[RFC 1/3] cpuidle/powernv : Pass state pointer instead of values to stop loop

Abhishek Goel
2019-08-23T07:09:38Z

Instead of passing psscr_val and psscr_mask, we will pass state pointer
to stop loop. This will help to figure out the method to enter/exit idle
state. Removed psscr_mask and psscr_val from driver idle code. Same has
also been done in platform idle code.
Also, added some cleanups and debugging info.

Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/processor.h | 5 +-
arch/powerpc/platforms/powernv/idle.c | 50 ++++++++-----------
drivers/cpuidle/cpuidle-powernv.c | 69 +++++++++++++--------------
3 files changed, 55 insertions(+), 69 deletions(-)

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index a9993e7a443b..855666e8d271 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -39,6 +39,7 @@
#include <linux/thread_info.h>
#include <asm/ptrace.h>
#include <asm/hw_breakpoint.h>
+#include <asm/cpuidle.h>

/* We do _not_ want to define new machine types at all, those must die
* in favor of using the device-tree
@@ -419,9 +420,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
extern int powersave_nap; /* set if nap mode can be used in idle loop */

extern void power7_idle_type(unsigned long type);
-extern void power9_idle_type(unsigned long stop_psscr_val,
- unsigned long stop_psscr_mask);
-
+extern void power9_idle_type(struct pnv_idle_states_t *state);
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
extern void poweroff_now(void);
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 09f49eed7fb8..db810c0a16e1 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -40,8 +40,7 @@ int nr_pnv_idle_states;
* The default stop state that will be used by ppc_md.power_save
* function on platforms that support stop instruction.
*/
-static u64 pnv_default_stop_val;
-static u64 pnv_default_stop_mask;
+struct pnv_idle_states_t *pnv_default_state;
static bool default_stop_found;

/*
@@ -54,9 +53,7 @@ static u64 pnv_first_spr_loss_level = MAX_STOP_STATE + 1;
* psscr value and mask of the deepest stop idle state.
* Used when a cpu is offlined.
*/
-static u64 pnv_deepest_stop_psscr_val;
-static u64 pnv_deepest_stop_psscr_mask;
-static u64 pnv_deepest_stop_flag;
+static struct pnv_idle_states_t *pnv_deepest_state;
static bool deepest_stop_found;

static unsigned long power7_offline_type;
@@ -78,7 +75,7 @@ static int pnv_save_sprs_for_deep_states(void)
uint64_t hid5_val = mfspr(SPRN_HID5);
uint64_t hmeer_val = mfspr(SPRN_HMEER);
uint64_t msr_val = MSR_IDLE;
- uint64_t psscr_val = pnv_deepest_stop_psscr_val;
+ uint64_t psscr_val = pnv_deepest_state->psscr_val;

for_each_present_cpu(cpu) {
uint64_t pir = get_hard_smp_processor_id(cpu);
@@ -804,9 +801,13 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
}

#ifdef CONFIG_HOTPLUG_CPU
-static unsigned long power9_offline_stop(unsigned long psscr)
+static unsigned long power9_offline_stop(struct pnv_idle_states_t *state)
{
unsigned long srr1;
+ unsigned long psscr;
+
+ psscr = mfspr(SPRN_PSSCR);
+ psscr = (psscr & ~state->psscr_mask) | state->psscr_val;

#ifndef CONFIG_KVM_BOOK3S_HV_POSSIBLE
__ppc64_runlatch_off();
@@ -841,8 +842,7 @@ static unsigned long power9_offline_stop(unsigned long psscr)
}
#endif

-void power9_idle_type(unsigned long stop_psscr_val,
- unsigned long stop_psscr_mask)
+void power9_idle_type(struct pnv_idle_states_t *state)
{
unsigned long psscr;
unsigned long srr1;
@@ -851,7 +851,7 @@ void power9_idle_type(unsigned long stop_psscr_val,
return;

psscr = mfspr(SPRN_PSSCR);
- psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;
+ psscr = (psscr & ~state->psscr_mask) | state->psscr_val;

__ppc64_runlatch_off();
srr1 = power9_idle_stop(psscr, true);
@@ -867,7 +867,7 @@ void power9_idle_type(unsigned long stop_psscr_val,
*/
void power9_idle(void)
{
- power9_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
+ power9_idle_type(pnv_default_state);
}

