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	 > 嵌入式系統(tǒng) > 設(shè)計(jì)應(yīng)用 > ARM-Linux驅(qū)動(dòng)--MTD驅(qū)動(dòng)分析(三)
          
    
          

          

          


	
	
	

          
	
          
		
          
			
          ARM-Linux驅(qū)動(dòng)--MTD驅(qū)動(dòng)分析(三)
          
						
          
				作者：
				時(shí)間：2016-11-20
				來(lái)源：網(wǎng)絡(luò)
				
				
				
				
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			主機(jī)：Gentoo Linux 11.2 with linux kernel 3.0.6
          硬件平臺(tái)：FL2440（S3C2440）with linux kernel 2.6.35
          本文引用地址：http://www.ex-cimer.com/article/201611/319014.htm
          本文分析MTD設(shè)備的分區(qū)管理機(jī)制
          分區(qū)管理實(shí)際上是將一個(gè)MTD設(shè)備分成幾個(gè)分區(qū)，將其作為單獨(dú)的MTD原始設(shè)備進(jìn)行管理。
          1、分區(qū)的結(jié)構(gòu)體描述結(jié)構(gòu)體mtd_part
          1. /*Ourpartitionnodestructure*/
          2. //分區(qū)結(jié)構(gòu)信息
          3. structmtd_part{
          4. structmtd_infomtd;//mtd_info數(shù)據(jù)結(jié)構(gòu)，會(huì)被加入mtd_table中
          5. structmtd_info*master;//該分區(qū)的主分區(qū)
          6. uint64_toffset;//該分區(qū)的偏移地址
          7. structlist_headlist;
          8. };

          2、分區(qū)鏈表mtd_partitions
          1. /*Ourpartitionlinkedlist*/
          2. //聲明mtd_partitions鏈表
          3. staticLIST_HEAD(mtd_partitions);

          3、add_mtd_partitions函數(shù)
          1. /*
          2. *Thisfunction,givenamasterMTDobjectandapartitiontable,creates
          3. *andregistersslaveMTDobjectswhichareboundtothemasteraccordingto
          4. *thepartitiondefinitions.
          5. *
          6. *Wedontregisterthemaster,orexpectthecallertohavedoneso,
          7. *forreasonsofdataintegrity.
          8. */
          9. //根據(jù)一個(gè)MTD主設(shè)備和分區(qū)表，創(chuàng)建新的主設(shè)備下的副設(shè)備并記錄到分區(qū)表中
          10. //這里我們不將注射被注冊(cè)到分區(qū)表中，只注冊(cè)副設(shè)備到到分區(qū)表中
          11. intadd_mtd_partitions(structmtd_info*master,
          12. conststructmtd_partition*parts,
          13. intnbparts)
          14. {
          15. structmtd_part*slave;
          16. uint64_tcur_offset=0;
          17. inti;
          19. printk(KERN_NOTICE"Creating%dMTDpartitionson"%s":n",nbparts,master->name);
          21. for(i=0;i
          22. slave=add_one_partition(master,parts+i,i,cur_offset);
          23. if(!slave)
          24. return-ENOMEM;
          25. cur_offset=slave->offset+slave->mtd.size;
          26. }
          28. return0;
          29. }
          30. EXPORT_SYMBOL(add_mtd_partitions);

