flashpic8.c

完整的Bell实验室的嵌入式文件系统TFS

/* flashpic8.c:
   This file contains the 8-bit flash-support code that is relocated to
   RAM prior to execution.
*/
#include "config.h"
#if INCLUDE_FLASH
#include "stddefs.h"
#include "cpu.h"
#include "flashdev.h"
#include "flash.h"
#include "flash8.h"

extern struct flashinfo Fdev;
extern int FlashProtectWindow;

/* Flasherase():
 *  Based on the 'snum' value, erase the appropriate sector(s).
 *  Return 0 if success, else -1.
 */
int
Flasherase29F040_8(fdev,snum)
struct  flashinfo *fdev;
int snum;
{
    ftype   val;
    ulong   add;
    int ret, sector;

    ret = 0;
    add = (ulong)(fdev->base);

    /* Erase the request sector(s): */
    for (sector=0;sector<fdev->sectorcnt;sector++) {
        if ((!FlashProtectWindow) &&
            (fdev->sectors[sector].protected)) {
    
            add += fdev->sectors[sector].size;
            continue;
        }
        if ((snum == ALL_SECTORS) || (snum == sector)) {
            register ulong *lp, *lp1;
            int noterased;
    
            /* See if the sector is already erased: */
            noterased = 0;
            lp = (ulong *)fdev->sectors[sector].begin; 
            lp1 = (ulong *)((char *)lp + fdev->sectors[sector].size); 
            while(lp < lp1) {
                if (*lp++ != 0xffffffff) {
                    noterased = 1;
                    break;
                }
            }
            if (noterased) {
                /* Issue the sector erase command sequence: */
                Write_aa_to_555();
                Write_55_to_2aa();
                Write_80_to_555();
                Write_aa_to_555();
                Write_55_to_2aa();
                Write_30_to_(add);
        
                /* Wait for sector erase to complete or timeout..
                 * DQ7 polling: wait for D7 to be 1.
                 * DQ5 timeout: if DQ7 is 0, and DQ5 == 1, timeout.
                 */
                for (;;) {
                    if (Is_ff(add)) {
                        break;
                    }
                    if (D5_Timeout(add)) {
                        if (D7_not_set(add)) {
                            ret = -1;
                            break;
                        }
                    }
                }
            }
        }
        add += fdev->sectors[sector].size;
    }

    /* If the erase failed for some reason, then issue the read/reset
     * command sequence prior to returning...
     */
    if (ret == -1) {
        Write_f0_to_555();
        val = Read_5555();
    }
    return(ret);
}

/* EndFlasherase():
 *  Function place holder to determine the "end" of the
 *  sectorerase() function.
 */
void
EndFlasherase29F040_8()
{
}


/* Flashwrite():
   Return 0 if successful, else -1.
*/
int
Flashwrite29F040_8(fdev,dest,src,bytecnt)
struct  flashinfo *fdev;
uchar   *src, *dest;
long    bytecnt;
{
    int     i, jj, ret;
    long    cnt;
    uchar   *src1;
    ftype   val;

    /* If destination address is not properly aligned, then build a fake
     * source buffer based on the current value in dest[-1] and src[0].
     * Then call this function to do that 2-byte operation.  Once that
     * completes, simply increment dest and src by 1 and continue in this
     * context.
     */
    if (NotAligned(dest)) {
        uchar buf[2];
        buf[0] = *(dest-1);
        buf[1] = *src;
        Flashwrite29F040_8(fdev,dest-1,buf,2);
        dest++; src++; bytecnt--;
    }

    /* Each pass through this loop writes 'fdev->width' bytes... */
    ret = 0;
    cnt = bytecnt & ~(fdev->width - 1);
    src1 = (uchar *)&val;

onemore:
    for (i=0;i<cnt;i+=fdev->width) {

        /* Flash write command */
        Write_aa_to_555();
        Write_55_to_2aa();
        Write_a0_to_555();
    
        /* Just in case src is not aligned... */
        for (jj = 0; jj < fdev->width; jj++) {
            src1[jj] = src[jj];
        }

        /* Write the value */
        Fwrite(dest,src1);

        /* Wait for write to complete or timeout. */
        while(1) {
            if (Is_D7_Equal(dest,src1)) {
                break;
            }
            /* Check D5 for timeout... */
            if (D5_Timeout(dest)) {
                if (Is_D7_Not_Equal(dest,src1)) {
                    ret = -1;
                    goto done;
                }
            }
        }
        dest += fdev->width; 
        src += fdev->width;
    }

