OVMS3-idf/components/freertos/xtensa/port.c

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

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

/*******************************************************************************
// Copyright (c) 2003-2015 Cadence Design Systems, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
--------------------------------------------------------------------------------
*/
#include <stdlib.h>
#include <string.h>
#include <xtensa/config/core.h>

#include "xtensa_rtos.h"

#include "soc/cpu.h"

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

#include "esp_debug_helpers.h"
#include "esp_heap_caps.h"
#include "esp_private/crosscore_int.h"

#include "esp_intr_alloc.h"
#include "esp_log.h"
#include "sdkconfig.h"
#include "esp_compiler.h"

/* Defined in portasm.h */
extern void _frxt_tick_timer_init(void);

/* Defined in xtensa_context.S */
extern void _xt_coproc_init(void);


#if CONFIG_FREERTOS_CORETIMER_0
    #define SYSTICK_INTR_ID (ETS_INTERNAL_TIMER0_INTR_SOURCE+ETS_INTERNAL_INTR_SOURCE_OFF)
#endif
#if CONFIG_FREERTOS_CORETIMER_1
    #define SYSTICK_INTR_ID (ETS_INTERNAL_TIMER1_INTR_SOURCE+ETS_INTERNAL_INTR_SOURCE_OFF)
#endif

_Static_assert(tskNO_AFFINITY == CONFIG_FREERTOS_NO_AFFINITY, "incorrect tskNO_AFFINITY value");

/*-----------------------------------------------------------*/
unsigned port_xSchedulerRunning[portNUM_PROCESSORS] = {0}; // Duplicate of inaccessible xSchedulerRunning; needed at startup to avoid counting nesting
unsigned port_interruptNesting[portNUM_PROCESSORS] = {0};  // Interrupt nesting level. Increased/decreased in portasm.c, _frxt_int_enter/_frxt_int_exit
BaseType_t port_uxCriticalNesting[portNUM_PROCESSORS] = {0};  
BaseType_t port_uxOldInterruptState[portNUM_PROCESSORS] = {0};  
/*-----------------------------------------------------------*/

// User exception dispatcher when exiting
void _xt_user_exit(void);

#if CONFIG_FREERTOS_TASK_FUNCTION_WRAPPER
// Wrapper to allow task functions to return (increases stack overhead by 16 bytes)
static void vPortTaskWrapper(TaskFunction_t pxCode, void *pvParameters)
{
	pxCode(pvParameters);
	//FreeRTOS tasks should not return. Log the task name and abort.
	char * pcTaskName = pcTaskGetTaskName(NULL);
	ESP_LOGE("FreeRTOS", "FreeRTOS Task \"%s\" should not return, Aborting now!", pcTaskName);
	abort();
}
#endif

/*
 * Stack initialization
 */
#if portUSING_MPU_WRAPPERS
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters, BaseType_t xRunPrivileged )
#else
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
#endif
{
	StackType_t *sp, *tp;
	XtExcFrame  *frame;
	#if XCHAL_CP_NUM > 0
	uint32_t *p;
	#endif
	uint32_t *threadptr;
	void *task_thread_local_start;
	extern int _thread_local_start, _thread_local_end, _rodata_start;
	// TODO: check that TLS area fits the stack
	uint32_t thread_local_sz = (uint8_t *)&_thread_local_end - (uint8_t *)&_thread_local_start;

	thread_local_sz = ALIGNUP(0x10, thread_local_sz);

	/* Initialize task's stack so that we have the following structure at the top:

		----LOW ADDRESSES ----------------------------------------HIGH ADDRESSES----------
		 task stack | interrupt stack frame | thread local vars | co-processor save area |
		----------------------------------------------------------------------------------
					|																	 |
					SP 																pxTopOfStack

		All parts are aligned to 16 byte boundary. */
	sp = (StackType_t *) (((UBaseType_t)(pxTopOfStack + 1) - XT_CP_SIZE - thread_local_sz - 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;

	frame = (XtExcFrame *) sp;

	/* Explicitly initialize certain saved registers */
	#if CONFIG_FREERTOS_TASK_FUNCTION_WRAPPER
	frame->pc	= (UBaseType_t) vPortTaskWrapper;	/* task wrapper						*/
	#else
	frame->pc   = (UBaseType_t) pxCode;				/* task entrypoint					*/
	#endif
	frame->a0	= 0;								/* to terminate GDB backtrace		*/
	frame->a1	= (UBaseType_t) sp + XT_STK_FRMSZ;	/* physical top of stack frame		*/
	frame->exit = (UBaseType_t) _xt_user_exit;		/* user exception exit dispatcher	*/