          而add_one_partition函數(shù)實(shí)現(xiàn)如下：
          1. //創(chuàng)建一個(gè)分區(qū)
          2. staticstructmtd_part*add_one_partition(structmtd_info*master,
          3. conststructmtd_partition*part,intpartno,
          4. uint64_tcur_offset)
          5. {
          6. structmtd_part*slave;
          8. /*allocatethepartitionstructure*/
          9. slave=kzalloc(sizeof(*slave),GFP_KERNEL);//分配內(nèi)存
          10. if(!slave){
          11. printk(KERN_ERR"memoryallocationerrorwhilecreatingpartitionsfor"%s"n",
          12. master->name);
          13. del_mtd_partitions(master);
          14. returnNULL;
          15. }
          16. list_add(&slave->list,&mtd_partitions);//將原始設(shè)備表添加到分區(qū)表中
          18. /*setuptheMTDobjectforthispartition*/
          19. //大部分根據(jù)master相應(yīng)的信息設(shè)置MTD分區(qū)slave的信息
          20. slave->mtd.type=master->type;
          21. slave->mtd.flags=master->flags&~part->mask_flags;
          22. slave->mtd.size=part->size;
          23. slave->mtd.writesize=master->writesize;
          24. slave->mtd.oobsize=master->oobsize;
          25. slave->mtd.oobavail=master->oobavail;
          26. slave->mtd.subpage_sft=master->subpage_sft;
          28. slave->mtd.name=part->name;
          29. slave->mtd.owner=master->owner;
          30. slave->mtd.backing_dev_info=master->backing_dev_info;
          32. /*NOTE:wedontarrangeMTDsasatree;itdbeerror-prone
          33. *tohavethesamedatabeintwodifferentpartitions.
          34. */
          35. slave->mtd.dev.parent=master->dev.parent;
          37. slave->mtd.read=part_read;
          38. slave->mtd.write=part_write;
          40. if(master->panic_write)
          41. slave->mtd.panic_write=part_panic_write;
          43. if(master->point&&master->unpoint){
          44. slave->mtd.point=part_point;
          45. slave->mtd.unpoint=part_unpoint;
          46. }
          48. if(master->get_unmapped_area)
          49. slave->mtd.get_unmapped_area=part_get_unmapped_area;
          50. if(master->read_oob)
          51. slave->mtd.read_oob=part_read_oob;
          52. if(master->write_oob)
          53. slave->mtd.write_oob=part_write_oob;
          54. if(master->read_user_prot_reg)
          55. slave->mtd.read_user_prot_reg=part_read_user_prot_reg;
          56. if(master->read_fact_prot_reg)
          57. slave->mtd.read_fact_prot_reg=part_read_fact_prot_reg;
          58. if(master->write_user_prot_reg)
          59. slave->mtd.write_user_prot_reg=part_write_user_prot_reg;
          60. if(master->lock_user_prot_reg)
          61. slave->mtd.lock_user_prot_reg=part_lock_user_prot_reg;
          62. if(master->get_user_prot_info)
          63. slave->mtd.get_user_prot_info=part_get_user_prot_info;
          64. if(master->get_fact_prot_info)
          65. slave->mtd.get_fact_prot_info=part_get_fact_prot_info;
          66. if(master->sync)
          67. slave->mtd.sync=part_sync;
          68. if(!partno&&!master->dev.class&&master->suspend&&master->resume){
          69. slave->mtd.suspend=part_suspend;
          70. slave->mtd.resume=part_resume;
          71. }
          72. if(master->writev)
          73. slave->mtd.writev=part_writev;
          74. if(master->lock)
          75. slave->mtd.lock=part_lock;
          76. if(master->unlock)
          77. slave->mtd.unlock=part_unlock;
          78. if(master->block_isbad)
          79. slave->mtd.block_isbad=part_block_isbad;
          80. if(master->block_markbad)
          81. slave->mtd.block_markbad=part_block_markbad;
          82. slave->mtd.erase=part_erase;
          83. slave->master=master;
          84. slave->offset=part->offset;
          86. if(slave->offset==MTDPART_OFS_APPEND)
          87. slave->offset=cur_offset;
