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 <[email protected]>
---
 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

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