[PATCH 2/2] powernv: Pass PSSCR value and mask to power9_idle_stop
From: Gautham R. Shenoy
Date: Thu Sep 29 2016 - 03:06:50 EST
From: "Gautham R. Shenoy" <ego@xxxxxxxxxxxxxxxxxx>
The power9_idle_stop method currently takes only the requested stop
level as a parameter and picks up the rest of the PSSCR bits from a
hand-coded macro. This is not a very flexible design, especially when
the firmware has the capability to communicate the psscr value and the
mask associated with a particular stop state via device tree.
This patch modifies the power9_idle_stop API to take as parameters the
PSSCR value and the PSSCR mask corresponding to the stop state that
needs to be set. These PSSCR value and mask are respectively obtained
by parsing the "ibm,cpu-idle-state-psscr" and
"ibm,cpu-idle-state-psscr-mask" fields from the device tree.
In addition to this, the patch adds support for handling stop states
for which ESL and EC bits in the PSSCR are zero. As per the
architecture, a wakeup from these stop states resumes execution from
the subsequent instruction as opposed to waking up at the System
Vector.
This patch depends on the following skiboot patch that exports the
PSSCR values and the mask for all the stop states:
https://lists.ozlabs.org/pipermail/skiboot/2016-September/004869.html
Signed-off-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/processor.h | 3 +-
arch/powerpc/kernel/idle_book3s.S | 31 ++++++++-----
arch/powerpc/platforms/powernv/idle.c | 76 +++++++++++++++++++++++++++-----
arch/powerpc/platforms/powernv/powernv.h | 3 +-
arch/powerpc/platforms/powernv/smp.c | 7 +--
drivers/cpuidle/cpuidle-powernv.c | 30 ++++++++++---
6 files changed, 115 insertions(+), 35 deletions(-)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 68e3bf5..4ead497 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -460,7 +460,8 @@ extern int powersave_nap; /* set if nap mode can be used in idle loop */
extern unsigned long power7_nap(int check_irq);
extern unsigned long power7_sleep(void);
extern unsigned long power7_winkle(void);
-extern unsigned long power9_idle_stop(unsigned long stop_level);
+extern unsigned long power9_idle_stop(unsigned long stop_psscr_val,
+ unsigned long stop_psscr_mask);
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 32d666b..9f77cd4 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -40,9 +40,7 @@
#define _WORC GPR11
#define _PTCR GPR12
-#define PSSCR_HV_TEMPLATE PSSCR_ESL | PSSCR_EC | \
- PSSCR_PSLL_MASK | PSSCR_TR_MASK | \
- PSSCR_MTL_MASK
+#define PSSCR_EC_ESL_MASK_SHIFTED (PSSCR_EC | PSSCR_ESL) >> 16
.text
@@ -247,13 +245,23 @@ enter_winkle:
IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
/*
- * r3 - requested stop state
+ * r3 - PSSCR value corresponding to the requested stop state.
*/
power_enter_stop:
/*
+ * Check if we are executing the lite variant with ESL=EC=0
+ */
+ andis. r4, r3, PSSCR_EC_ESL_MASK_SHIFTED
+ andi. r3, r3, PSSCR_RL_MASK /* r3 = requested stop state */
+ cmpdi r4, 0
+ bne 1f
+ IDLE_STATE_ENTER_SEQ(PPC_STOP)
+ li r3,0 /* Since we didn't lose state, return 0 */
+ b pnv_wakeup_noloss
+/*
* Check if the requested state is a deep idle state.
*/
- LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
+1: LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
ld r4,ADDROFF(pnv_first_deep_stop_state)(r5)
cmpd r3,r4
bge 2f
@@ -330,16 +338,17 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \
ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \
20: nop;
-
/*
- * r3 - requested stop state
+ * r3 - The PSSCR value corresponding to the stop state.
+ * r4 - The PSSCR mask corrresonding to the stop state.
*/
_GLOBAL(power9_idle_stop)
- LOAD_REG_IMMEDIATE(r4, PSSCR_HV_TEMPLATE)
- or r4,r4,r3
- mtspr SPRN_PSSCR, r4
- li r4, 1
+ mfspr r5, SPRN_PSSCR
+ andc r5, r5, r4
+ or r3, r3, r5
+ mtspr SPRN_PSSCR, r3
LOAD_REG_ADDR(r5,power_enter_stop)
+ li r4, 1
b pnv_powersave_common
/* No return */
/*
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 479c256..575f2aa 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -237,15 +237,21 @@ static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
show_fastsleep_workaround_applyonce,
store_fastsleep_workaround_applyonce);
+/*
+ * The default stop state that will be used by ppc_md.power_save
+ * function on platforms that support stop instruction.