          88. if(slave->offset==MTDPART_OFS_NXTBLK){
          89. slave->offset=cur_offset;
          90. if(mtd_mod_by_eb(cur_offset,master)!=0){
          91. /*Rounduptonexterasesize*/
          92. slave->offset=(mtd_div_by_eb(cur_offset,master)+1)*master->erasesize;
          93. printk(KERN_NOTICE"Movingpartition%d:"
          94. "0x%012llx->0x%012llxn",partno,
          95. (unsignedlonglong)cur_offset,(unsignedlonglong)slave->offset);
          96. }
          97. }
          98. if(slave->mtd.size==MTDPART_SIZ_FULL)
          99. slave->mtd.size=master->size-slave->offset;
          101. printk(KERN_NOTICE"0x%012llx-0x%012llx:"%s"n",(unsignedlonglong)slave->offset,
          102. (unsignedlonglong)(slave->offset+slave->mtd.size),slave->mtd.name);
          104. /*letsdosomesanitychecks*/
          105. if(slave->offset>=master->size){
          106. /*letsregisteritanywaytopreserveordering*/
          107. slave->offset=0;
          108. slave->mtd.size=0;
          109. printk(KERN_ERR"mtd:partition"%s"isoutofreach--disabledn",
          110. part->name);
          111. gotoout_register;
          112. }
          113. if(slave->offset+slave->mtd.size>master->size){
          114. slave->mtd.size=master->size-slave->offset;
          115. printk(KERN_WARNING"mtd:partition"%s"extendsbeyondtheendofdevice"%s"--sizetruncatedto%#llxn",
          116. part->name,master->name,(unsignedlonglong)slave->mtd.size);
          117. }
          118. if(master->numeraseregions>1){
          119. /*Dealwithvariableerasesizestuff*/
          120. inti,max=master->numeraseregions;
          121. u64end=slave->offset+slave->mtd.size;
          122. structmtd_erase_region_info*regions=master->eraseregions;
          124. /*Findthefirsteraseregionswhichispartofthis
          125. *partition.*/
          126. for(i=0;ioffset;i++)
          127. ;
          128. /*Theloopsearchedfortheregion_behind_thefirstone*/
          129. if(i>0)
          130. i--;
          132. /*Pickbiggesterasesize*/
          133. for(;i
          134. if(slave->mtd.erasesize
          135. slave->mtd.erasesize=regions[i].erasesize;
          136. }
          137. }
          138. BUG_ON(slave->mtd.erasesize==0);
          139. }else{
          140. /*Singleerasesize*/
          141. slave->mtd.erasesize=master->erasesize;
          142. }
          144. if((slave->mtd.flags&MTD_WRITEABLE)&&
          145. mtd_mod_by_eb(slave->offset,&slave->mtd)){
          146. /*Doesntstartonaboundaryofmajorerasesize*/
          147. /*FIXME:Letitbewritableifitisonaboundaryof
          148. *_minor_erasesizethough*/
          149. slave->mtd.flags&=~MTD_WRITEABLE;
          150. printk(KERN_WARNING"mtd:partition"%s"doesntstartonaneraseblockboundary--forceread-onlyn",
          151. part->name);
          152. }
          153. if((slave->mtd.flags&MTD_WRITEABLE)&&
          154. mtd_mod_by_eb(slave->mtd.size,&slave->mtd)){
          155. slave->mtd.flags&=~MTD_WRITEABLE;
          156. printk(KERN_WARNING"mtd:partition"%s"doesntendonaneraseblock--forceread-onlyn",
          157. part->name);
          158. }
          160. slave->mtd.ecclayout=master->ecclayout;
          161. if(master->block_isbad){
          162. uint64_toffs=0;
          164. while(offsmtd.size){
          165. if(master->block_isbad(master,
          166. offs+slave->offset))
          167. slave->mtd.ecc_stats.badblocks++;
          168. offs+=slave->mtd.erasesize;
          169. }
          170. }
          172. out_register:
          173. /*registerourpartition*/
          174. //最后調(diào)用add_mtd_device根據(jù)該設(shè)備的mtd_info信息添加設(shè)備鏈表，將其作為一個(gè)獨(dú)立的MTD原始設(shè)備
          175. add_mtd_device(&slave->mtd);
          177. returnslave;
          178. }

