[PATCH] powercap: Add Power Limit4 support

From: Sumeet Pawnikar
Date: Mon Jun 22 2020 - 10:48:35 EST

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Add power limit4 (PL4) support for only mobile processor peak power.
This is similar to VR Icc-Max limit, but works on Power instead of current.
This limit should be used in order to protect the system from instantaneous
power draw.

Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@xxxxxxxxx>
---
drivers/powercap/intel_rapl_common.c | 52 ++++++++++++++++++++++++++++++++--
drivers/powercap/intel_rapl_msr.c | 15 ++++++++++
include/linux/intel_rapl.h | 5 +++-
3 files changed, 69 insertions(+), 3 deletions(-)

diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_rapl_common.c
index eb328655bc01..8dad17fd4abb 100644
--- a/drivers/powercap/intel_rapl_common.c
+++ b/drivers/powercap/intel_rapl_common.c
@@ -42,6 +42,8 @@
#define POWER_HIGH_LOCK BIT_ULL(63)
#define POWER_LOW_LOCK BIT(31)

+#define POWER_LIMIT4_MASK 0x1FFF
+
#define TIME_WINDOW1_MASK (0x7FULL<<17)
#define TIME_WINDOW2_MASK (0x7FULL<<49)

@@ -85,6 +87,7 @@ enum unit_type {

static const char pl1_name[] = "long_term";
static const char pl2_name[] = "short_term";
+static const char pl4_name[] = "peak_power";

#define power_zone_to_rapl_domain(_zone) \
container_of(_zone, struct rapl_domain, power_zone)
@@ -340,6 +343,9 @@ static int set_power_limit(struct powercap_zone *power_zone, int cid,
case PL2_ENABLE:
rapl_write_data_raw(rd, POWER_LIMIT2, power_limit);
break;
+ case PL4_ENABLE:
+ rapl_write_data_raw(rd, POWER_LIMIT4, power_limit);
+ break;
default:
ret = -EINVAL;
}
@@ -374,6 +380,9 @@ static int get_current_power_limit(struct powercap_zone *power_zone, int cid,
case PL2_ENABLE:
prim = POWER_LIMIT2;
break;
+ case PL4_ENABLE:
+ prim = POWER_LIMIT4;
+ break;
default:
put_online_cpus();
return -EINVAL;
@@ -443,6 +452,12 @@ static int get_time_window(struct powercap_zone *power_zone, int cid,
case PL2_ENABLE:
ret = rapl_read_data_raw(rd, TIME_WINDOW2, true, &val);
break;
+ case PL4_ENABLE:
+ /* Time window parameter is not applicable for PL4 entry
+ * so assigining '0' as default value.
+ */
+ val = 0;
+ break;
default:
put_online_cpus();
return -EINVAL;
@@ -486,6 +501,9 @@ static int get_max_power(struct powercap_zone *power_zone, int id, u64 *data)
case PL2_ENABLE:
prim = MAX_POWER;
break;
+ case PL4_ENABLE:
+ prim = MAX_POWER;
+ break;
default:
put_online_cpus();
return -EINVAL;
@@ -495,6 +513,10 @@ static int get_max_power(struct powercap_zone *power_zone, int id, u64 *data)
else
*data = val;

+ /* As a generalization rule, PL4 would be around two times PL2. */
+ if (rd->rpl[id].prim_id == PL4_ENABLE)
+ *data = *data * 2;
+
put_online_cpus();

return ret;
@@ -527,12 +549,21 @@ static void rapl_init_domains(struct rapl_package *rp)
rd->id = i;
rd->rpl[0].prim_id = PL1_ENABLE;
rd->rpl[0].name = pl1_name;
- /* some domain may support two power limits */
- if (rp->priv->limits[i] == 2) {
+
+ /* The PL2 power domain is applicable for limits two
+ * and limits three
+ */
+ if (rp->priv->limits[i] >= 2) {
rd->rpl[1].prim_id = PL2_ENABLE;
rd->rpl[1].name = pl2_name;
}

+ /* Enable PL4 domain if the total power limits are three */
+ if (rp->priv->limits[i] == 3) {
+ rd->rpl[2].prim_id = PL4_ENABLE;
+ rd->rpl[2].name = pl4_name;
+ }
+
for (j = 0; j < RAPL_DOMAIN_REG_MAX; j++)
rd->regs[j] = rp->priv->regs[i][j];

