ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

PATCH New Cousson, Benoit 3 participants 5 messages Feb 28, 2012

Subsystems (2)

Arm (32-bit) Arm sub-architectures

lore

Share & tools

lore

Cousson, Benoit

author

2012-02-28 13:10 UTC #0 lore raw

PATCH 1/1 ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

The following commit: 2f31b51659c2d8315ea2888ba5b93076febe672b
Author: Tero Kristo <[email protected]>
Date: Fri Dec 16 14:37:00 2011 -0700

ARM: OMAP4: PRM: use PRCM interrupt handler

introduced the PRCM interrupt handler and thus the need for 64 more interrupts. Since SPARSE_IRQ is still not fully functional on OMAP, the NR_IRQS needs to be updated to avoid the failure that happen during irq_alloc_descs call inside the PRCM driver:

[    0.208221] PRCM: failed to allocate irq descs: -12

Later the mux framework is then unable to request an IRQ from the PRCM interrupt handler.

[    1.802795] mux: Failed to setup hwmod io irq -22

Fix that by adding 64 more interrupts for OMAP2PLUS config.

Signed-off-by Benoit Cousson <[email protected]>

Cc Tero Kristo <[email protected]>

---
Tony,

This patch should probably go for the next -rc if possible.

Thanks,
Benoit

 arch/arm/plat-omap/include/plat/irqs.h |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

arch/arm/plat-omap/include/plat/irqs.h +9 -1

index 2efd645..37bbbbb 100644
@@ -428,8 +428,16 @@
 #define OMAP_GPMC_NR_IRQS	8
 #define OMAP_GPMC_IRQ_END	(OMAP_GPMC_IRQ_BASE + OMAP_GPMC_NR_IRQS)
 
+/* PRCM IRQ handler */
+#ifdef CONFIG_ARCH_OMAP2PLUS
+#define OMAP_PRCM_IRQ_BASE	(OMAP_GPMC_IRQ_END)
+#define OMAP_PRCM_NR_IRQS	64
+#define OMAP_PRCM_IRQ_END	(OMAP_PRCM_IRQ_BASE + OMAP_PRCM_NR_IRQS)
+#else
+#define OMAP_PRCM_IRQ_END	OMAP_GPMC_IRQ_END
+#endif
 
-#define NR_IRQS			OMAP_GPMC_IRQ_END
+#define NR_IRQS			OMAP_PRCM_IRQ_END
 
 #define OMAP_IRQ_BIT(irq)	(1 << ((irq) % 32))

Signature · 1 line

1.7.0.4

Russell King - ARM Linux

2012-02-28 14:36 UTC #1 lore raw

PATCH 1/1 ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

Quoted 12 lines · Benoit

The following commit: 2f31b51659c2d8315ea2888ba5b93076febe672b
Author: Tero Kristo <[email protected]>
Date: Fri Dec 16 14:37:00 2011 -0700
ARM: OMAP4: PRM: use PRCM interrupt handler
introduced the PRCM interrupt handler and thus the need for 64 more interrupts. Since SPARSE_IRQ is still not fully functional on OMAP, the NR_IRQS needs to be updated to avoid the failure that happen during irq_alloc_descs call inside the PRCM driver:

Quoted 6 lines

[    0.208221] PRCM: failed to allocate irq descs: -12
Later the mux framework is then unable to request an IRQ from the PRCM interrupt handler.
[    1.802795] mux: Failed to setup hwmod io irq -22

This is fine for rc, but longer term...

Do any of these have hard-coded interrupt numbers associated with them? If not, just enabling sparse IRQ will sort this out.

As I tried to explain yesterday, there are two modes for IRQ allocation:

1. Without sparse IRQ enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs _within_ the existing from..NR_IRQS range, and will fail if there is insufficient IRQs available.

2. With sparse IRQs enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs starting at max(from, NR_IRQS) and working upwards.