          4、del_mtd_partition函數(shù)
          1. /*
          2. *ThisfunctionunregistersanddestroyallslaveMTDobjectswhichare
          3. *attachedtothegivenmasterMTDobject.
          4. */
          5. //將一個(gè)主設(shè)備下的所有副設(shè)備刪除
          6. intdel_mtd_partitions(structmtd_info*master)
          7. {
          8. structmtd_part*slave,*next;
          10. list_for_each_entry_safe(slave,next,&mtd_partitions,list)//遍歷mtd_partitions鏈表，查找到指定的主設(shè)備
          11. if(slave->master==master){
          12. list_del(&slave->list);//將主設(shè)備下的附屬設(shè)備刪除
          13. del_mtd_device(&slave->mtd);//調(diào)用del_mtd_device函數(shù)將每個(gè)設(shè)備從MTD原始設(shè)備表中刪除
          14. kfree(slave);//釋放內(nèi)存
          15. }
          17. return0;
          18. }
          19. EXPORT_SYMBOL(del_mtd_partitions);

          5、其他的分區(qū)管理函數(shù)
          1. /*
          2. *MTDmethodswhichsimplytranslatetheeffectiveaddressandpassthrough
          3. *tothe_real_device.
          4. */
          5. //讀取某個(gè)分區(qū)的指定數(shù)據(jù)
          6. staticintpart_read(structmtd_info*mtd,loff_tfrom,size_tlen,
          7. size_t*retlen,u_char*buf)
          8. {
          9. structmtd_part*part=PART(mtd);
          10. structmtd_ecc_statsstats;
          11. intres;
          13. stats=part->master->ecc_stats;
          15. if(from>=mtd->size)
          16. len=0;
          17. elseif(from+len>mtd->size)
          18. len=mtd->size-from;
          19. res=part->master->read(part->master,from+part->offset,
          20. len,retlen,buf);
          21. if(unlikely(res)){
          22. if(res==-EUCLEAN)
          23. mtd->ecc_stats.corrected+=part->master->ecc_stats.corrected-stats.corrected;
          24. if(res==-EBADMSG)
          25. mtd->ecc_stats.failed+=part->master->ecc_stats.failed-stats.failed;
          26. }
          27. returnres;
          28. }
          30. staticintpart_point(structmtd_info*mtd,loff_tfrom,size_tlen,
          31. size_t*retlen,void**virt,resource_size_t*phys)
          32. {
          33. structmtd_part*part=PART(mtd);
          34. if(from>=mtd->size)
          35. len=0;
          36. elseif(from+len>mtd->size)
          37. len=mtd->size-from;
          38. returnpart->master->point(part->master,from+part->offset,
          39. len,retlen,virt,phys);
          40. }
          42. staticvoidpart_unpoint(structmtd_info*mtd,loff_tfrom,size_tlen)
          43. {
          44. structmtd_part*part=PART(mtd);
          46. part->master->unpoint(part->master,from+part->offset,len);
          47. }
          48. //獲取空閑的內(nèi)存驅(qū)動(dòng)
          49. staticunsignedlongpart_get_unmapped_area(structmtd_info*mtd,
          50. unsignedlonglen,
          51. unsignedlongoffset,
          52. unsignedlongflags)
          53. {
          54. structmtd_part*part=PART(mtd);
          56. offset+=part->offset;
          57. returnpart->master->get_unmapped_area(part->master,len,offset,
          58. flags);
          59. }
          61. staticintpart_read_oob(structmtd_info*mtd,loff_tfrom,
          62. structmtd_oob_ops*ops)
          63. {
          64. structmtd_part*part=PART(mtd);
          65. intres;
          67. if(from>=mtd->size)
          68. return-EINVAL;
          69. if(ops->datbuf&&from+ops->len>mtd->size)
          70. return-EINVAL;
          71. res=part->master->read_oob(part->master,from+part->offset,ops);
          73. if(unlikely(res)){
          74. if(res==-EUCLEAN)
          75. mtd->ecc_stats.corrected++;
          76. if(res==-EBADMSG)
          77. mtd->ecc_stats.failed++;
          78. }
          79. returnres;
          80. }
