Interrupt Handler of Ethernet Device

Interrupt Handler of Ethernet Device

[Robert Clove]

Hello All,


I am new here.
I want to know the interrupt handler of the ethernet card and where can i
find the definition of it so as i can clear the flow of packet reception.

Thanks
Robert
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Interrupt Handler of Ethernet Device

[Rami Rosen]

Robert,
You should look for the request_irq() method in the driver.
This method registers an interrupt handler.
For example, you can look in:
http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
...
...
    if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
                 nic->netdev->name, nic->netdev)))

...

This means that e100_intr is registered as an interrupt handler.

Best,
Rami Rosen
http://ramirose.wix.com/ramirosen


On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com> wrote:
> Hello All,
>
>
> I am new here.
> I want to know the interrupt handler of the ethernet card and where can i
> find the definition of it so as i can clear the flow of packet reception.
>
> Thanks
> Robert
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

Interrupt Handler of Ethernet Device

[Robert Clove]

Thanks for the link.
I have another query too......should i ask right now?


On Fri, Apr 5, 2013 at 5:36 PM, Rami Rosen <roszenrami@gmail.com> wrote:

> Robert,
> You should look for the request_irq() method in the driver.
> This method registers an interrupt handler.
> For example, you can look in:
> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
> ...
> ...
>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
>                  nic->netdev->name, nic->netdev)))
>
> ...
>
> This means that e100_intr is registered as an interrupt handler.
>
> Best,
> Rami Rosen
> http://ramirose.wix.com/ramirosen
>
>
> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com>
> wrote:
> > Hello All,
> >
> >
> > I am new here.
> > I want to know the interrupt handler of the ethernet card and where can i
> > find the definition of it so as i can clear the flow of packet reception.
> >
> > Thanks
> > Robert
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
>
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Interrupt Handler of Ethernet Device

[Anuz Pratap Singh Tomar]

On Fri, Apr 5, 2013 at 1:11 PM, Robert Clove <cloverobert@gmail.com> wrote:

> Thanks for the link.
> I have another query too......should i ask right now?
>
>
> If the question is relevant to current discussion, please ask here but if
it just piggyback to totally different topic at hand make a new thread.
Also in case of doubt:
http://www.catb.org/esr/faqs/smart-questions.html

On Fri, Apr 5, 2013 at 5:36 PM, Rami Rosen <roszenrami@gmail.com> wrote:
>
>> Robert,
>> You should look for the request_irq() method in the driver.
>> This method registers an interrupt handler.
>> For example, you can look in:
>> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
>> ...
>> ...
>>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
>>                  nic->netdev->name, nic->netdev)))
>>
>> ...
>>
>> This means that e100_intr is registered as an interrupt handler.
>>
>> Best,
>> Rami Rosen
>> http://ramirose.wix.com/ramirosen
>>
>>
>> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com>
>> wrote:
>> > Hello All,
>> >
>> >
>> > I am new here.
>> > I want to know the interrupt handler of the ethernet card and where can
>> i
>> > find the definition of it so as i can clear the flow of packet
>> reception.
>> >
>> > Thanks
>> > Robert
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >
>>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>


-- 
Thank you
Warm Regards
Anuz
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Interrupt Handler of Ethernet Device

[ishare]

On Fri, Apr 05, 2013 at 03:06:37PM +0300, Rami Rosen wrote:
> Robert,
> You should look for the request_irq() method in the driver.
> This method registers an interrupt handler.
> For example, you can look in:
> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
> ...
> ...
>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
>                  nic->netdev->name, nic->netdev)))
> 
> ...
> 
> This means that e100_intr is registered as an interrupt handler.

  Is this nic->netdev represent a  Ethernet interface ?

  
> 
> Best,
> Rami Rosen
> http://ramirose.wix.com/ramirosen
> 
> 
> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com> wrote:
> > Hello All,
> >
> >
> > I am new here.
> > I want to know the interrupt handler of the ethernet card and where can i
> > find the definition of it so as i can clear the flow of packet reception.
> >
> > Thanks
> > Robert
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Interrupt Handler of Ethernet Device

[Rami Rosen]

Hi,
we have in :
 http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c

struct nic {
        /* Begin: frequently used values: keep adjacent for cache effect */
        u32 msg_enable                          ____cacheline_aligned;
        struct net_device *netdev;
         struct pci_dev *pdev;
     ...
     ...

