/*
 *  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
 *
 *  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/>.
 */

#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/qemu-print.h"
#include "cpu.h"
#include "internal.h"
#include "exec/exec-all.h"
#include "qapi/error.h"
#include "hw/qdev-properties.h"

static void hexagon_v67_cpu_init(Object *obj)
{
}

static ObjectClass *hexagon_cpu_class_by_name(const char *cpu_model)
{
    ObjectClass *oc;
    char *typename;
    char **cpuname;

    cpuname = g_strsplit(cpu_model, ",", 1);
    typename = g_strdup_printf(HEXAGON_CPU_TYPE_NAME("%s"), cpuname[0]);
    oc = object_class_by_name(typename);
    g_strfreev(cpuname);
    g_free(typename);
    if (!oc || !object_class_dynamic_cast(oc, TYPE_HEXAGON_CPU) ||
        object_class_is_abstract(oc)) {
        return NULL;
    }
    return oc;
}

static Property hexagon_lldb_compat_property =
    DEFINE_PROP_BOOL("lldb-compat", HexagonCPU, lldb_compat, false);
static Property hexagon_lldb_stack_adjust_property =
    DEFINE_PROP_UNSIGNED("lldb-stack-adjust", HexagonCPU, lldb_stack_adjust,
                         0, qdev_prop_uint32, target_ulong);

const char * const hexagon_regnames[TOTAL_PER_THREAD_REGS] = {
   "r0", "r1",  "r2",  "r3",  "r4",   "r5",  "r6",  "r7",
   "r8", "r9",  "r10", "r11", "r12",  "r13", "r14", "r15",
  "r16", "r17", "r18", "r19", "r20",  "r21", "r22", "r23",
  "r24", "r25", "r26", "r27", "r28",  "r29", "r30", "r31",
  "sa0", "lc0", "sa1", "lc1", "p3_0", "c5",  "m0",  "m1",
  "usr", "pc",  "ugp", "gp",  "cs0",  "cs1", "c14", "c15",
  "c16", "c17", "c18", "c19", "pkt_cnt",  "insn_cnt", "c22", "c23",
  "c24", "c25", "c26", "c27", "c28",  "c29", "c30", "c31",
};

/*
 * One of the main debugging techniques is to use "-d cpu" and compare against
 * LLDB output when single stepping.  However, the target and qemu put the
 * stacks at different locations.  This is used to compensate so the diff is
 * cleaner.
 */
static inline target_ulong adjust_stack_ptrs(CPUHexagonState *env,
                                             target_ulong addr)
{
    HexagonCPU *cpu = container_of(env, HexagonCPU, env);
    target_ulong stack_adjust = cpu->lldb_stack_adjust;
    target_ulong stack_start = env->stack_start;
    target_ulong stack_size = 0x10000;

    if (stack_adjust == 0) {
        return addr;
    }

    if (stack_start + 0x1000 >= addr && addr >= (stack_start - stack_size)) {
        return addr - stack_adjust;
    }
    return addr;
}

/* HEX_REG_P3_0 (aka C4) is an alias for the predicate registers */
static inline target_ulong read_p3_0(CPUHexagonState *env)
{
    int32_t control_reg = 0;
    int i;
    for (i = NUM_PREGS - 1; i >= 0; i--) {
        control_reg <<= 8;
        control_reg |= env->pred[i] & 0xff;
    }
    return control_reg;
}

static void print_reg(FILE *f, CPUHexagonState *env, int regnum)
{
    target_ulong value;

    if (regnum == HEX_REG_P3_0) {
        value = read_p3_0(env);
    } else {
        value = regnum < 32 ? adjust_stack_ptrs(env, env->gpr[regnum])
                            : env->gpr[regnum];
    }

    qemu_fprintf(f, "  %s = 0x" TARGET_FMT_lx "\n",
                 hexagon_regnames[regnum], value);
}

static void hexagon_dump(CPUHexagonState *env, FILE *f)
{
    HexagonCPU *cpu = container_of(env, HexagonCPU, env);

    if (cpu->lldb_compat) {
        /*
         * When comparing with LLDB, it doesn't step through single-cycle
         * hardware loops the same way.  So, we just skip them here
         */
        if (env->gpr[HEX_REG_PC] == env->last_pc_dumped) {
            return;
        }
        env->last_pc_dumped = env->gpr[HEX_REG_PC];
    }

    qemu_fprintf(f, "General Purpose Registers = {\n");
    for (int i = 0; i < 32; i++) {
        print_reg(f, env, i);
    }
    print_reg(f, env, HEX_REG_SA0);
    print_reg(f, env, HEX_REG_LC0);
    print_reg(f, env, HEX_REG_SA1);
    print_reg(f, env, HEX_REG_LC1);
    print_reg(f, env, HEX_REG_M0);
    print_reg(f, env, HEX_REG_M1);
    print_reg(f, env, HEX_REG_USR);
    print_reg(f, env, HEX_REG_P3_0);
    print_reg(f, env, HEX_REG_GP);
    print_reg(f, env, HEX_REG_UGP);
    print_reg(f, env, HEX_REG_PC);
#ifdef CONFIG_USER_ONLY
    /*
     * Not modelled in user mode, print junk to minimize the diff's
     * with LLDB output
     */
    qemu_fprintf(f, "  cause = 0x000000db\n");
    qemu_fprintf(f, "  badva = 0x00000000\n");
    qemu_fprintf(f, "  cs0 = 0x00000000\n");
    qemu_fprintf(f, "  cs1 = 0x00000000\n");
#else
    print_reg(f, env, HEX_REG_CAUSE);
    print_reg(f, env, HEX_REG_BADVA);
    print_reg(f, env, HEX_REG_CS0);
    print_reg(f, env, HEX_REG_CS1);
#endif
    qemu_fprintf(f, "}\n");
}