          82. staticintpart_read_user_prot_reg(structmtd_info*mtd,loff_tfrom,
          83. size_tlen,size_t*retlen,u_char*buf)
          84. {
          85. structmtd_part*part=PART(mtd);
          86. returnpart->master->read_user_prot_reg(part->master,from,
          87. len,retlen,buf);
          88. }
          90. staticintpart_get_user_prot_info(structmtd_info*mtd,
          91. structotp_info*buf,size_tlen)
          92. {
          93. structmtd_part*part=PART(mtd);
          94. returnpart->master->get_user_prot_info(part->master,buf,len);
          95. }
          97. staticintpart_read_fact_prot_reg(structmtd_info*mtd,loff_tfrom,
          98. size_tlen,size_t*retlen,u_char*buf)
          99. {
          100. structmtd_part*part=PART(mtd);
          101. returnpart->master->read_fact_prot_reg(part->master,from,
          102. len,retlen,buf);
          103. }
          105. staticintpart_get_fact_prot_info(structmtd_info*mtd,structotp_info*buf,
          106. size_tlen)
          107. {
          108. structmtd_part*part=PART(mtd);
          109. returnpart->master->get_fact_prot_info(part->master,buf,len);
          110. }
          111. //分區(qū)寫(xiě)函數(shù)
          112. staticintpart_write(structmtd_info*mtd,loff_tto,size_tlen,
          113. size_t*retlen,constu_char*buf)
          114. {
          115. structmtd_part*part=PART(mtd);
          116. if(!(mtd->flags&MTD_WRITEABLE))
          117. return-EROFS;
          118. if(to>=mtd->size)
          119. len=0;
          120. elseif(to+len>mtd->size)
          121. len=mtd->size-to;
          122. returnpart->master->write(part->master,to+part->offset,
          123. len,retlen,buf);
          124. }
          126. staticintpart_panic_write(structmtd_info*mtd,loff_tto,size_tlen,
          127. size_t*retlen,constu_char*buf)
          128. {
          129. structmtd_part*part=PART(mtd);
          130. if(!(mtd->flags&MTD_WRITEABLE))
          131. return-EROFS;
          132. if(to>=mtd->size)
          133. len=0;
          134. elseif(to+len>mtd->size)
          135. len=mtd->size-to;
          136. returnpart->master->panic_write(part->master,to+part->offset,
          137. len,retlen,buf);
          138. }
          140. staticintpart_write_oob(structmtd_info*mtd,loff_tto,
          141. structmtd_oob_ops*ops)
          142. {
          143. structmtd_part*part=PART(mtd);
          145. if(!(mtd->flags&MTD_WRITEABLE))
          146. return-EROFS;
          148. if(to>=mtd->size)
          149. return-EINVAL;
          150. if(ops->datbuf&&to+ops->len>mtd->size)
          151. return-EINVAL;
          152. returnpart->master->write_oob(part->master,to+part->offset,ops);
          153. }
          155. staticintpart_write_user_prot_reg(structmtd_info*mtd,loff_tfrom,
          156. size_tlen,size_t*retlen,u_char*buf)
          157. {
          158. structmtd_part*part=PART(mtd);
          159. returnpart->master->write_user_prot_reg(part->master,from,
          160. len,retlen,buf);
          161. }
          163. staticintpart_lock_user_prot_reg(structmtd_info*mtd,loff_tfrom,
          164. size_tlen)
          165. {
          166. structmtd_part*part=PART(mtd);
          167. returnpart->master->lock_user_prot_reg(part->master,from,len);
          168. }
          170. staticintpart_writev(structmtd_info*mtd,conststructkvec*vecs,
          171. unsignedlongcount,loff_tto,size_t*retlen)
          172. {
          173. structmtd_part*part=PART(mtd);
          174. if(!(mtd->flags&MTD_WRITEABLE))
          175. return-EROFS;
          176. returnpart->master->writev(part->master,vecs,count,
          177. to+part->offset,retlen);
