For a shared interrupt line how do I find which interrupt handler to use?
For a shared interrupt line,I can have several interrupt handlers. The kernel will sequentially invoke all the handlers for that particular shared line.
As far as I know, each handler, when invoked informs the kernel whether it was the correct handler to be invoked or not.
My questions is how is this determined,is there a way it checks a memory mapped register that tells status of a particular device or is there some other hardware mechanism ? How does the handler know that the corresponding device is indeed the one that issued the interrupt or not ?
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
linux-kernel linux-device-driver device-driver irq
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
add a comment |
For a shared interrupt line,I can have several interrupt handlers. The kernel will sequentially invoke all the handlers for that particular shared line.
As far as I know, each handler, when invoked informs the kernel whether it was the correct handler to be invoked or not.
My questions is how is this determined,is there a way it checks a memory mapped register that tells status of a particular device or is there some other hardware mechanism ? How does the handler know that the corresponding device is indeed the one that issued the interrupt or not ?
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
linux-kernel linux-device-driver device-driver irq
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
1
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18
add a comment |
For a shared interrupt line,I can have several interrupt handlers. The kernel will sequentially invoke all the handlers for that particular shared line.
As far as I know, each handler, when invoked informs the kernel whether it was the correct handler to be invoked or not.
My questions is how is this determined,is there a way it checks a memory mapped register that tells status of a particular device or is there some other hardware mechanism ? How does the handler know that the corresponding device is indeed the one that issued the interrupt or not ?
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
linux-kernel linux-device-driver device-driver irq
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
For a shared interrupt line,I can have several interrupt handlers. The kernel will sequentially invoke all the handlers for that particular shared line.
As far as I know, each handler, when invoked informs the kernel whether it was the correct handler to be invoked or not.
My questions is how is this determined,is there a way it checks a memory mapped register that tells status of a particular device or is there some other hardware mechanism ? How does the handler know that the corresponding device is indeed the one that issued the interrupt or not ?
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
linux-kernel linux-device-driver device-driver irq
linux-kernel linux-device-driver device-driver irq
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
edited Nov 27 '18 at 6:28
Guy Avraham
1,55022031
1,55022031
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
asked Jan 17 '13 at 2:57
hit.at.rohit.at.ro
6619
6619
1
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18
add a comment |
1
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18
1
1
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18
add a comment |
1 Answer
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oldest
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The kernel will sequentially invoke all the handlers for that particular shared line.
Exactly. Say Dev1 and Dev2 shares the IRQ10. When an interrupt is generated for IRQ10, all ISRs registered with this line will be invoked one by one.
In our scenario, say Dev2 was the one that generated the interrupt. If Dev1's ISR is registered first, than its ISR (i.e Dev1's ISR) only called first. In that ISR, the interrupt status register will be verified for interrupt. If no interrupt bit is set (which is the case, cause Dev2 raised the interrupt) then we can confirm that interrupt was not generated by Dev1 - so Dev1's ISR should return to the kernel IRQ_NONE - which means:"I did not handled that interrupt", so on the kernel continues to the next ISR (i.e Dev2's ISR), which in turn, will indeed verify that its corresponding device generated the interrupt, thus, this handler should handle it and eventually return IRQ_HANDLED - which means:"I handled this one".
See the return values IRQ_NONE/IRQ_HANDLED for more information.
How does the handler know that the corresponding device issued the interrupt or not ?
By reading the Interrupt status register only.
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
I'm not sure about this. But the OS will take care of calling ISRs based on the return values from ISR.
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type... u mean same driver for both the devices???
– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
add a comment |
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The kernel will sequentially invoke all the handlers for that particular shared line.
Exactly. Say Dev1 and Dev2 shares the IRQ10. When an interrupt is generated for IRQ10, all ISRs registered with this line will be invoked one by one.
In our scenario, say Dev2 was the one that generated the interrupt. If Dev1's ISR is registered first, than its ISR (i.e Dev1's ISR) only called first. In that ISR, the interrupt status register will be verified for interrupt. If no interrupt bit is set (which is the case, cause Dev2 raised the interrupt) then we can confirm that interrupt was not generated by Dev1 - so Dev1's ISR should return to the kernel IRQ_NONE - which means:"I did not handled that interrupt", so on the kernel continues to the next ISR (i.e Dev2's ISR), which in turn, will indeed verify that its corresponding device generated the interrupt, thus, this handler should handle it and eventually return IRQ_HANDLED - which means:"I handled this one".
See the return values IRQ_NONE/IRQ_HANDLED for more information.
How does the handler know that the corresponding device issued the interrupt or not ?
By reading the Interrupt status register only.
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
I'm not sure about this. But the OS will take care of calling ISRs based on the return values from ISR.
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type... u mean same driver for both the devices???
– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
add a comment |
The kernel will sequentially invoke all the handlers for that particular shared line.