+ */
+u64 pnv_default_stop_val;
+u64 pnv_default_stop_mask;
/*
* Used for ppc_md.power_save which needs a function with no parameters
*/
static void power9_idle(void)
{
- /* Requesting stop state 0 */
- power9_idle_stop(0);
+ power9_idle_stop(pnv_default_stop_val, pnv_default_stop_mask);
}
+
/*
* First deep stop state. Used to figure out when to save/restore
* hypervisor context.
@@ -253,9 +259,11 @@ static void power9_idle(void)
u64 pnv_first_deep_stop_state = MAX_STOP_STATE;
/*
- * Deepest stop idle state. Used when a cpu is offlined
+ * psscr value and mask of the deepest stop idle state.
+ * Used when a cpu is offlined.
*/
-u64 pnv_deepest_stop_state;
+u64 pnv_deepest_stop_psscr_val;
+u64 pnv_deepest_stop_psscr_mask;
/*
* Power ISA 3.0 idle initialization.
@@ -302,28 +310,61 @@ static int __init pnv_arch300_idle_init(struct device_node *np, u32 *flags,
int dt_idle_states)
{
u64 *psscr_val = NULL;
+ u64 *psscr_mask = NULL;
+ u32 *residency_ns = NULL;
+ u64 max_residency_ns = 0;
int rc = 0, i;
+ bool default_stop_found = false;
psscr_val = kcalloc(dt_idle_states, sizeof(*psscr_val),
GFP_KERNEL);
- if (!psscr_val) {
+ psscr_mask = kcalloc(dt_idle_states, sizeof(*psscr_mask),
+ GFP_KERNEL);
+ residency_ns = kcalloc(dt_idle_states, sizeof(*residency_ns),
+ GFP_KERNEL);
+
+ if (!psscr_val || !psscr_mask || !residency_ns) {
rc = -1;
goto out;
}
+
if (of_property_read_u64_array(np,
"ibm,cpu-idle-state-psscr",
psscr_val, dt_idle_states)) {
- pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
+ rc = -1;
+ goto out;
+ }
+
+ if (of_property_read_u64_array(np,
+ "ibm,cpu-idle-state-psscr-mask",
+ psscr_mask, dt_idle_states)) {
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n");
rc = -1;
goto out;
}
+ if (of_property_read_u32_array(np,
+ "ibm,cpu-idle-state-residency-ns",
+ residency_ns, dt_idle_states)) {
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns in DT\n");
+ rc = -1;
+ goto out;
+
+ }
+
/*
- * Set pnv_first_deep_stop_state and pnv_deepest_stop_state.
+ * Set pnv_first_deep_stop_state, pnv_deepest_stop_psscr_{val,mask},
+ * and the pnv_default_stop_{val,mask}.
+ *
* pnv_first_deep_stop_state should be set to the first stop
* level to cause hypervisor state loss.
- * pnv_deepest_stop_state should be set to the deepest stop
- * stop state.
+ *
+ * pnv_deepest_stop_{val,mask} should be set to values corresponding to
+ * the deepest stop state.
+ *
+ * pnv_default_stop_{val,mask} should be set to values corresponding to
+ * the shallowest (OPAL_PM_STOP_INST_FAST) loss-less stop state.
