【linux驱动分析】之dm9000驱动分析（七）：dm9000的卸载挂起和恢复以及打开和停止

 1 static int __devexit
 2   dm9000_drv_remove(struct platform_device *pdev)
 3 static int
 4  dm9000_drv_suspend(struct device *dev)
 5 static int
 6  dm9000_drv_resume(struct device *dev)
 7 static int
 8  dm9000_open(struct net_device *dev)
 9 static int
10  dm9000_stop(struct net_device *ndev)

一、卸载驱动

驱动中可以看到，在模块卸载时执行

platform_driver_unregister(&dm9000_driver);

在卸载platform_driver时会执行remove函数，remove函数的功能是把设备从内核中移除，释放内存区域。下面给出dm9000_drv_remove函数的代码：

 1 static int __devexit
 2 dm9000_drv_remove(struct platform_device *pdev)
 3 {
 4     struct net_device *ndev = platform_get_drvdata(pdev);
 5 
 6  platform_set_drvdata(pdev, NULL);
 7 
 8  unregister_netdev(ndev);
 9  dm9000_release_board(pdev, netdev_priv(ndev));
10     free_netdev(ndev);        /* free device structure */
11 
12     dev_dbg(&pdev->dev, "released and freed device\n");
13     return 0;
14 }
15 
16 
17 /* dm9000_release_board
18  *
19  * release a board, and any mapped resources
20  */
21 
22 static void
23 dm9000_release_board(struct platform_device *pdev, struct board_info *db)
24 {
25     /* unmap our resources */
26 
27     iounmap(db->io_addr);
28     iounmap(db->io_data);
29 
30     /* release the resources */
31 
32     release_resource(db->data_req);
33     kfree(db->data_req);
34 
35     release_resource(db->addr_req);
36     kfree(db->addr_req);
37 }

