qemu/target/ppc/timebase_helper.c

/*
 *  PowerPC emulation helpers for QEMU.
 *
 *  Copyright (c) 2003-2007 Jocelyn Mayer
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */
#include "qemu/osdep.h"
#include "cpu.h"
#include "hw/ppc/ppc.h"
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "qemu/log.h"
#include "qemu/main-loop.h"

/*****************************************************************************/
/* SPR accesses */

target_ulong helper_load_tbl(CPUPPCState *env)
{
    return (target_ulong)cpu_ppc_load_tbl(env);
}

target_ulong helper_load_tbu(CPUPPCState *env)
{
    return cpu_ppc_load_tbu(env);
}

target_ulong helper_load_atbl(CPUPPCState *env)
{
    return (target_ulong)cpu_ppc_load_atbl(env);
}

target_ulong helper_load_atbu(CPUPPCState *env)
{
    return cpu_ppc_load_atbu(env);
}

target_ulong helper_load_vtb(CPUPPCState *env)
{
    return cpu_ppc_load_vtb(env);
}

#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
target_ulong helper_load_purr(CPUPPCState *env)
{
    return (target_ulong)cpu_ppc_load_purr(env);
}

void helper_store_purr(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_purr(env, val);
}
#endif

#if !defined(CONFIG_USER_ONLY)
void helper_store_tbl(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_tbl(env, val);
}

void helper_store_tbu(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_tbu(env, val);
}

void helper_store_atbl(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_atbl(env, val);
}

void helper_store_atbu(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_atbu(env, val);
}

target_ulong helper_load_decr(CPUPPCState *env)
{
    return cpu_ppc_load_decr(env);
}

void helper_store_decr(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_decr(env, val);
}

target_ulong helper_load_hdecr(CPUPPCState *env)
{
    return cpu_ppc_load_hdecr(env);
}

void helper_store_hdecr(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_hdecr(env, val);
}

void helper_store_vtb(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_vtb(env, val);
}

void helper_store_tbu40(CPUPPCState *env, target_ulong val)
{
    cpu_ppc_store_tbu40(env, val);
}

target_ulong helper_load_40x_pit(CPUPPCState *env)
{
    return load_40x_pit(env);
}

void helper_store_40x_pit(CPUPPCState *env, target_ulong val)
{
    store_40x_pit(env, val);
}

void helper_store_40x_tcr(CPUPPCState *env, target_ulong val)
{
    store_40x_tcr(env, val);
}

void helper_store_40x_tsr(CPUPPCState *env, target_ulong val)
{
    store_40x_tsr(env, val);
}

void helper_store_booke_tcr(CPUPPCState *env, target_ulong val)
{
    store_booke_tcr(env, val);
}

void helper_store_booke_tsr(CPUPPCState *env, target_ulong val)
{
    store_booke_tsr(env, val);
}

#if defined(TARGET_PPC64)
/*
 * POWER processor Timebase Facility
 */

/*
 * The TBST is the timebase state machine, which is a per-core machine that
 * is used to synchronize the core TB with the ChipTOD. States 3,4,5 are
 * not used in POWER8/9/10.
 *
 * The state machine gets driven by writes to TFMR SPR from the core, and
 * by signals from the ChipTOD. The state machine table for common
 * transitions is as follows (according to hardware specs, not necessarily
 * this implementation):
 *
 * | Cur            | Event                            | New |
 * +----------------+----------------------------------+-----+
 * | 0 RESET        | TFMR |= LOAD_TOD_MOD             | 1   |
 * | 1 SEND_TOD_MOD | "immediate transition"           | 2   |
 * | 2 NOT_SET      | mttbu/mttbu40/mttbl              | 2   |
 * | 2 NOT_SET      | TFMR |= MOVE_CHIP_TOD_TO_TB      | 6   |
 * | 6 SYNC_WAIT    | "sync pulse from ChipTOD"        | 7   |
 * | 7 GET_TOD      | ChipTOD xscom MOVE_TOD_TO_TB_REG | 8   |
 * | 8 TB_RUNNING   | mttbu/mttbu40                    | 8   |
 * | 8 TB_RUNNING   | TFMR |= LOAD_TOD_MOD             | 1   |
 * | 8 TB_RUNNING   | mttbl                            | 9   |
 * | 9 TB_ERROR     | TFMR |= CLEAR_TB_ERRORS          | 0   |
 *
 * - LOAD_TOD_MOD will also move states 2,6 to state 1, omitted from table
 *   because it's not a typical init flow.
 *
 * - The ERROR state can be entered from most/all other states on invalid
 *   states (e.g., if some TFMR control bit is set from a state where it's
 *   not listed to cause a transition away from), omitted to avoid clutter.
 *
 * Note: mttbl causes a timebase error because this inevitably causes
 * ticks to be lost and TB to become unsynchronized, whereas TB can be
 * adjusted using mttbu* without losing ticks. mttbl behaviour is not
 * modelled.
 *
 * Note: the TB state machine does not actually cause any real TB adjustment!
 * TB starts out synchronized across all vCPUs (hardware threads) in
 * QMEU, so for now the purpose of the TBST and ChipTOD model is simply
 * to step through firmware initialisation sequences.
 */
static unsigned int tfmr_get_tb_state(uint64_t tfmr)
{
    return (tfmr & TFMR_TBST_ENCODED) >> (63 - 31);
}

