#include "os_port.h"
#include "os_stack.h"
#include "os_macros.h"
#include "os_align.h"
#include "os_compiler.h"
#include "os_systick.h"
#include "os_sched.h"
#include "qkv3.h"

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

#define SysTick_IRQn     12
#define Software_IRQn    14

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

static uint32_t _SysTick_Config(os_tick_t ticks)
{
    QKV3_PFIC->CFGR=0xFA050003;                   /* 关闭硬件压栈和嵌套 */
    /*
        位段值含义:
        Bit [31:16] :0xFA05      - 解锁密钥 (Key)。为了防止误触发，修改中断全局配置通常需要写入固定的“钥匙”值。
        Bit[1]      :1(来自0x3)   - 硬件压栈使能 (HPE)。开启后，硬件会自动保存寄存器状态，大幅提升中断响应速度。
        Bit[0]      :1(来自0x3)   - 嵌套中断使能 (NEST)。允许高优先级中断打断低优先级中断。
    */

    QKV3_NVIC_SetPriority(SysTick_IRQn,0xf0);
    QKV3_NVIC_SetPriority(Software_IRQn,0xf0);
    QKV3_SysTick->CTLR=0;
    QKV3_SysTick->CNTL0=0;QKV3_SysTick->CNTL1=0;QKV3_SysTick->CNTL2=0;QKV3_SysTick->CNTL3=0;
    QKV3_SysTick->CNTH0=0;QKV3_SysTick->CNTH1=0;QKV3_SysTick->CNTH2=0;QKV3_SysTick->CNTH3=0;
    QKV3_SysTick->CMPLR0=(uint8_t)(ticks-1);
    QKV3_SysTick->CMPLR1=(uint8_t)((ticks-1)>>8);
    QKV3_SysTick->CMPLR2=(uint8_t)((ticks-1)>>16);
    QKV3_SysTick->CMPLR3=(uint8_t)((ticks-1)>>24);
    QKV3_SysTick->CMPHR0=0;QKV3_SysTick->CMPHR1=0;QKV3_SysTick->CMPHR2=0;QKV3_SysTick->CMPHR3=0;
    QKV3_SysTick->CTLR=0x1;
    QKV3_NVIC_EnableIRQ(SysTick_IRQn);
    QKV3_NVIC_EnableIRQ(Software_IRQn);
    return 0;
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct {
    os_uintptr_t mepc;          /* zero, 用于 epc 保存 */
    os_uintptr_t ra;            /* 返回地址 */
    os_uintptr_t mstatus;       /* 栈指针, 用于mstatus */
    os_uintptr_t gp;            /* 全局指针 */
    os_uintptr_t tp;            /* 线程指针 */
    os_uintptr_t t0;            /* 临时寄存器0 */
    os_uintptr_t t1;            /* 临时寄存器1 */
    os_uintptr_t t2;            /* 临时寄存器2 */
    os_uintptr_t s0;            /* s0/fp */
    os_uintptr_t s1;            /* 保存寄存器1 */
    os_uintptr_t a0;            /* 函数参数/返回值 */
    os_uintptr_t a1;            /* 函数参数 */
    os_uintptr_t a2;            /* 函数参数 */
    os_uintptr_t a3;            /* 函数参数 */
    os_uintptr_t a4;            /* 函数参数 */
    os_uintptr_t a5;            /* 函数参数 */
    os_uintptr_t a6;            /* 函数参数 */
    os_uintptr_t a7;            /* 函数参数 */
    os_uintptr_t s2;            /* 保存寄存器 */
    os_uintptr_t s3;            /* 保存寄存器 */
    os_uintptr_t s4;            /* 保存寄存器 */
    os_uintptr_t s5;            /* 保存寄存器 */
    os_uintptr_t s6;            /* 保存寄存器 */
    os_uintptr_t s7;            /* 保存寄存器 */
    os_uintptr_t s8;            /* 保存寄存器 */
    os_uintptr_t s9;            /* 保存寄存器 */
    os_uintptr_t s10;           /* 保存寄存器 */
    os_uintptr_t s11;           /* 保存寄存器 */
    os_uintptr_t t3;            /* 临时寄存器 */
    os_uintptr_t t4;            /* 临时寄存器 */
    os_uintptr_t t5;            /* 临时寄存器 */
    os_uintptr_t t6;            /* 临时寄存器 */
}os_stack_frame_t;

