[PATCH v2 14/22] thermal: intel: hfi: Report the IPC class score of a CPU

[Ricardo Neri]

Implement the arch_get_ipcc_score() interface of the scheduler. Use the
performance capabilities of the extended Hardware Feedback Interface table
as the IPC score of a class of tasks when placed on a given CPU.

Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Tim C. Chen <tim.c.chen@xxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
---
Changes since v1:
 * Adjusted the returned HFI class (which starts at 0) to match the
   scheduler IPCC class (which starts at 1). (PeterZ)
 * Used the new interface names.
---
 arch/x86/include/asm/topology.h   |  2 ++
 drivers/thermal/intel/intel_hfi.c | 27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index cf46a3aea283..0fae13058f01 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -230,9 +230,11 @@ void init_freq_invariance_cppc(void);
 #if defined(CONFIG_IPC_CLASSES) && defined(CONFIG_INTEL_HFI_THERMAL)
 int intel_hfi_has_ipc_classes(void);
 void intel_hfi_update_ipcc(struct task_struct *curr);
+int intel_hfi_get_ipcc_score(unsigned short ipcc, int cpu);
 
 #define arch_has_ipc_classes intel_hfi_has_ipc_classes
 #define arch_update_ipcc intel_hfi_update_ipcc
+#define arch_get_ipcc_score intel_hfi_get_ipcc_score
 #endif /* defined(CONFIG_IPC_CLASSES) && defined(CONFIG_INTEL_HFI_THERMAL) */
 
 #endif /* _ASM_X86_TOPOLOGY_H */
diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
index f85394b532a7..1f7b18198bd4 100644
--- a/drivers/thermal/intel/intel_hfi.c
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -213,6 +213,33 @@ void intel_hfi_update_ipcc(struct task_struct *curr)
 	curr->ipcc = msr.split.classid + 1;
 }
 
+int intel_hfi_get_ipcc_score(unsigned short ipcc, int cpu)
+{
+	unsigned short hfi_class;
+	int *scores;
+
+	if (cpu < 0 || cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	if (ipcc == IPC_CLASS_UNCLASSIFIED)
+		return -EINVAL;
+
+	/*
+	 * Scheduler IPC classes start at 1. HFI classes start at 0.
+	 * See note intel_hfi_update_ipcc().
+	 */
+	hfi_class = ipcc - 1;
+
+	if (hfi_class >= hfi_features.nr_classes)
+		return -EINVAL;
+
+	scores = per_cpu_ptr(hfi_ipcc_scores, cpu);
+	if (!scores)
+		return -ENODEV;
+
+	return READ_ONCE(scores[hfi_class]);
+}
+
 static int alloc_hfi_ipcc_scores(void)
 {
 	hfi_ipcc_scores = __alloc_percpu(sizeof(*hfi_ipcc_scores) *
-- 
2.25.1