MTK的无线驱动代码流程分析

介绍

更好分析无线驱动代码在gitbub下的源代码：https://github.com/chaokw/mt7603e-p4rev-112670.git，有兴趣的可以下载下来看下
文章转自https://blog.csdn.net/u011212816/article/details/81137126

驱动流程

接下来直接讲述驱动的流程，加载内核模块ko之后会代码的入口xx_init_module_xx或者xx_module_init_xx函数作为代码初始入口

/*
	Driver module load/unload function
*/
int __init rt_pci_init_module(void)
{
	DBGPRINT(RT_DEBUG_ERROR, ("register %s\n", RTMP_DRV_NAME));

	/*add for initial hook callback function linking list*/
	RTMP_OS_TXRXHOOK_INIT();

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
	return pci_register_driver(&rt_pci_driver);
#else
    return pci_module_init(&rt_pci_driver);
#endif
}

由代码可见为PCI的驱动，主要查看rt_pci_driver中的.probe

/*
	PCI device probe & initialization function
*/
static int DEVINIT rt_pci_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
{
	...
	/* get DRIVER operations */
	RTMP_DRV_OPS_FUNCTION(pRtmpDrvOps, NULL, &PciConfig, NULL);
	....
	/*NetDevInit============================================== */
	net_dev = RtmpPhyNetDevInit(pAd, &netDevHook);
	rv = RtmpOSNetDevAttach(OpMode, net_dev, &netDevHook);
	....
}

RtmpPhyNetDevInit主要对网络设备初始化，对设备的operation进行赋值

	pNetDevHook->open = MainVirtualIF_open;
	pNetDevHook->stop = MainVirtualIF_close;
	pNetDevHook->xmit = rt28xx_send_packets;
	pNetDevHook->ioctl = rt28xx_ioctl;
	pNetDevHook->priv_flags = InfId; /*INT_MAIN; */
	pNetDevHook->get_stats = RT28xx_get_ether_stats;
	...

RtmpOSNetDevAttach主要设置适配内核的网络设备struct net_device

	pNetDev->open = pDevOpHook->open;
	pNetDev->stop = pDevOpHook->stop;
	pNetDev->hard_start_xmit =
		(HARD_START_XMIT_FUNC) (pDevOpHook->xmit);
	pNetDev->do_ioctl = pDevOpHook->ioctl;
	....
	ret = register_netdev(pNetDev);
	netif_stop_queue(pNetDev);

应用层命令调用ifconfig wlanX（ra） up无线接口，则会调用MainVirtualIF_open接口

int MainVirtualIF_open(struct net_device *net_dev)
{
....
	if (VIRTUAL_IF_UP(pAd) != 0)
		return -1;
....
//开启网络队列
	netif_start_queue(net_dev);
	netif_carrier_on(net_dev);
	netif_wake_queue(net_dev);

	return 0;
}

MainVirtualIF_open函数会通过ioclt最终调用rt28xx_open函数

int rt28xx_open(VOID *dev)
{
....
	/*
		Request interrupt service routine for PCI device
		register the interrupt routine with the os

		AP Channel auto-selection will be run in rt28xx_init(),
		so we must reqister IRQ hander here.
	*/
//开启硬件中断处理，主要RX
	RtmpOSIRQRequest(net_dev);

	/* Init IRQ parameters stored in pAd */
/*	rtmp_irq_init(pAd); */
	RTMP_DRIVER_IRQ_INIT(pAd);

	/* Chip & other init */
//主要设置mac以及数据帧处理定时器初始化
	if (rt28xx_init(pAd, mac, hostname) == FALSE)
		goto err;

//无线设置相关
	RT28xx_MBSS_Init(pAd, net_dev);
	RT28xx_WDS_Init(pAd, net_dev);
	RTMP_DRIVER_CFG80211_START(pAd);
....
	RTMPDrvOpen(pAd);//开启驱动底层，硬件相关的txrx
....
}

以上有三个比较重要的函数：

1. RtmpOSIRQRequest 注册中断服务，主要处理无线网卡的硬件中断用于收包
2. rt28xx_init 初始化驱动，读取配置文件和EEPROM就是在这个函数中
3. RTMPDrvOpen 开启终端，打开硬件开关等

int rt28xx_init()
{
....
	Status = RtmpNetTaskInit(pAd);//注册数据包kernel work
....	
	Status = RtmpMgmtTaskInit(pAd);//注册管理帧kernel work
	/* initialize MLME*/
	Status = MlmeInit(pAd);

	if (rtmp_cfg_init(pAd, pHostName) != TRUE)//读取配置文件.dat

	if (MCUSysInit(pAd) != NDIS_STATUS_SUCCESS)//load firmware

	/* hook e2p operation */
	RtmpChipOpsEepromHook(pAd, pAd->infType,E2P_NONE);//初始化chipops，为了读取EEPROM做准备
	
