[MIPS] Rewrite all the assembler interrupt handlers to C.

Saves like 1,600 lines of code, is way easier to debug, compilers
frequently do a better job than the cut and paste type of handlers many
boards had.  And finally having all the stuff done in a single place
also means alot of bug potencial for the MT ASE is gone.

The only surviving handler in assembler is the DECstation one; I hope
Maciej will rewrite it.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 74 insertions, 170 deletions

diff --git a/arch/mips/sibyte/bcm1480/Makefile b/arch/mips/sibyte/bcm1480/Makefile
index 538d5a5..7b36ff3 100644
--- a/arch/mips/sibyte/bcm1480/Makefile
+++ b/arch/mips/sibyte/bcm1480/Makefile
@@ -1,4 +1,4 @@
-obj-y := setup.o irq.o irq_handler.o time.o
+obj-y := setup.o irq.o time.o
 
 obj-$(CONFIG_SMP)			+= smp.o
 
diff --git a/arch/mips/sibyte/bcm1480/irq.c b/arch/mips/sibyte/bcm1480/irq.c
index 9cf7d71..e61760b 100644
--- a/arch/mips/sibyte/bcm1480/irq.c
+++ b/arch/mips/sibyte/bcm1480/irq.c
@@ -187,9 +187,6 @@ static void bcm1480_set_affinity(unsigned int irq, cpumask_t mask)
 #endif
 
 
-/* Defined in arch/mips/sibyte/bcm1480/irq_handler.S */
-extern void bcm1480_irq_handler(void);
-
 /*****************************************************************************/
 
 static unsigned int startup_bcm1480_irq(unsigned int irq)
@@ -422,7 +419,6 @@ void __init arch_init_irq(void)
 #endif
 	/* Enable necessary IPs, disable the rest */
 	change_c0_status(ST0_IM, imask);
-	set_except_vector(0, bcm1480_irq_handler);
 
 #ifdef CONFIG_KGDB
 	if (kgdb_flag) {
@@ -473,3 +469,76 @@ void bcm1480_kgdb_interrupt(struct pt_regs *regs)
 }
 
