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authorGautham R. Shenoy <ego@linux.vnet.ibm.com>2017-01-25 11:36:28 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-01-31 00:32:13 +0300
commit09206b600c76f20984e80d99f3b5343c79332a97 (patch)
tree20e426ba7d83f3891169495d2114b5b6690fc35a /drivers/cpuidle/cpuidle-powernv.c
parent9e9fc6f00a54f7064dc681ac187be6498d566a4f (diff)
downloadlinux-09206b600c76f20984e80d99f3b5343c79332a97.tar.xz
powernv: Pass PSSCR value and mask to power9_idle_stop
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. The older firmware sets only the Requested Level (RL) field in the psscr and psscr-mask exposed in the device tree. For older firmware where psscr-mask=0xf, this patch will set the default sane values that the set for for remaining PSSCR fields (i.e PSLL, MTL, ESL, EC, and TR). For the new firmware, the patch will validate that the invariants required by the ISA for the psscr values are maintained by the firmware. This skiboot patch that exports fully populated PSSCR values and the mask for all the stop states can be found here: https://lists.ozlabs.org/pipermail/skiboot/2016-September/004869.html [Optimize the number of instructions before entering STOP with ESL=EC=0, validate the PSSCR values provided by the firimware maintains the invariants required as per the ISA suggested by Balbir Singh] Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/cpuidle/cpuidle-powernv.c')
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c52
1 files changed, 41 insertions, 11 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 6871b7f34dc8..370593006f5f 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -19,6 +19,7 @@
#include <asm/firmware.h>
#include <asm/opal.h>
#include <asm/runlatch.h>
+#include <asm/cpuidle.h>
/*
* Expose only those Hardware idle states via the cpuidle framework
@@ -34,7 +35,12 @@ static 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;
@@ -106,7 +112,8 @@ 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;
}
@@ -178,7 +185,7 @@ 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_val, u64 psscr_mask)
{
strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
@@ -186,7 +193,8 @@ 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;
- stop_psscr_table[index] = psscr_val;
+ stop_psscr_table[index].val = psscr_val;
+ stop_psscr_table[index].mask = psscr_mask;
}
static int powernv_add_idle_states(void)
@@ -198,7 +206,9 @@ 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];
+ u32 has_stop_states = 0;
int i, rc;
/* Currently we have snooze statically defined */
@@ -245,15 +255,25 @@ 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))
+ has_stop_states = (flags[0] &
+ (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
+ if (has_stop_states) {
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);
@@ -276,6 +296,16 @@ static int powernv_add_idle_states(void)
else
target_residency = 0;
+ if (has_stop_states) {
+ int err = validate_psscr_val_mask(&psscr_val[i],
+ &psscr_mask[i],
+ flags[i]);
+ if (err) {
+ report_invalid_psscr_val(psscr_val[i], err);
+ continue;
+ }
+ }
+
/*
* For nap and fastsleep, use default target_residency
* values if f/w does not expose it.
@@ -286,13 +316,13 @@ 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);
+ target_residency, exit_latency, 0, 0);
} else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
!(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
add_powernv_state(nr_idle_states, names[i],
CPUIDLE_FLAG_NONE, stop_loop,
target_residency, exit_latency,
- psscr_val[i]);
+ psscr_val[i], psscr_mask[i]);
}
/*
@@ -308,13 +338,13 @@ 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);
+ target_residency, exit_latency, 0, 0);
} else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
add_powernv_state(nr_idle_states, names[i],
CPUIDLE_FLAG_TIMER_STOP, stop_loop,
target_residency, exit_latency,
- psscr_val[i]);
+ psscr_val[i], psscr_mask[i]);
}
#endif
nr_idle_states++;