/* pcr.c: Generic sparc64 performance counter infrastructure.
 *
 * Copyright (C) 2009 David S. Miller (davem@davemloft.net)
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/irq.h>

#include <linux/irq_work.h>
#include <linux/ftrace.h>

#include <asm/pil.h>
#include <asm/pcr.h>
#include <asm/nmi.h>
#include <asm/asi.h>
#include <asm/spitfire.h>

/* This code is shared between various users of the performance
 * counters.  Users will be oprofile, pseudo-NMI watchdog, and the
 * perf_event support layer.
 */

/* Performance counter interrupts run unmasked at PIL level 15.
 * Therefore we can't do things like wakeups and other work
 * that expects IRQ disabling to be adhered to in locking etc.
 *
 * Therefore in such situations we defer the work by signalling
 * a lower level cpu IRQ.
 */
void __irq_entry deferred_pcr_work_irq(int irq, struct pt_regs *regs)
{
        struct pt_regs *old_regs;

        clear_softint(1 << PIL_DEFERRED_PCR_WORK);

        old_regs = set_irq_regs(regs);
        irq_enter();
#ifdef CONFIG_IRQ_WORK
        irq_work_run();
#endif
        irq_exit();
        set_irq_regs(old_regs);
}

void arch_irq_work_raise(void)
{
        set_softint(1 << PIL_DEFERRED_PCR_WORK);
}

const struct pcr_ops *pcr_ops;
EXPORT_SYMBOL_GPL(pcr_ops);

static u64 direct_pcr_read(unsigned long reg_num)
{
        u64 val;

        WARN_ON_ONCE(reg_num != 0);
        __asm__ __volatile__("rd %%pcr, %0" : "=r" (val));
        return val;
}

static void direct_pcr_write(unsigned long reg_num, u64 val)
{
        WARN_ON_ONCE(reg_num != 0);
        __asm__ __volatile__("wr %0, 0x0, %%pcr" : : "r" (val));
}

static u64 direct_pic_read(unsigned long reg_num)
{
        u64 val;

        WARN_ON_ONCE(reg_num != 0);
        __asm__ __volatile__("rd %%pic, %0" : "=r" (val));
        return val;
}

static void direct_pic_write(unsigned long reg_num, u64 val)
{
        WARN_ON_ONCE(reg_num != 0);

        /* Blackbird errata workaround.  See commentary in
         * arch/sparc64/kernel/smp.c:smp_percpu_timer_interrupt()
         * for more information.
         */
        __asm__ __volatile__("ba,pt     %%xcc, 99f\n\t"
                             " nop\n\t"
                             ".align    64\n"
                          "99:wr        %0, 0x0, %%pic\n\t"
                             "rd        %%pic, %%g0" : : "r" (val));
}

static u64 direct_picl_value(unsigned int nmi_hz)
{
        u32 delta = local_cpu_data().clock_tick / nmi_hz;

        return ((u64)((0 - delta) & 0xffffffff)) << 32;
}

static const struct pcr_ops direct_pcr_ops = {
        .read_pcr               = direct_pcr_read,
        .write_pcr              = direct_pcr_write,
        .read_pic               = direct_pic_read,
        .write_pic              = direct_pic_write,
        .nmi_picl_value         = direct_picl_value,
        .pcr_nmi_enable         = (PCR_PIC_PRIV | PCR_STRACE | PCR_UTRACE),
        .pcr_nmi_disable        = PCR_PIC_PRIV,
};

static void n2_pcr_write(unsigned long reg_num, u64 val)
{
        unsigned long ret;

        WARN_ON_ONCE(reg_num != 0);
        if (val & PCR_N2_HTRACE) {
                ret = sun4v_niagara2_setperf(HV_N2_PERF_SPARC_CTL, val);
                if (ret != HV_EOK)
                        direct_pcr_write(reg_num, val);
        } else
                direct_pcr_write(reg_num, val);
}

static u64 n2_picl_value(unsigned int nmi_hz)
{
        u32 delta = local_cpu_data().clock_tick / (nmi_hz << 2);

        return ((u64)((0 - delta) & 0xffffffff)) << 32;
}

static const struct pcr_ops n2_pcr_ops = {
        .read_pcr               = direct_pcr_read,
        .write_pcr              = n2_pcr_write,
        .read_pic               = direct_pic_read,
        .write_pic              = direct_pic_write,
        .nmi_picl_value         = n2_picl_value,
        .pcr_nmi_enable         = (PCR_PIC_PRIV | PCR_STRACE | PCR_UTRACE |
                                   PCR_N2_TOE_OV1 |
                                   (2 << PCR_N2_SL1_SHIFT) |
                                   (0xff << PCR_N2_MASK1_SHIFT)),
        .pcr_nmi_disable        = PCR_PIC_PRIV,
};

static u64 n4_pcr_read(unsigned long reg_num)
{
        unsigned long val;

        (void) sun4v_vt_get_perfreg(reg_num, &val);

        return val;
}

static void n4_pcr_write(unsigned long reg_num, u64 val)
{
        (void) sun4v_vt_set_perfreg(reg_num, val);
}

static u64 n4_pic_read(unsigned long reg_num)
{
        unsigned long val;