#define STACK_FRAME_SIZE sizeof(os_stack_frame_t)

os_stack_t os_port_cpu_stack_init(os_task_entry_t entry, void* param
        , void* stack_base, os_size_t stack_size, void(*exit_entry)(void)){
    os_uintptr_t stack_max = (os_uintptr_t)((uint8_t *) stack_base + stack_size);
    os_uintptr_t real_max = OS_ALIGN_DOWN(stack_max, OS_ALIGN_SIZE); /* 实际栈顶的位置，对齐后的位置 */
    stack_size -= (stack_max - real_max); /* 实际栈大小 */

    os_stack_frame_t* p_frame = (os_stack_frame_t*)(real_max - STACK_FRAME_SIZE);
    for(os_size_t i=0; i<STACK_FRAME_SIZE/sizeof(os_uintptr_t); i++){
        ((os_uintptr_t*)(p_frame))[i] = 0x5ac0ffee;
    }

    p_frame->mepc = (os_uintptr_t)entry;
    p_frame->a0 = (os_uintptr_t)param;
    p_frame->ra = (os_uintptr_t)exit_entry;

    os_stack_t stack;
    stack.min = (os_uintptr_t)stack_base;
    stack.max = (os_uintptr_t)real_max;
    stack.type = kOsStackType_MaxToMin;
    stack.sp = p_frame;
    return stack;
}

void os_port_disable_irq(void){
    RISCV_disable_irq();
}

void os_port_enable_irq(void){
    RISCV_enable_irq();
}

os_uint_t os_port_save_disable_irq(void){
    return os_port_save_disable_irq_in_isr();
}

void os_port_restore_irq(os_uint_t level){
    os_port_restore_irq_in_isr(level);
}

os_uint_t os_port_save_disable_irq_in_isr(void){
    os_uint_t level = RISCV_get_MSTATUS();
    RISCV_set_MSTATUS(0x1800);
    return level;
}

void os_port_restore_irq_in_isr(os_uint_t level){
    RISCV_set_MSTATUS(level);
}

void os_sched(void){
    os_sched_in_isr();
}


extern volatile os_uint_t SystemCoreClock;

OS_WEAK
void os_port_init(void){

}

OS_WEAK
void os_port_startup(void){
    _SysTick_Config(SystemCoreClock/8/OS_CFG_TICKS_PER_SECOND);
}

/*
 * 发出上下文切换的请求
 */
void os_port_send_context_switch_request(void){
    QKV3_NVIC_SetPendingIRQ(Software_IRQn);
}

/*
 * 清除上下文切换的请求
 */
void os_port_clear_context_switch_request(void){
    QKV3_NVIC_ClearPendingIRQ(Software_IRQn);
}

extern void os_port_context_restore(os_uintptr_t to);

OS_USED
void os_port_context_switch(void* from_sp, void* to_sp){
    os_critical_enter_in_isr();
    if(g_os_port_context_switch_flag==OS_TRUE){
        os_critical_leave_in_isr();
        return;
    }
    g_os_port_context_switch_flag = OS_TRUE;
    if(from_sp==0){
        g_os_port_switch_to_sp = to_sp;
        os_critical_leave_in_isr();
        os_port_context_restore((os_uintptr_t)to_sp);
    }else{
        g_os_port_switch_from_sp = from_sp;
        g_os_port_switch_to_sp = to_sp;
        os_critical_leave_in_isr();
        os_port_send_context_switch_request();
    }
}


void SysTick_Handler(void) __attribute__((interrupt()));
void SysTick_Handler(void){
    QKV3_SysTick->CTLR=0;
    QKV3_SysTick->CNTL0=0;QKV3_SysTick->CNTL1=0;QKV3_SysTick->CNTL2=0;QKV3_SysTick->CNTL3=0;
    QKV3_SysTick->CNTH0=0;QKV3_SysTick->CNTH1=0;QKV3_SysTick->CNTH2=0;QKV3_SysTick->CNTH3=0;
    QKV3_SysTick->CTLR=0x1;

    // 调用系统心跳处理
    os_systick_tick();
}