//AHCI初始化

kernel_init

kernel_init_freeable

do_one_initcall

driver_register

bus_add_driver

bus_for_each_dev

__driver_attach

driver_probe_device

(ahci_platform.c, struct platform_driver ahci_driver, ahci_platform_ops)

|- ahci_probe

    |- ata_host_alloc_pinfo     //熱插拔

        |- ata_host_alloc      

            |- ata_port_alloc   //增加WARN_ON(1)

                |- INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug);   //初始化熱插拔檢測工作佇列

    |- ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED, &ahci_platform_sht);   //申請了中斷，並呼叫ata_host_register函式註冊host

        |- ata_host_register(host, sht);    //增加WARN_ON(1) 

            |- ata_scsi_add_hosts(host, sht);   //新增ATA的SCSI主機介面卡包括兩部分，為主機介面卡分配資料結構，然後將主機介面卡新增到系統

                |- scsi_host_alloc(sht, sizeof(struct ata_port *))  //繼續初始化scsi_host結構體

                    |- shost->ehandler = kthread_run(scsi_error_handler, shost, "scsi_eh_%d", shost->host_no);  //建立並執行scsi錯誤處理執行緒

                |- scsi_add_host_with_dma(ap->scsi_host, &ap->tdev, ap->host->dev);

            |- async_schedule(async_port_probe, ap) //async_port_probe呼叫ata_scsi_scan_host掃描scsi_devcie，並向上層註冊scsi_device

                |- __async_schedule

                    |- INIT_WORK(&entry->work, async_run_entry_fn);  //初始化硬碟掃描工作佇列

//

//硬碟識別前錯誤處理識別硬碟資訊

kthread

|- scsi_error_handler

    |- shost->transportt->eh_strategy_handler(shost) --> ata_scsi_error    // ata_init 中初始化

        |- ata_scsi_cmd_error_handler(host, ap, &eh_work_q);

        |- ata_scsi_port_error_handler(host, ap);

            |- ap->ops->error_handler(ap);--> ahci_error_handler

                |- sata_pmp_error_handler

                    |- ata_eh_report

                        |- ata_eh_link_report   //列印除錯資訊

                    |- sata_pmp_eh_recover

                        |- ata_eh_recover(ap, ops->prereset, ops->softreset, ops->hardreset, ops->postreset, NULL);

                            |- ata_eh_reset(link, ata_link_nr_vacant(link), prereset, softreset, hardreset, postreset);//列印hard resetting link

                                |- postreset(slave, classes) --> ata_std_postreset

                                    |- sata_print_link_status   //列印sata link狀態，SATA link up 1.5 Gbps (SStatus 113 SControl 310)

                            |- ata_set_mode(link, &dev) //Set ATA device disk transfer mode

                                |- ap->ops->set_mode(link, r_failed_dev) --> generic_set_mode

                                    |- ata_dev_info(dev, "configured for %s\n", name);

                            |- ata_eh_revalidate_and_attach(link, &dev);

                                |- ata_dev_read_id(dev, &dev->class, readid_flags, dev->id);  //初始化ata_taskfile的引數，其命令ATA_CMD_ID_ATA，返回值儲存在dev_id中，共512位元組

                                    |- ata_do_dev_read_id(dev, &tf, id);

                                        |- ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, sizeof(id[0]) * ATA_ID_WORDS, 0);

                                            |- ata_exec_internal_sg(dev, tf, cdb, dma_dir, psg, n_elem, timeout);   //通過完成變數阻塞執行命令

                                                |- ata_qc_issue(qc);   

                                |- ata_dev_configure(dev);

//

//執行硬碟掃描工作佇列                                                   

|- worker_thread

    |- process_one_work                                                        

        |- worker->current_func(work) --> ata_scsi_hotplug / async_run_entry_fn -- async_port_probe

|- ata_scsi_scan_host   //掃描scsi_devcie，並向上層註冊scsi_device

    |- sdev = __scsi_add_device //新增並註冊一個scsi_device

        |- scsi_alloc_target

        |- scsi_probe_and_add_lun   //如果sdev裝置已經存在，就返回SCSI_SCAN_LUN_PRESENT，不進行下面操作

            |- scsi_alloc_sdev 

                |- sdev->request_queue = scsi_alloc_queue(sdev)  //為SCSI裝置分配了請求佇列,設定回撥處理函式,設定超時處理函式

                    |- blk_queue_softirq_done(q, scsi_softirq_done);

                    |- blk_queue_rq_timed_out(q, scsi_times_out);

            |- scsi_probe_lun   //傳送SCSI INQUIRY命令探測lun單元

                |- scsi_execute_req     //scsi命令轉換成request

            |- scsi_add_lun     //通過SCSI INQUIRY 返回的引數初始化sdev的一些成員，初始化裝置型別sdev->type，其在sd_probe中會使用

                |- scsi_sysfs_add_sdev  //向上層註冊sdev

                    |- scsi_target_add

                        |- device_add(&starget->dev) //把裝置新增到所屬匯流排的裝置列表

                            |- bus_add_device

                            |- bus_probe_device(dev)    //為新找到的裝置匹配一個driver

                                |- device_attach(dev)

                                    |- bus_for_each_drv(dev->bus, NULL, dev, __device_attach);   //用bus上的每個drv來匹配dev

                                        |- __device_attach

                                            |- driver_match_device  //如果匹配成功，則執行driver_probe_device函式

                                                |- return drv->bus->match ? drv->bus->match(dev, drv) : 1 --> scsi_bus_type.match=scsi_bus_match

                                            |- driver_probe_device

                                                |- really_probe     //根據bus->probe是否為真來判斷是否呼叫drv->probe；無論呼叫哪個probe，都會執行到sd_probe函式。

