1 files changed, 70 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c24xx/include/mach/entry-macro.S b/arch/arm/mach-s3c24xx/include/mach/entry-macro.S
new file mode 100644
index 00000000000..7615a14773f
--- /dev/null
+++ b/arch/arm/mach-s3c24xx/include/mach/entry-macro.S
@@ -0,0 +1,70 @@
+/*
+ * arch/arm/mach-s3c2410/include/mach/entry-macro.S
+ *
+ * Low-level IRQ helper macros for S3C2410-based platforms
+ *
+ * This file is licensed under  the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+*/
+
+/* We have a problem that the INTOFFSET register does not always
+ * show one interrupt. Occasionally we get two interrupts through
+ * the prioritiser, and this causes the INTOFFSET register to show
+ * what looks like the logical-or of the two interrupt numbers.
+ *
+ * Thanks to Klaus, Shannon, et al for helping to debug this problem
+*/
+
+#define INTPND          (0x10)
+#define INTOFFSET       (0x14)
+
+#include <mach/hardware.h>
+#include <asm/irq.h>
+
+        .macro  get_irqnr_preamble, base, tmp
+        .endm
+
+        .macro  get_irqnr_and_base, irqnr, irqstat, base, tmp
+
+                mov     \base, #S3C24XX_VA_IRQ
+
+                @@ try the interrupt offset register, since it is there
+
+                ldr     \irqstat, [ \base, #INTPND ]
+                teq     \irqstat, #0
+                beq     1002f
+                ldr     \irqnr, [ \base, #INTOFFSET ]
+                mov     \tmp, #1
+                tst     \irqstat, \tmp, lsl \irqnr
+                bne     1001f
+
+                @@ the number specified is not a valid irq, so try
+                @@ and work it out for ourselves
+
+                mov     \irqnr, #0              @@ start here
+
+                @@ work out which irq (if any) we got
+
+                movs    \tmp, \irqstat, lsl#16
+                addeq   \irqnr, \irqnr, #16
+                moveq   \irqstat, \irqstat, lsr#16
+                tst     \irqstat, #0xff
+                addeq   \irqnr, \irqnr, #8
+                moveq   \irqstat, \irqstat, lsr#8
+                tst     \irqstat, #0xf
+                addeq   \irqnr, \irqnr, #4
+                moveq   \irqstat, \irqstat, lsr#4
+                tst     \irqstat, #0x3
+                addeq   \irqnr, \irqnr, #2
+                moveq   \irqstat, \irqstat, lsr#2
+                tst     \irqstat, #0x1
+                addeq   \irqnr, \irqnr, #1
+
+                @@ we have the value
+1001:
+                adds    \irqnr, \irqnr, #IRQ_EINT0
+1002:
+                @@ exit here, Z flag unset if IRQ
+
+        .endm