at91/bootspi/ee.c

/******************************************************************************
 *
 * Filename: eeprom.c
 *
 * Instantiation of eeprom routines
 *
 * Revision information:
 *
 * 28AUG2004    kb_admin    initial creation - adapted from Atmel sources
 * 12JAN2005    kb_admin    fixed clock generation, write polling, init
 *
 * BEGIN_KBDD_BLOCK
 * No warranty, expressed or implied, is included with this software.  It is
 * provided "AS IS" and no warranty of any kind including statutory or aspects
 * relating to merchantability or fitness for any purpose is provided.  All
 * intellectual property rights of others is maintained with the respective
 * owners.  This software is not copyrighted and is intended for reference
 * only.
 * END_BLOCK
 *
 * $FreeBSD$
 *****************************************************************************/

#include "at91rm9200_lowlevel.h"
#include "at91rm9200.h"
#include "lib.h"
#include "ee.h"

/******************************* GLOBALS *************************************/


/*********************** PRIVATE FUNCTIONS/DATA ******************************/


/* Use a macro to calculate the TWI clock generator value to save code space. */
#define AT91C_TWSI_CLOCK    100000
#define TWSI_EEPROM_ADDRESS 0x40

#define TWI_CLK_BASE_DIV    ((AT91C_MASTER_CLOCK/(4*AT91C_TWSI_CLOCK)) - 2)
#define SET_TWI_CLOCK   ((0x00010000) | (TWI_CLK_BASE_DIV) | (TWI_CLK_BASE_DIV << 8))


/*************************** GLOBAL FUNCTIONS ********************************/


/*
 * .KB_C_FN_DEFINITION_START
 * void InitEEPROM(void)
 *  This global function initializes the EEPROM interface (TWI).  Intended
 * to be called a single time.
 * .KB_C_FN_DEFINITION_END
 */
void
EEInit(void)
{

    AT91PS_TWI twiPtr = (AT91PS_TWI)AT91C_BASE_TWI;

    AT91PS_PIO pPio = (AT91PS_PIO)AT91C_BASE_PIOA;
    AT91PS_PMC pPMC = (AT91PS_PMC)AT91C_BASE_PMC;

    pPio->PIO_ASR = AT91C_PIO_PA25 | AT91C_PIO_PA26;
    pPio->PIO_PDR = AT91C_PIO_PA25 | AT91C_PIO_PA26;

    pPio->PIO_MDDR = ~AT91C_PIO_PA25;
    pPio->PIO_MDER = AT91C_PIO_PA25;

    pPMC->PMC_PCER = 1u << AT91C_ID_TWI;

    twiPtr->TWI_IDR = 0xffffffffu;
    twiPtr->TWI_CR = AT91C_TWI_SWRST;
    twiPtr->TWI_CR = AT91C_TWI_MSEN | AT91C_TWI_SVDIS;

    twiPtr->TWI_CWGR = SET_TWI_CLOCK;
}

static inline unsigned
iicaddr(unsigned ee_off)
{
    return (TWSI_EEPROM_ADDRESS | ((ee_off >> 8) & 0x7));
}


/*
 * .KB_C_FN_DEFINITION_START
 * void ReadEEPROM(unsigned ee_addr, char *data_addr, unsigned size)
 *  This global function reads data from the eeprom at ee_addr storing data
 * to data_addr for size bytes.  Assume the TWI has been initialized.
 * This function does not utilize the page read mode to simplify the code.
 * .KB_C_FN_DEFINITION_END
 */
void
EERead(unsigned ee_off, char *data_addr, unsigned size)
{
    const AT91PS_TWI    twiPtr = AT91C_BASE_TWI;
    unsigned int status;

    if ((ee_off & ~0xff) != ((ee_off + size) & ~0xff)) {
        printf("Crosses page boundary: 0x%x 0x%x\n", ee_off, size);
        return;
    }

    status = twiPtr->TWI_SR;
    status = twiPtr->TWI_RHR;
    twiPtr->TWI_MMR = (iicaddr(ee_off) << 16) | AT91C_TWI_IADRSZ_1_BYTE |
        AT91C_TWI_MREAD;
    twiPtr->TWI_IADR = ee_off & 0xff;
    twiPtr->TWI_CR = AT91C_TWI_START;
    while (size-- > 1) {
        while (!(twiPtr->TWI_SR & AT91C_TWI_RXRDY))
            continue;
        *(data_addr++) = twiPtr->TWI_RHR;
    }
    twiPtr->TWI_CR = AT91C_TWI_STOP;
    status = twiPtr->TWI_SR;
    while (!(twiPtr->TWI_SR & AT91C_TWI_TXCOMP))
        continue;
    *data_addr = twiPtr->TWI_RHR;
}


/*
 * .KB_C_FN_DEFINITION_START
 * void WriteEEPROM(unsigned ee_off, char *data_addr, unsigned size)
 *  This global function writes data to the eeprom at ee_off using data
 * from data_addr for size bytes.  Assume the TWI has been initialized.
 * This function does not utilize the page write mode as the write time is
 * much greater than the time required to access the device for byte-write
 * functionality.  This allows the function to be much simpler.
 * .KB_C_FN_DEFINITION_END
 */
void
EEWrite(unsigned ee_off, const char *data_addr, unsigned size)
{
    const AT91PS_TWI    twiPtr = AT91C_BASE_TWI;
    unsigned        status;
    char            test_data;

    while (size--) {
        // Set the TWI Master Mode Register
        twiPtr->TWI_MMR = (iicaddr(ee_off) << 16) |
            AT91C_TWI_IADRSZ_1_BYTE;
        twiPtr->TWI_IADR = ee_off++;
        status = twiPtr->TWI_SR;

        // Load one data byte
        twiPtr->TWI_THR = *(data_addr++);
        twiPtr->TWI_CR = AT91C_TWI_START;
        while (!(twiPtr->TWI_SR & AT91C_TWI_TXRDY))
            continue;
        twiPtr->TWI_CR = AT91C_TWI_STOP;
        status = twiPtr->TWI_SR;
        while (!(twiPtr->TWI_SR & AT91C_TWI_TXCOMP))
            continue;

        // wait for write operation to complete, it is done once
        // we can read it back...
        EERead(ee_off, &test_data, 1);
    }
}