/*
*********************************************************************************************************
*                                               uC/OS-II
*                                         The Real-Time Kernel
*
*
*                              (c) Copyright 2006-2012, Micrium, Weston, FL
*                                          All Rights Reserved
*
*                                           ARM Cortex-M0 Port
*
* File      : os_cpu_c.c
* Version   : V2.92.07.00
* By        : JJL
*             BN
*
* For       : ARMv6M Cortex-M0
* Mode      : Thumb2
* Toolchain : GNU C Compiler
*********************************************************************************************************
*/

#define  OS_CPU_GLOBALS
#include <ucos_ii.h>

/*
*********************************************************************************************************
*                                          LOCAL VARIABLES
*********************************************************************************************************
*/

#if OS_TMR_EN > 0u
static  INT16U  OSTmrCtr;
#endif

/*
*********************************************************************************************************
*                                          SYS TICK DEFINES
*********************************************************************************************************
*/

#define  OS_CPU_CM0_NVIC_ST_CTRL    (*((volatile INT32U *)0xE000E010uL)) /* SysTick Ctrl & Status Reg. */
#define  OS_CPU_CM0_NVIC_ST_RELOAD  (*((volatile INT32U *)0xE000E014uL)) /* SysTick Reload  Value Reg. */
#define  OS_CPU_CM0_NVIC_ST_CURRENT (*((volatile INT32U *)0xE000E018uL)) /* SysTick Current Value Reg. */
#define  OS_CPU_CM0_NVIC_ST_CAL     (*((volatile INT32U *)0xE000E01CuL)) /* SysTick Cal     Value Reg. */
#define  OS_CPU_CM0_NVIC_PRIO_ST    (*((volatile INT32U *)0xE000ED20uL)) /* SysTick Handler Prio  Reg. */

#define  OS_CPU_CM0_NVIC_ST_CTRL_COUNT                    0x00010000uL   /* Count flag.                */
#define  OS_CPU_CM0_NVIC_ST_CTRL_CLK_SRC                  0x00000004uL   /* Clock Source.              */
#define  OS_CPU_CM0_NVIC_ST_CTRL_INTEN                    0x00000002uL   /* Interrupt enable.          */
#define  OS_CPU_CM0_NVIC_ST_CTRL_ENABLE                   0x00000001uL   /* Counter mode.              */
#define  OS_CPU_CM0_NVIC_PRIO_MIN                         0xFF000000uL   /* Min handler prio.          */

/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                            (BEGINNING)
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSInitHookBegin (void)
{
    INT32U   size;
    OS_STK  *pstk;

                                                                /* Clear exception stack for stack checking.*/
    pstk = &OS_CPU_ExceptStk[0];
    size = OS_CPU_EXCEPT_STK_SIZE;
    while (size > 0u) {
        size--;
       *pstk++ = (OS_STK)0;
    }

    OS_CPU_ExceptStkBase = &OS_CPU_ExceptStk[OS_CPU_EXCEPT_STK_SIZE - 1u];

#if OS_TMR_EN > 0u
    OSTmrCtr = 0u;
#endif
}
#endif

/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                               (END)
*
* Description: This function is called by OSInit() at the end of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSInitHookEnd (void)
{
}
#endif

/*
*********************************************************************************************************
*                                          TASK CREATION HOOK
*
* Description: This function is called when a task is created.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being created.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSTaskCreateHook (OS_TCB *ptcb)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskCreateHook(ptcb);
#else
    (void)ptcb;                                                 /* Prevent compiler warning                           */
#endif
}
#endif


/*
*********************************************************************************************************
*                                           TASK DELETION HOOK
*
* Description: This function is called when a task is deleted.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being deleted.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSTaskDelHook (OS_TCB *ptcb)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskDelHook(ptcb);
#else
    (void)ptcb;                                                 /* Prevent compiler warning                           */
#endif
}
#endif

