Archipelago » qemu

/*

 * Virtual hardware watchdog.

 *

 * Copyright (C) 2009 Red Hat Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * 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, see <http://www.gnu.org/licenses/>.

 *

 * By Richard W.M. Jones (rjones@redhat.com).

 */

#include <inttypes.h>

#include "qemu-common.h"

#include "qemu-timer.h"

#include "watchdog.h"

#include "hw.h"

#include "pci.h"

/*#define I6300ESB_DEBUG 1*/

#ifdef I6300ESB_DEBUG

#define i6300esb_debug(fs,...) \

    fprintf(stderr,"i6300esb: %s: "fs,__func__,##__VA_ARGS__)

#else

#define i6300esb_debug(fs,...)

#endif

#ifndef PCI_DEVICE_ID_INTEL_ESB_9

#define PCI_DEVICE_ID_INTEL_ESB_9 0x25ab

#endif

/* PCI configuration registers */

#define ESB_CONFIG_REG  0x60            /* Config register                   */

#define ESB_LOCK_REG    0x68            /* WDT lock register                 */

/* Memory mapped registers (offset from base address) */

#define ESB_TIMER1_REG  0x00            /* Timer1 value after each reset     */

#define ESB_TIMER2_REG  0x04            /* Timer2 value after each reset     */

#define ESB_GINTSR_REG  0x08            /* General Interrupt Status Register */

#define ESB_RELOAD_REG  0x0c            /* Reload register                   */

/* Lock register bits */

#define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */

#define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */

#define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */

/* Config register bits */

#define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */

#define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */

#define ESB_WDT_INTTYPE (0x11 << 0)   /* Interrupt type on timer1 timeout  */

/* Reload register bits */

#define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */

/* Magic constants */

#define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */

#define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */

/* Device state. */

struct I6300State {

    PCIDevice dev;

    int reboot_enabled;         /* "Reboot" on timer expiry.  The real action

                                 * performed depends on the -watchdog-action

                                 * param passed on QEMU command line.

                                 */

    int clock_scale;            /* Clock scale. */

#define CLOCK_SCALE_1KHZ 0

#define CLOCK_SCALE_1MHZ 1

    int int_type;               /* Interrupt type generated. */

#define INT_TYPE_IRQ 0          /* APIC 1, INT 10 */

#define INT_TYPE_SMI 2

#define INT_TYPE_DISABLED 3

    int free_run;               /* If true, reload timer on expiry. */

    int locked;                 /* If true, enabled field cannot be changed. */

    int enabled;                /* If true, watchdog is enabled. */

    QEMUTimer *timer;           /* The actual watchdog timer. */

    uint32_t timer1_preload;    /* Values preloaded into timer1, timer2. */

    uint32_t timer2_preload;

    int stage;                  /* Stage (1 or 2). */

    int unlock_state;           /* Guest writes 0x80, 0x86 to unlock the

                                 * registers, and we transition through

                                 * states 0 -> 1 -> 2 when this happens.

                                 */

    int previous_reboot_flag;   /* If the watchdog caused the previous

                                 * reboot, this flag will be set.

                                 */

};

typedef struct I6300State I6300State;

/* This function is called when the watchdog has either been enabled

 * (hence it starts counting down) or has been keep-alived.

 */

static void i6300esb_restart_timer(I6300State *d, int stage)

{

    int64_t timeout;

    if (!d->enabled)

        return;

    d->stage = stage;

    if (d->stage <= 1)

        timeout = d->timer1_preload;

    else

        timeout = d->timer2_preload;

    if (d->clock_scale == CLOCK_SCALE_1KHZ)

        timeout <<= 15;

    else

        timeout <<= 5;

    /* Get the timeout in units of ticks_per_sec. */

    timeout = get_ticks_per_sec() * timeout / 33000000;

    i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout);

    qemu_mod_timer(d->timer, qemu_get_clock(vm_clock) + timeout);

}

/* This is called when the guest disables the watchdog. */

static void i6300esb_disable_timer(I6300State *d)

{

    i6300esb_debug("timer disabled\n");

    qemu_del_timer(d->timer);

}

static void i6300esb_reset(I6300State *d)

{

    /* XXX We should probably reset other parts of the state here,

     * but we should also reset our state on general machine reset

     * too.  For now just disable the timer so it doesn't fire

     * again after the reboot.

     */

    i6300esb_disable_timer(d);

}

/* This function is called when the watchdog expires.  Note that

 * the hardware has two timers, and so expiry happens in two stages.

 * If d->stage == 1 then we perform the first stage action (usually,

 * sending an interrupt) and then restart the timer again for the

 * second stage.  If the second stage expires then the watchdog

 * really has run out.

