nios2: add kgdb support

Signed-off-by: Ley Foon Tan <lftan@altera.com>

arch/nios2/include/asm/kgdb.h

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2015 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * Based on the code posted by Kazuyasu on the Altera Forum at:
+ * http://www.alteraforum.com/forum/showpost.php?p=77003&postcount=20
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef _ASM_NIOS2_KGDB_H
+#define _ASM_NIOS2_KGDB_H
+
+#define CACHE_FLUSH_IS_SAFE	1
+#define BUFMAX			2048
+
+enum regnames {
+	GDB_R0 = 0,
+	GDB_AT,
+	GDB_R2,
+	GDB_R3,
+	GDB_R4,
+	GDB_R5,
+	GDB_R6,
+	GDB_R7,
+	GDB_R8,
+	GDB_R9,
+	GDB_R10,
+	GDB_R11,
+	GDB_R12,
+	GDB_R13,
+	GDB_R14,
+	GDB_R15,
+	GDB_R16,
+	GDB_R17,
+	GDB_R18,
+	GDB_R19,
+	GDB_R20,
+	GDB_R21,
+	GDB_R22,
+	GDB_R23,
+	GDB_ET,
+	GDB_BT,
+	GDB_GP,
+	GDB_SP,
+	GDB_FP,
+	GDB_EA,
+	GDB_BA,
+	GDB_RA,
+	GDB_PC,
+	GDB_STATUS,
+	GDB_ESTATUS,
+	GDB_BSTATUS,
+	GDB_IENABLE,
+	GDB_IPENDING,
+	GDB_CPUID,
+	GDB_CTL6,
+	GDB_EXCEPTION,
+	GDB_PTEADDR,
+	GDB_TLBACC,
+	GDB_TLBMISC,
+	GDB_ECCINJ,
+	GDB_BADADDR,
+	GDB_CONFIG,
+	GDB_MPUBASE,
+	GDB_MPUACC,
+	/* do not change the last entry or anything below! */
+	GDB_NUMREGBYTES		/* number of registers */
+};
+
+#define GDB_SIZEOF_REG		sizeof(u32)
+#define DBG_MAX_REG_NUM	(49)
+#define NUMREGBYTES		(DBG_MAX_REG_NUM * sizeof(GDB_SIZEOF_REG))
+
+#define BREAK_INSTR_SIZE	4
+static inline void arch_kgdb_breakpoint(void)
+{
+	__asm__ __volatile__("trap 30\n");
+}
+
+#endif /* _ASM_NIOS2_KGDB_H */