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@@ -970,12 +970,7 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
__ppc64_runlatch_off();

if (cpu_has_feature(CPU_FTR_ARCH_300) && deepest_stop_found) {
- unsigned long psscr;
-
- psscr = mfspr(SPRN_PSSCR);
- psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
- pnv_deepest_stop_psscr_val;
- srr1 = power9_offline_stop(psscr);
+ srr1 = power9_offline_stop(pnv_deepest_state);
} else if (cpu_has_feature(CPU_FTR_ARCH_206) && power7_offline_type) {
srr1 = power7_offline();
} else {
@@ -1124,16 +1119,13 @@ static void __init pnv_power9_idle_init(void)

if (max_residency_ns < state->residency_ns) {
max_residency_ns = state->residency_ns;
- pnv_deepest_stop_psscr_val = state->psscr_val;
- pnv_deepest_stop_psscr_mask = state->psscr_mask;
- pnv_deepest_stop_flag = state->flags;
+ pnv_deepest_state = state;
deepest_stop_found = true;
}

if (!default_stop_found &&
(state->flags & OPAL_PM_STOP_INST_FAST)) {
- pnv_default_stop_val = state->psscr_val;
- pnv_default_stop_mask = state->psscr_mask;
+ pnv_default_state = state;
default_stop_found = true;
WARN_ON(state->flags & OPAL_PM_LOSE_FULL_CONTEXT);
}
@@ -1144,15 +1136,16 @@ static void __init pnv_power9_idle_init(void)
} else {
ppc_md.power_save = power9_idle;
pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
- pnv_default_stop_val, pnv_default_stop_mask);
+ pnv_default_state->psscr_val,
+ pnv_default_state->psscr_mask);
}

if (unlikely(!deepest_stop_found)) {
pr_warn("cpuidle-powernv: No suitable stop state for CPU-Hotplug. Offlined CPUs will busy wait");
} else {
pr_info("cpuidle-powernv: Deepest stop: psscr = 0x%016llx,mask=0x%016llx\n",
- pnv_deepest_stop_psscr_val,
- pnv_deepest_stop_psscr_mask);
+ pnv_deepest_state->psscr_val,
+ pnv_deepest_state->psscr_mask);
}

pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%llx\n",
@@ -1174,16 +1167,15 @@ static void __init pnv_disable_deep_states(void)
pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");

if (cpu_has_feature(CPU_FTR_ARCH_300) &&
- (pnv_deepest_stop_flag & OPAL_PM_LOSE_FULL_CONTEXT)) {
+ (pnv_deepest_state->flags & OPAL_PM_LOSE_FULL_CONTEXT)) {
/*
* Use the default stop state for CPU-Hotplug
* if available.
*/
if (default_stop_found) {
- pnv_deepest_stop_psscr_val = pnv_default_stop_val;
- pnv_deepest_stop_psscr_mask = pnv_default_stop_mask;
+ pnv_deepest_state = pnv_default_state;
pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
- pnv_deepest_stop_psscr_val);
+ pnv_deepest_state->psscr_val);
} else { /* Fallback to snooze loop for CPU-Hotplug */
deepest_stop_found = false;
pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 84b1ebe212b3..1b6c84d4ac77 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -36,13 +36,7 @@ static struct cpuidle_driver powernv_idle_driver = {
static int max_idle_state __read_mostly;
static struct cpuidle_state *cpuidle_state_table __read_mostly;

-struct stop_psscr_table {
- u64 val;
- u64 mask;
-};
-
-static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
-
+static unsigned int stop_driver_index[CPUIDLE_STATE_MAX] __read_mostly;
static u64 default_snooze_timeout __read_mostly;
static bool snooze_timeout_en __read_mostly;

@@ -144,8 +138,9 @@ static int stop_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
- power9_idle_type(stop_psscr_table[index].val,
- stop_psscr_table[index].mask);
+ unsigned int driver_index = stop_driver_index[index];
+
+ power9_idle_type(&pnv_idle_states[driver_index]);
return index;
}

@@ -234,7 +229,7 @@ static inline void add_powernv_state(int index, const char *name,
int),
unsigned int target_residency,
unsigned int exit_latency,
- u64 psscr_val, u64 psscr_mask)
+ unsigned int driver_index)
{
strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
@@ -242,9 +237,7 @@ static inline void add_powernv_state(int index, const char *name,
powernv_states[index].target_residency = target_residency;
powernv_states[index].exit_latency = exit_latency;
powernv_states[index].enter = idle_fn;
- /* For power8 and below psscr_* will be 0 */
- stop_psscr_table[index].val = psscr_val;
- stop_psscr_table[index].mask = psscr_mask;
+ stop_driver_index[index] = driver_index;
}