 */

static void i6300esb_timer_expired(void *vp)

{

    I6300State *d = vp;

    i6300esb_debug("stage %d\n", d->stage);

    if (d->stage == 1) {

        /* What to do at the end of stage 1? */

        switch (d->int_type) {

        case INT_TYPE_IRQ:

            fprintf(stderr, "i6300esb_timer_expired: I would send APIC 1 INT 10 here if I knew how (XXX)\n");

            break;

        case INT_TYPE_SMI:

            fprintf(stderr, "i6300esb_timer_expired: I would send SMI here if I knew how (XXX)\n");

            break;

        }

        /* Start the second stage. */

        i6300esb_restart_timer(d, 2);

    } else {

        /* Second stage expired, reboot for real. */

        if (d->reboot_enabled) {

            d->previous_reboot_flag = 1;

            watchdog_perform_action(); /* This reboots, exits, etc */

            i6300esb_reset(d);

        }

        /* In "free running mode" we start stage 1 again. */

        if (d->free_run)

            i6300esb_restart_timer(d, 1);

    }

}

static void i6300esb_config_write(PCIDevice *dev, uint32_t addr,

                                  uint32_t data, int len)

{

    I6300State *d = DO_UPCAST(I6300State, dev, dev);

    int old;

    i6300esb_debug("addr = %x, data = %x, len = %d\n", addr, data, len);

    if (addr == ESB_CONFIG_REG && len == 2) {

        d->reboot_enabled = (data & ESB_WDT_REBOOT) == 0;

        d->clock_scale =

            (data & ESB_WDT_FREQ) != 0 ? CLOCK_SCALE_1MHZ : CLOCK_SCALE_1KHZ;

        d->int_type = (data & ESB_WDT_INTTYPE);

    } else if (addr == ESB_LOCK_REG && len == 1) {

        if (!d->locked) {

            d->locked = (data & ESB_WDT_LOCK) != 0;

            d->free_run = (data & ESB_WDT_FUNC) != 0;

            old = d->enabled;

            d->enabled = (data & ESB_WDT_ENABLE) != 0;

            if (!old && d->enabled) /* Enabled transitioned from 0 -> 1 */

                i6300esb_restart_timer(d, 1);

            else if (!d->enabled)

                i6300esb_disable_timer(d);

        }

    } else {

        pci_default_write_config(dev, addr, data, len);

    }

}

static uint32_t i6300esb_config_read(PCIDevice *dev, uint32_t addr, int len)

{

    I6300State *d = DO_UPCAST(I6300State, dev, dev);

    uint32_t data;

    i6300esb_debug ("addr = %x, len = %d\n", addr, len);

    if (addr == ESB_CONFIG_REG && len == 2) {

        data =

            (d->reboot_enabled ? 0 : ESB_WDT_REBOOT) |

            (d->clock_scale == CLOCK_SCALE_1MHZ ? ESB_WDT_FREQ : 0) |

            d->int_type;

        return data;

    } else if (addr == ESB_LOCK_REG && len == 1) {

        data =

            (d->free_run ? ESB_WDT_FUNC : 0) |

            (d->locked ? ESB_WDT_LOCK : 0) |

            (d->enabled ? ESB_WDT_ENABLE : 0);

        return data;

    } else {

        return pci_default_read_config(dev, addr, len);

    }

}

static uint32_t i6300esb_mem_readb(void *vp, target_phys_addr_t addr)

{

    i6300esb_debug ("addr = %x\n", (int) addr);

    return 0;

}

static uint32_t i6300esb_mem_readw(void *vp, target_phys_addr_t addr)

{

    uint32_t data = 0;

    I6300State *d = vp;

    i6300esb_debug("addr = %x\n", (int) addr);

    if (addr == 0xc) {

        /* The previous reboot flag is really bit 9, but there is

         * a bug in the Linux driver where it thinks it's bit 12.

         * Set both.

         */

        data = d->previous_reboot_flag ? 0x1200 : 0;

    }

    return data;

}

static uint32_t i6300esb_mem_readl(void *vp, target_phys_addr_t addr)

{

    i6300esb_debug("addr = %x\n", (int) addr);

    return 0;

}

static void i6300esb_mem_writeb(void *vp, target_phys_addr_t addr, uint32_t val)

{

    I6300State *d = vp;

    i6300esb_debug("addr = %x, val = %x\n", (int) addr, val);

    if (addr == 0xc && val == 0x80)

        d->unlock_state = 1;

    else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)

        d->unlock_state = 2;

}

static void i6300esb_mem_writew(void *vp, target_phys_addr_t addr, uint32_t val)

{

    I6300State *d = vp;

    i6300esb_debug("addr = %x, val = %x\n", (int) addr, val);

    if (addr == 0xc && val == 0x80)

        d->unlock_state = 1;

    else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)

        d->unlock_state = 2;

    else {

        if (d->unlock_state == 2) {

            if (addr == 0xc) {

                if ((val & 0x100) != 0)

                    /* This is the "ping" from the userspace watchdog in

                     * the guest ...

