arm_pmu: acpi: spe: Add initial MADT/SPE probing
ACPI 6.3 adds additional fields to the MADT GICC
structure to describe SPE PPI's. We pick these out
of the cached reference to the madt_gicc structure
similarly to the core PMU code. We then create a platform
device referring to the IRQ and let the user/module loader
decide whether to load the SPE driver.
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 0f19751..864d7eb 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -74,6 +74,76 @@ static void arm_pmu_acpi_unregister_irq(int cpu)
acpi_unregister_gsi(gsi);
}
+#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
+static struct resource spe_resources[] = {
+ {
+ /* irq */
+ .flags = IORESOURCE_IRQ,
+ }
+};
+
+static struct platform_device spe_dev = {
+ .name = ARMV8_SPE_PDEV_NAME,
+ .id = -1,
+ .resource = spe_resources,
+ .num_resources = ARRAY_SIZE(spe_resources)
+};
+
+/*
+ * For lack of a better place, hook the normal PMU MADT walk
+ * and create a SPE device if we detect a recent MADT with
+ * a homogeneous PPI mapping.
+ */
+static void arm_spe_acpi_register_device(void)
+{
+ int cpu, hetid, irq, ret;
+ bool first = true;
+ u16 gsi = 0;
+
+ /*
+ * Sanity check all the GICC tables for the same interrupt number.
+ * For now, we only support homogeneous ACPI/SPE machines.
+ */
+ for_each_possible_cpu(cpu) {
+ struct acpi_madt_generic_interrupt *gicc;
+
+ gicc = acpi_cpu_get_madt_gicc(cpu);
+ if (gicc->header.length < ACPI_MADT_GICC_SPE)
+ return;
+
+ if (first) {
+ gsi = gicc->spe_interrupt;
+ if (!gsi)
+ return;
+ hetid = find_acpi_cpu_topology_hetero_id(cpu);
+ first = false;
+ } else if ((gsi != gicc->spe_interrupt) ||
+ (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
+ pr_warn("ACPI: SPE must be homogeneous\n");
+ return;
+ }
+ }
+
+ irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,
+ ACPI_ACTIVE_HIGH);
+ if (irq < 0) {
+ pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);
+ return;
+ }
+
+ spe_resources[0].start = irq;
+ ret = platform_device_register(&spe_dev);
+ if (ret < 0) {
+ pr_warn("ACPI: SPE: Unable to register device\n");
+ acpi_unregister_gsi(gsi);
+ }
+}
+#else
+static inline void arm_spe_acpi_register_device(void)
+{
+}
+#endif /* CONFIG_ARM_SPE_PMU */
+
static int arm_pmu_acpi_parse_irqs(void)
{
int irq, cpu, irq_cpu, err;
@@ -279,6 +349,8 @@ static int arm_pmu_acpi_init(void)
if (acpi_disabled)
return 0;
+ arm_spe_acpi_register_device();
+
ret = arm_pmu_acpi_parse_irqs();
if (ret)
return ret;