二、关于电源管理的设备的挂起和恢复函数

suspend函数并不真正把设备从内核中移除，而只是标志设备为removed状态，并设置挂起标志位为1，最后关闭设备。
resume函数将挂起的设备复位并初始化，软后将设备标志为attached状态，并设置挂起标志位为0。
 1 static int
 2 dm9000_drv_suspend(struct device *dev)
 3 {
 4     struct platform_device *pdev = to_platform_device(dev);
 5     struct net_device *ndev = platform_get_drvdata(pdev);
 6     board_info_t *db;
 7 
 8     if (ndev) {
 9         db = netdev_priv(ndev);
10         db->in_suspend = 1;
11 
12         if (!netif_running(ndev))
13             return 0;
14 
15  netif_device_detach(ndev);
16 
17         /* only shutdown if not using WoL */
18         if (!db->wake_state)
19  dm9000_shutdown(ndev);
20  }
21     return 0;
22 }
23 
24 static int
25 dm9000_drv_resume(struct device *dev)
26 {
27     struct platform_device *pdev = to_platform_device(dev);
28     struct net_device *ndev = platform_get_drvdata(pdev);
29     board_info_t *db = netdev_priv(ndev);
30 
31     if (ndev) {
32         if (netif_running(ndev)) {
33             /* reset if we were not in wake mode to ensure if
34  * the device was powered off it is in a known state */
35             if (!db->wake_state) {
36  dm9000_reset(db);
37  dm9000_init_dm9000(ndev);
38  }
39 
40  netif_device_attach(ndev);
41  }
42 
43         db->in_suspend = 0;
44  }
45     return 0;
46 }
三、dm9000的打开和停止
1、打开函数dm9000_open
 1 /* 2  * Open the interface. 3  * The interface is opened whenever "ifconfig" actives it. 4  */ 5 static int 6 dm9000_open(struct net_device *dev) 7 { 8     board_info_t *db = netdev_priv(dev); 9     unsigned long irqflags = db->irq_res->flags & IRQF_TRIGGER_MASK;10 11     /* db结构体中的成员msg_enble,在probe函数中赋值为NETIF_MSG_LINK */12     if (netif_msg_ifup(db))13         dev_dbg(db->dev, "enabling %s\n", dev->name);14 15     /* If there is no IRQ type specified, default to something that16  * may work, and tell the user that this is a problem */17 18     if (irqflags == IRQF_TRIGGER_NONE)19         dev_warn(db->dev, "WARNING: no IRQ resource flags set.\n");20 21     irqflags |= IRQF_SHARED;22     /* 申请中断，中断函数dm9000_interrupt */23     if (request_irq(dev->irq, dm9000_interrupt, irqflags, dev->name, dev))24         return -EAGAIN;25 26     /* GPIO0 on pre-activate PHY, Reg 1F is not set by reset */27     iow(db, DM9000_GPR, 0);    /* REG_1F bit0 activate phyxcer */28     mdelay(1); /* delay needs by DM9000B */29 30     /* Initialize DM9000 board */31  dm9000_reset(db);32     /* dm9000初始化，下面会对这个函数做详细分析 */33  dm9000_init_dm9000(dev);34 35     /* Init driver variable */36     db->dbug_cnt = 0;37 38     /* 检查mii接口 39  * Returns 1 if the duplex mode changed, 0 if not.40  * If the media type is forced, always returns 0.41  * */42     mii_check_media(&db->mii, netif_msg_link(db), 1);43     /* 开启网络接口数据发送队列 */44  netif_start_queue(dev);45     /*延时一段时间执行dm9000_poll_work，原来在probe函数里把这个函数加入了工作队列，现在来调度执行*/46  dm9000_schedule_poll(db);47 48     return 0;49 }2、dm9000_init_dm9000函数
 1 /* 2  * Initialize dm9000 board 3  */ 4 static void 5 dm9000_init_dm9000(struct net_device *dev) 6 { 7     board_info_t *db = netdev_priv(dev); 8     unsigned int imr; 9     unsigned int ncr;10 11     dm9000_dbg(db, 1, "entering %s\n", __func__);12 13     /* I/O mode */14     db->io_mode = ior(db, DM9000_ISR) >> 6;    /* ISR bit7:6 keeps I/O mode */15 16     /* Checksum mode */17     dm9000_set_rx_csum_unlocked(dev, db->rx_csum);18 19     iow(db, DM9000_GPCR, GPCR_GEP_CNTL);    /* Let GPIO0 output */20 21     ncr = (db->flags & DM9000_PLATF_EXT_PHY) ? NCR_EXT_PHY : 0;22 23     /* if wol is needed, then always set NCR_WAKEEN otherwise we end24  * up dumping the wake events if we disable this. There is already25  * a wake-mask in DM9000_WCR */26     if (db->wake_supported)27         ncr |= NCR_WAKEEN;28 29  iow(db, DM9000_NCR, ncr);30 31     /* Program operating register */32     iow(db, DM9000_TCR, 0);            /* TX Polling clear */33     iow(db, DM9000_BPTR, 0x3f);    /* Less 3Kb, 200us */34     iow(db, DM9000_FCR, 0xff);    /* Flow Control */35     iow(db, DM9000_SMCR, 0);        /* Special Mode */36     /* clear TX status */37     iow(db, DM9000_NSR, NSR_WAKEST | NSR_TX2END | NSR_TX1END);38     iow(db, DM9000_ISR, ISR_CLR_STATUS); /* Clear interrupt status */39 40     /* Set address filter table */41  dm9000_hash_table_unlocked(dev);42 43     imr = IMR_PAR | IMR_PTM | IMR_PRM;44     if (db->type != TYPE_DM9000E)45         imr |= IMR_LNKCHNG;46 47     db->imr_all = imr;48 49     /* Enable TX/RX interrupt mask */50  iow(db, DM9000_IMR, imr);51 52     /* Init Driver variable */53     db->tx_pkt_cnt = 0;54     db->queue_pkt_len = 0;55     dev->trans_start = jiffies;56 }3、停止函数dm9000_stop它会做与dm9000_stop相反的事情。
 1 /* 2  * Stop the interface. 3  * The interface is stopped when it is brought. 4  */ 5 static int 6 dm9000_stop(struct net_device *ndev) 7 { 8     board_info_t *db = netdev_priv(ndev); 9 10     if (netif_msg_ifdown(db))11         dev_dbg(db->dev, "shutting down %s\n", ndev->name);12 13     cancel_delayed_work_sync(&db->phy_poll);14 15  netif_stop_queue(ndev);16  netif_carrier_off(ndev);17 18     /* free interrupt */19     free_irq(ndev->irq, ndev);20 21  dm9000_shutdown(ndev);22 23     return 0;24 }