And indeed  nic->netdev represents an Ethernet interface, which
is the struct net_device (see: include/linux/netdevice.h)

Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen


On Sun, Apr 7, 2013 at 5:52 AM, ishare <june.tune.sea@gmail.com> wrote:
> On Fri, Apr 05, 2013 at 03:06:37PM +0300, Rami Rosen wrote:
>> Robert,
>> You should look for the request_irq() method in the driver.
>> This method registers an interrupt handler.
>> For example, you can look in:
>> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
>> ...
>> ...
>>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
>>                  nic->netdev->name, nic->netdev)))
>>
>> ...
>>
>> This means that e100_intr is registered as an interrupt handler.
>
>   Is this nic->netdev represent a  Ethernet interface ?
>
>
>>
>> Best,
>> Rami Rosen
>> http://ramirose.wix.com/ramirosen
>>
>>
>> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com> wrote:
>> > Hello All,
>> >
>> >
>> > I am new here.
>> > I want to know the interrupt handler of the ethernet card and where can i
>> > find the definition of it so as i can clear the flow of packet reception.
>> >
>> > Thanks
>> > Robert
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

simple question about the function memcmp in kernel

[Ben Wu]

Dear All:
?
?? 
int memcmp(const void *cs, const void *ct, size_t count)
{
???? const unsigned char *su1, *su2;
???? int res = 0;

???? for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
????????? if ((res = *su1 - *su2) != 0)
?????????????? break;
???? return res;
}

I want to know why it use the temp pointer su1, su2? why it doesn't directly use the cs and ct pointer?


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simple question about the function memcmp in kernel

[Valdis.Kletnieks at vt.edu]

On Mon, 08 Apr 2013 08:57:01 +0800, Ben Wu said:

> int memcmp(const void *cs, const void *ct, size_t count)
> {

> I want to know why it use the temp pointer su1, su2? why it doesn't directly
> use the cs and ct pointer?

This is a C 101 question, not a kernel question.  But anyhow..

They're declared const, so the compiler will whine about ++'ing them.

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simple question about the function memcmp in kernel

[Max Filippov]

On Mon, Apr 8, 2013 at 5:33 AM,  <Valdis.Kletnieks@vt.edu> wrote:
> On Mon, 08 Apr 2013 08:57:01 +0800, Ben Wu said:
>
>> int memcmp(const void *cs, const void *ct, size_t count)
>> {
>
>> I want to know why it use the temp pointer su1, su2? why it doesn't directly
>> use the cs and ct pointer?
>
> This is a C 101 question, not a kernel question.  But anyhow..
>
> They're declared const, so the compiler will whine about ++'ing them.

const is the the object they point to, not the pointers themselves
(that would be
void * const cs).

memcmp compares bytes at which cs and ct point, but these are void pointers,
and the expression res = *cs - *ct is thus meaningless. One must convert them
to (const unsigned char *), which looks ugly, otherwise such implementation
looks like pretty much valid:

int memcmp(const void *cs, const void *ct, size_t count)
{
     int res = 0;

     for (; 0 < count; ++cs, ++ct, count--)
          if ((res =*(const unsigned char *)cs - *(const unsigned char
*)ct) != 0)
               break;
     return res;
}

-- 
Thanks.
-- Max

simple question about the function memcmp in kernel

[Valdis.Kletnieks at vt.edu]

On Mon, 08 Apr 2013 05:56:29 +0400, Max Filippov said:

> const is the the object they point to, not the pointers themselves
> (that would be
> void * const cs).
>
> memcmp compares bytes at which cs and ct point, but these are void pointers,
> and the expression res = *cs - *ct is thus meaningless.

Max is right, and I'm obviously under-caffienated or something. :)
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simple question about the function memcmp in kernel

[Burke]

? 2013-4-8 10:29, Valdis.Kletnieks at vt.edu ??:
> On Mon, 08 Apr 2013 05:56:29 +0400, Max Filippov said:
>
>> const is the the object they point to, not the pointers themselves
>> (that would be
>> void * const cs).
>>
>> memcmp compares bytes at which cs and ct point, but these are void pointers,
>> and the expression res = *cs - *ct is thus meaningless.
> Max is right, and I'm obviously under-caffienated or something. :)
Dear Max,Valdis:
I got it, many thanks for your kindly reply.

Interrupt Handler of Ethernet Device

[Robert Clove]

As far i have read the packet reception i have found out that
When working in interrupt driven model, the nic registers an
interrupt handler;
? This interrupt handler will be called when a frame is received;
? Typically in the handler, we allocate sk buff by calling
dev alloc skb();
? Copies data from nic?s buffer to this struct just created;
? nic call generic reception routine netif rx();
? netif rx() put frame in per cpu queue;
? if queue is full, drop!

BUT i didn't found the netif_rx() in the following link
http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c#L2204




On Sun, Apr 7, 2013 at 8:52 PM, Rami Rosen <roszenrami@gmail.com> wrote:

> Hi,
> we have in :
>  http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
>
> struct nic {
>         /* Begin: frequently used values: keep adjacent for cache effect */
>         u32 msg_enable                          ____cacheline_aligned;
>         struct net_device *netdev;
>          struct pci_dev *pdev;
>      ...
>      ...
>
> And indeed  nic->netdev represents an Ethernet interface, which
> is the struct net_device (see: include/linux/netdevice.h)
>
> Regards,
> Rami Rosen
> http://ramirose.wix.com/ramirosen
>
>
> On Sun, Apr 7, 2013 at 5:52 AM, ishare <june.tune.sea@gmail.com> wrote:
> > On Fri, Apr 05, 2013 at 03:06:37PM +0300, Rami Rosen wrote:
> >> Robert,
> >> You should look for the request_irq() method in the driver.
> >> This method registers an interrupt handler.
> >> For example, you can look in:
> >> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
> >> ...
> >> ...
> >>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
> >>                  nic->netdev->name, nic->netdev)))
> >>
> >> ...
> >>
> >> This means that e100_intr is registered as an interrupt handler.
> >
> >   Is this nic->netdev represent a  Ethernet interface ?
> >
> >
> >>
> >> Best,
> >> Rami Rosen
> >> http://ramirose.wix.com/ramirosen
> >>
> >>
> >> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com>
> wrote:
> >> > Hello All,
> >> >
> >> >
> >> > I am new here.
> >> > I want to know the interrupt handler of the ethernet card and where
> can i
> >> > find the definition of it so as i can clear the flow of packet
> reception.
> >> >
> >> > Thanks
> >> > Robert
> >> >
> >> > _______________________________________________
> >> > Kernelnewbies mailing list
> >> > Kernelnewbies at kernelnewbies.org
> >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >> >
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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Interrupt Handler of Ethernet Device

[Rami Rosen]

Hi,
>When working in interrupt driven model, the nic registers an
>interrupt handler;
The nic registers an interrupt handle also when working in polling mode;
See all the new drivers like e1000, e1000e and more.

when working in interrupt mode, each packet received triggers an interrupt;
when working in polling mode, we start in interrupt model; but only
the first packet triggers interrupt, afterward we work in poll mode.
If traffic is low
we switch again to interrupt mode.

There are cases when netif_rx() is used for interrupt driven driver;
look in:
http://lxr.free-electrons.com/source/drivers/net/ethernet/davicom/dm9000.c

dm9000_rx() is called from the interrupt isr, dm9000_interrupt.

And grepping for the network drivers subtree will easily find some
more examples.

Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen



On Mon, Apr 8, 2013 at 8:42 AM, Robert Clove <cloverobert@gmail.com> wrote:
> As far i have read the packet reception i have found out that
> When working in interrupt driven model, the nic registers an
> interrupt handler;
> ? This interrupt handler will be called when a frame is received;
> ? Typically in the handler, we allocate sk buff by calling
> dev alloc skb();
> ? Copies data from nic?s buffer to this struct just created;
> ? nic call generic reception routine netif rx();
> ? netif rx() put frame in per cpu queue;
> ? if queue is full, drop!
>
> BUT i didn't found the netif_rx() in the following link
> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c#L2204
>
>
>
>
> On Sun, Apr 7, 2013 at 8:52 PM, Rami Rosen <roszenrami@gmail.com> wrote:
>>
>> Hi,
>> we have in :
>>  http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
>>
>> struct nic {
>>         /* Begin: frequently used values: keep adjacent for cache effect
>> */
>>         u32 msg_enable                          ____cacheline_aligned;
>>         struct net_device *netdev;
>>          struct pci_dev *pdev;
>>      ...
>>      ...
>>
>> And indeed  nic->netdev represents an Ethernet interface, which
>> is the struct net_device (see: include/linux/netdevice.h)
>>
>> Regards,
>> Rami Rosen
>> http://ramirose.wix.com/ramirosen
>>
>>
>> On Sun, Apr 7, 2013 at 5:52 AM, ishare <june.tune.sea@gmail.com> wrote:
>> > On Fri, Apr 05, 2013 at 03:06:37PM +0300, Rami Rosen wrote:
>> >> Robert,
>> >> You should look for the request_irq() method in the driver.
>> >> This method registers an interrupt handler.
>> >> For example, you can look in:
>> >> http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
>> >> ...
>> >> ...
>> >>     if ((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
>> >>                  nic->netdev->name, nic->netdev)))
>> >>
>> >> ...
>> >>
>> >> This means that e100_intr is registered as an interrupt handler.
>> >
>> >   Is this nic->netdev represent a  Ethernet interface ?
>> >
>> >
>> >>
>> >> Best,
>> >> Rami Rosen
>> >> http://ramirose.wix.com/ramirosen
>> >>
>> >>
>> >> On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove <cloverobert@gmail.com>
>> >> wrote:
>> >> > Hello All,
>> >> >
>> >> >
>> >> > I am new here.
>> >> > I want to know the interrupt handler of the ethernet card and where
>> >> > can i
>> >> > find the definition of it so as i can clear the flow of packet
>> >> > reception.
>> >> >
>> >> > Thanks
>> >> > Robert
>> >> >
>> >> > _______________________________________________
>> >> > Kernelnewbies mailing list
>> >> > Kernelnewbies at kernelnewbies.org
>> >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >> >
>> >>
>> >> _______________________________________________
>> >> Kernelnewbies mailing list
>> >> Kernelnewbies at kernelnewbies.org
>> >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>