* Patch by Scott McNutt, 04 Oct 2003:

  - add support for Altera Nios-32 CPU
  - add support for Nios Cyclone Development Kit (DK-1C20)

* Patch by Steven Scholz, 29 Sep 2003:
  - A second parameter for bootm overwrites the load address for
    "Standalone Application" images.
  - bootm sets environment variable "filesize" to the resulting
    (uncompressed) data length for "Standalone Application" images
    when autostart is set to "no". Now you can do something like
       if bootm $fpgadata $some_free_ram ; then
               fpga load 0 $some_free_ram $filesize
       fi

* Patch by Denis Peter, 25 Sept 2003:
  add support for the MIP405 Rev. C board

1 files changed, 186 insertions, 0 deletions

diff --git a/cpu/nios/start.S b/cpu/nios/start.S
new file mode 100644
index 0000000..7cbd1a7
--- /dev/null
+++ b/cpu/nios/start.S
@@ -0,0 +1,186 @@
+/*
+ * (C) Copyright 2003, Psyent Corporation <www.psyent.com>
+ * Scott McNutt <smcnutt@psyent.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+
+#include <config.h>
+#include <version.h>
+
+#if !defined(CONFIG_IDENT_STRING)
+#define CONFIG_IDENT_STRING ""
+#endif
+
+#define STATUS_INIT	0x8600		/* IE=1, IPRI=2 */
+
+/*************************************************************************
+ * RESTART
+ ************************************************************************/
+
+	.text
+	.global _start
+
+_start:
+	bsr	0f
+	nop
+	.long	_start
+
+	/* GERMS -- The "standard-32" configuration GERMS monitor looks
+	 * for the string "Nios" at flash_base + 0xc (actually it only
+	 * tests for 'N', 'i'). You can leave support for this in place
+	 * as it's only a few words.
+	 */
+	. = _start + 0x000c
+	.string "Nios"
+
+	.align 4
+0:
+	/*
+	 * Early setup -- set cwp = HI_LIMIT, IPRI = 2, IE = 1 to
+	 * enable underflow exceptions. Disable cache.
+	 * NOTE: %o7 has return addr -- save in %g7 use later.
+	 */
+	mov	%g7, %o7
+
+	pfx	2			/* WVALID */
+	rdctl	%g0
+	lsri	%g0, 1
+	pfx	%hi(STATUS_INIT)
+	or	%g0, %lo(STATUS_INIT)
+	wrctl	%g0			/* update status */
+	nop
+
+	/*
+	 * STACK
+	 */
+	pfx	%hi(CFG_INIT_SP)
+	movi	%sp, %lo(CFG_INIT_SP)
+	pfx	%xhi(CFG_INIT_SP)
+	movhi	%sp, %xlo(CFG_INIT_SP)
+	mov	%fp, %sp
+
+	pfx	%hi(4*16)
+	subi	%sp, %lo(4*16)		/* Space for reg window mgmt */
+
+	/*
+	 * RELOCATE -- %g7 has return addr from bsr at _start.
+	 */
+	pfx	%hi(__u_boot_cmd_end)
+	movi	%g5, %lo(__u_boot_cmd_end)
+	pfx	%xhi(__u_boot_cmd_end)
+	movhi	%g5, %xlo(__u_boot_cmd_end) /* %g5 <- end address */
+
+	lsli	%g7, 1			/* mem = retaddr << 1 */
+	mov	%g6, %g7
+	subi	%g6, 4			/* %g6 <- src addr */
+	ld	%g7, [%g7]		/* %g7 <- dst addr */
+
+1:	cmp	%g7, %g5
+	skps	cc_nz
+	br	2f
+	nop				/* delay slot */
+
+	ld	%g0, [%g6]
+	addi	%g6, 4			/* src++ */
+	st	[%g7], %g0
+	addi	%g7, 4			/* dst++ */
+	br	1b
+	nop				/* delay slot */
+2:
+
+	/*
+	 * Jump to relocation address
+	 */
+	 pfx	%hi(reloc@h)
+	 movi	%g0, %lo(reloc@h)
+	 pfx	%xhi(reloc@h)
+	 movhi	%g0, %xlo(reloc@h)
+	 jmp	%g0
+reloc:
+
+	/*
+	 * CLEAR BSS
+	 */
+	pfx	%hi(__bss_end)
+	movi	%g5, %lo(__bss_end)
+	pfx	%xhi(__bss_end)
+	movhi	%g5, %xlo(__bss_end)	/* %g5 <- end address */
+	pfx	%hi(__bss_start)
+	movi	%g7, %lo(__bss_start)
+	pfx	%xhi(__bss_start)
+	movhi	%g7, %xlo(__bss_start)	/* %g7 <- end address */
+
+	movi	%g0, 0
+3:	cmp	%g7, %g5
+	skps	cc_nz
+	br	4f
+	nop				/* delay slot */
+
+	st	[%g7], %g0
+	addi	%g7, 4			/* (delay slot) dst++ */
+	br	3b
+	nop				/* delay slot */
+4:
+
+	/*
+	 * Call board_init -- never returns
+	 */
+	pfx	%hi(board_init@h)
+	movi	%g1, %lo(board_init@h)
+	pfx	%xhi(board_init@h)
+	movhi	%g1, %xlo(board_init@h)
+	call	%g1
+	nop				/* Delaly slot */
+	/* NEVER RETURNS */
+
+/*
+ * dly_clks -- Nios doesn't have a time/clk reference for simple
+ * delay loops, so we do our best by counting instruction cycles.
+ * A control register that counts system clock cycles would be
+ * a handy feature -- hint for Altera ;-)
+ */
+ 	.globl dly_clks
+	/* Each loop is 4 instructions as delay slot is always
+	 * executed. Each instruction is approximately 4 clocks
+	 * (according to some lame info from Altera). So ...
+	 * ... each loop is about 16 clocks.
+	 */
+
+dly_clks:
+	lsri	%o0, 4			/* cnt/16 */
+
+8:	skprnz	%o0
+	br	9f
+	subi	%o0, 1			/* cnt--, Delay slot */
+	br	8b
+	nop
+
+9:	lret
+	nop				/* Delay slot */
+
+
+	.data
+	.globl	version_string
+
+version_string:
+	.ascii U_BOOT_VERSION
+	.ascii " (", __DATE__, " - ", __TIME__, ")"
+	.ascii CONFIG_IDENT_STRING, "\0"