static uint64_t tfmr_new_tb_state(uint64_t tfmr, unsigned int tbst)
{
    tfmr &= ~TFMR_TBST_LAST;
    tfmr |= (tfmr & TFMR_TBST_ENCODED) >> 4; /* move state to last state */
    tfmr &= ~TFMR_TBST_ENCODED;
    tfmr |= (uint64_t)tbst << (63 - 31); /* move new state to state */

    if (tbst == TBST_TB_RUNNING) {
        tfmr |= TFMR_TB_VALID;
    } else {
        tfmr &= ~TFMR_TB_VALID;
    }

    return tfmr;
}

static void tb_state_machine_step(CPUPPCState *env)
{
    uint64_t tfmr = env->spr[SPR_TFMR];
    unsigned int tbst = tfmr_get_tb_state(tfmr);

    if (!(tfmr & TFMR_TB_ECLIPZ) || tbst == TBST_TB_ERROR) {
        return;
    }

    if (env->pnv_tod_tbst.tb_sync_pulse_timer) {
        env->pnv_tod_tbst.tb_sync_pulse_timer--;
    } else {
        tfmr |= TFMR_TB_SYNC_OCCURED;
        env->spr[SPR_TFMR] = tfmr;
    }

    if (env->pnv_tod_tbst.tb_state_timer) {
        env->pnv_tod_tbst.tb_state_timer--;
        return;
    }

    if (tfmr & TFMR_LOAD_TOD_MOD) {
        tfmr &= ~TFMR_LOAD_TOD_MOD;
        if (tbst == TBST_GET_TOD) {
            tfmr = tfmr_new_tb_state(tfmr, TBST_TB_ERROR);
            tfmr |= TFMR_FIRMWARE_CONTROL_ERROR;
        } else {
            tfmr = tfmr_new_tb_state(tfmr, TBST_SEND_TOD_MOD);
            /* State seems to transition immediately */
            tfmr = tfmr_new_tb_state(tfmr, TBST_NOT_SET);
        }
    } else if (tfmr & TFMR_MOVE_CHIP_TOD_TO_TB) {
        if (tbst == TBST_SYNC_WAIT) {
            tfmr = tfmr_new_tb_state(tfmr, TBST_GET_TOD);
            env->pnv_tod_tbst.tb_state_timer = 3;
        } else if (tbst == TBST_GET_TOD) {
            if (env->pnv_tod_tbst.tod_sent_to_tb) {
                tfmr = tfmr_new_tb_state(tfmr, TBST_TB_RUNNING);
                tfmr &= ~TFMR_MOVE_CHIP_TOD_TO_TB;
                env->pnv_tod_tbst.tb_ready_for_tod = 0;
                env->pnv_tod_tbst.tod_sent_to_tb = 0;
            }
        } else {
            qemu_log_mask(LOG_GUEST_ERROR, "TFMR error: MOVE_CHIP_TOD_TO_TB "
                          "state machine in invalid state 0x%x\n", tbst);
            tfmr = tfmr_new_tb_state(tfmr, TBST_TB_ERROR);
            tfmr |= TFMR_FIRMWARE_CONTROL_ERROR;
            env->pnv_tod_tbst.tb_ready_for_tod = 0;
        }
    }

    env->spr[SPR_TFMR] = tfmr;
}

target_ulong helper_load_tfmr(CPUPPCState *env)
{
    tb_state_machine_step(env);

    return env->spr[SPR_TFMR] | TFMR_TB_ECLIPZ;
}

void helper_store_tfmr(CPUPPCState *env, target_ulong val)
{
    uint64_t tfmr = env->spr[SPR_TFMR];
    uint64_t clear_on_write;
    unsigned int tbst = tfmr_get_tb_state(tfmr);

    if (!(val & TFMR_TB_ECLIPZ)) {
        qemu_log_mask(LOG_UNIMP, "TFMR non-ECLIPZ mode not implemented\n");
        tfmr &= ~TFMR_TBST_ENCODED;
        tfmr &= ~TFMR_TBST_LAST;
        goto out;
    }

    /* Update control bits */
    tfmr = (tfmr & ~TFMR_CONTROL_MASK) | (val & TFMR_CONTROL_MASK);

    /* Several bits are clear-on-write, only one is implemented so far */
    clear_on_write = val & TFMR_FIRMWARE_CONTROL_ERROR;
    tfmr &= ~clear_on_write;

