http://blog.csdn.net/suiyuan19840208/article/details/17562465
1：數據處理函數tasklet,workqueue
在之前的初始化代碼中的函數__ath_attach()中，有如下的代碼：#ifndef ATH_SUPPORT_HTC
#ifdef ADF_SUPPORT
ATH_INIT_TQUEUE(&osdev->intr_tq, (adf_os_defer_fn_t)ath_tasklet, (void*)dev);
#else
ATH_INIT_TQUEUE(&osdev->intr_tq, ath_tasklet, dev);
#endif
#endif
首先開看看 ATH_INIT_TQUEUE()是怎麼定義的：
#ifdef DECLARE_TASKLET /* native tasklets */
#define tq_struct tasklet_struct
#define ATH_INIT_TQUEUE(a,b,c) tasklet_init((a),(b),(unsigned long)(c))
#define ATH_SCHEDULE_TQUEUE(a,b) tasklet_schedule((a))
typedef unsigned long TQUEUE_ARG;
#define mark_bh(a)
#else /* immediate work queue */
#define ATH_INIT_TQUEUE(a,b,c) INIT_TQUEUE(a,b,c)
#define ATH_SCHEDULE_TQUEUE(a,b) do { \
*(b) |= queue_task((a), &tq_immediate); \
} while(0)
typedef void *TQUEUE_ARG;
#define tasklet_disable(t) do { (void) t; local_bh_disable(); } while (0)
#define tasklet_enable(t) do { (void) t; local_bh_enable(); } while (0)
#endif /* !DECLARE_TASKLET */
有上面的定義可以知道：次數定義的是中斷處理函數的下半部，其實現採用倆種方式：tasklet和work_queue。
在中斷處理函數中將會調用task或者queue的調度函數即上面定義的：ATH_SCHEDULE_TQUEUE
函數ath_tasklet()定義如下：
static void ath_tasklet(TQUEUE_ARG data)
{
struct net_device *dev = (struct net_device *)data;
struct ath_softc_net80211 *scn = ath_netdev_priv(dev);
do_ath_handle_intr(scn->sc_dev);
}
#define do_ath_handle_intr(_dev) do{ ath_handle_intr_generic(_dev);}while(0)
#define ath_handle_intr_generic(_dev) scn->sc_ops->handle_intr(_dev)
static const struct ath_ops ath_ar_ops = {
ath_handle_intr, /* handle_intr */
ath_rx_tasklet, /* rx_proc */
}
2:中斷的申請
在__ath_attach()有如下中斷申請代碼
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
if (request_irq(dev->irq, ath_isr, SA_SHIRQ, dev->name, dev)) {
#else
#ifdef ATH_AHB
if (request_irq(dev->irq, ath_isr, IRQF_DISABLED, dev->name, dev)) {
#else
if (request_irq(dev->irq, ath_isr, IRQF_SHARED, dev->name, dev)) {
#endif
#endif
printk(KERN_WARNING "%s: request_irq failed\n", dev->name);
error = -EIO;
goto bad3;
} 由此可知，中斷處理函數爲：
ath_isr(int irq, void *dev_id, struct pt_regs *regs)
{
do_ath_isr(irq,dev_id,regs);
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)
#define do_ath_isr(_irq,_dev_id) do{ return ath_isr_generic(_irq,_dev_id);}while(0)
#else
#define do_ath_isr(_irq,_dev_id,_regs) do{ return ath_isr_generic(_irq,_dev_id,_regs);}while(0)
#endif //if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)
irqreturn_t ath_isr_generic(int irq, void *dev_id, struct pt_regs *regs)
#endif
{
struct net_device *dev = dev_id;
struct ath_softc_net80211 *scn = ath_netdev_priv(dev);
int sched, needmark = 0;
/* always acknowledge the interrupt */
sched = scn->sc_ops->isr(scn->sc_dev);
switch(sched)
{
case ATH_ISR_NOSCHED:
return IRQ_HANDLED;
case ATH_ISR_NOTMINE:
return IRQ_NONE;
default:
if ((dev->flags & (IFF_RUNNING|IFF_UP)) != (IFF_RUNNING|IFF_UP))
{
DPRINTF_INTSAFE(scn, ATH_DEBUG_INTR, "%s: flags 0x%x\n", __func__, dev->flags);
scn->sc_ops->disable_interrupt(scn->sc_dev); /* disable further intr's */
return IRQ_HANDLED;
}
}
/*
** See if the transmit queue processing needs to be scheduled
*/
ATH_SCHEDULE_TQUEUE(&scn->sc_osdev->intr_tq, &needmark);
if (needmark)
mark_bh(IMMEDIATE_BH);
return IRQ_HANDLED;
}上面已經說明了在中斷處理函數中對tasklet或者workqueue的調度。
3:代碼執行流程
其代碼執行過程如下：
當數據數據之後，會交給函數ieee80211_input()，在測函數中會處理80211的三大數據包類似，數據幀，管理幀和控制幀。
