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QmsgSend called in ISR to insert in
circular queue & QmsgWait called in ur tasklet to pick(spin locked
operation) from queue. Irqreturn_t InterruptServiceRoutine( …………..) { …………. /*device handling */ ………. QmsgSend(); Return IRQ_HANDLED; } #define QUEUE_DEPTH XYZ /* Should
depend on Int queue[QUEUE_DEPTH]; Unsigned Q_head, Q_tail, Q_entries; #define QmsgSend() \ If(Q_entries == QUEUE_DEPTH) \ Panic(overflow); \ Queue[Q_tail] = “data from the
device register”; \ Q_tail = (Q_tail + 1) % QUEUE_DEPTH; \ Q_entries ++; Tasklet_schedule(&isr_tasklet) #define QmsgWait(x) \ Spin_lock_irqsave(&x, flags);
\ If(!Q_entries){ \ Spin_lock_irqsave(&x,flags);
break;} \ “data from device register”
= queue[Q_head]; \ Q_head = (Q_head + 1 ) % QUEUE_DEPTH ;
\ Q_entries --; \ Spin_unlock_irqsave(&x, flags); From: Olav Torheim
[mailto:olaveth@xxxxxxxxx] Thanks for answering. Do you have any concrete code examples of
how this can be done? Olav On 9/15/05, Aggarwal,
Vikas (OFT) <Vikas.Aggarwal@xxxxxxxxxxxxxxx>
wrote:
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by reply e-mail and delete the e-mail from your system. From: kernelnewbies-bounce@xxxxxxxxxxxx
[mailto:kernelnewbies-bounce@xxxxxxxxxxxx]
On Behalf Of Olav Torheim Hi all Right now
I am trying to create a driver for a PCI card. The PCI card uses interrupt to
report back to the processor when a DMA transfer has occured. When the the
interrupt service routine is fired, it checks the interrupt status register on
the device. If the status register equals anything else than 0, the service
routine goes on placing a new task on the kerneld task queue with the return
value from the interrupt status register as part of the task context. So far so
good. My only problem is, what if the device fires another interrupt while the
scheduled task is waiting in the task queue. Interrupts are still enabled in my
current design, so I am afraid that the interrupt service routine is simply
going to change the context of the waiting task and the former interrupt request
will be "forgotten" by the device... What is
the best solution to this problem? Disable interrupts while waiting for the
scheduled task to run? Adding more logic to the interrupt service routine, for
example a counter keeping track of how many interrupt requests have been
detected since the last time the task was scheduled? Invoking a separate task
for each interrupt request? I hope
somebody can give me some advice. Olav
Torheim Source
code is shown below: /* Setup
the task structure for the rorcdriver_dispatcher routine. /* The
interrupt service routine schedules the dispatcher to service the request from
the device. u32 ireg; };
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