[PATCH v14 2/6] arm64: pmu: Cache PMU interrupt numbers from MADT parse

[Jeremy Linton]

From: Mark Salter <msalter at redhat.com>

In the case of ACPI, the PMU IRQ information is contained in the
MADT table. Also, since the PMU does not exist as a device in the
ACPI DSDT table, it is necessary to create a platform device so
that the appropriate driver probing is triggered. Since the platform
device creation needs to happen after the CPU's have been started, and
the MADT parsing needs to happen before, we save off the interrupt
numbers discovered during the parsing.

Signed-off-by: Mark Salter <msalter at redhat.com>
Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
---
 arch/arm64/kernel/smp.c      |  5 +++++
 drivers/perf/Kconfig         |  4 ++++
 drivers/perf/Makefile        |  1 +
 drivers/perf/arm_pmu_acpi.c  | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/perf/arm_pmu.h |  7 +++++++
 5 files changed, 53 insertions(+)
 create mode 100644 drivers/perf/arm_pmu_acpi.c

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index cb87234..789587d 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -37,6 +37,7 @@
 #include <linux/completion.h>
 #include <linux/of.h>
 #include <linux/irq_work.h>
+#include <linux/perf/arm_pmu.h>
 
 #include <asm/alternative.h>
 #include <asm/atomic.h>
@@ -551,6 +552,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
 		}
 		bootcpu_valid = true;
 		early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid));
+		arm_pmu_parse_acpi(0, processor);
 		return;
 	}
 
@@ -571,6 +573,9 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
 	 */
 	acpi_set_mailbox_entry(cpu_count, processor);
 
+	/* get PMU irq info */
+	arm_pmu_parse_acpi(cpu_count, processor);
+
 	early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count, hwid));
 
 	cpu_count++;
diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index 4d5c5f9..697df05 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -19,4 +19,8 @@ config XGENE_PMU
         help
           Say y if you want to use APM X-Gene SoC performance monitors.
 
+config ARM_PMU_ACPI
+	def_bool y
+	depends on ARM_PMU && ACPI
+
 endmenu
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index b116e98..d1d7762 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_ARM_PMU) += arm_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
+obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
new file mode 100644
index 0000000..becc861
--- /dev/null
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -0,0 +1,36 @@
+/*
+ * ARM ACPI PMU support
+ *
+ * Copyright (C) 2015 Red Hat Inc.
+ * Author: Mark Salter <msalter at redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include <asm/cpu.h>
+#include <linux/acpi.h>
+#include <linux/irq.h>
+
+struct pmu_irq {
+	int  gsi;
+	int  trigger;
+	bool used;
+};
+
+static struct pmu_irq pmu_irqs[NR_CPUS];
+
+/*
+ * Called from acpi_map_gic_cpu_interface()'s MADT parsing during boot.
+ * This routine saves off the GSI's and their trigger state for use when we are
+ * ready to build the PMU platform device.
+ */
+void __init arm_pmu_parse_acpi(int cpu, struct acpi_madt_generic_interrupt *gic)
+{
+	pmu_irqs[cpu].gsi = gic->performance_interrupt;
+	if (gic->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
+		pmu_irqs[cpu].trigger = ACPI_EDGE_SENSITIVE;
+	else
+		pmu_irqs[cpu].trigger = ACPI_LEVEL_SENSITIVE;
+}
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 8462da2..df1ba55 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -164,4 +164,11 @@ int arm_pmu_device_probe(struct platform_device *pdev,
 
 #endif /* CONFIG_ARM_PMU */
 
+#ifdef CONFIG_ARM_PMU_ACPI
+struct acpi_madt_generic_interrupt;
+void arm_pmu_parse_acpi(int cpu, struct acpi_madt_generic_interrupt *gic);
+#else
+#define arm_pmu_parse_acpi(a, b) do { } while (0)
+#endif /* CONFIG_ARM_PMU_ACPI */
+
 #endif /* __ARM_PMU_H__ */
-- 
2.7.4