Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) 2012 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */
#define pr_fmt(fmt) "CPU PMU: " fmt

#include <linux/bitmap.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/irqdesc.h>

#include <asm/cputype.h>
#include <asm/irq_regs.h>
#include <asm/pmu.h>

/* Set at runtime when we know what CPU type we are. */
static struct arm_pmu *cpu_pmu;

/*
 * Despite the names, these two functions are CPU-specific and are used
 * by the OProfile/perf code.
 */
const char *perf_pmu_name(void)
{
	if (!cpu_pmu)
		return NULL;

	return cpu_pmu->name;
}
EXPORT_SYMBOL_GPL(perf_pmu_name);

int perf_num_counters(void)
{
	int max_events = 0;

	if (cpu_pmu != NULL)
		max_events = cpu_pmu->num_events;

	return max_events;
}
EXPORT_SYMBOL_GPL(perf_num_counters);

/* Include the PMU-specific implementations. */
#include "perf_event_xscale.c"
#include "perf_event_v6.c"
#include "perf_event_v7.c"

static void cpu_pmu_enable_percpu_irq(void *data)
{
	int irq = *(int *)data;

	enable_percpu_irq(irq, IRQ_TYPE_NONE);
}

static void cpu_pmu_disable_percpu_irq(void *data)
{
	int irq = *(int *)data;

	disable_percpu_irq(irq);
}

static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
{
	int i, irq, irqs;
	struct platform_device *pmu_device = cpu_pmu->plat_device;
	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;

	irqs = min(pmu_device->num_resources, num_possible_cpus());

	irq = platform_get_irq(pmu_device, 0);
	if (irq >= 0 && irq_is_percpu(irq)) {
		on_each_cpu(cpu_pmu_disable_percpu_irq, &irq, 1);
		free_percpu_irq(irq, &hw_events->percpu_pmu);
	} else {
		for (i = 0; i < irqs; ++i) {
			int cpu = i;

			if (cpu_pmu->irq_affinity)
				cpu = cpu_pmu->irq_affinity[i];

			if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
				continue;
			irq = platform_get_irq(pmu_device, i);
			if (irq >= 0)
				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
		}
	}
}

static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
{
	int i, err, irq, irqs;
	struct platform_device *pmu_device = cpu_pmu->plat_device;
	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;

	if (!pmu_device)
		return -ENODEV;

	irqs = min(pmu_device->num_resources, num_possible_cpus());
	if (irqs < 1) {
		pr_warn_once("perf/ARM: No irqs for PMU defined, sampling events not supported\n");
		return 0;
	}

	irq = platform_get_irq(pmu_device, 0);
	if (irq >= 0 && irq_is_percpu(irq)) {
		err = request_percpu_irq(irq, handler, "arm-pmu",
					 &hw_events->percpu_pmu);
		if (err) {
			pr_err("unable to request IRQ%d for ARM PMU counters\n",
				irq);
			return err;
		}
		on_each_cpu(cpu_pmu_enable_percpu_irq, &irq, 1);
	} else {
		for (i = 0; i < irqs; ++i) {
			int cpu = i;

			err = 0;
			irq = platform_get_irq(pmu_device, i);
			if (irq < 0)
				continue;

			if (cpu_pmu->irq_affinity)
				cpu = cpu_pmu->irq_affinity[i];

