DM9000驱动分析之初始化

/*分析DM9000网卡驱动之初始化*/

/*找到DM9000.c   文件路径: linux/drivers/net下
  
  找到模块的入口函数处
*/

static int __init
dm9000_init(void)
{
	printk(KERN_INFO "%s Ethernet Driver, V%s\n", CARDNAME, DRV_VERSION);

	return platform_driver_register(&dm9000_driver);
}

/*很明显DM9000是platform驱动。 既然DM9000是平台驱动，那当然也就有平台设备了*/

/*平台驱动结构初始化*/
static struct platform_driver dm9000_driver = {
	.driver	= {
		.name    = "dm9000",
		.owner	 = THIS_MODULE,
		.pm	 = &dm9000_drv_pm_ops,
	},
	.probe   = dm9000_probe,
	.remove  = __devexit_p(dm9000_drv_remove),
};

/*平台设备结构初始化： 路径： arch\arm\mach-s3c64xx\Mach-smdk6410*/
static struct platform_device s3c_device_dm9000 = {
	.name			= "dm9000",
	.id				= 0,
	.num_resources	= ARRAY_SIZE(dm9000_resources),
	.resource		= dm9000_resources,
	.dev			= {
		.platform_data = &dm9000_setup,
	}
};


/*当平台设备与驱动相匹配后，就会调用dm9000_probe函数*/

/*
 * Search DM9000 board, allocate space and register it
 *
 *从注释上可以得出： 这个函数主要是找到DM9000设备，然后分配空间，然后注册
 *
 *  1. 分配 	net_device结构 
 *  2. 初始化board_info结构
 *  3. 获得DM9000的资源。包括DM9000的内存和中断资源
 *  4. 地址映射
 *  5. 初始化net_device的基地址和中断号
 *  6. 重启DM9000设备
 *  7. 获取DM9000的版本
 *  8. 注册net_device结构
 */
static int __devinit
dm9000_probe(struct platform_device *pdev)
{
	struct dm9000_plat_data *pdata = pdev->dev.platform_data;
	struct board_info *db;	/* Point a board information structure */
	struct net_device *ndev;
	const unsigned char *mac_src;
	int ret = 0;
	int iosize;
	int i;
	u32 id_val;

	/* Init network device */
	//分配 	net_device结构 
	ndev = alloc_etherdev(sizeof(struct board_info));
	if (!ndev) {
		dev_err(&pdev->dev, "could not allocate device.\n");
		return -ENOMEM;
	}

	SET_NETDEV_DEV(ndev, &pdev->dev);

	dev_dbg(&pdev->dev, "dm9000_probe()\n");

	/* setup board info structure */
	//初始化board_info结构
	db = netdev_priv(ndev);

	db->dev = &pdev->dev;
	db->ndev = ndev;

	spin_lock_init(&db->lock);
	mutex_init(&db->addr_lock);

	INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);

	//获得DM9000的资源。包括DM9000的内存和中断资源
	db->addr_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	db->data_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	db->irq_res  = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (db->addr_res == NULL || db->data_res == NULL ||
	    db->irq_res == NULL) {
		dev_err(db->dev, "insufficient resources\n");
		ret = -ENOENT;
		goto out;
	}

	db->irq_wake = platform_get_irq(pdev, 1);
	if (db->irq_wake >= 0) {
		dev_dbg(db->dev, "wakeup irq %d\n", db->irq_wake);

		ret = request_irq(db->irq_wake, dm9000_wol_interrupt,
				  IRQF_SHARED, dev_name(db->dev), ndev);
		if (ret) {
			dev_err(db->dev, "cannot get wakeup irq (%d)\n", ret);
		} else {

			/* test to see if irq is really wakeup capable */
			ret = irq_set_irq_wake(db->irq_wake, 1);
			if (ret) {
				dev_err(db->dev, "irq %d cannot set wakeup (%d)\n",
					db->irq_wake, ret);
				ret = 0;
			} else {
				irq_set_irq_wake(db->irq_wake, 0);
				db->wake_supported = 1;
			}
		}
	}