 #endif 	/* CONFIG_KGDB */
+
+static inline int dclz(unsigned long long x)
+{
+	int lz;
+
+	__asm__ (
+	"	.set	push						\n"
+	"	.set	mips64						\n"
+	"	dclz	%0, %1						\n"
+	"	.set	pop						\n"
+	: "=r" (lz)
+	: "r" (x));
+
+	return lz;
+}
+
+extern void bcm1480_timer_interrupt(struct pt_regs *regs);
+extern void bcm1480_mailbox_interrupt(struct pt_regs *regs);
+extern void bcm1480_kgdb_interrupt(struct pt_regs *regs);
+
+asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
+{
+	unsigned int pending;
+
+#ifdef CONFIG_SIBYTE_BCM1480_PROF
+	/* Set compare to count to silence count/compare timer interrupts */
+	write_c0_compare(read_c0_count());
+#endif
+
+	pending = read_c0_cause();
+
+#ifdef CONFIG_SIBYTE_BCM1480_PROF
+	if (pending & CAUSEF_IP7)	/* Cpu performance counter interrupt */
+		sbprof_cpu_intr(exception_epc(regs));
+#endif
+
+	if (pending & CAUSEF_IP4)
+		bcm1480_timer_interrupt(regs);
+
+#ifdef CONFIG_SMP
+	if (pending & CAUSEF_IP3)
+		bcm1480_mailbox_interrupt(regs);
+#endif
+
+#ifdef CONFIG_KGDB
+	if (pending & CAUSEF_IP6)
+		bcm1480_kgdb_interrupt(regs);		/* KGDB (uart 1) */
+#endif
+
+	if (pending & CAUSEF_IP2) {
+		unsigned long long mask_h, mask_l;
+		unsigned long base;
+
+		/*
+		 * Default...we've hit an IP[2] interrupt, which means we've
+		 * got to check the 1480 interrupt registers to figure out what
+		 * to do.  Need to detect which CPU we're on, now that
+		 * smp_affinity is supported.
+		 */
+		base = A_BCM1480_IMR_MAPPER(smp_processor_id());
+		mask_h = __raw_readq(
+			IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_H));
+		mask_l = __raw_readq(
+			IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_L));
+
+		if (!mask_h) {
+			if (mask_h ^ 1)
+				do_IRQ(63 - dclz(mask_h), regs);
+			else
+				do_IRQ(127 - dclz(mask_l), regs);
+		}
+	}
+}
diff --git a/arch/mips/sibyte/bcm1480/irq_handler.S b/arch/mips/sibyte/bcm1480/irq_handler.S
deleted file mode 100644
index 408db88..0000000
--- a/arch/mips/sibyte/bcm1480/irq_handler.S
+++ /dev/null
@@ -1,165 +0,0 @@
-/*
- * Copyright (C) 2000,2001,2002,2003,2004 Broadcom Corporation
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
- */
-
-/*
- * bcm1480_irq_handler() is the routine that is actually called when an
- * interrupt occurs.  It is installed as the exception vector handler in
- * init_IRQ() in arch/mips/sibyte/bcm1480/irq.c
- *
- * In the handle we figure out which interrupts need handling, and use that
- * to call the dispatcher, which will take care of actually calling
- * registered handlers
- *
- * Note that we take care of all raised interrupts in one go at the handler.
- * This is more BSDish than the Indy code, and also, IMHO, more sane.
- */
-#include <linux/config.h>
-
-#include <asm/addrspace.h>
-#include <asm/asm.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-#include <asm/sibyte/sb1250_defs.h>
-#include <asm/sibyte/bcm1480_regs.h>
-#include <asm/sibyte/bcm1480_int.h>
-
-/*
- * What a pain. We have to be really careful saving the upper 32 bits of any
- * register across function calls if we don't want them trashed--since were
- * running in -o32, the calling routing never saves the full 64 bits of a
- * register across a function call.  Being the interrupt handler, we're
- * guaranteed that interrupts are disabled during this code so we don't have
- * to worry about random interrupts blasting the high 32 bits.
- */
-
-	.text
-	.set	push
-	.set	noreorder
-	.set	noat
-	.set	mips64
-	#.set	mips4
-	.align	5
-	NESTED(bcm1480_irq_handler, PT_SIZE, sp)
-	SAVE_ALL
-	CLI
-
-#ifdef CONFIG_SIBYTE_BCM1480_PROF
-	/* Set compare to count to silence count/compare timer interrupts */
-	mfc0	t1, CP0_COUNT
-	mtc0	t1, CP0_COMPARE /* pause to clear IP[7] bit of cause ? */
-#endif
-	/* Read cause */
-	mfc0	s0, CP0_CAUSE
-
-#ifdef CONFIG_SIBYTE_BCM1480_PROF
-	/* Cpu performance counter interrupt is routed to IP[7] */
-	andi	t1, s0, CAUSEF_IP7
-	beqz	t1, 0f
-	 srl	t1, s0, (CAUSEB_BD-2)	/* Shift BD bit to bit 2 */
-	and	t1, t1, 0x4		/* mask to get just BD bit */
-#ifdef CONFIG_MIPS64
-	dmfc0	a0, CP0_EPC
-	daddu	a0, a0, t1		/* a0 = EPC + (BD ? 4 :	0) */
-#else
-	mfc0	a0, CP0_EPC
-	addu	a0, a0, t1		/* a0 = EPC + (BD ? 4 :	0) */
-#endif
-	jal	sbprof_cpu_intr
-	 nop
-	j	ret_from_irq
-	 nop
-0:
-#endif
-
-	/* Timer interrupt is routed to IP[4] */
-	andi	t1, s0, CAUSEF_IP4
-	beqz	t1, 1f
-	 nop
-	jal	bcm1480_timer_interrupt
-	 move	a0, sp			/* Pass the registers along */
-	j	ret_from_irq
-	 nop				/* delay slot  */
-1:
-
-#ifdef CONFIG_SMP
-	/* Mailbox interrupt is routed to IP[3] */
-	andi	 t1, s0, CAUSEF_IP3
-	beqz	 t1, 2f
-	 nop
-	jal	 bcm1480_mailbox_interrupt
-	 move	 a0, sp
-	j	 ret_from_irq
-	 nop				/* delay slot  */
-2:
-#endif
-
-#ifdef CONFIG_KGDB
-	/* KGDB (uart 1) interrupt is routed to IP[6] */
-	andi	 t1, s0, CAUSEF_IP6
-	beqz	 t1, 3f
-	 nop				/* delay slot  */
-	jal	 bcm1480_kgdb_interrupt
-	 move	 a0, sp
-	j	 ret_from_irq
-	 nop				/* delay slot  */
-3:
-#endif
-
-	and	 t1, s0, CAUSEF_IP2
-	beqz	 t1, 9f
-	 nop
-
-	/*
-	 * Default...we've hit an IP[2] interrupt, which means we've got
-	 * to check the 1480 interrupt registers to figure out what to do
-	 * Need to detect which CPU we're on, now that smp_affinity is
-	 * supported.
-	 */
-	PTR_LA	 v0, CKSEG1 + A_BCM1480_IMR_CPU0_BASE
-#ifdef CONFIG_SMP
-	lw	 t1, TI_CPU($28)
-	sll	 t1, t1, BCM1480_IMR_REGISTER_SPACING_SHIFT
-	addu	 v0, v0, t1
-#endif
-
-	/* Read IP[2] status (get both high and low halves of status) */
-	ld	 s0, R_BCM1480_IMR_INTERRUPT_STATUS_BASE_H(v0)
-	ld	 s1, R_BCM1480_IMR_INTERRUPT_STATUS_BASE_L(v0)
-
-	move	 s2, zero	/* intr number  */
-	li	 s3, 64
-
-	beqz	 s0, 9f		/* No interrupts.  Return.  */
-	 move	 a1, sp
-
-	xori	 s4, s0, 1	/* if s0 (_H) == 1, it's a low intr, so...  */
-	movz	 s2, s3, s4	/* start the intr number at 64, and  */
-	movz	 s0, s1, s4	/* look at the low status value.  */
-
-	dclz	 s1, s0		/* Find the next interrupt.  */
-	dsubu	 a0, zero, s1
-	daddiu	 a0, a0, 63
-	jal	 do_IRQ
-	 daddu	 a0, a0, s2
-
-9:	j	 ret_from_irq
-	 nop
-
-	.set pop
-	END(bcm1480_irq_handler)