			/*
			 * If we have a single PMU interrupt that we can't shift,
			 * assume that we're running on a uniprocessor machine and
			 * continue. Otherwise, continue without this interrupt.
			 */
			if (irq_set_affinity(irq, cpumask_of(cpu)) && irqs > 1) {
				pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
					irq, cpu);
				continue;
			}

			err = request_irq(irq, handler,
					  IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
					  per_cpu_ptr(&hw_events->percpu_pmu, cpu));
			if (err) {
				pr_err("unable to request IRQ%d for ARM PMU counters\n",
					irq);
				return err;
			}

			cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
		}
	}

	return 0;
}

/*
 * PMU hardware loses all context when a CPU goes offline.
 * When a CPU is hotplugged back in, since some hardware registers are
 * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
 * junk values out of them.
 */
static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
			  void *hcpu)
{
	struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb);

	if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
		return NOTIFY_DONE;

	if (pmu->reset)
		pmu->reset(pmu);
	else
		return NOTIFY_DONE;

	return NOTIFY_OK;
}

static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
{
	int err;
	int cpu;
	struct pmu_hw_events __percpu *cpu_hw_events;

	cpu_hw_events = alloc_percpu(struct pmu_hw_events);
	if (!cpu_hw_events)
		return -ENOMEM;

	cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify;
	err = register_cpu_notifier(&cpu_pmu->hotplug_nb);
	if (err)
		goto out_hw_events;

	for_each_possible_cpu(cpu) {
		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
		raw_spin_lock_init(&events->pmu_lock);
		events->percpu_pmu = cpu_pmu;
	}

	cpu_pmu->hw_events	= cpu_hw_events;
	cpu_pmu->request_irq	= cpu_pmu_request_irq;
	cpu_pmu->free_irq	= cpu_pmu_free_irq;

	/* Ensure the PMU has sane values out of reset. */
	if (cpu_pmu->reset)
		on_each_cpu(cpu_pmu->reset, cpu_pmu, 1);

	/* If no interrupts available, set the corresponding capability flag */
	if (!platform_get_irq(cpu_pmu->plat_device, 0))
		cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;

	return 0;

out_hw_events:
	free_percpu(cpu_hw_events);
	return err;
}

static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
{
	unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
	free_percpu(cpu_pmu->hw_events);
}

/*
 * PMU platform driver and devicetree bindings.
 */
static const struct of_device_id cpu_pmu_of_device_ids[] = {
	{.compatible = "arm,cortex-a17-pmu",	.data = armv7_a17_pmu_init},
	{.compatible = "arm,cortex-a15-pmu",	.data = armv7_a15_pmu_init},
	{.compatible = "arm,cortex-a12-pmu",	.data = armv7_a12_pmu_init},
	{.compatible = "arm,cortex-a9-pmu",	.data = armv7_a9_pmu_init},
	{.compatible = "arm,cortex-a8-pmu",	.data = armv7_a8_pmu_init},
	{.compatible = "arm,cortex-a7-pmu",	.data = armv7_a7_pmu_init},
	{.compatible = "arm,cortex-a5-pmu",	.data = armv7_a5_pmu_init},
	{.compatible = "arm,arm11mpcore-pmu",	.data = armv6mpcore_pmu_init},
	{.compatible = "arm,arm1176-pmu",	.data = armv6_1176_pmu_init},
	{.compatible = "arm,arm1136-pmu",	.data = armv6_1136_pmu_init},
	{.compatible = "qcom,krait-pmu",	.data = krait_pmu_init},
	{.compatible = "qcom,scorpion-pmu",	.data = scorpion_pmu_init},
	{.compatible = "qcom,scorpion-mp-pmu",	.data = scorpion_mp_pmu_init},
	{},
};

static struct platform_device_id cpu_pmu_plat_device_ids[] = {
	{.name = "arm-pmu"},
	{.name = "armv6-pmu"},
	{.name = "armv7-pmu"},
	{.name = "xscale-pmu"},
	{},
};

static const struct pmu_probe_info pmu_probe_table[] = {
	ARM_PMU_PROBE(ARM_CPU_PART_ARM1136, armv6_1136_pmu_init),
	ARM_PMU_PROBE(ARM_CPU_PART_ARM1156, armv6_1156_pmu_init),
	ARM_PMU_PROBE(ARM_CPU_PART_ARM1176, armv6_1176_pmu_init),
	ARM_PMU_PROBE(ARM_CPU_PART_ARM11MPCORE, armv6mpcore_pmu_init),
	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A8, armv7_a8_pmu_init),
	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A9, armv7_a9_pmu_init),
	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V1, xscale1pmu_init),
	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V2, xscale2pmu_init),
	{ /* sentinel value */ }
};