	/* We should read EEPROM for all cases */
	NICReadEEPROMParameters(pAd, (RTMP_STRING *)pDefaultMac);//读取EEPROM

	APStartUp(pAd);//初始化wdev，实际的发包函数
	
	MlmeRadioOn(pAd);

}

RtmpNetTaskInit函数

NDIS_STATUS RtmpNetTaskInit(RTMP_ADAPTER *pAd)
{
....
	RTMP_OS_TASKLET_INIT(pAd, &pObj->rx_done_task, rx_done_tasklet, (unsigned long)pAd);
....
	RTMP_OS_TASKLET_INIT(pAd, &pObj->bcn_dma_done_task, bcn_dma_done_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mt_mac_int_0_task, mt_mac_int_0_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mt_mac_int_1_task, mt_mac_int_1_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mt_mac_int_2_task, mt_mac_int_2_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mt_mac_int_3_task, mt_mac_int_3_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mt_mac_int_4_task, mt_mac_int_4_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->bmc_dma_done_task, bmc_dma_done_tasklet, (unsigned long)pAd);
	RTMP_OS_TASKLET_INIT(pAd, &pObj->mgmt_dma_done_task, mgmt_dma_done_tasklet, (unsigned long)pAd);
....
	RTMP_OS_TASKLET_INIT(pAd, &pObj->dfs_task, dfs_tasklet, (unsigned long)pAd);
....
}

rtmp_cfg_init 读取/var/Wireless/RT2860AP/RT2860AP.dat，配置无线

RTMPReadParametersHook //读取AP_PROFILE_PATH_RBUS 中的配置参数，可以看作是hostapd.conf

NICReadEEPROMParameters从flash或者eeprom中读取校准eeprom 值，具体在RtmpChipOpsEepromHook定义，调用rtmp_nv_init，之后将eeprom中的值配置到无线中

NDIS_STATUS rtmp_nv_init(RTMP_ADAPTER *pAd)
{
....
	RtmpFlashRead(pAd->eebuf, pAd->flash_offset, EEPROM_SIZE);
....
	return rtmp_ee_flash_init(pAd, pAd->eebuf);
}

APStartUp 中调用wdev_init，初始化wdev，可以看到发包的实际函数APHardTransmit

INT wdev_init(RTMP_ADAPTER *pAd, struct wifi_dev *wdev, UINT wdev_type)
{
....
	wdev->wdev_type = WDEV_TYPE_AP;

	wdev->tx_pkt_allowed = ApAllowToSendPacket;
	wdev->tx_pkt_handle = APSendPacket;
	wdev->wdev_hard_tx = APHardTransmit;
		
	wdev->rx_pkt_allowed = ap_rx_pkt_allow;
	wdev->rx_ps_handle = ap_rx_ps_handle;
	wdev->rx_pkt_foward = ap_rx_foward_handle;

	pMbss = (BSS_STRUCT *)wdev->func_dev;
....
}

无线收发包pNetDev->hard_start_xmit调用pNetDevHook->xmit = rt28xx_send_packets->rt28xx_packet_xmit->RTMPSendPackets->wdev_tx_pkts

INT wdev_tx_pkts(NDIS_HANDLE dev_hnd, PPNDIS_PACKET pkt_list, UINT pkt_cnt, struct wifi_dev *wdev)
{
....

	if (((wdev->allow_data_tx == TRUE) && (wdev->tx_pkt_allowed)) {
		allowToSend = wdev->tx_pkt_allowed(pAd, wdev, pPacket, &wcid);
	}
	else {
		allowToSend = FALSE;
		//RELEASE_NDIS_PACKET(pAd, pPacket, NDIS_STATUS_FAILURE);
	}

	if (allowToSend == TRUE)
	{
		if (wdev->tx_pkt_handle)
			wdev->tx_pkt_handle(pAd, pPacket);
		else
		{
			DBGPRINT(RT_DEBUG_ERROR, ("%s():tx_pkt_handle not assigned!\n", __FUNCTION__));
			RELEASE_NDIS_PACKET(pAd, pPacket, NDIS_STATUS_FAILURE);
		}
	}

	RTMPDeQueuePacket(pAd, FALSE, NUM_OF_TX_RING, WCID_ALL, MAX_TX_PROCESS);
....
}

wdev_tx_pkts中比较重要的函数有三个：tx_pkt_allowed；tx_pkt_handle；RTMPDeQueuePacket
前两个函数是在之前APStartUp 中调用wdev_init 初始化的，分别对应的函数是

wdev->tx_pkt_allowed = ApAllowToSendPacket;
wdev->tx_pkt_handle = APSendPacket;