In either case, irq_alloc_descs(start, 0, num, -1) will allocate 'num' IRQs at 'start' or fail if the range is already in use (and 0..NR_IRQS is defined as 'being in use' when sparse IRQs are enabled.)

So, if the PRCM interrupts aren't statically assigned (the code suggests that they aren't) then it's already sparse-IRQ compliant, and enabling sparse IRQ support will mean that they will be allocated above NR_IRQS.

Therefore, I suggest rather than raising NR_IRQS, you instead enable SPARSE_IRQ now so that anyone using the dynamic IRQ allocation can benefit from sparse IRQ support without having to have a large NR_IRQS.

So, you don't have to wait until everything is converted to use sparse IRQ. You just need to make sure that nothing uses irq_alloc_descs(start, from, num, ...) where start < NR_IRQS, and nothing using that requires statically defined IRQ numbering.

Cousson, Benoit

author

2012-02-28 20:32 UTC #2 lore raw

PATCH 1/1 ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

Hi Russell,

Quoted 18 lines · Russell King - ARM Linux

Quoted 17 lines · Benoit
The following commit: 2f31b51659c2d8315ea2888ba5b93076febe672b
Author: Tero Kristo<[email protected]>
Date: Fri Dec 16 14:37:00 2011 -0700
ARM: OMAP4: PRM: use PRCM interrupt handler
introduced the PRCM interrupt handler and thus the need for 64 more interrupts. Since SPARSE_IRQ is still not fully functional on OMAP, the NR_IRQS needs to be updated to avoid the failure that happen during irq_alloc_descs call inside the PRCM driver:
[    0.208221] PRCM: failed to allocate irq descs: -12
Later the mux framework is then unable to request an IRQ from the PRCM interrupt handler.

Quoted 6 lines

Quoted 1 line
[    1.802795] mux: Failed to setup hwmod io irq -22
This is fine for rc, but longer term...
Do any of these have hard-coded interrupt numbers associated with them? If not, just enabling sparse IRQ will sort this out.

You're right, in that case, it does not depend on any hard-coded number.

Quoted 17 lines

As I tried to explain yesterday, there are two modes for IRQ allocation:
1. Without sparse IRQ enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs _within_ the existing from..NR_IRQS range, and will fail if there is insufficient IRQs available.
2. With sparse IRQs enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs starting at max(from, NR_IRQS) and working upwards.
In either case, irq_alloc_descs(start, 0, num, -1) will allocate 'num' IRQs at 'start' or fail if the range is already in use (and 0..NR_IRQS is defined as 'being in use' when sparse IRQs are enabled.)
So, if the PRCM interrupts aren't statically assigned (the code suggests that they aren't) then it's already sparse-IRQ compliant, and enabling sparse IRQ support will mean that they will be allocated above NR_IRQS.

Quoted 8 lines

Therefore, I suggest rather than raising NR_IRQS, you instead enable SPARSE_IRQ now so that anyone using the dynamic IRQ allocation can benefit from sparse IRQ support without having to have a large NR_IRQS.
So, you don't have to wait until everything is converted to use sparse IRQ. You just need to make sure that nothing uses irq_alloc_descs(start, from, num, ...) where start< NR_IRQS, and nothing using that requires statically defined IRQ numbering.

Yes, I fully agree, and that's still the plan. That's why I started sending last week a bunch of cleanup for SPARSE_IRQ support. Unfortunately, they might not be ready for 3.4 either, but I'm still working on it.

Meanwhile, we need the current temporary fix.

I can emphasis the temporary duration on that patch in the changelog if needed.

