/* mailbox.cpp: datastructs common to ARM and PRU

 Copyright (c) 2018, Joerg Hoppe
 j_hoppe@t-online.de, www.retrocmp.com

 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
 JOERG HOPPE 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.


 12-nov-2018  JH      entered beta phase
 */

#define _MAILBOX_CPP_

#include <stdio.h>
#include <string.h>
#include "prussdrv.h"

#include "pru.hpp"
#include "logger.hpp"
#include "ddrmem.h"
#include "mailbox.h"

// is located in PRU 12kb shared memory.
// address symbol "" fetched from linker map

volatile mailbox_t *mailbox = NULL;

// Init all fields, most to 0's
int mailbox_connect(void) 
{
	void *pru_shared_dataram;
	// get pointer to RAM
	if (prussdrv_map_prumem(PRU_MAILBOX_RAM_ID, &pru_shared_dataram)) {
		printf("ERROR: prussdrv_map_prumem() failed\n");
		return -1;

	}
	// prussdrv_map_prumem( PRU_MAILBOX_RAM_ID, &pru_shared_dataram) ;
	// point to struct inside RAM
	mailbox = (mailbox_t *) ((char *) pru_shared_dataram + PRU_MAILBOX_RAM_OFFSET);

	// now ARM and PRU can access the mailbox

	memset((void*) mailbox, 0, sizeof(mailbox_t));

	// tell PRU location of shared DDR RAM
	mailbox->ddrmem_base_physical = (ddrmem_t *) ddrmem->base_physical;

	return 0;
}

void mailbox_print(void) 
{
	printf("INFO: Content of mailbox to PRU:\n"
			"arm2pru: req=0x%x\n", mailbox->arm2pru_req);
}

/* simulate simple register accesses:
 * write test_addr + OP,
 * result in "val"
 */
static unsigned n = 0;
void mailbox_test1() 
{
	unsigned reg_sel = 0;
	for (reg_sel = 0; reg_sel < 8; reg_sel++) {
		//TODO: memory barrier??
//		__sync_synchronize() ;
		mailbox->mailbox_test.addr = n & 0xff;
//		__sync_synchronize() ;
		while (mailbox->mailbox_test.addr != (n & 0xff))
			; // cache ?
		__sync_synchronize(); // write to arm2pru_req must be last operation
		mailbox->arm2pru_req = ARM2PRU_MAILBOXTEST1; // go!
		while (mailbox->arm2pru_req)
			; // wait until processed
//		__sync_synchronize() ;
		n++;
		// PRU copies addr to val and may output on GPIOs
		/*
		 if (mailbox->mailbox_test.val != mailbox->mailbox_test.addr) {
		 printf("?");
		 fflush(stdout);
		 }
		 */
	}
}

/* start cmd to PRU via mailbox. Wait until ready
 * mailbox union members must have been filled.
 */
//uint32_t xxx;

pthread_mutex_t arm2pru_mutex = PTHREAD_MUTEX_INITIALIZER ;

bool  mailbox_execute(uint8_t request) 
{
// write to arm2pru_req must be last memory operation
	pthread_mutex_lock(&arm2pru_mutex) ;

	__sync_synchronize();
	while (mailbox->arm2pru_req != ARM2PRU_NONE)
		; // wait to complete

	mailbox->arm2pru_req = request; // go!

	// wait until ACKed	
	while (mailbox->arm2pru_req == request);
	/*
	do {
		xxx = mailbox->arm2pru_req;
	} while (xxx != ARM2PRU_NONE);

	while (mailbox->arm2pru_req != ARM2PRU_NONE)
		; // wait until processed
	*/
	// result false = error
	bool result = (mailbox->arm2pru_req == ARM2PRU_NONE) ;
	pthread_mutex_unlock(&arm2pru_mutex) ;
	return result ;
}