ARM: vexpress: Enable SPARSE_IRQ selection

To enable vexpress to be included in multiplatform kernels containing boards which require SPARSE_IRQ, we need to also support this option. This turns out to be very simple...

[PATCH 1/2] ARM: vexpress: Remove IRQ defines from mach/irq.h [PATCH 2/2] ARM: vexpress: Enable selection of SPARSE_IRQ

From: Jon Medhurst <[email protected]>

The irq numbers are only used in one place so remove these defines and hardcode the value at the location it is used.

This leaves mach/irq.h only containing NR_IRQ and so it is safe when it gets dropped from inclusion when SPARSE_IRQ is defined.

---
 arch/arm/mach-vexpress/include/mach/irqs.h |    3 ---
 arch/arm/mach-vexpress/ct-ca9x4.c          |    2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

index 4b10ee7..e109c66 100644
@@ -1,4 +1 @@
-#define IRQ_LOCALTIMER		29
-#define IRQ_LOCALWDOG		30
-
 #define NR_IRQS	256

index c65cc3b..123d68af 100644
@@ -45,7 +45,7 @@ static void __init ct_ca9x4_map_io(void)
 }
 
 #ifdef CONFIG_HAVE_ARM_TWD
-static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, A9_MPCORE_TWD, IRQ_LOCALTIMER);
+static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, A9_MPCORE_TWD, 29);
 
 static void __init ca9x4_twd_init(void)
 {

1.7.10

From: Jon Medhurst <[email protected]>

This is required to add vexpress to multiplatform kernels containing other boards which require SPARSE_IRQ.

---
 arch/arm/Kconfig |    1 +
 1 file changed, 1 insertion(+)

index 84449dd..bdede09 100644
@@ -311,6 +311,7 @@ config ARCH_VEXPRESS
 	select HAVE_CLK
 	select HAVE_PATA_PLATFORM
 	select ICST
+	select MAY_HAVE_SPARSE_IRQ
 	select NO_IOPORT
 	select PLAT_VERSATILE
 	select PLAT_VERSATILE_CLCD

1.7.10

I did consider that but my conservative side won out. If there are no real downsides to sparse irqs that people would object to then I'm happy to unconditionally enable it. (I'll post a v2 patch that does this.)

Tixy

So you're relying on the GIC IRQs starting at 0, and so that the local timer interrupt stays at 29 ? And the local timer interrupt is now just some random number buried in some C file.

Well, the existing code already did that ;-)

Yes, that did leave a bit of a bad taste, I guess in the back of my mind I had the (erroneous?) thought that this non-device-tree code would be going away soon.

However, for the purpose of enabling sparse irqs, we don't actually need to mess with the IRQ defines so I'll follow up with an alternative patch which leaves them alone...

Tixy

To enable vexpress to be included in multiplatform kernels containing boards which require SPARSE_IRQ, we need to also support this option. This turns out to be very simple...

We remove NR_IRQS from mach/irq.h as that is unused with SPARSE_IRQ and include this header directly in ct-ca9x4.c as it will no longer be included via asm/irq.h.

---
 arch/arm/mach-vexpress/include/mach/irqs.h |    2 --
 arch/arm/mach-vexpress/ct-ca9x4.c          |    1 +
 arch/arm/Kconfig                           |    1 +
 3 files changed, 2 insertions(+), 2 deletions(-)

index 4b10ee7..b64611d 100644
@@ -1,4 +1,2 @@
 #define IRQ_LOCALTIMER		29
 #define IRQ_LOCALWDOG		30
-
-#define NR_IRQS	256

index 3ef3fda..0f477a5 100644
@@ -26,6 +26,7 @@
 
 #include "core.h"
 
+#include <mach/irqs.h>
 #include <mach/motherboard.h>
 
 #include <plat/clcd.h>

index 6f3370e..9dd9701 100644
@@ -314,6 +314,7 @@ config ARCH_VEXPRESS
 	select NO_IOPORT
 	select PLAT_VERSATILE
 	select PLAT_VERSATILE_CLCD
+	select SPARSE_IRQ
 	help
 	  This enables support for the ARM Ltd Versatile Express boards.
 

1.7.10