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/*

 * QEMU PowerPC Booke hardware System Emulator

 *

 * Copyright (c) 2011 AdaCore

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "hw/hw.h"

#include "hw/ppc/ppc.h"

#include "qemu/timer.h"

#include "sysemu/sysemu.h"

#include "hw/timer/m48t59.h"

#include "qemu/log.h"

#include "hw/loader.h"

#include "kvm_ppc.h"

/* Timer Control Register */

#define TCR_WP_SHIFT  30        /* Watchdog Timer Period */

#define TCR_WP_MASK   (0x3 << TCR_WP_SHIFT)

#define TCR_WRC_SHIFT 28        /* Watchdog Timer Reset Control */

#define TCR_WRC_MASK  (0x3 << TCR_WRC_SHIFT)

#define TCR_WIE       (1 << 27) /* Watchdog Timer Interrupt Enable */

#define TCR_DIE       (1 << 26) /* Decrementer Interrupt Enable */

#define TCR_FP_SHIFT  24        /* Fixed-Interval Timer Period */

#define TCR_FP_MASK   (0x3 << TCR_FP_SHIFT)

#define TCR_FIE       (1 << 23) /* Fixed-Interval Timer Interrupt Enable */

#define TCR_ARE       (1 << 22) /* Auto-Reload Enable */

/* Timer Control Register (e500 specific fields) */

#define TCR_E500_FPEXT_SHIFT 13 /* Fixed-Interval Timer Period Extension */

#define TCR_E500_FPEXT_MASK  (0xf << TCR_E500_FPEXT_SHIFT)

#define TCR_E500_WPEXT_SHIFT 17 /* Watchdog Timer Period Extension */

#define TCR_E500_WPEXT_MASK  (0xf << TCR_E500_WPEXT_SHIFT)

/* Timer Status Register  */

#define TSR_FIS       (1 << 26) /* Fixed-Interval Timer Interrupt Status */

#define TSR_DIS       (1 << 27) /* Decrementer Interrupt Status */

#define TSR_WRS_SHIFT 28        /* Watchdog Timer Reset Status */

#define TSR_WRS_MASK  (0x3 << TSR_WRS_SHIFT)

#define TSR_WIS       (1 << 30) /* Watchdog Timer Interrupt Status */

#define TSR_ENW       (1 << 31) /* Enable Next Watchdog Timer */

typedef struct booke_timer_t booke_timer_t;

struct booke_timer_t {

    uint64_t fit_next;

    struct QEMUTimer *fit_timer;

    uint64_t wdt_next;

    struct QEMUTimer *wdt_timer;

    uint32_t flags;

};

static void booke_update_irq(PowerPCCPU *cpu)

{

    CPUPPCState *env = &cpu->env;

    ppc_set_irq(cpu, PPC_INTERRUPT_DECR,

                (env->spr[SPR_BOOKE_TSR] & TSR_DIS

                 && env->spr[SPR_BOOKE_TCR] & TCR_DIE));

    ppc_set_irq(cpu, PPC_INTERRUPT_WDT,

                (env->spr[SPR_BOOKE_TSR] & TSR_WIS

                 && env->spr[SPR_BOOKE_TCR] & TCR_WIE));

    ppc_set_irq(cpu, PPC_INTERRUPT_FIT,

                (env->spr[SPR_BOOKE_TSR] & TSR_FIS

                 && env->spr[SPR_BOOKE_TCR] & TCR_FIE));

}

/* Return the location of the bit of time base at which the FIT will raise an

   interrupt */

static uint8_t booke_get_fit_target(CPUPPCState *env, ppc_tb_t *tb_env)

{

    uint8_t fp = (env->spr[SPR_BOOKE_TCR] & TCR_FP_MASK) >> TCR_FP_SHIFT;

    if (tb_env->flags & PPC_TIMER_E500) {

        /* e500 Fixed-interval timer period extension */

        uint32_t fpext = (env->spr[SPR_BOOKE_TCR] & TCR_E500_FPEXT_MASK)

