调试U-Boot笔记（六）

volatile static int write_hword (flash_info_t * info, ulong dest, ushort data)
    {
        vu_short *addr = (vu_short *) dest;
        ushort result;
        int rc = ERR_OK;
        int cflag, iflag;
        int chip;
        /*
         * Check if Flash is (sufficiently) erased
         */
        result = *addr;
        if ((result & data) != data)
            return ERR_NOT_ERASED;
        /*
         * Disable interrupts which might cause a timeout
         * here. Remember that our exception vectors are
         * at address 0 in the flash, and we don't want a
         * (ticker) exception to happen while the flash
         * chip is in programming mode.
         */
        cflag = icache_status ();
        icache_disable ();
        iflag = disable_interrupts ();
        MEM_FLASH_ADDR1 = CMD_UNLOCK1;
        MEM_FLASH_ADDR2 = CMD_UNLOCK2;
        MEM_FLASH_ADDR1 = CMD_UNLOCK_BYPASS;
        *addr = CMD_PROGRAM;
        *addr = data;
        /* arm simple, non interrupt dependent timer */
        reset_timer_masked ();
        /* wait until flash is ready */
        chip = 0;
        do {
            result = *addr;
            /* check timeout */
            if (get_timer_masked () > CFG_FLASH_ERASE_TOUT) {
                chip = ERR | TMO;
                break;
            }
            if (!chip && ((result & 0x80) == (data & 0x80)))
                chip = READY;
            if (!chip && ((result & 0xFFFF) & BIT_PROGRAM_ERROR)) {
                result = *addr;
                if ((result & 0x80) == (data & 0x80))
                    chip = READY;
                else
                    chip = ERR;
            }
        } while (!chip);
        *addr = CMD_READ_ARRAY;
        if (chip == ERR || *addr != data)
            rc = ERR_PROG_ERROR;
        if (iflag)
            enable_interrupts ();
        if (cflag)
            icache_enable ();
        return rc;
    }