                     */

                    i6300esb_restart_timer(d, 1);

                /* Setting bit 9 resets the previous reboot flag.

                 * There's a bug in the Linux driver where it sets

                 * bit 12 instead.

                 */

                if ((val & 0x200) != 0 || (val & 0x1000) != 0) {

                    d->previous_reboot_flag = 0;

                }

            }

            d->unlock_state = 0;

        }

    }

}

static void i6300esb_mem_writel(void *vp, target_phys_addr_t addr, uint32_t val)

{

    I6300State *d = vp;

    i6300esb_debug ("addr = %x, val = %x\n", (int) addr, val);

    if (addr == 0xc && val == 0x80)

        d->unlock_state = 1;

    else if (addr == 0xc && val == 0x86 && d->unlock_state == 1)

        d->unlock_state = 2;

    else {

        if (d->unlock_state == 2) {

            if (addr == 0)

                d->timer1_preload = val & 0xfffff;

            else if (addr == 4)

                d->timer2_preload = val & 0xfffff;

            d->unlock_state = 0;

        }

    }

}

static void i6300esb_map(PCIDevice *dev, int region_num,

                         uint32_t addr, uint32_t size, int type)

{

    static CPUReadMemoryFunc * const mem_read[3] = {

        i6300esb_mem_readb,

        i6300esb_mem_readw,

        i6300esb_mem_readl,

    };

    static CPUWriteMemoryFunc * const mem_write[3] = {

        i6300esb_mem_writeb,

        i6300esb_mem_writew,

        i6300esb_mem_writel,

    };

    I6300State *d = DO_UPCAST(I6300State, dev, dev);

    int io_mem;

    i6300esb_debug("addr = %x, size = %x, type = %d\n", addr, size, type);

    io_mem = cpu_register_io_memory(mem_read, mem_write, d);

    cpu_register_physical_memory (addr, 0x10, io_mem);

    /* qemu_register_coalesced_mmio (addr, 0x10); ? */

}

static const VMStateDescription vmstate_i6300esb = {

    .name = "i6300esb_wdt",

    .version_id = sizeof(I6300State),

    .minimum_version_id = sizeof(I6300State),

    .minimum_version_id_old = sizeof(I6300State),

    .fields      = (VMStateField []) {

        VMSTATE_PCI_DEVICE(dev, I6300State),

        VMSTATE_INT32(reboot_enabled, I6300State),

        VMSTATE_INT32(clock_scale, I6300State),

        VMSTATE_INT32(int_type, I6300State),

        VMSTATE_INT32(free_run, I6300State),

        VMSTATE_INT32(locked, I6300State),

        VMSTATE_INT32(enabled, I6300State),

        VMSTATE_TIMER(timer, I6300State),

        VMSTATE_UINT32(timer1_preload, I6300State),

        VMSTATE_UINT32(timer2_preload, I6300State),

        VMSTATE_INT32(stage, I6300State),

        VMSTATE_INT32(unlock_state, I6300State),

        VMSTATE_INT32(previous_reboot_flag, I6300State),

        VMSTATE_END_OF_LIST()

    }

};

static int i6300esb_init(PCIDevice *dev)

{

    I6300State *d = DO_UPCAST(I6300State, dev, dev);

    uint8_t *pci_conf;

    d->reboot_enabled = 1;

    d->clock_scale = CLOCK_SCALE_1KHZ;

    d->int_type = INT_TYPE_IRQ;

    d->free_run = 0;

    d->locked = 0;

    d->enabled = 0;

    d->timer = qemu_new_timer(vm_clock, i6300esb_timer_expired, d);

    d->timer1_preload = 0xfffff;

    d->timer2_preload = 0xfffff;

    d->stage = 1;

    d->unlock_state = 0;

    d->previous_reboot_flag = 0;

    pci_conf = d->dev.config;

    pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_INTEL);

    pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_ESB_9);

    pci_config_set_class(pci_conf, PCI_CLASS_SYSTEM_OTHER);

    pci_conf[0x0e] = 0x00;

    pci_register_bar(&d->dev, 0, 0x10,

                            PCI_ADDRESS_SPACE_MEM, i6300esb_map);

    vmstate_register(-1, &vmstate_i6300esb, d);

    return 0;

}

static WatchdogTimerModel model = {

    .wdt_name = "i6300esb",

    .wdt_description = "Intel 6300ESB",

};

static PCIDeviceInfo i6300esb_info = {

    .qdev.name    = "i6300esb",

    .qdev.size    = sizeof(I6300State),

    .config_read  = i6300esb_config_read,

    .config_write = i6300esb_config_write,

    .init         = i6300esb_init,

};

static void i6300esb_register_devices(void)

{

    watchdog_add_model(&model);

    pci_qdev_register(&i6300esb_info);

}

device_init(i6300esb_register_devices);