[PATCH v8 8/9] arm64: pmu: Detect and enable multiple PMUs in an ACPI system
Jeremy Linton
jeremy.linton at arm.com
Mon Aug 29 14:48:19 PDT 2016
Its possible that an ACPI system has multiple CPU types in it
with differing PMU counters. Iterate the CPU's and make a determination
about how many of each type exist in the system. Then take and create
a PMU platform device for each type, and assign it the interrupts parsed
from the MADT. Creating a platform device is necessary because the PMUs
are not described as devices in the DSDT table.
This code is loosely based on earlier work by Mark Salter.
Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
---
drivers/perf/arm_pmu.c | 8 +-
drivers/perf/arm_pmu_acpi.c | 178 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 185 insertions(+), 1 deletion(-)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index f3e9fcf..5ef78da 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -1073,7 +1073,13 @@ int arm_pmu_device_probe(struct platform_device *pdev,
if (!ret)
ret = init_fn(pmu);
} else if (probe_table) {
- ret = probe_plat_pmu(pmu, probe_table, read_cpuid_id());
+ if (acpi_disabled) {
+ /* use the current cpu. */
+ ret = probe_plat_pmu(pmu, probe_table,
+ read_cpuid_id());
+ } else {
+ ret = probe_plat_pmu(pmu, probe_table, pdev->id);
+ }
}
if (ret) {
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index c1cf00c..bf2800a 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -2,13 +2,17 @@
* ARM ACPI PMU support
*
* Copyright (C) 2015 Red Hat Inc.
+ * Copyright (C) 2016 ARM Ltd.
* Author: Mark Salter <msalter at redhat.com>
+ * Jeremy Linton <jeremy.linton at arm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
+#define pr_fmt(fmt) "ACPI-PMU: " fmt
+
#include <asm/cpu.h>
#include <linux/acpi.h>
#include <linux/irq.h>
@@ -23,6 +27,12 @@ struct pmu_irq {
bool registered;
};
+struct pmu_types {
+ struct list_head list;
+ int cpu_type;
+ int cpu_count;
+};
+
static struct pmu_irq pmu_irqs[NR_CPUS] __initdata;
/*
@@ -38,3 +48,171 @@ void __init arm_pmu_parse_acpi(int cpu, struct acpi_madt_generic_interrupt *gic)
else
pmu_irqs[cpu].trigger = ACPI_LEVEL_SENSITIVE;
}
+
+/* Count number and type of CPU cores in the system. */
+static void __init arm_pmu_acpi_determine_cpu_types(struct list_head *pmus)
+{
+ int i;
+ bool alloc_failure = false;
+
+ for_each_possible_cpu(i) {
+ struct cpuinfo_arm64 *cinfo = per_cpu_ptr(&cpu_data, i);
+ u32 partnum = MIDR_PARTNUM(cinfo->reg_midr);
+ struct pmu_types *pmu;
+
+ list_for_each_entry(pmu, pmus, list) {
+ if (pmu->cpu_type == partnum) {
+ pmu->cpu_count++;
+ break;
+ }
+ }
+
+ /* we didn't find the CPU type, add an entry to identify it */
+ if ((&pmu->list == pmus) && (!alloc_failure)) {
+ pmu = kzalloc(sizeof(struct pmu_types), GFP_KERNEL);
+ if (!pmu) {
+ pr_warn("Unable to allocate pmu_types\n");
+ /*
+ * continue to count cpus for any pmu_types
+ * already allocated, but don't allocate any
+ * more pmu_types. This avoids undercounting.
+ */
+ alloc_failure = true;
+ } else {
+ pmu->cpu_type = partnum;
+ pmu->cpu_count++;
+ list_add_tail(&pmu->list, pmus);
+ }
+ }
+ }
+}
+
+/*
+ * Registers the group of PMU interfaces which correspond to the 'last_cpu_id'.
+ * This group utilizes 'count' resources in the 'res'.