  //地址映射
	iosize = resource_size(db->addr_res);
	db->addr_req = request_mem_region(db->addr_res->start, iosize,
					  pdev->name);

	if (db->addr_req == NULL) {
		dev_err(db->dev, "cannot claim address reg area\n");
		ret = -EIO;
		goto out;
	}

	db->io_addr = ioremap(db->addr_res->start, iosize);

	if (db->io_addr == NULL) {
		dev_err(db->dev, "failed to ioremap address reg\n");
		ret = -EINVAL;
		goto out;
	}

	iosize = resource_size(db->data_res);
	db->data_req = request_mem_region(db->data_res->start, iosize,
					  pdev->name);

	if (db->data_req == NULL) {
		dev_err(db->dev, "cannot claim data reg area\n");
		ret = -EIO;
		goto out;
	}

	db->io_data = ioremap(db->data_res->start, iosize);

	if (db->io_data == NULL) {
		dev_err(db->dev, "failed to ioremap data reg\n");
		ret = -EINVAL;
		goto out;
	}

	/* fill in parameters for net-dev structure */
	//初始化net_device的基地址和中断号
	ndev->base_addr = (unsigned long)db->io_addr;
	ndev->irq	= db->irq_res->start;

	/* ensure at least we have a default set of IO routines */
	
	dm9000_set_io(db, iosize);

	/* check to see if anything is being over-ridden */
	if (pdata != NULL) {
		/* check to see if the driver wants to over-ride the
		 * default IO width */

		if (pdata->flags & DM9000_PLATF_8BITONLY)
			dm9000_set_io(db, 1);

		if (pdata->flags & DM9000_PLATF_16BITONLY)
			dm9000_set_io(db, 2);

		if (pdata->flags & DM9000_PLATF_32BITONLY)
			dm9000_set_io(db, 4);

		/* check to see if there are any IO routine
		 * over-rides */

		if (pdata->inblk != NULL)
			db->inblk = pdata->inblk;

		if (pdata->outblk != NULL)
			db->outblk = pdata->outblk;

		if (pdata->dumpblk != NULL)
			db->dumpblk = pdata->dumpblk;

		db->flags = pdata->flags;
	}

#ifdef CONFIG_DM9000_FORCE_SIMPLE_PHY_POLL
	db->flags |= DM9000_PLATF_SIMPLE_PHY;
#endif

//重启DM9000设备
	dm9000_reset(db);

	/* try multiple times, DM9000 sometimes gets the read wrong */
	//判断DM9000的id是否正确，如果正确则说明找到了DM9000设备
	for (i = 0; i < 8; i++) {
		id_val  = ior(db, DM9000_VIDL);
		id_val |= (u32)ior(db, DM9000_VIDH) << 8;
		id_val |= (u32)ior(db, DM9000_PIDL) << 16;
		id_val |= (u32)ior(db, DM9000_PIDH) << 24;

		if (id_val == DM9000_ID)
			break;
		dev_err(db->dev, "read wrong id 0x%08x\n", id_val);
	}

	if (id_val != DM9000_ID) {
		dev_err(db->dev, "wrong id: 0x%08x\n", id_val);
		ret = -ENODEV;
		goto out;
	}

	/* Identify what type of DM9000 we are working on */

	//获取DM9000的chipID， 判断是那种类型
	id_val = ior(db, DM9000_CHIPR);
	dev_dbg(db->dev, "dm9000 revision 0x%02x\n", id_val);

	switch (id_val) {
	case CHIPR_DM9000A:
		db->type = TYPE_DM9000A;
		break;
	case CHIPR_DM9000B:
		db->type = TYPE_DM9000B;
		break;
	default:
		dev_dbg(db->dev, "ID %02x => defaulting to DM9000E\n", id_val);
		db->type = TYPE_DM9000E;
	}