Exactly. Say Dev1 and Dev2 shares the IRQ10. When an interrupt is generated for IRQ10, all ISRs registered with this line will be invoked one by one.
In our scenario, say Dev2 was the one that generated the interrupt. If Dev1's ISR is registered first, than its ISR (i.e Dev1's ISR) only called first. In that ISR, the interrupt status register will be verified for interrupt. If no interrupt bit is set (which is the case, cause Dev2 raised the interrupt) then we can confirm that interrupt was not generated by Dev1 - so Dev1's ISR should return to the kernel IRQ_NONE - which means:"I did not handled that interrupt", so on the kernel continues to the next ISR (i.e Dev2's ISR), which in turn, will indeed verify that its corresponding device generated the interrupt, thus, this handler should handle it and eventually return IRQ_HANDLED - which means:"I handled this one".
See the return values IRQ_NONE/IRQ_HANDLED for more information.
How does the handler know that the corresponding device issued the interrupt or not ?
By reading the Interrupt status register only.
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
I'm not sure about this. But the OS will take care of calling ISRs based on the return values from ISR.
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type... u mean same driver for both the devices???
– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
add a comment |
The kernel will sequentially invoke all the handlers for that particular shared line.
Exactly. Say Dev1 and Dev2 shares the IRQ10. When an interrupt is generated for IRQ10, all ISRs registered with this line will be invoked one by one.
In our scenario, say Dev2 was the one that generated the interrupt. If Dev1's ISR is registered first, than its ISR (i.e Dev1's ISR) only called first. In that ISR, the interrupt status register will be verified for interrupt. If no interrupt bit is set (which is the case, cause Dev2 raised the interrupt) then we can confirm that interrupt was not generated by Dev1 - so Dev1's ISR should return to the kernel IRQ_NONE - which means:"I did not handled that interrupt", so on the kernel continues to the next ISR (i.e Dev2's ISR), which in turn, will indeed verify that its corresponding device generated the interrupt, thus, this handler should handle it and eventually return IRQ_HANDLED - which means:"I handled this one".
See the return values IRQ_NONE/IRQ_HANDLED for more information.
How does the handler know that the corresponding device issued the interrupt or not ?
By reading the Interrupt status register only.
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
I'm not sure about this. But the OS will take care of calling ISRs based on the return values from ISR.
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
The kernel will sequentially invoke all the handlers for that particular shared line.
Exactly. Say Dev1 and Dev2 shares the IRQ10. When an interrupt is generated for IRQ10, all ISRs registered with this line will be invoked one by one.
In our scenario, say Dev2 was the one that generated the interrupt. If Dev1's ISR is registered first, than its ISR (i.e Dev1's ISR) only called first. In that ISR, the interrupt status register will be verified for interrupt. If no interrupt bit is set (which is the case, cause Dev2 raised the interrupt) then we can confirm that interrupt was not generated by Dev1 - so Dev1's ISR should return to the kernel IRQ_NONE - which means:"I did not handled that interrupt", so on the kernel continues to the next ISR (i.e Dev2's ISR), which in turn, will indeed verify that its corresponding device generated the interrupt, thus, this handler should handle it and eventually return IRQ_HANDLED - which means:"I handled this one".
See the return values IRQ_NONE/IRQ_HANDLED for more information.
How does the handler know that the corresponding device issued the interrupt or not ?
By reading the Interrupt status register only.
Is this information relayed through the interrupt controller that is between the devices and the processor interrupt line ??
I'm not sure about this. But the OS will take care of calling ISRs based on the return values from ISR.
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
edited Nov 26 '18 at 17:08
Guy Avraham
1,55022031
1,55022031
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
answered Jan 17 '13 at 5:45
JeyaramJeyaram
6,71942950
6,71942950
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type... u mean same driver for both the devices???
– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
add a comment |
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type... u mean same driver for both the devices???
– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
Hi Jeyram, if dev1 and dev2 are of the same device type but different devices(for example dev1 is a regular mouse,say dev2 is a gaming mouse). Then it might know the device type but how will the interrupt handler for dev1 confirm that it is not the correct handler in its return value?
– hit.at.ro
Jan 17 '13 at 6:20
same device type ... u mean same driver for both the devices???– Jeyaram
Jan 17 '13 at 6:44
same device type ... u mean same driver for both the devices???– Jeyaram
Jan 17 '13 at 6:44
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
return value of ISR used by OS. Not the ISR of next device. Based on return value only, OS will decide whether call or do not call next ISR registered for that IRQ line.
– Jeyaram
Jan 17 '13 at 6:47
add a comment |
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1
unix.stackexchange.com/questions/47306/…
– Ciro Santilli 新疆改造中心 六四事件 法轮功
Oct 31 '15 at 9:40
See also section "Shared Handlers" on page 119 (chapter 7) in Robert Love's "Linux Kernel Development, 3rd edition".
– Guy Avraham
Nov 26 '18 at 17:18