op_model_avr32.c

Go to the documentation of this file.

/*
 * AVR32 Performance Counter Driver
 *
 * Copyright (C) 2005-2007 Atmel Corporation
 *
 * 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.
 *
 * Author: Ronny Pedersen
 */
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/oprofile.h>
#include <linux/sched.h>
#include <linux/types.h>

#include <asm/sysreg.h>

#define AVR32_PERFCTR_IRQ_GROUP 0
#define AVR32_PERFCTR_IRQ_LINE  1

void avr32_backtrace(struct pt_regs * const regs, unsigned int depth);

enum { PCCNT, PCNT0, PCNT1, NR_counter };

struct avr32_perf_counter {
    unsigned long   enabled;
    unsigned long   event;
    unsigned long   count;
    unsigned long   unit_mask;
    unsigned long   kernel;
    unsigned long   user;

    u32     ie_mask;
    u32     flag_mask;
};

static struct avr32_perf_counter counter[NR_counter] = {
    {
        .ie_mask    = SYSREG_BIT(IEC),
        .flag_mask  = SYSREG_BIT(FC),
    }, {
        .ie_mask    = SYSREG_BIT(IE0),
        .flag_mask  = SYSREG_BIT(F0),
    }, {
        .ie_mask    = SYSREG_BIT(IE1),
        .flag_mask  = SYSREG_BIT(F1),
    },
};

static void avr32_perf_counter_reset(void)
{
    /* Reset all counter and disable/clear all interrupts */
    sysreg_write(PCCR, (SYSREG_BIT(PCCR_R)
                | SYSREG_BIT(PCCR_C)
                | SYSREG_BIT(FC)
                | SYSREG_BIT(F0)
                | SYSREG_BIT(F1)));
}

static irqreturn_t avr32_perf_counter_interrupt(int irq, void *dev_id)
{
    struct avr32_perf_counter *ctr = dev_id;
    struct pt_regs *regs;
    u32 pccr;

    if (likely(!(intc_get_pending(AVR32_PERFCTR_IRQ_GROUP)
                    & (1 << AVR32_PERFCTR_IRQ_LINE))))
        return IRQ_NONE;

    regs = get_irq_regs();
    pccr = sysreg_read(PCCR);

    /* Clear the interrupt flags we're about to handle */
    sysreg_write(PCCR, pccr);

    /* PCCNT */
    if (ctr->enabled && (pccr & ctr->flag_mask)) {
        sysreg_write(PCCNT, -ctr->count);
        oprofile_add_sample(regs, PCCNT);
    }
    ctr++;
    /* PCNT0 */
    if (ctr->enabled && (pccr & ctr->flag_mask)) {
        sysreg_write(PCNT0, -ctr->count);
        oprofile_add_sample(regs, PCNT0);
    }
    ctr++;
    /* PCNT1 */
    if (ctr->enabled && (pccr & ctr->flag_mask)) {
        sysreg_write(PCNT1, -ctr->count);
        oprofile_add_sample(regs, PCNT1);
    }

    return IRQ_HANDLED;
}

static int avr32_perf_counter_create_files(struct super_block *sb,
        struct dentry *root)
{
    struct dentry *dir;
    unsigned int i;
    char filename[4];

    for (i = 0; i < NR_counter; i++) {
        snprintf(filename, sizeof(filename), "%u", i);
        dir = oprofilefs_mkdir(sb, root, filename);

        oprofilefs_create_ulong(sb, dir, "enabled",
                &counter[i].enabled);
        oprofilefs_create_ulong(sb, dir, "event",
                &counter[i].event);
        oprofilefs_create_ulong(sb, dir, "count",
                &counter[i].count);

        /* Dummy entries */
        oprofilefs_create_ulong(sb, dir, "kernel",
                &counter[i].kernel);
        oprofilefs_create_ulong(sb, dir, "user",
                &counter[i].user);
        oprofilefs_create_ulong(sb, dir, "unit_mask",
                &counter[i].unit_mask);
    }

    return 0;
}

static int avr32_perf_counter_setup(void)
{
    struct avr32_perf_counter *ctr;
    u32 pccr;
    int ret;
    int i;

    pr_debug("avr32_perf_counter_setup\n");

    if (sysreg_read(PCCR) & SYSREG_BIT(PCCR_E)) {
        printk(KERN_ERR
            "oprofile: setup: perf counter already enabled\n");
        return -EBUSY;
    }

    ret = request_irq(AVR32_PERFCTR_IRQ_GROUP,
            avr32_perf_counter_interrupt, IRQF_SHARED,
            "oprofile", counter);
    if (ret)
        return ret;

    avr32_perf_counter_reset();

    pccr = 0;
    for (i = PCCNT; i < NR_counter; i++) {
        ctr = &counter[i];
        if (!ctr->enabled)
            continue;

        pr_debug("enabling counter %d...\n", i);

        pccr |= ctr->ie_mask;

        switch (i) {
        case PCCNT:
            /* PCCNT always counts cycles, so no events */
            sysreg_write(PCCNT, -ctr->count);
            break;
        case PCNT0:
            pccr |= SYSREG_BF(CONF0, ctr->event);
            sysreg_write(PCNT0, -ctr->count);
            break;
        case PCNT1:
            pccr |= SYSREG_BF(CONF1, ctr->event);
            sysreg_write(PCNT1, -ctr->count);
            break;
        }
    }

    pr_debug("oprofile: writing 0x%x to PCCR...\n", pccr);

    sysreg_write(PCCR, pccr);

    return 0;
}

static void avr32_perf_counter_shutdown(void)
{
    pr_debug("avr32_perf_counter_shutdown\n");

    avr32_perf_counter_reset();
    free_irq(AVR32_PERFCTR_IRQ_GROUP, counter);
}

static int avr32_perf_counter_start(void)
{
    pr_debug("avr32_perf_counter_start\n");

    sysreg_write(PCCR, sysreg_read(PCCR) | SYSREG_BIT(PCCR_E));

    return 0;
}

static void avr32_perf_counter_stop(void)
{
    pr_debug("avr32_perf_counter_stop\n");

    sysreg_write(PCCR, sysreg_read(PCCR) & ~SYSREG_BIT(PCCR_E));
}

static struct oprofile_operations avr32_perf_counter_ops __initdata = {
    .create_files   = avr32_perf_counter_create_files,
    .setup      = avr32_perf_counter_setup,
    .shutdown   = avr32_perf_counter_shutdown,
    .start      = avr32_perf_counter_start,
    .stop       = avr32_perf_counter_stop,
    .cpu_type   = "avr32",
};

int __init oprofile_arch_init(struct oprofile_operations *ops)
{
    if (!(current_cpu_data.features & AVR32_FEATURE_PCTR))
        return -ENODEV;

    memcpy(ops, &avr32_perf_counter_ops,
            sizeof(struct oprofile_operations));

    ops->backtrace = avr32_backtrace;

    printk(KERN_INFO "oprofile: using AVR32 performance monitoring.\n");

    return 0;
}

void oprofile_arch_exit(void)
{

}