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  • /* LowLevel function for DataFlash environment support
     * Author : Gilles Gastaldi (Atmel)
     *
     * This program is free software; you can redistribute it and/or
     * modify it under the terms of the GNU General Public License as
     * published by the Free Software Foundation; either version 2 of
     * the License, or (at your option) any later version.
     *
     * This program is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     * GNU General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
     * MA 02111-1307 USA
     *
     */
    #include <common.h>
    
    #if defined(CFG_ENV_IS_IN_DATAFLASH) /* Environment is in DataFlash */
    
    #include <command.h>
    #include <environment.h>
    #include <linux/stddef.h>
    #include <dataflash.h>
    
    env_t *env_ptr = NULL;
    
    char * env_name_spec = "dataflash";
    
    extern int read_dataflash (unsigned long addr, unsigned long size, char
    *result);
    extern int write_dataflash (unsigned long addr_dest, unsigned long addr_src,
    		     unsigned long size);
    extern int AT91F_DataflashInit (void);
    extern uchar default_environment[];
    /* extern int default_environment_size; */
    
    
    uchar env_get_char_spec (int index)
    {
    	uchar c;
    	read_dataflash (CFG_ENV_ADDR+index+offsetof(env_t,data),1,&c);
    	return (c);
    }
    
    void env_relocate_spec (void)
    {
    	read_dataflash (CFG_ENV_ADDR,CFG_ENV_SIZE,(uchar *)env_ptr);
    }
    
    int saveenv(void)
    {
    /* env must be copied to do not alter env structure in memory*/
    unsigned char temp[CFG_ENV_SIZE];
    int i;
    	memcpy(temp, env_ptr, CFG_ENV_SIZE);
    	return write_dataflash (CFG_ENV_ADDR, (unsigned long)temp, CFG_ENV_SIZE);
    }
    
    /************************************************************************
     * Initialize Environment use
     *
     * We are still running from ROM, so data use is limited
     * Use a (moderately small) buffer on the stack
     */
    int env_init(void)
    {
    	DECLARE_GLOBAL_DATA_PTR;
    
    	ulong crc, len, new;
    	unsigned off;
    	uchar buf[64];
    	if (gd->env_valid == 0){
    		AT91F_DataflashInit();	/* prepare for DATAFLASH read/write */
    
    		/* read old CRC */
    		read_dataflash (CFG_ENV_ADDR+offsetof(env_t,crc),sizeof(ulong),&crc);
    		new = 0;
    		len = ENV_SIZE;
    		off = offsetof(env_t,data);
    		while (len > 0) {
    			int n = (len > sizeof(buf)) ? sizeof(buf) : len;
    			read_dataflash (CFG_ENV_ADDR+off,n , buf);
    			new = crc32 (new, buf, n);
    			len -= n;
    			off += n;
    		}
    		if (crc == new) {
    			gd->env_addr  = offsetof(env_t,data);
    			gd->env_valid = 1;
    		} else {
    			gd->env_addr  = (ulong)&default_environment[0];
    			gd->env_valid = 0;
    		}
    	}
    
     	return (0);
    }
    
    #endif /* CFG_ENV_IS_IN_DATAFLASH */