/************************************************************************************
 * flash.c
 *   
 *  synopsis: Contains flash memory writing routines
 *
 *  in this file: flashProductInfo, waitFlashComplete, programFlashSector,
 *                programFlash
 *
 *  author: Joseph Virzi    U.C. Berkeley LBNL         jsvirzi@lbl.gov
 ************************************************************************************/
#include "fxnProto.h"

#pragma CODE_SECTION(flashProductInfo,   "xcode");
#pragma CODE_SECTION(waitFlashComplete,  "xcode");
#pragma CODE_SECTION(programFlashSector, "xcode");
#pragma CODE_SECTION(programFlash,       "xcode");

#define FLASH_BASE 0x1400000
#define SECTOR_LEN 0x1000
#define SECTOR_LEN_LOG 12
/* 128 sectors * 4096 bytes per sector = 512K bytes = 4 Mbits */
#define N_SECTORS 128

INT32 flashProductInfo(void) {
	INT32 returnCode;
	volatile unsigned char *cptr; 
	unsigned char manufacturer, device;
	
/* software id enter */
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xaa;
	cptr = (unsigned char *)(FLASH_BASE + (0x2aaa << 2)); *cptr = 0x55;
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0x90;

/* wait some time. very little */	
	for(returnCode = 0; returnCode < 0x100; ) returnCode += 1;

	cptr = (unsigned char *)FLASH_BASE;
	manufacturer = *cptr++;
	device = *cptr;

/* software id exit */
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xaa;
	cptr = (unsigned char *)(FLASH_BASE + (0x2aaa << 2)); *cptr = 0x55;
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xf0;

/* wait some time. very little */
	for(returnCode = 0; returnCode < 0x100; ) returnCode += 1;

	returnCode = manufacturer;
	returnCode <<= 16;
	returnCode |= device;
	return returnCode;
}

void waitFlashComplete(unsigned char *ptr) {
	volatile unsigned char d0, d1, *cptr;
/* wait for completion of erase or program process */
	cptr = (volatile unsigned char *)ptr;
	d0 = (*cptr) & 0x40;
	d1 = (*cptr) & 0x40;
	d0 = (*cptr) & 0x40;
	d1 = (*cptr) & 0x40;
	while(d0 != d1) {
		d0 = d1;
		d1 = (*cptr) & 0x40;
	}
}

int programFlashSector(int sector, unsigned char *buff) {
	int k, addr, status, blank;
	unsigned int *wptr;
	volatile unsigned char *cptr;

/* erase sector */
	addr = (sector << SECTOR_LEN_LOG);
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xaa;
	cptr = (unsigned char *)(FLASH_BASE + (0x2aaa << 2)); *cptr = 0x55;
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0x80;
	cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xaa;
	cptr = (unsigned char *)(FLASH_BASE + (0x2aaa << 2)); *cptr = 0x55;
	cptr = (unsigned char *)(FLASH_BASE + (addr << 2)); *cptr = 0x30; 
	
	waitFlashComplete((unsigned char *)cptr);
	
	blank = 1;
	wptr = (unsigned int *)buff;
	k = SECTOR_LEN / sizeof(unsigned int);
	while(k--) {
		if(*wptr++ != ~0) {
			blank = 0;
			break;
		}
	}
	
	if(blank) return 0; /* nothing to do because the buffer was blank */
	
/* program sector */
	for(k = 0; k < SECTOR_LEN; ++k, ++addr) {
		cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xaa;
		cptr = (unsigned char *)(FLASH_BASE + (0x2aaa << 2)); *cptr = 0x55;
		cptr = (unsigned char *)(FLASH_BASE + (0x5555 << 2)); *cptr = 0xa0;
		cptr = (unsigned char *)(FLASH_BASE + (addr << 2)); *cptr = buff[k];
	 	waitFlashComplete((unsigned char *)cptr);
	}

/* verify sector */	
	addr = (sector << SECTOR_LEN_LOG);
	cptr = (unsigned char *)(FLASH_BASE + addr);
	status = 0;
	for(k = 0; k < SECTOR_LEN; ++k) {
		if(*buff++ != *cptr++) ++status;
	}
	
	return status;
}

INT32 programFlash(INT32 len, void *base) {
	INT32 nSectors, sector, status;
	UINT8 *buff;

	status= 0;
	nSectors= (len + SECTOR_LEN - 1) >> SECTOR_LEN_LOG;

	buff= (UINT8 *)base;
	for(sector= 0; sector < nSectors; ++sector) {
		if(status= programFlashSector(sector, buff)) {
			status= (sector << 16) +(status & 0xffff);
			break;
		}
		buff += SECTOR_LEN;
	}

	return status;
}