head-arm-netarm.s

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/*
 * =================== STARTUP CODE, Kernel 2.4.x =====================
 *
 * linux/arch/armnommu/kernel/head-arm-netarm.S
 *
 * Copyright (C) 2000, 2001 NETsilicon, Inc.
 * Copyright (C) 2000, 2001 Red Hat, Inc.
 *
 * This software is copyrighted by Red Hat. LICENSEE agrees that
 * it will not delete this copyright notice, trademarks or protective
 * notices from any copy made by LICENSEE.
 *
 * This software is provided "AS-IS" and any express or implied 
 * warranties or conditions, including but not limited to any
 * implied warranties of merchantability and fitness for a particular
 * purpose regarding this software. In no event shall Red Hat
 * be liable for any indirect, consequential, or incidental damages,
 * loss of profits or revenue, loss of use or data, or interruption
 * of business, whether the alleged damages are labeled in contract,
 * tort, or indemnity.
 *
 * 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.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * author(s) : Joe deBlaquiere
 */

#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/mach-types.h>
#include <asm/arch/netarm_registers.h>
#include <asm/arch/netarm_mmap.h>

#define	NETARM_INIT_CPSR	(CPSR_I_BIT | CPSR_F_BIT | CPSR_SVC_MODE)

/*
 * Define which output pin to use for NET+ARM development board blink routine
 */
#define NA_YELLOW_LED 0x04
#define NA_GREEN_LED  0x02

#ifdef CONFIG_NETARM_EMLIN
/* The (one) green LED is on bit 6 (0x40) */
#define NA_BLINK_LED 0x40
#define NA_FAIL_LED  0x40
#else
/* Use green and yellow LEDs */
#define NA_BLINK_LED NA_YELLOW_LED
#define NA_FAIL_LED NA_GREEN_LED
#endif

/*
 * We place the page tables 16K below TEXTADDR.  Therefore, we must make sure
 * that TEXTADDR is correctly set.  Currently, we expect the least significant
 * "short" to be 0x8000, but we could probably relax this restriction to
 * TEXTADDR > PAGE_OFFSET + 0x4000
 *
 * Note that swapper_pg_dir is the virtual address of the page tables, and
 * pgtbl gives us a position-independent reference to these tables.  We can
 * do this because stext == TEXTADDR
 *
 * swapper_pg_dir, pgtbl and krnladr are all closely related.
 * (FIXME: do we need this at all in a no-mmu configuration? rp)
 */
	.globl	SYMBOL_NAME(swapper_pg_dir)
	.equ	SYMBOL_NAME(swapper_pg_dir), TEXTADDR - 0x4000
	
/*
 * This define is used to determine the number of wait states needed
 * for the 90 ns flash used on the NET+ARM reference board.  The macro
 * is only valid for 90 ns flash.  To get this value, the following
 * calculation was used:
 *
 *   ceil(90 / ((1 / FSYSCLK) * 1000)) - 1
 *
 * This define gives the same value as the above calculation, but based
 * on the PLLCNT (instead of on the FSYSCLK).
*/
#define FLASH_90ns_WAIT_STATES	((NETARM_PLL_COUNT_VAL + 2) / 3)

		.text
		.align	12

/*
 * Reset condition : 
 *	R14_svc 	= unknown
 *	SPSR_svc 	= CPSR
 *	CPSR		= 0b1101_0011 ; not IRQ, no FIQ, SVC mode
 *	PC		= 0x0
 */

		.section ".text.init",#alloc,#execinstr
		.type	stext, #function
ENTRY(stext)
       		mov	r0, #NETARM_INIT_CPSR
		msr	cpsr, r0

/* delay (0x10000) to allow developer to attach debugger before boot */
		mov	r1, #0x10000
1:
		subs	r1, r1, #1
		bge	1b	

/*
 * prior to software reset : need to set pin PORTC4 to be *HRESET
 */

		ldr	r4, =NETARM_GEN_MODULE_BASE

		ldr	r1, =( NETARM_GEN_PORT_MODE(0x10) | \
		               NETARM_GEN_PORT_DIR(0x10) )
		str	r1, [r4, #+NETARM_GEN_PORTC]		