	/* dm9000a/b are capable of hardware checksum offload */
	if (db->type == TYPE_DM9000A || db->type == TYPE_DM9000B) {
		ndev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
		ndev->features |= ndev->hw_features;
	}

	/* from this point we assume that we have found a DM9000 */
	/*从这里意味着找到了DM9000设备*/

	/* driver system function */
	/*初始化ndev结构*/
	ether_setup(ndev);

	ndev->netdev_ops	= &dm9000_netdev_ops;
	ndev->watchdog_timeo	= msecs_to_jiffies(watchdog);
	ndev->ethtool_ops	= &dm9000_ethtool_ops;

	db->msg_enable       = NETIF_MSG_LINK;
	db->mii.phy_id_mask  = 0x1f;
	db->mii.reg_num_mask = 0x1f;
	db->mii.force_media  = 0;
	db->mii.full_duplex  = 0;
	db->mii.dev	     = ndev;
	db->mii.mdio_read    = dm9000_phy_read;
	db->mii.mdio_write   = dm9000_phy_write;

	mac_src = "eeprom";

	/* try reading the node address from the attached EEPROM */
	for (i = 0; i < 6; i += 2)
		dm9000_read_eeprom(db, i / 2, ndev->dev_addr+i);

	if (!is_valid_ether_addr(ndev->dev_addr) && pdata != NULL) {
		mac_src = "platform data";
		memcpy(ndev->dev_addr, pdata->dev_addr, 6);
	}

	if (!is_valid_ether_addr(ndev->dev_addr)) {
		/* try reading from mac */
		
		mac_src = "chip";
		for (i = 0; i < 6; i++)
			ndev->dev_addr[i] = ior(db, i+DM9000_PAR);
	}

	if (!is_valid_ether_addr(ndev->dev_addr)) {
		dev_warn(db->dev, "%s: Invalid ethernet MAC address. Please "
			 "set using ifconfig\n", ndev->name);

		random_ether_addr(ndev->dev_addr);
		mac_src = "random";
	}


	/*注册ndev结构*/
	platform_set_drvdata(pdev, ndev);
	ret = register_netdev(ndev);

	if (ret == 0)
		printk(KERN_INFO "%s: dm9000%c at %p,%p IRQ %d MAC: %pM (%s)\n",
		       ndev->name, dm9000_type_to_char(db->type),
		       db->io_addr, db->io_data, ndev->irq,
		       ndev->dev_addr, mac_src);
	return 0;

out:
	dev_err(db->dev, "not found (%d).\n", ret);

	dm9000_release_board(pdev, db);
	free_netdev(ndev);

	return ret;
}

/*我们似乎发现，和硬件相关的设置很少。难道不用设置硬件？ 其实不然
 当我们使用ifconfig的时候，会调用ndev->ndev_ops中open函数设置必要的参数
*/

/*
 *  Open the interface.
 *  The interface is opened whenever "ifconfig" actives it.
 * 
 *  从注释中看出当使用ifconfig就会激活网卡设备 
 *
 */
static int
dm9000_open(struct net_device *dev)
{
	board_info_t *db = netdev_priv(dev);
	unsigned long irqflags = db->irq_res->flags & IRQF_TRIGGER_MASK;

	if (netif_msg_ifup(db))
		dev_dbg(db->dev, "enabling %s\n", dev->name);

	/* If there is no IRQ type specified, default to something that
	 * may work, and tell the user that this is a problem */

	if (irqflags == IRQF_TRIGGER_NONE)
		dev_warn(db->dev, "WARNING: no IRQ resource flags set.\n");

	irqflags |= IRQF_SHARED;

	/* GPIO0 on pre-activate PHY, Reg 1F is not set by reset */
	iow(db, DM9000_GPR, 0);	/* REG_1F bit0 activate phyxcer */		/*power up PHY*/
	mdelay(1); /* delay needs by DM9000B */