        __asm__ __volatile__("ldxa [%1] %2, %0"
                             : "=r" (val)
                             : "r" (reg_num * 0x8UL), "i" (ASI_PIC));

        return val;
}

static void n4_pic_write(unsigned long reg_num, u64 val)
{
        __asm__ __volatile__("stxa %0, [%1] %2"
                             : /* no outputs */
                             : "r" (val), "r" (reg_num * 0x8UL), "i" (ASI_PIC));
}

static u64 n4_picl_value(unsigned int nmi_hz)
{
        u32 delta = local_cpu_data().clock_tick / (nmi_hz << 2);

        return ((u64)((0 - delta) & 0xffffffff));
}

static const struct pcr_ops n4_pcr_ops = {
        .read_pcr               = n4_pcr_read,
        .write_pcr              = n4_pcr_write,
        .read_pic               = n4_pic_read,
        .write_pic              = n4_pic_write,
        .nmi_picl_value         = n4_picl_value,
        .pcr_nmi_enable         = (PCR_N4_PICNPT | PCR_N4_STRACE |
                                   PCR_N4_UTRACE | PCR_N4_TOE |
                                   (26 << PCR_N4_SL_SHIFT)),
        .pcr_nmi_disable        = PCR_N4_PICNPT,
};

static u64 n5_pcr_read(unsigned long reg_num)
{
        unsigned long val;

        (void) sun4v_t5_get_perfreg(reg_num, &val);

        return val;
}

static void n5_pcr_write(unsigned long reg_num, u64 val)
{
        (void) sun4v_t5_set_perfreg(reg_num, val);
}

static const struct pcr_ops n5_pcr_ops = {
        .read_pcr               = n5_pcr_read,
        .write_pcr              = n5_pcr_write,
        .read_pic               = n4_pic_read,
        .write_pic              = n4_pic_write,
        .nmi_picl_value         = n4_picl_value,
        .pcr_nmi_enable         = (PCR_N4_PICNPT | PCR_N4_STRACE |
                                   PCR_N4_UTRACE | PCR_N4_TOE |
                                   (26 << PCR_N4_SL_SHIFT)),
        .pcr_nmi_disable        = PCR_N4_PICNPT,
};

static u64 m7_pcr_read(unsigned long reg_num)
{
        unsigned long val;

        (void) sun4v_m7_get_perfreg(reg_num, &val);

        return val;
}

static void m7_pcr_write(unsigned long reg_num, u64 val)
{
        (void) sun4v_m7_set_perfreg(reg_num, val);
}

static const struct pcr_ops m7_pcr_ops = {
        .read_pcr               = m7_pcr_read,
        .write_pcr              = m7_pcr_write,
        .read_pic               = n4_pic_read,
        .write_pic              = n4_pic_write,
        .nmi_picl_value         = n4_picl_value,
        .pcr_nmi_enable         = (PCR_N4_PICNPT | PCR_N4_STRACE |
                                   PCR_N4_UTRACE | PCR_N4_TOE |
                                   (26 << PCR_N4_SL_SHIFT)),
        .pcr_nmi_disable        = PCR_N4_PICNPT,
};

static unsigned long perf_hsvc_group;
static unsigned long perf_hsvc_major;
static unsigned long perf_hsvc_minor;

static int __init register_perf_hsvc(void)
{
        unsigned long hverror;

        if (tlb_type == hypervisor) {
                switch (sun4v_chip_type) {
                case SUN4V_CHIP_NIAGARA1:
                        perf_hsvc_group = HV_GRP_NIAG_PERF;
                        break;

                case SUN4V_CHIP_NIAGARA2:
                        perf_hsvc_group = HV_GRP_N2_CPU;
                        break;

                case SUN4V_CHIP_NIAGARA3:
                        perf_hsvc_group = HV_GRP_KT_CPU;
                        break;

                case SUN4V_CHIP_NIAGARA4:
                        perf_hsvc_group = HV_GRP_VT_CPU;
                        break;

                case SUN4V_CHIP_NIAGARA5:
                        perf_hsvc_group = HV_GRP_T5_CPU;
                        break;

                case SUN4V_CHIP_SPARC_M7:
                        perf_hsvc_group = HV_GRP_M7_PERF;
                        break;

                default:
                        return -ENODEV;
                }


                perf_hsvc_major = 1;
                perf_hsvc_minor = 0;
                hverror = sun4v_hvapi_register(perf_hsvc_group,
                                               perf_hsvc_major,
                                               &perf_hsvc_minor);
                if (hverror) {
                        pr_err("perfmon: Could not register hvapi(0x%lx).\n",
                               hverror);
                        return -ENODEV;
                }
        }
        return 0;
}

static void __init unregister_perf_hsvc(void)
{
        if (tlb_type != hypervisor)
                return;
        sun4v_hvapi_unregister(perf_hsvc_group);
}

static int __init setup_sun4v_pcr_ops(void)
{
        int ret = 0;

        switch (sun4v_chip_type) {
        case SUN4V_CHIP_NIAGARA1:
        case SUN4V_CHIP_NIAGARA2:
        case SUN4V_CHIP_NIAGARA3:
                pcr_ops = &n2_pcr_ops;
                break;

        case SUN4V_CHIP_NIAGARA4:
                pcr_ops = &n4_pcr_ops;
                break;

        case SUN4V_CHIP_NIAGARA5:
                pcr_ops = &n5_pcr_ops;
                break;

        case SUN4V_CHIP_SPARC_M7:
                pcr_ops = &m7_pcr_ops;
                break;

        default:
                ret = -ENODEV;
                break;
        }

        return ret;
}

int __init pcr_arch_init(void)
{
        int err = register_perf_hsvc();

        if (err)
                return err;

        switch (tlb_type) {
        case hypervisor:
                err = setup_sun4v_pcr_ops();
                if (err)
                        goto out_unregister;
                break;

        case cheetah:
        case cheetah_plus:
                pcr_ops = &direct_pcr_ops;
                break;

        case spitfire:
                /* UltraSPARC-I/II and derivatives lack a profile
                 * counter overflow interrupt so we can't make use of
                 * their hardware currently.
                 */
                /* fallthrough */
        default:
                err = -ENODEV;
                goto out_unregister;
        }

        return nmi_init();

out_unregister:
        unregister_perf_hsvc();
        return err;
}