+ */
+static int __init arm_pmu_acpi_register_pmu(int count, struct resource *res,
+ int last_cpu_id)
+{
+ int i;
+ int err = -ENOMEM;
+ bool free_gsi = false;
+ struct platform_device *pdev;
+
+ if (count) {
+ pdev = platform_device_alloc(ARMV8_PMU_PDEV_NAME, last_cpu_id);
+ if (pdev) {
+ err = platform_device_add_resources(pdev, res, count);
+ if (!err) {
+ err = platform_device_add(pdev);
+ if (err) {
+ pr_warn("Unable to register PMU device\n");
+ free_gsi = true;
+ }
+ } else {
+ pr_warn("Unable to add resources to device\n");
+ free_gsi = true;
+ platform_device_put(pdev);
+ }
+ } else {
+ pr_warn("Unable to allocate platform device\n");
+ free_gsi = true;
+ }
+ }
+
+ /* unmark (and possibly unregister) registered GSIs */
+ for_each_possible_cpu(i) {
+ if (pmu_irqs[i].registered) {
+ if (free_gsi)
+ acpi_unregister_gsi(pmu_irqs[i].gsi);
+ pmu_irqs[i].registered = false;
+ }
+ }
+
+ return err;
+}
+
+/*
+ * For the given cpu/pmu type, walk all known GSIs, register them, and add
+ * them to the resource structure. Return the number of GSI's contained
+ * in the res structure, and the id of the last CPU/PMU we added.
+ */
+static int __init arm_pmu_acpi_gsi_res(struct pmu_types *pmus,
+ struct resource *res, int *last_cpu_id)
+{
+ int i, count;
+ int irq;
+
+ /* lets group all the PMU's from similar CPU's together */
+ count = 0;
+ for_each_possible_cpu(i) {
+ struct cpuinfo_arm64 *cinfo = per_cpu_ptr(&cpu_data, i);
+
+ if (pmus->cpu_type == MIDR_PARTNUM(cinfo->reg_midr)) {
+ if ((pmu_irqs[i].gsi == 0) && (cinfo->reg_midr != 0)) {
+ pr_info("CPU %d is assigned interrupt 0\n", i);
+ continue;
+ }
+
+ irq = acpi_register_gsi(NULL, pmu_irqs[i].gsi,
+ pmu_irqs[i].trigger,
+ ACPI_ACTIVE_HIGH);
+
+ res[count].start = res[count].end = irq;
+ res[count].flags = IORESOURCE_IRQ;
+
+ if (pmu_irqs[i].trigger == ACPI_EDGE_SENSITIVE)
+ res[count].flags |= IORESOURCE_IRQ_HIGHEDGE;
+ else
+ res[count].flags |= IORESOURCE_IRQ_HIGHLEVEL;
+
+ pmu_irqs[i].registered = true;
+ count++;
+ (*last_cpu_id) = cinfo->reg_midr;
+ }
+ }
+ return count;
+}
+
+static int __init pmu_acpi_init(void)
+{
+ struct resource *res;
+ int err = -ENOMEM;
+ int count, cpu_id;
+ struct pmu_types *pmu, *safe_temp;
+ LIST_HEAD(pmus);
+
+ if (acpi_disabled)
+ return 0;
+
+ arm_pmu_acpi_determine_cpu_types(&pmus);
+
+ list_for_each_entry_safe(pmu, safe_temp, &pmus, list) {
+ res = kcalloc(pmu->cpu_count,
+ sizeof(struct resource), GFP_KERNEL);
+
+ /* for a given PMU type collect all the GSIs. */
+ if (res) {
+ count = arm_pmu_acpi_gsi_res(pmu, res,
+ &cpu_id);
+ /*
+ * register this set of interrupts
+ * with a new PMU device
+ */
+ err = arm_pmu_acpi_register_pmu(count, res, cpu_id);
+ if (!err)
+ pr_info("Registered %d devices for %X\n",
+ count, pmu->cpu_type);
+ kfree(res);
+ } else {
+ pr_warn("PMU unable to allocate interrupt resource space\n");
+ }
+
+ list_del(&pmu->list);
+ kfree(pmu);
+ }
+
+ return err;
+}
+
+arch_initcall(pmu_acpi_init);
--
2.5.5
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