rb);
break;
case TO_SPR(8, 0): /* PMR */
env->pmr = rb;
if (env->pmr & PMR_DME || env->pmr & PMR_SME) {
cpu_restore_state(cs, GETPC());
env->pc += 4;
cs->halted = 1;
raise_exception(cpu, EXCP_HALTED);
}
break;
case TO_SPR(9, 0): /* PICMR */
env->picmr |= rb;
break;
......@@ -287,6 +297,9 @@ target_ulong HELPER(mfspr)(CPUOpenRISCState *env,
return env->mac >> 32;
break;
case TO_SPR(8, 0): /* PMR */
return env->pmr;
case TO_SPR(9, 0): /* PICMR */
return env->picmr;
......
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