Thanks,
Benoit

Russell King - ARM Linux

2012-02-28 20:43 UTC #3 lore raw

PATCH 1/1 ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

Quoted 56 lines · Benoit

Hi Russell,
Quoted 18 lines · Russell King - ARM Linux
Quoted 17 lines · Benoit
The following commit: 2f31b51659c2d8315ea2888ba5b93076febe672b
Author: Tero Kristo<[email protected]>
Date: Fri Dec 16 14:37:00 2011 -0700
ARM: OMAP4: PRM: use PRCM interrupt handler
introduced the PRCM interrupt handler and thus the need for 64 more interrupts. Since SPARSE_IRQ is still not fully functional on OMAP, the NR_IRQS needs to be updated to avoid the failure that happen during irq_alloc_descs call inside the PRCM driver:
[    0.208221] PRCM: failed to allocate irq descs: -12
Later the mux framework is then unable to request an IRQ from the PRCM interrupt handler.
Quoted 6 lines
Quoted 1 line
[    1.802795] mux: Failed to setup hwmod io irq -22
This is fine for rc, but longer term...
Do any of these have hard-coded interrupt numbers associated with them? If not, just enabling sparse IRQ will sort this out.
You're right, in that case, it does not depend on any hard-coded number.
Quoted 17 lines
As I tried to explain yesterday, there are two modes for IRQ allocation:
1. Without sparse IRQ enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs _within_ the existing from..NR_IRQS range, and will fail if there is insufficient IRQs available.
2. With sparse IRQs enabled, irq_alloc_descs(-1, from, num, -1) will allocate IRQs starting at max(from, NR_IRQS) and working upwards.
In either case, irq_alloc_descs(start, 0, num, -1) will allocate 'num' IRQs at 'start' or fail if the range is already in use (and 0..NR_IRQS is defined as 'being in use' when sparse IRQs are enabled.)
So, if the PRCM interrupts aren't statically assigned (the code suggests that they aren't) then it's already sparse-IRQ compliant, and enabling sparse IRQ support will mean that they will be allocated above NR_IRQS.
Quoted 8 lines
Therefore, I suggest rather than raising NR_IRQS, you instead enable SPARSE_IRQ now so that anyone using the dynamic IRQ allocation can benefit from sparse IRQ support without having to have a large NR_IRQS.
So, you don't have to wait until everything is converted to use sparse IRQ. You just need to make sure that nothing uses irq_alloc_descs(start, from, num, ...) where start< NR_IRQS, and nothing using that requires statically defined IRQ numbering.

Quoted 4 lines

Yes, I fully agree, and that's still the plan. That's why I started sending last week a bunch of cleanup for SPARSE_IRQ support. Unfortunately, they might not be ready for 3.4 either, but I'm still working on it.

One thing I didn't consider is that the GIC has been converted to sparse IRQ support, so enabling it on OMAP will make the irq_alloc_descs() in there to fail if you try and keep it below NR_IRQS.

That rules out a piecemeal conversion, which rather sucks.

Tony Lindgren

2012-02-28 23:55 UTC #4 lore raw

PATCH 1/1 ARM: OMAP: irqs: Fix NR_IRQS value to handle PRCM interrupts

In reply to Cousson, Benoit

Quoted 19 lines · Cousson, Benoit

The following commit: 2f31b51659c2d8315ea2888ba5b93076febe672b
Author: Tero Kristo <[email protected]>
Date: Fri Dec 16 14:37:00 2011 -0700
ARM: OMAP4: PRM: use PRCM interrupt handler
introduced the PRCM interrupt handler and thus the need for 64 more interrupts. Since SPARSE_IRQ is still not fully functional on OMAP, the NR_IRQS needs to be updated to avoid the failure that happen during irq_alloc_descs call inside the PRCM driver:
[    0.208221] PRCM: failed to allocate irq descs: -12
Later the mux framework is then unable to request an IRQ from the PRCM interrupt handler.
[    1.802795] mux: Failed to setup hwmod io irq -22

Quoted 8 lines

Fix that by adding 64 more interrupts for OMAP2PLUS config.
Signed-off-by Benoit Cousson <[email protected]>
Cc Tero Kristo <[email protected]>
---
Tony,
This patch should probably go for the next -rc if possible.

Thanks applying into fixes as it seems like the only available fix right now.

Tony