/*
*********************************************************************************************************
*                                             IDLE TASK HOOK
*
* Description: This function is called by the idle task.  This hook has been added to allow you to do
*              such things as STOP the CPU to conserve power.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are enabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSTaskIdleHook (void)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskIdleHook();
#endif
}
#endif

/*
*********************************************************************************************************
*                                            TASK RETURN HOOK
*
* Description: This function is called if a task accidentally returns.  In other words, a task should
*              either be an infinite loop or delete itself when done.
*
* Arguments  : ptcb      is a pointer to the task control block of the task that is returning.
*
* Note(s)    : none
*********************************************************************************************************
*/

#if OS_CPU_HOOKS_EN > 0u
void  OSTaskReturnHook (OS_TCB  *ptcb)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskReturnHook(ptcb);
#else
    (void)ptcb;
#endif
}
#endif

/*
*********************************************************************************************************
*                                           STATISTIC TASK HOOK
*
* Description: This function is called every second by uC/OS-II's statistics task.  This allows your
*              application to add functionality to the statistics task.
*
* Arguments  : none
*********************************************************************************************************
*/

#if OS_CPU_HOOKS_EN > 0u
void  OSTaskStatHook (void)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskStatHook();
#endif
}
#endif

/*
*********************************************************************************************************
*                                        INITIALIZE A TASK'S STACK
*
* Description: This function is called by either OSTaskCreate() or OSTaskCreateExt() to initialize the
*              stack frame of the task being created.  This function is highly processor specific.
*
* Arguments  : task          is a pointer to the task code
*
*              p_arg         is a pointer to a user supplied data area that will be passed to the task
*                            when the task first executes.
*
*              ptos          is a pointer to the top of stack.  It is assumed that 'ptos' points to
*                            a 'free' entry on the task stack.  If OS_STK_GROWTH is set to 1 then
*                            'ptos' will contain the HIGHEST valid address of the stack.  Similarly, if
*                            OS_STK_GROWTH is set to 0, the 'ptos' will contains the LOWEST valid address
*                            of the stack.
*
*              opt           specifies options that can be used to alter the behavior of OSTaskStkInit().
*                            (see uCOS_II.H for OS_TASK_OPT_xxx).
*
* Returns    : Always returns the location of the new top-of-stack once the processor registers have
*              been placed on the stack in the proper order.
*
* Note(s)    : 1) Interrupts are enabled when your task starts executing.
*              2) All tasks run in Thread mode, using process stack.
*********************************************************************************************************
*/

OS_STK *OSTaskStkInit (void (*task)(void *p_arg), void *p_arg, OS_STK *ptos, INT16U opt)
{
    OS_STK *stk;


    (void)opt;                                                  /* 'opt' is not used, prevent warning                 */
    stk       = ptos;                                           /* Load stack pointer                                 */

                                                                /* Registers stacked as if auto-saved on exception    */
    *(stk)    = (INT32U)0x01000000uL;                           /* xPSR                                               */
    *(--stk)  = (INT32U)task;                                   /* Entry Point                                        */
    *(--stk)  = (INT32U)OS_TaskReturn;                          /* R14 (LR)                                           */
    *(--stk)  = (INT32U)0x12121212uL;                           /* R12                                                */
    *(--stk)  = (INT32U)0x03030303uL;                           /* R3                                                 */
    *(--stk)  = (INT32U)0x02020202uL;                           /* R2                                                 */
    *(--stk)  = (INT32U)0x01010101uL;                           /* R1                                                 */
    *(--stk)  = (INT32U)p_arg;                                  /* R0 : argument                                      */
                                                                /* Remaining registers saved on process stack         */
    *(--stk)  = (INT32U)0x07070707uL;                           /* R7                                                 */
    *(--stk)  = (INT32U)0x06060606uL;                           /* R6                                                 */
    *(--stk)  = (INT32U)0x05050505uL;                           /* R5                                                 */
    *(--stk)  = (INT32U)0x04040404uL;                           /* R4                                                 */