                                                    |- drv->probe(dev) --> sd_probe   //匹配到裝置時呼叫，在給定的ID和裝置名之間建立對映，同時確定了塊裝置的主次裝置號。並關聯到了通用塊層 //增加WARN_ON(1)

                                                        |- gd = alloc_disk(SD_MINORS);

                                                        |- async_schedule_domain(sd_probe_async, sdkp, &scsi_sd_probe_domain)

                                                            |- __async_schedule

                                                                |- sd_probe_async   //正常是通過工作佇列執行,當工作佇列滿了或者記憶體不足時直接執行

                                                                    |- gendisk引數初始化

                                                                    |- scsi_disk引數初始化

                                                                    |- sd_revalidate_disk   //列印資訊

                                                                        |- sd_read_capacity    

                                                                        |- sd_read_write_protect_flag

                                                                        |- sd_read_cache_type

                                                                    |- blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);

                                                                    |- add_disk(gd);    //註冊到通用塊層

//

//硬碟識別過程中scsi_alloc_sdev呼叫，初始化request_fn和make_request_fn

scsi_alloc_queue

    |- q = __scsi_alloc_queue(sdev->host, scsi_request_fn);

        |- q = blk_init_queue(request_fn, NULL);

            |- blk_init_queue_node

                |- blk_init_allocated_queue

                    |- q->request_fn = rfn   //request_fn初始化為scsi_request_fn

                    |- blk_queue_make_request(q, blk_queue_bio)

                        |- q->make_request_fn = mfn  //make_request_fn初始化為blk_queue_bio

                    |- elevator_init(q, NULL)

    |- blk_queue_prep_rq(q, scsi_prep_fn);  //在sd_probe中修改為sd_prep_fn

    |- blk_queue_softirq_done(q, scsi_softirq_done);

    |- blk_queue_rq_timed_out(q, scsi_times_out);

    |- blk_queue_lld_busy(q, scsi_lld_busy);

//

//scsi命令轉換成request再轉換成scsi命令傳送

scsi_probe_lun

    |- result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,inq_result, try_inquiry_len, &sshdr, HZ / 2 + HZ * scsi_inq_timeout, 3,&resid);

        |- scsi_execute_req_flags

            |- result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense, timeout, retries, flags, resid);

                |- blk_get_request  //申請request並初始化

                    |- rq = get_request(q, rw, NULL, gfp_mask);

                        |- __get_request

                            |- rq = mempool_alloc(rl->rq_pool, gfp_mask);   

                            |- blk_rq_init(q, rq); 

                |- blk_execute_rq(req->q, NULL, req, 1); //利用完成變數來進行同步操作，探測lun

                    |- rq->end_io_data = &wait; 

                    |- blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); //把請求插入I/O排程佇列，之後處理請求

                        |- rq->end_io = blk_end_sync_rq; //scsi第一次回撥過程中會呼叫該函式，其會呼叫complete(waiting)，scsi_probe_lun繼續執行

                        |- __elv_add_request(q, rq, where);

                        |- __blk_run_queue(q);

                            |- __blk_run_queue_uncond(q);

                                |- q->request_fn(q) --> scsi_request_fn

                    |- wait_for_completion_io(&wait);   //scsi_probe_lun一直會阻塞在這裡直到接收到完成訊號，預設超時時間為LONG_MAX,可忽略

            |- scsi_execute_req_flags   //將感測資料格式化為公共格式

//

//SCSI中間層(SCSI協議層)

request_queue->request_fn---> scsi_request_fn //scsi裝置請求佇列處理函式

        |- req = blk_peek_request(q).

            |- rq = __elv_next_request(q)   //從請求佇列中獲取一個請求

            |- q->end_sector = rq_end_sector(rq);

            |- ret = q->prep_rq_fn(q, rq)--> sd_prep_fn   //根據request初始化SCSI命令，構建SCSI CDB

        |- blk_queue_start_tag

            |- blk_start_request(rq);

                |- blk_dequeue_request(req);

                    |- list_del_init(&rq->queuelist);    //把request從request queue佇列裡刪除掉

        |- rtn = scsi_dispatch_cmd(cmd)     //分發請求,把SCSI命令提交給SCSI控制器 

            |- cmd->scsi_done = scsi_done;

            |- host->hostt->queuecommand(host, cmd)   --> ata_scsi_queuecmd   

//SCSI底層(SCSI傳輸層/SCSI控制器驅動層)//向ata管理器發出scsi cdb

                |- __ata_scsi_queuecmd(cmd, dev)

                    |- xlat_func = ata_get_xlat_func(dev, scsi_op);

                    |- ata_scsi_translate(dev, scmd, xlat_func);    //Scis命令真實轉換為ata命令的流程

                        |- qc = ata_scsi_qc_new(dev, cmd)

                            |- qc->scsidone = cmd->scsi_done == scsi_done //設定ata—scsi回撥函式

                        |- qc->complete_fn = ata_scsi_qc_complete;   //設定ata處理完成回撥函式

                        |- xlat_func(qc) ---> 假設是READ_6呼叫函式 ata_scsi_rw_xlat //前面返回的xlat_func函式

                            |- ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags, qc->tag);//打包ata命令,主要是scsi_cmd初始化qc->tf,其代表ata—cmd

                        |- ata_qc_issue(qc);    //傳送命令給指定裝置

                            |- ap->ops->qc_prep(qc) --> ahci_qc_prep   //把ata cmd 轉換成fis

                                |- ata_tf_to_fis(&qc->tf, qc->dev->link->pmp, 1, cmd_tbl); 

                                |- ahci_fill_sg(qc, cmd_tbl);   //

                                |- ahci_fill_cmd_slot(pp, qc->tag, opts);    //

  &nbs