[MIPS] Fix the crime against humanity that mipsIRQ.S is.

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

2 files changed, 121 insertions, 1 deletions

diff --git a/arch/mips/mips-boards/atlas/Makefile b/arch/mips/mips-boards/atlas/Makefile
index d8dab75906bf..50fec2a5aee6 100644
--- a/arch/mips/mips-boards/atlas/Makefile
+++ b/arch/mips/mips-boards/atlas/Makefile
@@ -16,5 +16,5 @@
 # 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 #
 
-obj-y			:= atlas_int.o atlas_setup.o
+obj-y			:= atlas_int.o atlas-irq.o atlas_setup.o
 obj-$(CONFIG_KGDB)	+= atlas_gdb.o
diff --git a/arch/mips/mips-boards/atlas/atlas-irq.S b/arch/mips/mips-boards/atlas/atlas-irq.S
new file mode 100644
index 000000000000..31bc99a52383
--- /dev/null
+++ b/arch/mips/mips-boards/atlas/atlas-irq.S
@@ -0,0 +1,120 @@
+/*
+ * Carsten Langgaard, carstenl@mips.com
+ * Copyright (C) 1999, 2000 MIPS Technologies, Inc.  All rights reserved.
+ *
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope 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.
+ *
+ * Interrupt exception dispatch code.
+ */
+#include <linux/config.h>
+
+#include <asm/asm.h>
+#include <asm/mipsregs.h>
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
+#include <asm/mips-boards/atlasint.h>
+
+/*
+ * Furthermore, the IRQs on the MIPS board look basically (barring software
+ * IRQs which we don't use at all and all external interrupt sources are
+ * combined together on hardware interrupt 0 (MIPS IRQ 2)) like:
+ *
+ *	MIPS IRQ	Source
+ *      --------        ------
+ *             0	Software (ignored)
+ *             1        Software (ignored)
+ *             2        Combined hardware interrupt (hw0)
+ *             3        Hardware (ignored)
+ *             4        Hardware (ignored)
+ *             5        Hardware (ignored)
+ *             6        Hardware (ignored)
+ *             7        R4k timer (what we use)
+ *
+ * Note: On the SEAD board thing are a little bit different.
+ *       Here IRQ 2 (hw0) is wired to the UART0 and IRQ 3 (hw1) is wired
+ *       wired to UART1.
+ *
+ * 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.
+ */
+
+	.text
+	.set	noreorder
+	.set	noat
+	.align	5
+	NESTED(mipsIRQ, PT_SIZE, sp)
+	SAVE_ALL
+	CLI
+	.set	at
+
+	mfc0	s0, CP0_CAUSE		# get irq bits
+	mfc0	s1, CP0_STATUS		# get irq mask
+	andi	s0, ST0_IM		# CAUSE.CE may be non-zero!
+	and	s0, s1
+
+#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
+	.set	mips32
+	clz	a0, s0
+	.set	mips0
+	negu	a0
+	addu	a0, 31-CAUSEB_IP
+	bltz	a0, spurious
+#else
+	beqz	s0, spurious
+	 li	a0, 7
+
+	and	t0, s0, 0xf000
+	sltiu	t0, t0, 1
+	sll	t0, 2
+	subu	a0, t0
+	sll	s0, t0
+
+	and	t0, s0, 0xc000
+	sltiu	t0, t0, 1
+	sll	t0, 1
+	subu	a0, t0
+	sll	s0, t0
+
+	and	t0, s0, 0x8000
+	sltiu	t0, t0, 1
+	# sll	t0, 0
+	subu	a0, t0
+	# sll	s0, t0
+#endif
+
+	 li	a1, MIPSCPU_INT_ATLAS
+	bne	a0, a1, 1f
+	 addu	a0, MIPSCPU_INT_BASE
+
+	jal	atlas_hw0_irqdispatch
+	 move	 a0, sp
+
+	j	ret_from_irq
+	 nop
+
+1:	jal	do_IRQ
+	 move	a1, sp
+
+	j	ret_from_irq
+	 nop
+
+spurious:
+	j	spurious_interrupt
+	 nop
+	END(mipsIRQ)