*/
pnv_first_deep_stop_state = MAX_STOP_STATE;
for (i = 0; i < dt_idle_states; i++) {
@@ -333,12 +374,23 @@ static int __init pnv_arch300_idle_init(struct device_node *np, u32 *flags,
(pnv_first_deep_stop_state > psscr_rl))
pnv_first_deep_stop_state = psscr_rl;
- if (pnv_deepest_stop_state < psscr_rl)
- pnv_deepest_stop_state = psscr_rl;
- }
+ if (max_residency_ns < residency_ns[i]) {
+ max_residency_ns = residency_ns[i];
+ pnv_deepest_stop_psscr_val = psscr_val[i];
+ pnv_deepest_stop_psscr_mask = psscr_mask[i];
+ }
+ if (!default_stop_found &&
+ (flags[i] & OPAL_PM_STOP_INST_FAST)) {
+ pnv_default_stop_val = psscr_val[i];
+ pnv_default_stop_mask = psscr_mask[i];
+ default_stop_found = true;
+ }
+ }
out:
kfree(psscr_val);
+ kfree(psscr_mask);
+ kfree(residency_ns);
return rc;
}
diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index da7c843..6130522 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -18,7 +18,8 @@ static inline void pnv_pci_shutdown(void) { }
#endif
extern u32 pnv_get_supported_cpuidle_states(void);
-extern u64 pnv_deepest_stop_state;
+extern u64 pnv_deepest_stop_psscr_val;
+extern u64 pnv_deepest_stop_psscr_mask;
extern void pnv_lpc_init(void);
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index c789258..55c4aaa 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -182,9 +182,10 @@ static void pnv_smp_cpu_kill_self(void)
ppc64_runlatch_off();
- if (cpu_has_feature(CPU_FTR_ARCH_300))
- srr1 = power9_idle_stop(pnv_deepest_stop_state);
- else if (idle_states & OPAL_PM_WINKLE_ENABLED)
+ if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+ srr1 = power9_idle_stop(pnv_deepest_stop_psscr_val,
+ pnv_deepest_stop_psscr_mask);
+ } else if (idle_states & OPAL_PM_WINKLE_ENABLED)
srr1 = power7_winkle();
else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
(idle_states & OPAL_PM_SLEEP_ENABLED_ER1))
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index f7ca891..6f2bee0 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -30,7 +30,11 @@ struct cpuidle_driver powernv_idle_driver = {
static int max_idle_state;
static struct cpuidle_state *cpuidle_state_table;
-static u64 stop_psscr_table[CPUIDLE_STATE_MAX];
+struct stop_psscr_table {
+ u64 val;
+ u64 mask;
+};
+static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX];
static u64 snooze_timeout;
static bool snooze_timeout_en;
@@ -102,7 +106,8 @@ static int stop_loop(struct cpuidle_device *dev,
int index)
{
ppc64_runlatch_off();
- power9_idle_stop(stop_psscr_table[index]);
+ power9_idle_stop(stop_psscr_table[index].val,
+ stop_psscr_table[index].mask);
ppc64_runlatch_on();
return index;
}
@@ -186,6 +191,7 @@ static int powernv_add_idle_states(void)
u32 residency_ns[CPUIDLE_STATE_MAX];
u32 flags[CPUIDLE_STATE_MAX];
u64 psscr_val[CPUIDLE_STATE_MAX];
+ u64 psscr_mask[CPUIDLE_STATE_MAX];
const char *names[CPUIDLE_STATE_MAX];
int i, rc;
@@ -233,14 +239,22 @@ static int powernv_add_idle_states(void)
/*
* If the idle states use stop instruction, probe for psscr values
- * which are necessary to specify required stop level.
+ * and psscr mask which are necessary to specify required stop level.
*/
- if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP))
+ if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)) {
if (of_property_read_u64_array(power_mgt,
"ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) {
- pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
+ goto out;
+ }
+
+ if (of_property_read_u64_array(power_mgt,
+ "ibm,cpu-idle-state-psscr-mask", psscr_mask,
+ dt_idle_states)) {
+ pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n");
goto out;
}
+ }
rc = of_property_read_u32_array(power_mgt,
"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
@@ -274,7 +288,8 @@ static int powernv_add_idle_states(void)
powernv_states[nr_idle_states].flags = 0;
powernv_states[nr_idle_states].enter = stop_loop;
- stop_psscr_table[nr_idle_states] = psscr_val[i];
+ stop_psscr_table[nr_idle_states].val = psscr_val[i];
+ stop_psscr_table[nr_idle_states].mask = psscr_mask[i];
}
/*
@@ -299,7 +314,8 @@ static int powernv_add_idle_states(void)
powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
powernv_states[nr_idle_states].enter = stop_loop;
- stop_psscr_table[nr_idle_states] = psscr_val[i];
+ stop_psscr_table[nr_idle_states].val = psscr_val[i];
+ stop_psscr_table[nr_idle_states].mask = psscr_mask[i];
}
#endif
powernv_states[nr_idle_states].exit_latency =
--
1.9.4