ApAllowToSendPacket检查目的mac是否是关联的设备，如果是就允许，不是就不允许

INT APSendPacket(RTMP_ADAPTER *pAd, PNDIS_PACKET pPacket)
{
....
	RTMP_SET_PACKET_FRAGMENTS(pPacket, NumberOfFrag);

	if (pAd->TxSwQueue[QueIdx].Number >= pAd->TxSwQMaxLen)
	{
		{
#ifdef BLOCK_NET_IF
			StopNetIfQueue(pAd, QueIdx, pPacket);
#endif /* BLOCK_NET_IF */
			drop_reason = DROP_TXQ_FULL;
			goto drop_pkt;
		}
	}

		if (rtmp_enq_req(pAd, pPacket, QueIdx, tr_entry, FALSE,NULL) == FALSE) {
			drop_reason = DROP_TXQ_ENQ_FAIL;
			goto drop_pkt;
		}
....
}

报文入队后，调用RTMPDeQueuePacket 对各队列中的报文进行发包处理，其中实际调用的发包函数为wdev_init中定义的APHardTransmit，驱动实际的发包函数发往硬件

VOID RTMPDeQueuePacket()
{
....

	do
	{
		DEQUEUE_LOCK(&pAd->irq_lock, in_hwIRQ, IrqFlags);//加锁
		rtmp_deq_req(pAd, max_cnt, &deq_info);

		RTMP_START_DEQUEUE(pAd, QueIdx, IrqFlags);
		deq_packet_gatter(pAd, &deq_info, pTxBlk, in_hwIRQ);
		if (pTxBlk->wdev && pTxBlk->wdev->wdev_hard_tx) {
			pTxBlk->wdev->wdev_hard_tx(pAd, pTxBlk);//调用APHardTransmit
		}
		RTMP_STOP_DEQUEUE(pAd, QueIdx, IrqFlags);
		rtmp_deq_report(pAd, &deq_info);
		DEQUEUE_UNLOCK(&pAd->irq_lock, in_hwIRQ, IrqFlags);//解锁

		if (round >= 1024) {//最多循环1024
			DBGPRINT(RT_DEBUG_OFF, ("%s():ForceToBreak!!Buggy here?\n", __FUNCTION__));
			break;
		}
	}while(1);
....
}

无线收包
之前在无线接口 open的时候我们讲到 调用RtmpOSIRQRequest注册了中断服务

request_irq(pci_dev->irq,  rt2860_interrupt, SA_SHIRQ, (net_dev)->name, (net_dev));

硬件收到包之后会触发中断处理函数rt2860_interrupt->RTMPHandleInterrupt

VOID RTMPHandleInterrupt(VOID *pAdSrc)
{
....
		if (pAd->chipCap.hif_type == HIF_MT)
		{
			/* Fix Rx Ring FULL lead DMA Busy, when DUT is in reset stage */
        		IntSource = IntSource & (MT_INT_CMD | MT_INT_RX | WF_MAC_INT_3);
		}
....
	if (IntSource & INT_RX_DATA)
	{
		pAd->RxDMACheckTimes = 0;
		pAd->RxPseCheckTimes = 0;
		if ((pAd->int_disable_mask & INT_RX_DATA) == 0)
		{
			rt2860_int_disable(pAd, INT_RX_DATA);
			RTMP_OS_TASKLET_SCHE(&pObj->rx_done_task);
		}
		pAd->int_pending |= INT_RX_DATA;
	}
....
}

而rx_done_task 在 RtmpNetTaskInit中已经定义了tasklet 的function：rx_done_tasklet，调用rtmp_rx_done_handle

BOOLEAN rtmp_rx_done_handle(RTMP_ADAPTER *pAd)
{
....
	pRxPacket = GetPacketFromRxRing(pAd, pRxBlk, &bReschedule, &RxPending, 0);
....
	switch (pHeader->FC.Type)
	{
		case FC_TYPE_DATA:
			dev_rx_data_frm(pAd, &rxblk);
			break;

		case FC_TYPE_MGMT:
			dev_rx_mgmt_frm(pAd, &rxblk);
			break;

		case FC_TYPE_CNTL:
			dev_rx_ctrl_frm(pAd, &rxblk);
			break;

		default:
			RELEASE_NDIS_PACKET(pAd, pRxPacket, NDIS_STATUS_FAILURE);
			break;
	}
....
}

dev_rx_data_frm函数的调用栈如下，到达netif_rx就到了网络协议栈了，这里没考虑ampdu，forward等情况，只是简单列下调用过程

dev_rx_data_frm()
    ---rx_data_frm_announce()
        ---Indicate_Legacy_Packet()
            ---Announce_or_Forward_802_3_Packet()
                ---announce_802_3_packet()
                    ---RtmpOsPktRcvHandle()
                        ---netif_rx()