            >> TCR_E500_FPEXT_SHIFT;

        fp = 63 - (fp | fpext << 2);

    } else {

        fp = env->fit_period[fp];

    }

    return fp;

}

/* Return the location of the bit of time base at which the WDT will raise an

   interrupt */

static uint8_t booke_get_wdt_target(CPUPPCState *env, ppc_tb_t *tb_env)

{

    uint8_t wp = (env->spr[SPR_BOOKE_TCR] & TCR_WP_MASK) >> TCR_WP_SHIFT;

    if (tb_env->flags & PPC_TIMER_E500) {

        /* e500 Watchdog timer period extension */

        uint32_t wpext = (env->spr[SPR_BOOKE_TCR] & TCR_E500_WPEXT_MASK)

            >> TCR_E500_WPEXT_SHIFT;

        wp = 63 - (wp | wpext << 2);

    } else {

        wp = env->wdt_period[wp];

    }

    return wp;

}

static void booke_update_fixed_timer(CPUPPCState         *env,

                                     uint8_t           target_bit,

                                     uint64_t          *next,

                                     struct QEMUTimer *timer)

{

    ppc_tb_t *tb_env = env->tb_env;

    uint64_t delta_tick, ticks = 0;

    uint64_t tb;

    uint64_t period;

    uint64_t now;

    now = qemu_get_clock_ns(vm_clock);

    tb  = cpu_ppc_get_tb(tb_env, now, tb_env->tb_offset);

    period = 1ULL << target_bit;

    delta_tick = period - (tb & (period - 1));

    /* the timer triggers only when the selected bit toggles from 0 to 1 */

    if (tb & period) {

        ticks = period;

    }

    if (ticks + delta_tick < ticks) {

        /* Overflow, so assume the biggest number we can express. */

        ticks = UINT64_MAX;

    } else {

        ticks += delta_tick;

    }

    *next = now + muldiv64(ticks, get_ticks_per_sec(), tb_env->tb_freq);

    if ((*next < now) || (*next > INT64_MAX)) {

        /* Overflow, so assume the biggest number the qemu timer supports. */

        *next = INT64_MAX;

    }

    /* XXX: If expire time is now. We can't run the callback because we don't

     * have access to it. So we just set the timer one nanosecond later.

     */

    if (*next == now) {

        (*next)++;

    }

    qemu_mod_timer(timer, *next);

}

static void booke_decr_cb(void *opaque)

{

    PowerPCCPU *cpu = opaque;

    CPUPPCState *env = &cpu->env;

    env->spr[SPR_BOOKE_TSR] |= TSR_DIS;

    booke_update_irq(cpu);

    if (env->spr[SPR_BOOKE_TCR] & TCR_ARE) {

        /* Auto Reload */

        cpu_ppc_store_decr(env, env->spr[SPR_BOOKE_DECAR]);

    }

}

static void booke_fit_cb(void *opaque)

{

    PowerPCCPU *cpu = opaque;

    CPUPPCState *env = &cpu->env;

    ppc_tb_t *tb_env;

    booke_timer_t *booke_timer;

    tb_env = env->tb_env;

    booke_timer = tb_env->opaque;

    env->spr[SPR_BOOKE_TSR] |= TSR_FIS;

    booke_update_irq(cpu);

    booke_update_fixed_timer(env,

                             booke_get_fit_target(env, tb_env),

                             &booke_timer->fit_next,

                             booke_timer->fit_timer);

}

static void booke_wdt_cb(void *opaque)

{

    PowerPCCPU *cpu = opaque;

    CPUPPCState *env = &cpu->env;

    ppc_tb_t *tb_env;

    booke_timer_t *booke_timer;

    tb_env = env->tb_env;

    booke_timer = tb_env->opaque;

