ARM-Linux驱动--MTD驱动分析(三)

时间：11-20 来源：互联网点击：

slave->>mtd.unlock=part_unlock;
if(master->block_isbad)
slave->mtd.block_isbad=part_block_isbad;
if(master->block_markbad)
slave->mtd.block_markbad=part_block_markbad;
slave->mtd.erase=part_erase;
slave->master=master;
slave->offset=part->offset;
if(slave->offset==MTDPART_OFS_APPEND)
slave->offset=cur_offset;
if(slave->offset==MTDPART_OFS_NXTBLK){
slave->offset=cur_offset;
if(mtd_mod_by_eb(cur_offset,master)!=0){
/*Rounduptonexterasesize*/
slave->offset=(mtd_div_by_eb(cur_offset,master)+1)*master->erasesize;
printk(KERN_NOTICE"Movingpartition%d:"
"0x%012llx->0x%012llx\n",partno,
(unsignedlonglong)cur_offset,(unsignedlonglong)slave->offset);
}
}
if(slave->mtd.size==MTDPART_SIZ_FULL)
slave->mtd.size=master->size-slave->offset;
printk(KERN_NOTICE"0x%012llx-0x%012llx:\"%s\"\n",(unsignedlonglong)slave->offset,
(unsignedlonglong)(slave->offset+slave->mtd.size),slave->mtd.name);
/*letsdosomesanitychecks*/
if(slave->offset>=master->size){
/*letsregisteritanywaytopreserveordering*/
slave->offset=0;
slave->mtd.size=0;
printk(KERN_ERR"mtd:partition\"%s\"isoutofreach--disabled\n",
part->name);
gotoout_register;
}
if(slave->offset+slave->mtd.size>master->size){
slave->mtd.size=master->size-slave->offset;
printk(KERN_WARNING"mtd:partition\"%s\"extendsbeyondtheendofdevice\"%s\"--sizetruncatedto%#llx\n",
part->name,master->name,(unsignedlonglong)slave->mtd.size);
}
if(master->numeraseregions>1){
/*Dealwithvariableerasesizestuff*/
inti,max=master->numeraseregions;
u64end=slave->offset+slave->mtd.size;
structmtd_erase_region_info*regions=master->eraseregions;
/*Findthefirsteraseregionswhichispartofthis
*partition.*/
for(i=0;ioffset;i++)
;
/*Theloopsearchedfortheregion_behind_thefirstone*/
if(i>0)
i--;
/*Pickbiggesterasesize*/
for(;i
if(slave->mtd.erasesize
slave->mtd.erasesize=regions[i].erasesize;
}
}
BUG_ON(slave->mtd.erasesize==0);
}else{
/*Singleerasesize*/
slave->mtd.erasesize=master->erasesize;
}
if((slave->mtd.flags&MTD_WRITEABLE)&&
mtd_mod_by_eb(slave->offset,&slave->mtd)){
/*Doesntstartonaboundaryofmajorerasesize*/
/*FIXME:Letitbewritableifitisonaboundaryof
*_minor_erasesizethough*/
slave->mtd.flags&=~MTD_WRITEABLE;
printk(KERN_WARNING"mtd:partition\"%s\"doesntstartonaneraseblockboundary--forceread-only\n",
part->name);
}
if((slave->mtd.flags&MTD_WRITEABLE)&&
mtd_mod_by_eb(slave->mtd.size,&slave->mtd)){
slave->mtd.flags&=~MTD_WRITEABLE;
printk(KERN_WARNING"mtd:partition\"%s\"doesntendonaneraseblock--forceread-only\n",
part->name);
}
slave->mtd.ecclayout=master->ecclayout;
if(master->block_isbad){
uint64_toffs=0;
while(offsmtd.size){
if(master->block_isbad(master,
offs+slave->offset))
slave->mtd.ecc_stats.badblocks++;
offs+=slave->mtd.erasesize;
}
}
out_register:
/*registerourpartition*/
//最后调用add_mtd_device根据该设备的mtd_info信息添加设备链表，将其作为一个独立的MTD原始设备
add_mtd_device(&slave->mtd);
returnslave;
}

4、del_mtd_partition函数

/*
*ThisfunctionunregistersanddestroyallslaveMTDobjectswhichare
*attachedtothegivenmasterMTDobject.
*/
//将一个主设备下的所有副设备删除
intdel_mtd_partitions(structmtd_info*master)
{
structmtd_part*slave,*next;
list_for_each_entry_safe(slave,next,&mtd_partitions,list)//遍历mtd_partitions链表，查找到指定的主设备
if(slave->master==master){
list_del(&slave->list);//将主设备下的附属设备删除
del_mtd_device(&slave->mtd);//调用del_mtd_device函数将每个设备从MTD原始设备表中删除
kfree(slave);//释放内存
}
return0;
}
EXPORT_SYMBOL(del_mtd_partitions);

5、其他的分区管理函数

/*
*MTDmethodswhichsimplytranslatetheeffectiveaddressandpassthrough
*tothe_real_device.
*/
//读取某个分区的指定数据
staticintpart_read(structmtd_info*mtd,loff_tfrom,size_tlen,
size_t*retlen,u_char*buf)
{
structmtd_part*part=PART(mtd);
structmtd_ecc_statsstats;
intres;
stats=part->master->sta

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