[Top] [All Lists]

Re: [PATCH] MIPS: Add some irq definitins required by OF

To: Grant Likely <>
Subject: Re: [PATCH] MIPS: Add some irq definitins required by OF
From: David Daney <>
Date: Fri, 15 Oct 2010 12:50:08 -0700
In-reply-to: <>
Original-recipient: rfc822;
References: <> <>
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20100907 Fedora/3.0.7-1.fc12 Thunderbird/3.0.7
On 10/14/2010 06:27 PM, Grant Likely wrote:
On Thu, Oct 14, 2010 at 3:02 PM, David Daney<>  wrote:
Using the forthcoming open firmware (OF) on mips patches, requires
that several interrupt related definitions be added.

In the future we may want to allow some sort of override for
irq_create_mapping, but for now it is just supplies an identity

Signed-off-by: David Daney<>
Cc: Grant Likely<>

Hi David,

If you try my current next-devicetree branch then this patch should
not be necessary.  I was able to build the mips patch before I posted it.

This is what I get building on your next-devicetree branch:

  CC      drivers/of/of_i2c.o
drivers/of/of_i2c.c: In function 'of_i2c_register_devices':
drivers/of/of_i2c.c:70: error: implicit declaration of function 'irq_dispose_mapping'

Hence the part of my patch where I added those irq_create_mapping() and irq_dispose_mapping() functions.

David Daney

  arch/mips/include/asm/irq.h |   33 +++++++++++++++++++++++++++++++++
  1 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index dea4aed..f109e67 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -16,6 +16,39 @@


+#define NO_IRQ UINT_MAX

Really?  The verdict came down a long time ago that 0 is to be the
value that means no irq, and only a few architectures still define
NO_IRQ as -1.  It is assumed that the architectures which do not
define NO_IRQ use 0 as the invalid value.  Mostly notably x86 does not
define NO_IRQ, and Linus nack'd the patch to add it.

linux-2.6$ git grep '#define[ \t]*NO_IRQ[^_]'
arch/arm/include/asm/irq.h:#define NO_IRQ       ((unsigned int)(-1))
arch/microblaze/include/asm/irq.h:#define NO_IRQ (-1)
arch/mn10300/include/asm/irq.h:#define NO_IRQ           INT_MAX
arch/parisc/include/asm/irq.h:#define NO_IRQ            (-1)
arch/powerpc/include/asm/irq.h:#define NO_IRQ                   (0)
arch/xtensa/variants/s6000/include/variant/irq.h:#define NO_IRQ         (-1)
drivers/input/touchscreen/ucb1400_ts.c:#define NO_IRQ   0
drivers/of/irq.c:#define NO_IRQ 0
drivers/pcmcia/pd6729.c:#define NO_IRQ  ((unsigned int)(0))
drivers/rtc/rtc-m48t59.c:#define NO_IRQ (-1)
drivers/scsi/arm/fas216.h:#define NO_IRQ 255

As far as I can tell, only arm, microblaze, mn10200, parisc, and
xtensa define NO_IRQ to -1, and of those I've got a pending patch to
change Microblaze to use 0.  arm is the hard holdout because of all
the legacy board ports.

+ * This type is the placeholder for a hardware interrupt number. It
+ * has to be big enough to enclose whatever representation is used by
+ * a given platform.
+ */
+typedef unsigned long irq_hw_number_t;
+static inline void irq_dispose_mapping(unsigned int virq)
+       return;
+struct irq_host;
+ * irq_create_mapping - Map a hardware interrupt into linux virq space
+ * @host: host owning this hardware interrupt or NULL for default host
+ * @hwirq: hardware irq number in that host space
+ *
+ * Only one mapping per hardware interrupt is permitted. Returns a linux
+ * virq number.
+ * If the sense/trigger is to be specified, set_irq_type() should be called
+ * on the number returned from that call.
+ */
+static inline unsigned int irq_create_mapping(struct irq_host *host,
+                                             irq_hw_number_t hwirq)
+       /* For now, an identity mapping. */
+       return (unsigned int)hwirq;
  #ifdef CONFIG_I8259
  static inline int irq_canonicalize(int irq)

<Prev in Thread] Current Thread [Next in Thread>