          178. }
          180. staticintpart_erase(structmtd_info*mtd,structerase_info*instr)
          181. {
          182. structmtd_part*part=PART(mtd);
          183. intret;
          184. if(!(mtd->flags&MTD_WRITEABLE))
          185. return-EROFS;
          186. if(instr->addr>=mtd->size)
          187. return-EINVAL;
          188. instr->addr+=part->offset;
          189. ret=part->master->erase(part->master,instr);
          190. if(ret){
          191. if(instr->fail_addr!=MTD_FAIL_ADDR_UNKNOWN)
          192. instr->fail_addr-=part->offset;
          193. instr->addr-=part->offset;
          194. }
          195. returnret;
          196. }
          198. voidmtd_erase_callback(structerase_info*instr)
          199. {
          200. if(instr->mtd->erase==part_erase){
          201. structmtd_part*part=PART(instr->mtd);
          203. if(instr->fail_addr!=MTD_FAIL_ADDR_UNKNOWN)
          204. instr->fail_addr-=part->offset;
          205. instr->addr-=part->offset;
          206. }
          207. if(instr->callback)
          208. instr->callback(instr);
          209. }
          210. EXPORT_SYMBOL_GPL(mtd_erase_callback);
          212. staticintpart_lock(structmtd_info*mtd,loff_tofs,uint64_tlen)
          213. {
          214. structmtd_part*part=PART(mtd);
          215. if((len+ofs)>mtd->size)
          216. return-EINVAL;
          217. returnpart->master->lock(part->master,ofs+part->offset,len);
          218. }
          220. staticintpart_unlock(structmtd_info*mtd,loff_tofs,uint64_tlen)
          221. {
          222. structmtd_part*part=PART(mtd);
          223. if((len+ofs)>mtd->size)
          224. return-EINVAL;
          225. returnpart->master->unlock(part->master,ofs+part->offset,len);
          226. }
          227. //分區(qū)同步函數(shù)
          228. staticvoidpart_sync(structmtd_info*mtd)
          229. {
          230. structmtd_part*part=PART(mtd);
          231. part->master->sync(part->master);
          232. }
          233. //支持電源管理的功能函數(shù)
          234. staticintpart_suspend(structmtd_info*mtd)
          235. {
          236. structmtd_part*part=PART(mtd);
          237. returnpart->master->suspend(part->master);
          238. }
          240. staticvoidpart_resume(structmtd_info*mtd)
          241. {
          242. structmtd_part*part=PART(mtd);
          243. part->master->resume(part->master);
          244. }
          246. staticintpart_block_isbad(structmtd_info*mtd,loff_tofs)
          247. {
          248. structmtd_part*part=PART(mtd);
          249. if(ofs>=mtd->size)
          250. return-EINVAL;
          251. ofs+=part->offset;
          252. returnpart->master->block_isbad(part->master,ofs);
          253. }
          254. //標(biāo)記設(shè)備地址壞塊
          255. staticintpart_block_markbad(structmtd_info*mtd,loff_tofs)
          256. {
          257. structmtd_part*part=PART(mtd);
          258. intres;
          260. if(!(mtd->flags&MTD_WRITEABLE))
          261. return-EROFS;
          262. if(ofs>=mtd->size)
          263. return-EINVAL;
          264. ofs+=part->offset;
          265. res=part->master->block_markbad(part->master,ofs);
          266. if(!res)
          267. mtd->ecc_stats.badblocks++;
          268. returnres;
          269. }

          下篇分析具體的MTD設(shè)備，字符設(shè)備和塊設(shè)備，待續(xù)........				             
				
            
                
			
							
          
                
			              
              
            
          
		
          
		
          
		
          
		
          
		
          
			
            
				
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