    return (stk);
}

/*
*********************************************************************************************************
*                                           TASK SWITCH HOOK
*
* Description: This function is called when a task switch is performed.  This allows you to perform other
*              operations during a context switch.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are disabled during this call.
*              2) It is assumed that the global pointer 'OSTCBHighRdy' points to the TCB of the task that
*                 will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCur' points to the
*                 task being switched out (i.e. the preempted task).
*********************************************************************************************************
*/
#if (OS_CPU_HOOKS_EN > 0u) && (OS_TASK_SW_HOOK_EN > 0u)
void  OSTaskSwHook (void)
{
#if OS_APP_HOOKS_EN > 0u
    App_TaskSwHook();
#endif
}
#endif

/*
*********************************************************************************************************
*                                           OS_TCBInit() HOOK
*
* Description: This function is called by OS_TCBInit() after setting up most of the TCB.
*
* Arguments  : ptcb    is a pointer to the TCB of the task being created.
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0u
void  OSTCBInitHook (OS_TCB *ptcb)
{
#if OS_APP_HOOKS_EN > 0u
    App_TCBInitHook(ptcb);
#else
    (void)ptcb;                                                 /* Prevent compiler warning                           */
#endif
}
#endif

/*
*********************************************************************************************************
*                                               TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if (OS_CPU_HOOKS_EN > 0u) && (OS_TIME_TICK_HOOK_EN > 0u)
void  OSTimeTickHook (void)
{
#if OS_APP_HOOKS_EN > 0u
    App_TimeTickHook();
#endif

#if OS_TMR_EN > 0u
    OSTmrCtr++;
    if (OSTmrCtr >= (OS_TICKS_PER_SEC / OS_TMR_CFG_TICKS_PER_SEC)) {
        OSTmrCtr = 0;
        OSTmrSignal();
    }
#endif
}
#endif

/*
*********************************************************************************************************
*                                          SYS TICK HANDLER
*
* Description: Handle the system tick (SysTick) interrupt, which is used to generate the uC/OS-II tick
*              interrupt.
*
* Arguments  : none.
*
* Note(s)    : 1) This function MUST be placed on entry 15 of the Cortex-M0 vector table.
*********************************************************************************************************
*/

void  OS_CPU_SysTickHandler (void)
{
    OS_CPU_SR  cpu_sr;


    OS_ENTER_CRITICAL();                                        /* Tell uC/OS-II that we are starting an ISR          */
    OSIntNesting++;
    OS_EXIT_CRITICAL();

    OSTimeTick();                                               /* Call uC/OS-II's OSTimeTick()                       */

    OSIntExit();                                                /* Tell uC/OS-II that we are leaving the ISR          */
}

/*
*********************************************************************************************************
*                                          INITIALIZE SYS TICK
*
* Description: Initialize the SysTick.
*
* Arguments  : cnts          is the number of SysTick counts between two OS tick interrupts.
*
* Note(s)    : 1) This function MUST be called after OSStart() & after processor initialization.
*********************************************************************************************************
*/

void  OS_CPU_SysTickInit (INT32U  cnts)
{
    INT32U  prio;


    OS_CPU_CM0_NVIC_ST_RELOAD = cnts - 1u;

    prio  = OS_CPU_CM0_NVIC_PRIO_ST;
    prio &= ~(OS_CPU_CM0_NVIC_PRIO_MIN);
    prio |= OS_CPU_CM0_NVIC_PRIO_MIN;
                                                 /* Set prio of SysTick handler to min prio.           */
    OS_CPU_CM0_NVIC_PRIO_ST   = prio;
                                                 /* Enable timer.                                      */
    OS_CPU_CM0_NVIC_ST_CTRL  |= OS_CPU_CM0_NVIC_ST_CTRL_CLK_SRC | OS_CPU_CM0_NVIC_ST_CTRL_ENABLE;
                                                 /* Enable timer interrupt.                            */
    OS_CPU_CM0_NVIC_ST_CTRL  |= OS_CPU_CM0_NVIC_ST_CTRL_INTEN;
}