    /*
     * mtspr always clears this. The sync pulse timer makes it come back
     * after the second mfspr.
     */
    tfmr &= ~TFMR_TB_SYNC_OCCURED;
    env->pnv_tod_tbst.tb_sync_pulse_timer = 1;

    if (ppc_cpu_tir(env_archcpu(env)) != 0 &&
        (val & (TFMR_LOAD_TOD_MOD | TFMR_MOVE_CHIP_TOD_TO_TB))) {
        qemu_log_mask(LOG_UNIMP, "TFMR timebase state machine can only be "
                                 "driven by thread 0\n");
        goto out;
    }

    if (((tfmr | val) & (TFMR_LOAD_TOD_MOD | TFMR_MOVE_CHIP_TOD_TO_TB)) ==
                        (TFMR_LOAD_TOD_MOD | TFMR_MOVE_CHIP_TOD_TO_TB)) {
        qemu_log_mask(LOG_GUEST_ERROR, "TFMR error: LOAD_TOD_MOD and "
                                       "MOVE_CHIP_TOD_TO_TB both set\n");
        tfmr = tfmr_new_tb_state(tfmr, TBST_TB_ERROR);
        tfmr |= TFMR_FIRMWARE_CONTROL_ERROR;
        env->pnv_tod_tbst.tb_ready_for_tod = 0;
        goto out;
    }

    if (tfmr & TFMR_CLEAR_TB_ERRORS) {
        /*
         * Workbook says TFMR_CLEAR_TB_ERRORS should be written twice.
         * This is not simulated/required here.
         */
        tfmr = tfmr_new_tb_state(tfmr, TBST_RESET);
        tfmr &= ~TFMR_CLEAR_TB_ERRORS;
        tfmr &= ~TFMR_LOAD_TOD_MOD;
        tfmr &= ~TFMR_MOVE_CHIP_TOD_TO_TB;
        tfmr &= ~TFMR_FIRMWARE_CONTROL_ERROR; /* XXX: should this be cleared? */
        env->pnv_tod_tbst.tb_ready_for_tod = 0;
        env->pnv_tod_tbst.tod_sent_to_tb = 0;
        goto out;
    }

    if (tbst == TBST_TB_ERROR) {
        qemu_log_mask(LOG_GUEST_ERROR, "TFMR error: mtspr TFMR in TB_ERROR"
                                       " state\n");
        tfmr |= TFMR_FIRMWARE_CONTROL_ERROR;
        return;
    }

    if (tfmr & TFMR_LOAD_TOD_MOD) {
        /* Wait for an arbitrary 3 mfspr until the next state transition. */
        env->pnv_tod_tbst.tb_state_timer = 3;
    } else if (tfmr & TFMR_MOVE_CHIP_TOD_TO_TB) {
        if (tbst == TBST_NOT_SET) {
            tfmr = tfmr_new_tb_state(tfmr, TBST_SYNC_WAIT);
            env->pnv_tod_tbst.tb_ready_for_tod = 1;
            env->pnv_tod_tbst.tb_state_timer = 3; /* arbitrary */
        } else {
            qemu_log_mask(LOG_GUEST_ERROR, "TFMR error: MOVE_CHIP_TOD_TO_TB "
                                           "not in TB not set state 0x%x\n",
                                           tbst);
            tfmr = tfmr_new_tb_state(tfmr, TBST_TB_ERROR);
            tfmr |= TFMR_FIRMWARE_CONTROL_ERROR;
            env->pnv_tod_tbst.tb_ready_for_tod = 0;
        }
    }

out:
    env->spr[SPR_TFMR] = tfmr;
}
#endif

/*****************************************************************************/
/* Embedded PowerPC specific helpers */

/* XXX: to be improved to check access rights when in user-mode */
target_ulong helper_load_dcr(CPUPPCState *env, target_ulong dcrn)
{
    uint32_t val = 0;

    if (unlikely(env->dcr_env == NULL)) {
        qemu_log_mask(LOG_GUEST_ERROR, "No DCR environment\n");
        raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
                               POWERPC_EXCP_INVAL |
                               POWERPC_EXCP_INVAL_INVAL, GETPC());
    } else {
        int ret;

        bql_lock();
        ret = ppc_dcr_read(env->dcr_env, (uint32_t)dcrn, &val);
        bql_unlock();
        if (unlikely(ret != 0)) {
            qemu_log_mask(LOG_GUEST_ERROR, "DCR read error %d %03x\n",
                          (uint32_t)dcrn, (uint32_t)dcrn);
            raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
                                   POWERPC_EXCP_INVAL |
                                   POWERPC_EXCP_INVAL_INVAL, GETPC());
        }
    }
    return val;
}

void helper_store_dcr(CPUPPCState *env, target_ulong dcrn, target_ulong val)
{
    if (unlikely(env->dcr_env == NULL)) {
        qemu_log_mask(LOG_GUEST_ERROR, "No DCR environment\n");
        raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
                               POWERPC_EXCP_INVAL |
                               POWERPC_EXCP_INVAL_INVAL, GETPC());
    } else {
        int ret;
        bql_lock();
        ret = ppc_dcr_write(env->dcr_env, (uint32_t)dcrn, (uint32_t)val);
        bql_unlock();
        if (unlikely(ret != 0)) {
            qemu_log_mask(LOG_GUEST_ERROR, "DCR write error %d %03x\n",
                          (uint32_t)dcrn, (uint32_t)dcrn);
            raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
                                   POWERPC_EXCP_INVAL |
                                   POWERPC_EXCP_INVAL_INVAL, GETPC());
        }
    }
}
#endif