    /* TODO: There's lots of complicated stuff to do here */

    booke_update_irq(cpu);

    booke_update_fixed_timer(env,

                             booke_get_wdt_target(env, tb_env),

                             &booke_timer->wdt_next,

                             booke_timer->wdt_timer);

}

void store_booke_tsr(CPUPPCState *env, target_ulong val)

{

    PowerPCCPU *cpu = ppc_env_get_cpu(env);

    env->spr[SPR_BOOKE_TSR] &= ~val;

    kvmppc_clear_tsr_bits(cpu, val);

    booke_update_irq(cpu);

}

void store_booke_tcr(CPUPPCState *env, target_ulong val)

{

    PowerPCCPU *cpu = ppc_env_get_cpu(env);

    ppc_tb_t *tb_env = env->tb_env;

    booke_timer_t *booke_timer = tb_env->opaque;

    tb_env = env->tb_env;

    env->spr[SPR_BOOKE_TCR] = val;

    kvmppc_set_tcr(cpu);

    booke_update_irq(cpu);

    booke_update_fixed_timer(env,

                             booke_get_fit_target(env, tb_env),

                             &booke_timer->fit_next,

                             booke_timer->fit_timer);

    booke_update_fixed_timer(env,

                             booke_get_wdt_target(env, tb_env),

                             &booke_timer->wdt_next,

                             booke_timer->wdt_timer);

}

static void ppc_booke_timer_reset_handle(void *opaque)

{

    PowerPCCPU *cpu = opaque;

    CPUPPCState *env = &cpu->env;

    store_booke_tcr(env, 0);

    store_booke_tsr(env, -1);

}

/*

 * This function will be called whenever the CPU state changes.

 * CPU states are defined "typedef enum RunState".

 * Regarding timer, When CPU state changes to running after debug halt

 * or similar cases which takes time then in between final watchdog

 * expiry happenes. This will cause exit to QEMU and configured watchdog

 * action will be taken. To avoid this we always clear the watchdog state when

 * state changes to running.

 */

static void cpu_state_change_handler(void *opaque, int running, RunState state)

{

    PowerPCCPU *cpu = opaque;

    CPUPPCState *env = &cpu->env;

    if (!running) {

        return;

    }

    /*

     * Clear watchdog interrupt condition by clearing TSR.

     */

    store_booke_tsr(env, TSR_ENW | TSR_WIS | TSR_WRS_MASK);

}

void ppc_booke_timers_init(PowerPCCPU *cpu, uint32_t freq, uint32_t flags)

{

    ppc_tb_t *tb_env;

    booke_timer_t *booke_timer;

    int ret = 0;

    tb_env      = g_malloc0(sizeof(ppc_tb_t));

    booke_timer = g_malloc0(sizeof(booke_timer_t));

    cpu->env.tb_env = tb_env;

    tb_env->flags = flags | PPC_TIMER_BOOKE | PPC_DECR_ZERO_TRIGGERED;

    tb_env->tb_freq    = freq;

    tb_env->decr_freq  = freq;

    tb_env->opaque     = booke_timer;

    tb_env->decr_timer = qemu_new_timer_ns(vm_clock, &booke_decr_cb, cpu);

    booke_timer->fit_timer =

        qemu_new_timer_ns(vm_clock, &booke_fit_cb, cpu);

    booke_timer->wdt_timer =

        qemu_new_timer_ns(vm_clock, &booke_wdt_cb, cpu);

    ret = kvmppc_booke_watchdog_enable(cpu);

    if (ret) {

        /* TODO: Start the QEMU emulated watchdog if not running on KVM.

         * Also start the QEMU emulated watchdog if KVM does not support

         * emulated watchdog or somehow it is not enabled (supported but

         * not enabled is though some bug and requires debugging :)).

         */

    }

    qemu_add_vm_change_state_handler(cpu_state_change_handler, cpu);

    qemu_register_reset(ppc_booke_timer_reset_handle, cpu);

}