esp-open-rtos/FreeRTOS/Source/portable/esp8266/port.c

/*
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.

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    ***************************************************************************
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*/

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for ESP8266
 *
 * This is based on the version supplied in esp_iot_rtos_sdk,
 * which is in turn based on the ARM CM3 port.
 *----------------------------------------------------------*/

#include <xtensa/config/core.h>
#include <malloc.h>
#include <unistd.h>
#include <stdio.h>

#include "FreeRTOS.h"
#include "task.h"
#include "xtensa_rtos.h"

unsigned cpu_sr;
char level1_int_disabled;

/* Supervisor stack pointer entry. On reset, sdk_user_start sets a
 * tentative 512 byte supervisor stack size.

 When the scheduler starts, this changes to the "high water mark" of
 how far the supervisor stack grew down before task started.

 After tasks start, task stacks are all allocated from the heap and
 FreeRTOS checks for stack overflow.
*/
void *xPortSupervisorStackPointer;

/*
 * Stack initialization
 */
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
    #define SET_STKREG(r,v) sp[(r) >> 2] = (portSTACK_TYPE)(v)
    portSTACK_TYPE *sp, *tp;

    /* Create interrupt stack frame aligned to 16 byte boundary */
    sp = (portSTACK_TYPE*) (((uint32_t)(pxTopOfStack+1) - XT_CP_SIZE - XT_STK_FRMSZ) & ~0xf);

    /* Clear the entire frame (do not use memset() because we don't depend on C library) */
    for (tp = sp; tp <= pxTopOfStack; ++tp)
        *tp = 0;

    /* Explicitly initialize certain saved registers */
    SET_STKREG( XT_STK_PC,      pxCode                        );  /* task entrypoint                  */
    SET_STKREG( XT_STK_A0,      0                           );  /* to terminate GDB backtrace       */
    SET_STKREG( XT_STK_A1,      (uint32_t)sp + XT_STK_FRMSZ   );  /* physical top of stack frame      */
    SET_STKREG( XT_STK_A2,      pvParameters   );           /* parameters      */
    SET_STKREG( XT_STK_EXIT,    _xt_user_exit               );  /* user exception exit dispatcher   */

    /* Set initial PS to int level 0, EXCM disabled ('rfe' will enable), user mode. */
    SET_STKREG( XT_STK_PS,      PS_UM | PS_EXCM     );
    return sp;
}

static int pending_soft_sv;
static int pending_maclayer_sv;

/* PendSV is called in place of vPortYield() to request a supervisor
   call.

   The portYIELD macro calls pendSV if it's a software request.

   The libpp and libudhcp libraries also call this function, assuming
   always with arg==2 (but maybe sometimes with arg==1?)

   In the original esp_iot_rtos_sdk implementation, arg was a char. Using an
   enum is ABI-compatible, though.
*/
void IRAM PendSV(enum SVC_ReqType req)
{
	vPortEnterCritical();

	if(req == SVC_Software)
	{
		pending_soft_sv = 1;
	}
	else if(req == SVC_MACLayer)
		pending_maclayer_sv= 1;

	xthal_set_intset(BIT(INUM_SOFT));
	vPortExitCritical();
}

/* This MAC layer ISR handler is defined in libpp.a, and is called
 * after a Blob SV requests a soft interrupt by calling
 * PendSV(SVC_MACLayer).
 */
extern portBASE_TYPE sdk_MacIsrSigPostDefHdl(void);

void IRAM SV_ISR(void)
{
	portBASE_TYPE xHigherPriorityTaskWoken=pdFALSE ;
	if(pending_maclayer_sv)
	{
		xHigherPriorityTaskWoken = sdk_MacIsrSigPostDefHdl();
		pending_maclayer_sv = 0;
	}
	if( xHigherPriorityTaskWoken || pending_soft_sv)
	{
	    sdk__xt_timer_int1();
	    pending_soft_sv = 0;
	}
}

void xPortSysTickHandle (void)
{
	//CloseNMI();
	{
		if(xTaskIncrementTick() !=pdFALSE )
		{
			vTaskSwitchContext();
		}
	}
	//OpenNMI();
}

/*
 * See header file for description.
 */
portBASE_TYPE xPortStartScheduler( void )
{
    _xt_isr_attach(INUM_SOFT, SV_ISR);
    _xt_isr_unmask(BIT(INUM_SOFT));

    /* Initialize system tick timer interrupt and schedule the first tick. */
    _xt_isr_attach(INUM_TICK, sdk__xt_timer_int);
    _xt_isr_unmask(BIT(INUM_TICK));
    sdk__xt_tick_timer_init();

    vTaskSwitchContext();

    /* mark the supervisor stack pointer high water mark. xt_int_exit
       actually frees ~0x50 bytes off the stack, so this value is
       conservative.
    */
    __asm__ __volatile__ ("mov %0, a1\n" : "=a"(xPortSupervisorStackPointer));

    sdk__xt_int_exit();

    /* Should not get here as the tasks are now running! */
    return pdTRUE;
}

/* Determine free heap size via libc sbrk function & mallinfo

   sbrk gives total size in totally unallocated memory,
   mallinfo.fordblks gives free space inside area dedicated to heap.

   mallinfo is possibly non-portable, although glibc & newlib both support
   the fordblks member.
*/
size_t xPortGetFreeHeapSize( void )
{
    struct mallinfo mi = mallinfo();
    uint32_t brk_val = (uint32_t) sbrk(0);

    intptr_t sp = (intptr_t)xPortSupervisorStackPointer;
    if(sp == 0) /* scheduler not started */
        __asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp));
    return sp - brk_val + mi.fordblks;
}

void vPortEndScheduler( void )
{
    /* No-op, nothing to return to */
}

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

/* Each task maintains its own interrupt status in the critical nesting
variable. */
static unsigned portBASE_TYPE uxCriticalNesting = 0;

/* These nested vPortEnter/ExitCritical macros are called by SDK
 * libraries in libmain, libnet80211, libpp
 *
 * It may be possible to replace the global nesting count variable
 * with a save/restore of interrupt level, although it's difficult as
 * the functions have no return value.
 */
void IRAM vPortEnterCritical( void )
{
    portDISABLE_INTERRUPTS();
    uxCriticalNesting++;
}
/*-----------------------------------------------------------*/

void IRAM vPortExitCritical( void )
{
    uxCriticalNesting--;
    if( uxCriticalNesting == 0 )
	portENABLE_INTERRUPTS();
}