    /* If bytecount was odd...
     * If cnt != bytecnt then bytecnt is odd and width > 1, so one more
     * byte must be written to flash.  To do this, the one byte must
     * be combined with the next byte that is already stored in flash;
     * then re-written...
     */
    if (cnt != bytecnt) {
        val = (ftype)*dest | ((ftype)(*src) << 8);
        src = (uchar *)&val;
        bytecnt = cnt = 1;
        goto onemore;
    }

done:
    /* Read/reset command: */
    Write_f0_to_555();
    val = Read_5555();
    return(ret);
}

/* EndFlashwrite():
 *  Function place holder to determine the "end" of the
 *  Flashwrite() function.
 */
void
EndFlashwrite29F040_8()
{
}

/* Ewrite():
 *  Erase all sectors that are part of the address space to be written,
 *  then write the data to that address space.  This is basically a
 *  concatenation of flasherase and flashwrite done in one step.  This is
 *  necessary primarily for re-writing the bootcode; because after the boot
 *  code is erased, there is nowhere to return so the re-write must be done
 *  while executing out of ram also.
 */

int
Flashewrite29F040_8(fdev,dest,src,bytecnt)
struct  flashinfo *fdev;
ftype   *src, *dest;
int bytecnt;
{
    int     i;
    ulong   add;
    void    (*reset)();
    ftype   val, *src1, *dest1;

    add = (ulong)(fdev->base);
    src1 = src;
    dest1 = dest;

    /* For each sector, if it overlaps any of the destination space
     * then erase that sector.
     */
    for (i=0;i<fdev->sectorcnt;i++) {
        if ((((uchar *)dest) > (fdev->sectors[i].end)) ||
            (((uchar *)dest+(bytecnt-1)) < (fdev->sectors[i].begin))) {

            add += fdev->sectors[i].size;
            continue;
        }

        /* Sector erase command: */
        Write_aa_to_555();
        Write_55_to_2aa();
        Write_80_to_555();
        Write_aa_to_555();
        Write_55_to_2aa();
        Write_30_to_(add);

        /* Wait for sector erase to complete or timeout..
         * DQ7 polling: wait for D7 to be 1.
         * DQ6 toggling: wait for D6 to not toggle.
         * DQ5 timeout: if DQ7 is 0, and DQ5 = 1, timeout.
         */
        while(1) {
            if (Is_ff(add)) {
                break;
            }
            /* Check D5 for timeout...
             * In this case, there is nothing to return to
             * because the flash was just erased, so just break.
             */
            if (D5_Timeout(add)) {
                if (D7_not_set(add)) {
                    /* Read/reset command: */
                    Write_f0_to_555();
                    val = Read_5555();
                    reset = RESETFUNC();
                    reset();
                    break;
                }
            }
        }
        add += fdev->sectors[i].size;
    }

    /* Read/reset command: */
    Write_f0_to_555();
    val = Read_5555();

    for(i=0;i<bytecnt;i+=fdev->width) {
        /* Write command: */
        Write_aa_to_555();
        Write_55_to_2aa();
        Write_a0_to_555();
        Fwrite(dest,src);

        while(1) {
            if (Is_D7_Equal(dest,src)) {
                break;
            }
            /* Check D5 for timeout... */
            if (D5_Timeout(dest)) {
                if (Is_D7_Not_Equal(dest,src)) {
                    /* Read/reset command: */
                    Write_f0_to_555();
                    val = Read_5555();
                    return(-1);
                }
            }
        }
        dest++; 
        src++;
    }

    /* Issue the read/reset command sequence: */
    Write_f0_to_555();
    val = Read_5555();

    /* Wait till flash is readable, or timeout: */
    for(i=0;i<FLASH_TIMEOUT;i++) {
        if (Is_Equal(dest1,src1))
            break;
    }

    /* Now that the re-programming of flash is complete, reset: */
    reset = RESETFUNC();
    reset();

    return(0);  /* won't get here */
}

/* EndFlashewrite():
 *  Function place holder to determine the "end" of the
 *  FlashEraseAndWrite() function.
 */
void
EndFlashewrite29F040_8()
{
}


/* Flashtype():
 *  Use the AUTOSELECT command sequence to determine the type of device.
 */

int
Flashtype29F040_8(fdev)
struct flashinfo *fdev;
{
    ftype   val;
    ushort  man, dev;
    ulong   id;

    val = Read_0000();

    /* Issue the autoselect command sequence: */
    Write_aa_to_555();
    Write_55_to_2aa();
    Write_90_to_555();

    man = (ushort)Read_0000();  /* manufacturer ID */
    dev = (ushort)Read_0001();  /* device ID */
    id = man;
    id <<= 16;
    id |= dev;

    fdev->id = id;

    /* Issue the read/reset command sequence: */
    Write_f0_to_555();
    val = Read_0000();
    return((int)(fdev->id));
}

/* EndFlashtype():
    Function place holder to determine the "end" of the
    Flashtype() function.
*/
void
EndFlashtype29F040_8()
{
}
#endif