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Diffstat (limited to 'arch/mips/mips-boards/sead/sead_int.c')
-rw-r--r--arch/mips/mips-boards/sead/sead_int.c86
1 files changed, 82 insertions, 4 deletions
diff --git a/arch/mips/mips-boards/sead/sead_int.c b/arch/mips/mips-boards/sead/sead_int.c
index 90fda0d9915f..9168d934c661 100644
--- a/arch/mips/mips-boards/sead/sead_int.c
+++ b/arch/mips/mips-boards/sead/sead_int.c
@@ -24,16 +24,94 @@
#include <linux/irq.h>
#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
#include <asm/system.h>
#include <asm/mips-boards/seadint.h>
-extern asmlinkage void mipsIRQ(void);
+static inline int clz(unsigned long x)
+{
+ __asm__ (
+ " .set push \n"
+ " .set mips32 \n"
+ " clz %0, %1 \n"
+ " .set pop \n"
+ : "=r" (x)
+ : "r" (x));
+
+ return x;
+}
+
+/*
+ * Version of ffs that only looks at bits 12..15.
+ */
+static inline unsigned int irq_ffs(unsigned int pending)
+{
+#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
+ return -clz(pending) + 31 - CAUSEB_IP;
+#else
+ unsigned int a0 = 7;
+ unsigned int t0;
+
+ t0 = s0 & 0xf000;
+ t0 = t0 < 1;
+ t0 = t0 << 2;
+ a0 = a0 - t0;
+ s0 = s0 << t0;
+
+ t0 = s0 & 0xc000;
+ t0 = t0 < 1;
+ t0 = t0 << 1;
+ a0 = a0 - t0;
+ s0 = s0 << t0;
+
+ t0 = s0 & 0x8000;
+ t0 = t0 < 1;
+ //t0 = t0 << 2;
+ a0 = a0 - t0;
+ //s0 = s0 << t0;
+
+ return a0;
+#endif
+}
+
+/*
+ * IRQs on the SEAD board look basically are combined together on hardware
+ * interrupt 0 (MIPS IRQ 2)) like:
+ *
+ * MIPS IRQ Source
+ * -------- ------
+ * 0 Software (ignored)
+ * 1 Software (ignored)
+ * 2 UART0 (hw0)
+ * 3 UART1 (hw1)
+ * 4 Hardware (ignored)
+ * 5 Hardware (ignored)
+ * 6 Hardware (ignored)
+ * 7 R4k timer (what we use)
+ *
+ * We handle the IRQ according to _our_ priority which is:
+ *
+ * Highest ---- R4k Timer
+ * Lowest ---- Combined hardware interrupt
+ *
+ * then we just return, if multiple IRQs are pending then we will just take
+ * another exception, big deal.
+ */
+asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
+{
+ unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
+ int irq;
+
+ irq = irq_ffs(pending);
+
+ if (irq >= 0)
+ do_IRQ(MIPSCPU_INT_BASE + irq, regs);
+ else
+ spurious_interrupt(regs);
+}
void __init arch_init_irq(void)
{
mips_cpu_irq_init(MIPSCPU_INT_BASE);
-
- /* Now safe to set the exception vector. */
- set_except_vector(0, mipsIRQ);
}