[PATCH] perf/x86/rapl: Enable Baytrail/Braswell RAPL support

[Harry Pan]

This patch enables RAPL counters (energy consumption counters)
support for Intel Baytrail and Braswell processors (Model 55 and 76):

The Silvermont/Airmont microarchitecture actually uses fixed
energy status unit (ESU) in smallest unit of microjoule,
this patch adds quirk for these Atom processors (BYT/BSW)
to calculate energy increment in 2^ESU microjoules.

ESU and power domains refer to Intel Software Developers' Manual,
Vol. 3C, Order No. 325384, Table 35-8.

v2: simplify setting rapl_hw_unit[] to reduce runtime overhead.

Usage example:

$ perf list
$ perf stat -a -e power/energy-cores/,power/energy-pkg/ sleep 10

This patch also enables multiple quirks.

Signed-off-by: Harry Pan <harry.pan@xxxxxxxxx>
---
 arch/x86/events/intel/rapl.c | 49 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
index 94abfdb..2af6c18 100644
--- a/arch/x86/events/intel/rapl.c
+++ b/arch/x86/events/intel/rapl.c
@@ -110,6 +110,10 @@ static const char *const rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
 #define RAPL_IDX_KNL	(1<<RAPL_IDX_PKG_NRG_STAT|\
 			 1<<RAPL_IDX_RAM_NRG_STAT)
 
+/* Baytrail/Braswell clients have PP0, PKG */
+#define RAPL_IDX_BYT	(1<<RAPL_IDX_PP0_NRG_STAT|\
+			 1<<RAPL_IDX_PKG_NRG_STAT)
+
 /*
  * event code: LSB 8 bits, passed in attr->config
  * any other bit is reserved
@@ -458,6 +462,14 @@ RAPL_EVENT_ATTR_STR(energy-ram.scale,     rapl_ram_scale, "2.3283064365386962890
 RAPL_EVENT_ATTR_STR(energy-gpu.scale,     rapl_gpu_scale, "2.3283064365386962890625e-10");
 RAPL_EVENT_ATTR_STR(energy-psys.scale,   rapl_psys_scale, "2.3283064365386962890625e-10");
 
+/*
+ * Some Atom series processors (BYT/BSW) have fixed
+ * energy status unit (ESU) in smallest unit of microjoule,
+ * and its increment is in 2^ESU microjoules.
+ */
+RAPL_EVENT_ATTR_STR(energy-cores.scale, rapl_byt_cores_scale, "1.0e-6");
+RAPL_EVENT_ATTR_STR(energy-pkg.scale, rapl_byt_pkg_scale, "1.0e-6");
+
 static struct attribute *rapl_events_srv_attr[] = {
 	EVENT_PTR(rapl_cores),
 	EVENT_PTR(rapl_pkg),
@@ -539,6 +551,18 @@ static struct attribute *rapl_events_knl_attr[] = {
 	NULL,
 };
 
+static struct attribute *rapl_events_byt_attr[] = {
+	EVENT_PTR(rapl_cores),
+	EVENT_PTR(rapl_pkg),
+
+	EVENT_PTR(rapl_cores_unit),
+	EVENT_PTR(rapl_pkg_unit),
+
+	EVENT_PTR(rapl_byt_cores_scale),
+	EVENT_PTR(rapl_byt_pkg_scale),
+	NULL,
+};
+
 static struct attribute_group rapl_pmu_events_group = {
 	.name = "events",
 	.attrs = NULL, /* patched at runtime */
@@ -634,6 +658,23 @@ static void rapl_hsx_quirk(void)
 	rapl_hw_unit[RAPL_IDX_RAM_NRG_STAT] = 16;
 }
 
+static void rapl_byt_quirk(void)
+{
+	int i;
+
+	/*
+	 * Some Atom processors (BYT/BSW) have 2^ESU microjoules
+	 * increment, refer to Software Developers' Manual, Vol. 3C,
+	 * Order No. 325384, Table 35-8 of MSR_RAPL_POWER_UNIT.
+	 *
+	 * TODO: In order to fit BYT/BSW quirk model, here remind
+	 *	 this generates timer rate in 80ms; by default
+	 *	 ESU of BYT/BSW is 5, so it leads (1000/200)*2^4.
+	 */
+	for (i = 0; i < NR_RAPL_DOMAINS; i++)
+		rapl_hw_unit[i] = 32 - rapl_hw_unit[i];
+}
+
 static int rapl_check_hw_unit(const struct intel_rapl_model_desc *model)
 {
 	u64 msr_rapl_power_unit_bits;
@@ -745,6 +786,12 @@ static const struct intel_rapl_model_desc skl_rapl_init __initconst = {
 	.attrs		= rapl_events_skl_attr,
 };
 
+static const struct intel_rapl_model_desc byt_rapl_init __initconst = {
+	.quirk		= rapl_byt_quirk,
+	.cntr_mask	= RAPL_IDX_BYT,
+	.attrs		= rapl_events_byt_attr,
+};
+
 static const struct x86_cpu_id rapl_cpu_match[] __initconst = {
 	X86_RAPL_MODEL_MATCH(INTEL_FAM6_SANDYBRIDGE,   snb_rapl_init),
 	X86_RAPL_MODEL_MATCH(INTEL_FAM6_SANDYBRIDGE_X, snbep_rapl_init),
@@ -768,6 +815,8 @@ static const struct x86_cpu_id rapl_cpu_match[] __initconst = {
 	X86_RAPL_MODEL_MATCH(INTEL_FAM6_SKYLAKE_DESKTOP, skl_rapl_init),
 	X86_RAPL_MODEL_MATCH(INTEL_FAM6_SKYLAKE_X,	 hsx_rapl_init),
 
+	X86_RAPL_MODEL_MATCH(INTEL_FAM6_ATOM_SILVERMONT1, byt_rapl_init),
+	X86_RAPL_MODEL_MATCH(INTEL_FAM6_ATOM_AIRMONT, byt_rapl_init),
 	X86_RAPL_MODEL_MATCH(INTEL_FAM6_ATOM_GOLDMONT, hsw_rapl_init),
 	{},
 };
-- 
2.6.6