	/* Initialize DM9000 board */
	dm9000_reset(db);                    //初始化DM9000
	dm9000_init_dm9000(dev);

	//注册Dm9000中断
	if (request_irq(dev->irq, dm9000_interrupt, irqflags, dev->name, dev))							
		return -EAGAIN;

	/* Init driver variable */
	db->dbug_cnt = 0;

	mii_check_media(&db->mii, netif_msg_link(db), 1);
	netif_start_queue(dev);												//启动发生队列
	
	dm9000_schedule_poll(db);

	return 0;
}

/*分析 DM9000重启函数*
	写0到NCR寄存器的第0位就可以重新启动。软件复位
*/
static void
dm9000_reset(board_info_t * db)
{
	dev_dbg(db->dev, "resetting device\n");

	/* RESET device */
	writeb(DM9000_NCR, db->io_addr);//告诉DM9000地址端口为Network Control Register这个寄存器
	udelay(200);
	writeb(NCR_RST, db->io_data);	//写0到RST位，
	udelay(200);
}


/*
 * Initialize dm9000 board
 * 这个函数才是真正意义上的硬件初始化
 * 这个函数注释很详细，不用解释
 */
static void
dm9000_init_dm9000(struct net_device *dev)
{
	board_info_t *db = netdev_priv(dev);
	unsigned int imr;
	unsigned int ncr;

	dm9000_dbg(db, 1, "entering %s\n", __func__);

	/* I/O mode */
	db->io_mode = ior(db, DM9000_ISR) >> 6;	/* ISR bit7:6 keeps I/O mode */

	/* Checksum mode */
	if (dev->hw_features & NETIF_F_RXCSUM)
		iow(db, DM9000_RCSR,
			(dev->features & NETIF_F_RXCSUM) ? RCSR_CSUM : 0);

	iow(db, DM9000_GPCR, GPCR_GEP_CNTL);	/* Let GPIO0 output */

	ncr = (db->flags & DM9000_PLATF_EXT_PHY) ? NCR_EXT_PHY : 0;

	/* if wol is needed, then always set NCR_WAKEEN otherwise we end
	 * up dumping the wake events if we disable this. There is already
	 * a wake-mask in DM9000_WCR */
	if (db->wake_supported)
		ncr |= NCR_WAKEEN;

	iow(db, DM9000_NCR, ncr); //设置内部PHY

	/* Program operating register */
	iow(db, DM9000_TCR, 0);	        /* TX Polling clear */
	iow(db, DM9000_BPTR, 0x3f);	/* Less 3Kb, 200us */
	iow(db, DM9000_FCR, 0xff);	/* Flow Control */
	iow(db, DM9000_SMCR, 0);        /* Special Mode */
	/* clear TX status */
	iow(db, DM9000_NSR, NSR_WAKEST | NSR_TX2END | NSR_TX1END);
	iow(db, DM9000_ISR, ISR_CLR_STATUS); /* Clear interrupt status */

	/* Set address filter table */
	dm9000_hash_table_unlocked(dev);

	imr = IMR_PAR | IMR_PTM | IMR_PRM;
	if (db->type != TYPE_DM9000E)
		imr |= IMR_LNKCHNG;

	db->imr_all = imr;

	/* Enable TX/RX interrupt mask */
	iow(db, DM9000_IMR, imr);

	/* Init Driver variable */
	db->tx_pkt_cnt = 0;
	db->queue_pkt_len = 0;
	dev->trans_start = jiffies;
}


/*
 总结：
 *  1. 分配 	net_device结构 
 *  2. 初始化board_info结构
 *  3. 获得DM9000的资源。包括DM9000的内存和中断资源
 *  4. 地址映射
 *  5. 初始化net_device的基地址和中断号
 *  6. 重启DM9000设备
 *  7. 获取DM9000的版本
 *  8. 注册net_device结构
 *  9. 硬件相关的初始化
 * 10. 注册Dm9000中断
 * 11. 启动发送队列
*/