	/* Set initial PS to int level 0, EXCM disabled ('rfe' will enable), user mode. */
	/* Also set entry point argument parameter. */
	#ifdef __XTENSA_CALL0_ABI__
		#if CONFIG_FREERTOS_TASK_FUNCTION_WRAPPER
		frame->a2 = (UBaseType_t) pxCode;
		frame->a3 = (UBaseType_t) pvParameters;
		#else
		frame->a2 = (UBaseType_t) pvParameters;
		#endif
	frame->ps = PS_UM | PS_EXCM;
	#else
	/* + for windowed ABI also set WOE and CALLINC (pretend task was 'call4'd). */
		#if CONFIG_FREERTOS_TASK_FUNCTION_WRAPPER
		frame->a6 = (UBaseType_t) pxCode;
		frame->a7 = (UBaseType_t) pvParameters;
		#else
		frame->a6 = (UBaseType_t) pvParameters;
		#endif
	frame->ps = PS_UM | PS_EXCM | PS_WOE | PS_CALLINC(1);
	#endif

	#ifdef XT_USE_SWPRI
	/* Set the initial virtual priority mask value to all 1's. */
	frame->vpri = 0xFFFFFFFF;
	#endif

	/* Init threadptr reg and TLS vars */
	task_thread_local_start = (void *)(((uint32_t)pxTopOfStack - XT_CP_SIZE - thread_local_sz) & ~0xf);
	memcpy(task_thread_local_start, &_thread_local_start, thread_local_sz);
	threadptr = (uint32_t *)(sp + XT_STK_EXTRA);
	/* Calculate THREADPTR value:
	 * The generated code will add THREADPTR value to a constant value determined at link time,
	 * to get the address of the TLS variable.
	 * The constant value is calculated by the linker as follows
	 * (search for 'tpoff' in elf32-xtensa.c in BFD):
	 *    offset = address - tls_section_vma + align_up(TCB_SIZE, tls_section_alignment)
	 * where TCB_SIZE is hardcoded to 8. There doesn't seem to be a way to propagate
	 * the section alignment value from the ld script into the code, so it is hardcoded
	 * in both places.
	 */
	const uint32_t tls_section_alignment = 0x10;  /* has to be in sync with ALIGN value of .flash.rodata section */
	const uint32_t tcb_size = 8; /* Unrelated to FreeRTOS, this is the constant from BFD */
	const uint32_t base = (tcb_size + tls_section_alignment - 1) & (~(tls_section_alignment - 1));
	*threadptr = (uint32_t)task_thread_local_start - ((uint32_t)&_thread_local_start - (uint32_t)&_rodata_start) - base;

	#if XCHAL_CP_NUM > 0
	/* Init the coprocessor save area (see xtensa_context.h) */
	/* No access to TCB here, so derive indirectly. Stack growth is top to bottom.
         * //p = (uint32_t *) xMPUSettings->coproc_area;
	 */
	p = (uint32_t *)(((uint32_t) pxTopOfStack - XT_CP_SIZE) & ~0xf);
	p[0] = 0;
	p[1] = 0;
	p[2] = (((uint32_t) p) + 12 + XCHAL_TOTAL_SA_ALIGN - 1) & -XCHAL_TOTAL_SA_ALIGN;
	#endif

	return sp;
}

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

void vPortEndScheduler( void )
{
	/* It is unlikely that the Xtensa port will get stopped.  If required simply
	disable the tick interrupt here. */
}

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

BaseType_t xPortStartScheduler( void )
{
	// Interrupts are disabled at this point and stack contains PS with enabled interrupts when task context is restored

	#if XCHAL_CP_NUM > 0
	/* Initialize co-processor management for tasks. Leave CPENABLE alone. */
	_xt_coproc_init();
	#endif

	/* Init the tick divisor value */
	_xt_tick_divisor_init();

	/* Setup the hardware to generate the tick. */
	_frxt_tick_timer_init();

	port_xSchedulerRunning[xPortGetCoreID()] = 1;

	// Cannot be directly called from C; never returns
	__asm__ volatile ("call0    _frxt_dispatch\n");

	/* Should not get here. */
	return pdTRUE;
}
/*-----------------------------------------------------------*/

BaseType_t xPortSysTickHandler( void )
{
	BaseType_t ret;

	portbenchmarkIntLatency();
	traceISR_ENTER(SYSTICK_INTR_ID);
	ret = xTaskIncrementTick();
	if( ret != pdFALSE )
	{
		portYIELD_FROM_ISR();
	} else {
		traceISR_EXIT();
	}
	return ret;
}


void vPortYieldOtherCore( BaseType_t coreid ) {
	esp_crosscore_int_send_yield( coreid );
}