static void hexagon_dump_state(CPUState *cs, FILE *f, int flags)
{
    HexagonCPU *cpu = HEXAGON_CPU(cs);
    CPUHexagonState *env = &cpu->env;

    hexagon_dump(env, f);
}

void hexagon_debug(CPUHexagonState *env)
{
    hexagon_dump(env, stdout);
}

static void hexagon_cpu_set_pc(CPUState *cs, vaddr value)
{
    HexagonCPU *cpu = HEXAGON_CPU(cs);
    CPUHexagonState *env = &cpu->env;
    env->gpr[HEX_REG_PC] = value;
}

static void hexagon_cpu_synchronize_from_tb(CPUState *cs,
                                            const TranslationBlock *tb)
{
    HexagonCPU *cpu = HEXAGON_CPU(cs);
    CPUHexagonState *env = &cpu->env;
    env->gpr[HEX_REG_PC] = tb->pc;
}

static bool hexagon_cpu_has_work(CPUState *cs)
{
    return true;
}

void restore_state_to_opc(CPUHexagonState *env, TranslationBlock *tb,
                          target_ulong *data)
{
    env->gpr[HEX_REG_PC] = data[0];
}

static void hexagon_cpu_reset(DeviceState *dev)
{
    CPUState *cs = CPU(dev);
    HexagonCPU *cpu = HEXAGON_CPU(cs);
    HexagonCPUClass *mcc = HEXAGON_CPU_GET_CLASS(cpu);

    mcc->parent_reset(dev);
}

static void hexagon_cpu_disas_set_info(CPUState *s, disassemble_info *info)
{
    info->print_insn = print_insn_hexagon;
}

static void hexagon_cpu_realize(DeviceState *dev, Error **errp)
{
    CPUState *cs = CPU(dev);
    HexagonCPUClass *mcc = HEXAGON_CPU_GET_CLASS(dev);
    Error *local_err = NULL;

    cpu_exec_realizefn(cs, &local_err);
    if (local_err != NULL) {
        error_propagate(errp, local_err);
        return;
    }

    qemu_init_vcpu(cs);
    cpu_reset(cs);

    mcc->parent_realize(dev, errp);
}

static void hexagon_cpu_init(Object *obj)
{
    HexagonCPU *cpu = HEXAGON_CPU(obj);

    cpu_set_cpustate_pointers(cpu);
    qdev_property_add_static(DEVICE(obj), &hexagon_lldb_compat_property);
    qdev_property_add_static(DEVICE(obj), &hexagon_lldb_stack_adjust_property);
}

static bool hexagon_tlb_fill(CPUState *cs, vaddr address, int size,
                             MMUAccessType access_type, int mmu_idx,
                             bool probe, uintptr_t retaddr)
{
#ifdef CONFIG_USER_ONLY
    switch (access_type) {
    case MMU_INST_FETCH:
        cs->exception_index = HEX_EXCP_FETCH_NO_UPAGE;
        break;
    case MMU_DATA_LOAD:
        cs->exception_index = HEX_EXCP_PRIV_NO_UREAD;
        break;
    case MMU_DATA_STORE:
        cs->exception_index = HEX_EXCP_PRIV_NO_UWRITE;
        break;
    }
    cpu_loop_exit_restore(cs, retaddr);
#else
#error System mode not implemented for Hexagon
#endif
}

#include "hw/core/tcg-cpu-ops.h"

static struct TCGCPUOps hexagon_tcg_ops = {
    .initialize = hexagon_translate_init,
    .synchronize_from_tb = hexagon_cpu_synchronize_from_tb,
    .tlb_fill = hexagon_tlb_fill,
};

static void hexagon_cpu_class_init(ObjectClass *c, void *data)
{
    HexagonCPUClass *mcc = HEXAGON_CPU_CLASS(c);
    CPUClass *cc = CPU_CLASS(c);
    DeviceClass *dc = DEVICE_CLASS(c);

    device_class_set_parent_realize(dc, hexagon_cpu_realize,
                                    &mcc->parent_realize);

    device_class_set_parent_reset(dc, hexagon_cpu_reset, &mcc->parent_reset);

    cc->class_by_name = hexagon_cpu_class_by_name;
    cc->has_work = hexagon_cpu_has_work;
    cc->dump_state = hexagon_dump_state;
    cc->set_pc = hexagon_cpu_set_pc;
    cc->gdb_read_register = hexagon_gdb_read_register;
    cc->gdb_write_register = hexagon_gdb_write_register;
    cc->gdb_num_core_regs = TOTAL_PER_THREAD_REGS;
    cc->gdb_stop_before_watchpoint = true;
    cc->disas_set_info = hexagon_cpu_disas_set_info;
    cc->tcg_ops = &hexagon_tcg_ops;
}

#define DEFINE_CPU(type_name, initfn)      \
    {                                      \
        .name = type_name,                 \
        .parent = TYPE_HEXAGON_CPU,        \
        .instance_init = initfn            \
    }

static const TypeInfo hexagon_cpu_type_infos[] = {
    {
        .name = TYPE_HEXAGON_CPU,
        .parent = TYPE_CPU,
        .instance_size = sizeof(HexagonCPU),
        .instance_init = hexagon_cpu_init,
        .abstract = true,
        .class_size = sizeof(HexagonCPUClass),
        .class_init = hexagon_cpu_class_init,
    },
    DEFINE_CPU(TYPE_HEXAGON_CPU_V67,              hexagon_v67_cpu_init),
};

DEFINE_TYPES(hexagon_cpu_type_infos)