/*
@@ -265,7 +258,7 @@ extern u32 pnv_get_supported_cpuidle_states(void);
static int powernv_add_idle_states(void)
{
int nr_idle_states = 1; /* Snooze */
- int dt_idle_states;
+ int dt_idle_states = 0;
u32 has_stop_states = 0;
int i;
u32 supported_flags = pnv_get_supported_cpuidle_states();
@@ -284,36 +277,38 @@ static int powernv_add_idle_states(void)
* Since snooze is used as first idle state, max idle states allowed is
* CPUIDLE_STATE_MAX -1
*/
- if (nr_pnv_idle_states > CPUIDLE_STATE_MAX - 1) {
+ if (dt_idle_states > CPUIDLE_STATE_MAX - 1) {
pr_warn("cpuidle-powernv: discovered idle states more than allowed");
dt_idle_states = CPUIDLE_STATE_MAX - 1;
}

- /*
- * If the idle states use stop instruction, probe for psscr values
- * and psscr mask which are necessary to specify required stop level.
- */
- has_stop_states = (pnv_idle_states[0].flags &
- (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
-
for (i = 0; i < dt_idle_states; i++) {
unsigned int exit_latency, target_residency;
bool stops_timebase = false;
struct pnv_idle_states_t *state = &pnv_idle_states[i];

+ has_stop_states = (pnv_idle_states[i].flags &
+ (OPAL_PM_STOP_INST_FAST |
+ OPAL_PM_STOP_INST_DEEP));
+
/*
* Skip the platform idle state whose flag isn't in
* the supported_cpuidle_states flag mask.
*/
- if ((state->flags & supported_flags) != state->flags)
+ if ((state->flags & supported_flags) != state->flags) {
+ pr_warn("State %d does not have supported flag\n", i);
continue;
+ }
+
/*
* If an idle state has exit latency beyond
- * POWERNV_THRESHOLD_LATENCY_NS then don't use it
- * in cpu-idle.
+ * POWERNV_THRESHOLD_LATENCY_NS then don't use it in cpu-idle.
*/
- if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS)
+ if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS) {
+ pr_info("State %d is not idletype\n", i);
continue;
+ }
+
/*
* Firmware passes residency and latency values in ns.
* cpuidle expects it in us.
@@ -321,8 +316,10 @@ static int powernv_add_idle_states(void)
exit_latency = DIV_ROUND_UP(state->latency_ns, 1000);
target_residency = DIV_ROUND_UP(state->residency_ns, 1000);

- if (has_stop_states && !(state->valid))
- continue;
+ if (has_stop_states && !(state->valid)) {
+ pr_warn("State %d is invalid\n", i);
+ continue;
+ }

if (state->flags & OPAL_PM_TIMEBASE_STOP)
stops_timebase = true;
@@ -331,13 +328,11 @@ static int powernv_add_idle_states(void)
/* Add NAP state */
add_powernv_state(nr_idle_states, "Nap",
CPUIDLE_FLAG_NONE, nap_loop,
- target_residency, exit_latency, 0, 0);
+ target_residency, exit_latency, 0);
} else if (has_stop_states && !stops_timebase) {
add_powernv_state(nr_idle_states, state->name,
CPUIDLE_FLAG_NONE, stop_loop,
- target_residency, exit_latency,
- state->psscr_val,
- state->psscr_mask);
+ target_residency, exit_latency, i);
}

/*
@@ -351,17 +346,17 @@ static int powernv_add_idle_states(void)
add_powernv_state(nr_idle_states, "FastSleep",
CPUIDLE_FLAG_TIMER_STOP,
fastsleep_loop,
- target_residency, exit_latency, 0, 0);
+ target_residency, exit_latency, 0);
} else if (has_stop_states && stops_timebase) {
add_powernv_state(nr_idle_states, state->name,
CPUIDLE_FLAG_TIMER_STOP, stop_loop,
- target_residency, exit_latency,
- state->psscr_val,
- state->psscr_mask);
+ target_residency, exit_latency, i);
}
#endif
- else
+ else {
+ pr_warn("cpuidle-powernv : could not add state\n");
continue;
+ }
nr_idle_states++;
}
out:
--
2.17.1