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

/*
 * Used to set coprocessor area in stack. Current hack is to reuse MPU pointer for coprocessor area.
 */
#if portUSING_MPU_WRAPPERS
void vPortStoreTaskMPUSettings( xMPU_SETTINGS *xMPUSettings, const struct xMEMORY_REGION * const xRegions, StackType_t *pxBottomOfStack, uint32_t usStackDepth )
{
	#if XCHAL_CP_NUM > 0
	xMPUSettings->coproc_area = (StackType_t*)((((uint32_t)(pxBottomOfStack + usStackDepth - 1)) - XT_CP_SIZE ) & ~0xf);


	/* NOTE: we cannot initialize the coprocessor save area here because FreeRTOS is going to
         * clear the stack area after we return. This is done in pxPortInitialiseStack().
	 */
	#endif
}

void vPortReleaseTaskMPUSettings( xMPU_SETTINGS *xMPUSettings )
{
	/* If task has live floating point registers somewhere, release them */
	_xt_coproc_release( xMPUSettings->coproc_area );
}

#endif

/*
 * Returns true if the current core is in ISR context; low prio ISR, med prio ISR or timer tick ISR. High prio ISRs
 * aren't detected here, but they normally cannot call C code, so that should not be an issue anyway.
 */
BaseType_t xPortInIsrContext(void)
{
	unsigned int irqStatus;
	BaseType_t ret;
	irqStatus=portENTER_CRITICAL_NESTED();
	ret=(port_interruptNesting[xPortGetCoreID()] != 0);
	portEXIT_CRITICAL_NESTED(irqStatus);
	return ret;
}

/*
 * This function will be called in High prio ISRs. Returns true if the current core was in ISR context
 * before calling into high prio ISR context.
 */
BaseType_t IRAM_ATTR xPortInterruptedFromISRContext(void)
{
	return (port_interruptNesting[xPortGetCoreID()] != 0);
}

void vPortAssertIfInISR(void)
{
	configASSERT(xPortInIsrContext());
}

void vPortSetStackWatchpoint( void* pxStackStart ) {
	//Set watchpoint 1 to watch the last 32 bytes of the stack.
	//Unfortunately, the Xtensa watchpoints can't set a watchpoint on a random [base - base+n] region because
	//the size works by masking off the lowest address bits. For that reason, we futz a bit and watch the lowest 32
	//bytes of the stack we can actually watch. In general, this can cause the watchpoint to be triggered at most
	//28 bytes early. The value 32 is chosen because it's larger than the stack canary, which in FreeRTOS is 20 bytes.
	//This way, we make sure we trigger before/when the stack canary is corrupted, not after.
	int addr=(int)pxStackStart;
	addr=(addr+31)&(~31);
	esp_set_watchpoint(1, (char*)addr, 32, ESP_WATCHPOINT_STORE);
}

uint32_t xPortGetTickRateHz(void) {
	return (uint32_t)configTICK_RATE_HZ;
}

void __attribute__((optimize("-O3"))) vPortEnterCritical(portMUX_TYPE *mux)
{
	BaseType_t oldInterruptLevel = portENTER_CRITICAL_NESTED();
	/* Interrupts may already be disabled (because we're doing this recursively) 
	* but we can't get the interrupt level after
	* vPortCPUAquireMutex, because it also may mess with interrupts.
	* Get it here first, then later figure out if we're nesting
	* and save for real there.
	*/ 
	vPortCPUAcquireMutex( mux );
	BaseType_t coreID = xPortGetCoreID();
	BaseType_t newNesting = port_uxCriticalNesting[coreID] + 1;
	port_uxCriticalNesting[coreID] = newNesting;

	if( newNesting == 1 )
	{
		//This is the first time we get called. Save original interrupt level.
		port_uxOldInterruptState[coreID] = oldInterruptLevel;
	}
}

void __attribute__((optimize("-O3"))) vPortExitCritical(portMUX_TYPE *mux)
{
	vPortCPUReleaseMutex( mux );
	BaseType_t coreID = xPortGetCoreID();
	BaseType_t nesting =  port_uxCriticalNesting[coreID];
	
	if(nesting > 0U)
	{
		nesting--;
		port_uxCriticalNesting[coreID] = nesting;

		if( nesting == 0U )
		{
			portEXIT_CRITICAL_NESTED(port_uxOldInterruptState[coreID]);
		}
	}
}