@@ -590,6 +621,8 @@ static u64 rapl_unit_xlate(struct rapl_domain *rd, enum unit_type type,
RAPL_DOMAIN_REG_LIMIT, POWER_UNIT, 0),
PRIMITIVE_INFO_INIT(POWER_LIMIT2, POWER_LIMIT2_MASK, 32,
RAPL_DOMAIN_REG_LIMIT, POWER_UNIT, 0),
+ PRIMITIVE_INFO_INIT(POWER_LIMIT4, POWER_LIMIT4_MASK, 0,
+ RAPL_DOMAIN_REG_PL4, POWER_UNIT, 0),
PRIMITIVE_INFO_INIT(FW_LOCK, POWER_LOW_LOCK, 31,
RAPL_DOMAIN_REG_LIMIT, ARBITRARY_UNIT, 0),
PRIMITIVE_INFO_INIT(PL1_ENABLE, POWER_LIMIT1_ENABLE, 15,
@@ -600,6 +633,8 @@ static u64 rapl_unit_xlate(struct rapl_domain *rd, enum unit_type type,
RAPL_DOMAIN_REG_LIMIT, ARBITRARY_UNIT, 0),
PRIMITIVE_INFO_INIT(PL2_CLAMP, POWER_LIMIT2_CLAMP, 48,
RAPL_DOMAIN_REG_LIMIT, ARBITRARY_UNIT, 0),
+ PRIMITIVE_INFO_INIT(PL4_ENABLE, POWER_LIMIT4_MASK, 0,
+ RAPL_DOMAIN_REG_PL4, ARBITRARY_UNIT, 0),
PRIMITIVE_INFO_INIT(TIME_WINDOW1, TIME_WINDOW1_MASK, 17,
RAPL_DOMAIN_REG_LIMIT, TIME_UNIT, 0),
PRIMITIVE_INFO_INIT(TIME_WINDOW2, TIME_WINDOW2_MASK, 49,
@@ -1254,6 +1289,7 @@ void rapl_remove_package(struct rapl_package *rp)
if (find_nr_power_limit(rd) > 1) {
rapl_write_data_raw(rd, PL2_ENABLE, 0);
rapl_write_data_raw(rd, PL2_CLAMP, 0);
+ rapl_write_data_raw(rd, PL4_ENABLE, 0);
}
if (rd->id == RAPL_DOMAIN_PACKAGE) {
rd_package = rd;
@@ -1362,6 +1398,13 @@ static void power_limit_state_save(void)
if (ret)
rd->rpl[i].last_power_limit = 0;
break;
+ case PL4_ENABLE:
+ ret = rapl_read_data_raw(rd,
+ POWER_LIMIT4, true,
+ &rd->rpl[i].last_power_limit);
+ if (ret)
+ rd->rpl[i].last_power_limit = 0;
+ break;
}
}
}
@@ -1392,6 +1435,11 @@ static void power_limit_state_restore(void)
rapl_write_data_raw(rd, POWER_LIMIT2,
rd->rpl[i].last_power_limit);
break;
+ case PL4_ENABLE:
+ if (rd->rpl[i].last_power_limit)
+ rapl_write_data_raw(rd, POWER_LIMIT4,
+ rd->rpl[i].last_power_limit);
+ break;
}
}
}
diff --git a/drivers/powercap/intel_rapl_msr.c b/drivers/powercap/intel_rapl_msr.c
index d5487965bdfe..83c76454623e 100644
--- a/drivers/powercap/intel_rapl_msr.c
+++ b/drivers/powercap/intel_rapl_msr.c
@@ -28,6 +28,7 @@

/* Local defines */
#define MSR_PLATFORM_POWER_LIMIT 0x0000065C
+#define MSR_VR_CURRENT_CONFIG 0x00000601

/* private data for RAPL MSR Interface */
static struct rapl_if_priv rapl_msr_priv = {
@@ -123,13 +124,27 @@ static int rapl_msr_write_raw(int cpu, struct reg_action *ra)
return ra->err;
}

+/* List of verified CPUs. */
+static const struct x86_cpu_id pl4_support_ids[] = {
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_TIGERLAKE_L, X86_FEATURE_ANY },
+ {}
+};
+
static int rapl_msr_probe(struct platform_device *pdev)
{
int ret;
+ const struct x86_cpu_id *id = x86_match_cpu(pl4_support_ids);

rapl_msr_priv.read_raw = rapl_msr_read_raw;
rapl_msr_priv.write_raw = rapl_msr_write_raw;

+ if (id) {
+ rapl_msr_priv.limits[RAPL_DOMAIN_PACKAGE] = 3;
+ rapl_msr_priv.regs[RAPL_DOMAIN_PACKAGE][RAPL_DOMAIN_REG_PL4] =
+ MSR_VR_CURRENT_CONFIG;
+ pr_info("PL4 support detected.\n");
+ }
+
rapl_msr_priv.control_type = powercap_register_control_type(NULL, "intel-rapl", NULL);
if (IS_ERR(rapl_msr_priv.control_type)) {
pr_debug("failed to register powercap control_type.\n");
diff --git a/include/linux/intel_rapl.h b/include/linux/intel_rapl.h
index efb3ce892c20..3582176a1eca 100644
--- a/include/linux/intel_rapl.h
+++ b/include/linux/intel_rapl.h
@@ -29,6 +29,7 @@ enum rapl_domain_reg_id {
RAPL_DOMAIN_REG_PERF,
RAPL_DOMAIN_REG_POLICY,
RAPL_DOMAIN_REG_INFO,
+ RAPL_DOMAIN_REG_PL4,
RAPL_DOMAIN_REG_MAX,
};

@@ -38,12 +39,14 @@ enum rapl_primitives {
ENERGY_COUNTER,
POWER_LIMIT1,
POWER_LIMIT2,
+ POWER_LIMIT4,
FW_LOCK,

PL1_ENABLE, /* power limit 1, aka long term */
PL1_CLAMP, /* allow frequency to go below OS request */
PL2_ENABLE, /* power limit 2, aka short term, instantaneous */
PL2_CLAMP,
+ PL4_ENABLE, /* power limit 4, aka max peak power */

TIME_WINDOW1, /* long term */
TIME_WINDOW2, /* short term */
@@ -65,7 +68,7 @@ struct rapl_domain_data {
unsigned long timestamp;
};

-#define NR_POWER_LIMITS (2)
+#define NR_POWER_LIMITS (3)
struct rapl_power_limit {
struct powercap_zone_constraint *constraint;
int prim_id; /* primitive ID used to enable */
--
1.7.9.5

Next message: Colin King: "[PATCH][next] mm: cma: remove redundant null check of the array cma->name"
Previous message: Chi-Hsien Lin: "Re: drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c:1710:40: sparse: sparse: incorrect type in initializer (different base types)"
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