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

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

1 files changed, 122 insertions, 0 deletions

diff --git a/arch/mips/mips-boards/malta/malta-irq.S b/arch/mips/mips-boards/malta/malta-irq.S
new file mode 100644
index 000000000000..6217aff3be03
--- /dev/null
+++ b/arch/mips/mips-boards/malta/malta-irq.S
@@ -0,0 +1,122 @@
+/*
+ * 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/maltaint.h>
+
+/*
+ * IRQs on the Malta 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)
+ *
+ * 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_I8259A
+        bne     a0, a1, 1f
+         addu   a0, MIPSCPU_INT_BASE
+
+        jal     malta_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)