Linux Device Drivers Development

Workqueue as bottom halves

Let's just start with a sample:

static DECLARE_WAIT_QUEUE_HEAD(my_wq);  /* declare and init the wait queue */ 
static struct work_struct my_work; 
 
/* some where in the probe function */ 
/* 
 * work queue initialization. "work_handler" is the call back that will be 
 * executed when our work is scheduled. 
 */ 
INIT_WORK(my_work, work_handler); 
 
static irqreturn_t my_interrupt_handler(int irq, void *dev_id) 
{ 
    uint32_t val; 
    struct my_data = dev_id; 
 
    val = readl(my_data->reg_base + REG_OFFSET); 
   if (val == 0xFFCD45EE)) { 
       my_data->done = true; 
         wake_up_interruptible(&my_wq); 
   } else { 
         schedule_work(&my_work); 
   } 
 
   return IRQ_HANDLED; 
}; 

In the preceding sample, we used either a wait queue or a work queue in order to wake up a possibly ...