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/*
* Linux performance counter support for ARC700 series
*
* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
*
* This code is inspired by the perf support of various other architectures.
*
* 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.
*
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <asm/arcregs.h>
struct arc_pmu {
struct pmu pmu;
int counter_size; /* in bits */
int n_counters;
unsigned long used_mask[BITS_TO_LONGS(ARC_PMU_MAX_HWEVENTS)];
int ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
};
/* read counter #idx; note that counter# != event# on ARC! */
static uint64_t arc_pmu_read_counter(int idx)
{
uint32_t tmp;
uint64_t result;
/*
* ARC supports making 'snapshots' of the counters, so we don't
* need to care about counters wrapping to 0 underneath our feet
*/
write_aux_reg(ARC_REG_PCT_INDEX, idx);
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, tmp | ARC_REG_PCT_CONTROL_SN);
result = (uint64_t) (read_aux_reg(ARC_REG_PCT_SNAPH)) << 32;
result |= read_aux_reg(ARC_REG_PCT_SNAPL);
return result;
}
static void arc_perf_event_update(struct perf_event *event,
struct hw_perf_event *hwc, int idx)
{
struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
uint64_t prev_raw_count, new_raw_count;
int64_t delta;
do {
prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = arc_pmu_read_counter(idx);
} while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count);
delta = (new_raw_count - prev_raw_count) &
((1ULL << arc_pmu->counter_size) - 1ULL);
local64_add(delta, &event->count);
local64_sub(delta, &hwc->period_left);
}
static void arc_pmu_read(struct perf_event *event)
{
arc_perf_event_update(event, &event->hw, event->hw.idx);
}
static int arc_pmu_cache_event(u64 config)
{
unsigned int cache_type, cache_op, cache_result;
int ret;
cache_type = (config >> 0) & 0xff;
cache_op = (config >> 8) & 0xff;
cache_result = (config >> 16) & 0xff;
if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
return -EINVAL;
if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
return -EINVAL;
if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
ret = arc_pmu_cache_map[cache_type][cache_op][cache_result];
if (ret == CACHE_OP_UNSUPPORTED)
return -ENOENT;
return ret;
}
/* initializes hw_perf_event structure if event is supported */
static int arc_pmu_event_init(struct perf_event *event)
{
struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
struct hw_perf_event *hwc = &event->hw;
int ret;
/* ARC 700 PMU does not support sampling events */
if (is_sampling_event(event))
return -ENOENT;
switch (event->attr.type) {
case PERF_TYPE_HARDWARE:
if (event->attr.config >= PERF_COUNT_HW_MAX)
return -ENOENT;
if (arc_pmu->ev_hw_idx[event->attr.config] < 0)
return -ENOENT;
hwc->config = arc_pmu->ev_hw_idx[event->attr.config];
pr_debug("initializing event %d with cfg %d\n",
(int) event->attr.config, (int) hwc->config);
return 0;
case PERF_TYPE_HW_CACHE:
ret = arc_pmu_cache_event(event->attr.config);
if (ret < 0)
return ret;
hwc->config = arc_pmu->ev_hw_idx[ret];
return 0;
default:
return -ENOENT;
}
}
/* starts all counters */
static void arc_pmu_enable(struct pmu *pmu)
{
uint32_t tmp;
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x1);
}
/* stops all counters */
static void arc_pmu_disable(struct pmu *pmu)
{
uint32_t tmp;
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x0);
}
/*
* Assigns hardware counter to hardware condition.
* Note that there is no separate start/stop mechanism;
* stopping is achieved by assigning the 'never' condition
*/
static void arc_pmu_start(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (WARN_ON_ONCE(idx == -1))
return;
if (flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
event->hw.state = 0;
/* enable ARC pmu here */
write_aux_reg(ARC_REG_PCT_INDEX, idx);
write_aux_reg(ARC_REG_PCT_CONFIG, hwc->config);
}
static void arc_pmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (!(event->hw.state & PERF_HES_STOPPED)) {
/* stop ARC pmu here */
write_aux_reg(ARC_REG_PCT_INDEX, idx);
/* condition code #0 is always "never" */
write_aux_reg(ARC_REG_PCT_CONFIG, 0);
event->hw.state |= PERF_HES_STOPPED;
}
if ((flags & PERF_EF_UPDATE) &&
!(event->hw.state & PERF_HES_UPTODATE)) {
arc_perf_event_update(event, &event->hw, idx);
event->hw.state |= PERF_HES_UPTODATE;
}
}
static void arc_pmu_del(struct perf_event *event, int flags)
{
struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
arc_pmu_stop(event, PERF_EF_UPDATE);
__clear_bit(event->hw.idx, arc_pmu->used_mask);
perf_event_update_userpage(event);
}
/* allocate hardware counter and optionally start counting */
static int arc_pmu_add(struct perf_event *event, int flags)
{
struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (__test_and_set_bit(idx, arc_pmu->used_mask)) {
idx = find_first_zero_bit(arc_pmu->used_mask,
arc_pmu->n_counters);
if (idx == arc_pmu->n_counters)
return -EAGAIN;
__set_bit(idx, arc_pmu->used_mask);
hwc->idx = idx;
}
write_aux_reg(ARC_REG_PCT_INDEX, idx);
write_aux_reg(ARC_REG_PCT_CONFIG, 0);
write_aux_reg(ARC_REG_PCT_COUNTL, 0);
write_aux_reg(ARC_REG_PCT_COUNTH, 0);
local64_set(&hwc->prev_count, 0);
hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (flags & PERF_EF_START)
arc_pmu_start(event, PERF_EF_RELOAD);
perf_event_update_userpage(event);
return 0;
}
static int arc_pmu_device_probe(struct platform_device *pdev)
{
struct arc_pmu *arc_pmu;
struct arc_reg_pct_build pct_bcr;
struct arc_reg_cc_build cc_bcr;
int i, j, ret;
union cc_name {
struct {
uint32_t word0, word1;
char sentinel;
} indiv;
char str[9];
} cc_name;
READ_BCR(ARC_REG_PCT_BUILD, pct_bcr);
if (!pct_bcr.v) {
pr_err("This core does not have performance counters!\n");
return -ENODEV;
}
arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu),
GFP_KERNEL);
if (!arc_pmu)
return -ENOMEM;
arc_pmu->n_counters = pct_bcr.c;
BUG_ON(arc_pmu->n_counters > ARC_PMU_MAX_HWEVENTS);
arc_pmu->counter_size = 32 + (pct_bcr.s << 4);
pr_info("ARC PMU found with %d counters of size %d bits\n",
arc_pmu->n_counters, arc_pmu->counter_size);
READ_BCR(ARC_REG_CC_BUILD, cc_bcr);
if (!<
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