/*
 * CPU PMU identification and probing.
 */
static int probe_current_pmu(struct arm_pmu *pmu)
{
	int cpu = get_cpu();
	unsigned int cpuid = read_cpuid_id();
	int ret = -ENODEV;
	const struct pmu_probe_info *info;

	pr_info("probing PMU on CPU %d\n", cpu);

	for (info = pmu_probe_table; info->init != NULL; info++) {
		if ((cpuid & info->mask) != info->cpuid)
			continue;
		ret = info->init(pmu);
		break;
	}

	put_cpu();
	return ret;
}

static int of_pmu_irq_cfg(struct platform_device *pdev)
{
	int i, irq;
	int *irqs;

	/* Don't bother with PPIs; they're already affine */
	irq = platform_get_irq(pdev, 0);
	if (irq >= 0 && irq_is_percpu(irq))
		return 0;

	irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
	if (!irqs)
		return -ENOMEM;

	for (i = 0; i < pdev->num_resources; ++i) {
		struct device_node *dn;
		int cpu;

		dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity",
				      i);
		if (!dn) {
			pr_warn("Failed to parse %s/interrupt-affinity[%d]\n",
				of_node_full_name(pdev->dev.of_node), i);
			break;
		}

		for_each_possible_cpu(cpu)
			if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL))
				break;

		of_node_put(dn);
		if (cpu >= nr_cpu_ids) {
			pr_warn("Failed to find logical CPU for %s\n",
				dn->name);
			break;
		}

		irqs[i] = cpu;
	}

	if (i == pdev->num_resources)
		cpu_pmu->irq_affinity = irqs;
	else
		kfree(irqs);

	return 0;
}

static int cpu_pmu_device_probe(struct platform_device *pdev)
{
	const struct of_device_id *of_id;
	const int (*init_fn)(struct arm_pmu *);
	struct device_node *node = pdev->dev.of_node;
	struct arm_pmu *pmu;
	int ret = -ENODEV;

	if (cpu_pmu) {
		pr_info("attempt to register multiple PMU devices!\n");
		return -ENOSPC;
	}

	pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
	if (!pmu) {
		pr_info("failed to allocate PMU device!\n");
		return -ENOMEM;
	}

	cpu_pmu = pmu;
	cpu_pmu->plat_device = pdev;

	if (node && (of_id = of_match_node(cpu_pmu_of_device_ids, pdev->dev.of_node))) {
		init_fn = of_id->data;

		ret = of_pmu_irq_cfg(pdev);
		if (!ret)
			ret = init_fn(pmu);
	} else {
		ret = probe_current_pmu(pmu);
	}

	if (ret) {
		pr_info("failed to probe PMU!\n");
		goto out_free;
	}

	ret = cpu_pmu_init(cpu_pmu);
	if (ret)
		goto out_free;

	ret = armpmu_register(cpu_pmu, -1);
	if (ret)
		goto out_destroy;

	return 0;

out_destroy:
	cpu_pmu_destroy(cpu_pmu);
out_free:
	pr_info("failed to register PMU devices!\n");
	kfree(pmu);
	return ret;
}

static struct platform_driver cpu_pmu_driver = {
	.driver		= {
		.name	= "arm-pmu",
		.pm	= &armpmu_dev_pm_ops,
		.of_match_table = cpu_pmu_of_device_ids,
	},
	.probe		= cpu_pmu_device_probe,
	.id_table	= cpu_pmu_plat_device_ids,
};

static int __init register_pmu_driver(void)
{
	return platform_driver_register(&cpu_pmu_driver);
}
device_initcall(register_pmu_driver);