/*
 * software reset : see HW Ref. Guide 8.2.4 : Software Service Register
 *                  for an explanation of this process
 */

		ldr	r4, =NETARM_GEN_MODULE_BASE

		ldr	r1, =NETARM_GEN_SW_SVC_RESETA
		str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
		
		ldr	r1, =NETARM_GEN_SW_SVC_RESETB
		str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
		
		ldr	r1, =NETARM_GEN_SW_SVC_RESETA
		str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
		
		ldr	r1, =NETARM_GEN_SW_SVC_RESETB
		str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]

/*
 * set up PLL and System Config
 */

@ r4 already set
		ldr	r4, =NETARM_GEN_MODULE_BASE
#ifdef	CONFIG_NETARM_NET40_REV2
		ldr	r1, =( NETARM_GEN_SYS_CFG_LENDIAN |	\
			       NETARM_GEN_SYS_CFG_BUSFULL |	\
			       NETARM_GEN_SYS_CFG_USER_EN |	\
			       NETARM_GEN_SYS_CFG_ALIGN_ABORT | \
		               NETARM_GEN_SYS_CFG_BUSARB_INT )
#else
		ldr	r1, =( NETARM_GEN_SYS_CFG_LENDIAN |	\
			       NETARM_GEN_SYS_CFG_BUSFULL |	\
			       NETARM_GEN_SYS_CFG_USER_EN |	\
			       NETARM_GEN_SYS_CFG_ALIGN_ABORT |	\
		               NETARM_GEN_SYS_CFG_BUSARB_INT |	\
			       NETARM_GEN_SYS_CFG_BUSMON_EN )
#endif
		str	r1, [r4, #+NETARM_GEN_SYSTEM_CONTROL]

		ldr	r1, =NETARM_GEN_PLL_CTL_PLLCNT(NETARM_PLL_COUNT_VAL)
		str	r1, [r4, #+NETARM_GEN_PLL_CONTROL ]

/*
 * initialize both serial ports
 */
		
		bl	_netarm_debug_serial_init

		mov	r0, #'A'
		bl	_printch
		
/*
 *	if CS0 is already mapped high, assume it's mapped correctly
 */

		ldr	r4, =NETARM_MEM_MODULE_BASE
		ldr	r1, [r4, #NETARM_MEM_CS0_BASE_ADDR]
		ldr	r2, =NETARM_MEM_BAR_BASE_MASK
		and	r1, r1, r2
		cmp	r1, #0
		bne	_exec_in_RAM
		
		mov	r0, #'B'
		bl	_printch

/*		b	_netarm_led_FAIL2 */

/*
 *	since the system boots without knowing the size of the ROM
 *	the code is mirrored on every page... so we'll jump to
 *	a page way up where we're moving the PROM to
 */
		
		ldr	pc, =(_jump_to_high + NETARM_MMAP_CS0_BASE)

/*
 *	either we now set up the RAM or we were always running from RAM
 *	and we didn't change the memory settings...
 */

_jump_to_high:

		mov	r0, #'C'
		bl	_printch
		
/*
 * test point - jump to blink
 */

		ldr	r4, =NETARM_MEM_MODULE_BASE

#ifndef CONFIG_NETARM_EMLIN
/* Settings for NetSilicon's development boards (NET+40, NET+50, ...) */

/* mem config */
		ldr	r1, =( NETARM_MEM_REFR_PERIOD_USEC(16) | \
			       NETARM_MEM_CFG_REFRESH_EN | \
			       NETARM_MEM_CFG_REFR_CYCLE_5CLKS )
		str	r1, [r4, #NETARM_MEM_MODULE_CONFIG]
		
@		mov	r0, #'D'
@		bl	_printch
		
/* CS0 */
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS0_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS0_BASE_ADDR]

@		mov	r0, #'E'
@		bl	_printch
		
		/* trust that the bus size for flash was strapped correctly */
		/* this saves the bus width in r2 and then ORs it back in */
		/* it's a pretty safe assumption, otherwise it wouldn't boot */

		ldr	r2, [r4, #NETARM_MEM_CS0_OPTIONS]
		and	r2, r2, #NETARM_MEM_OPT_BUS_SIZE_MASK

/*		just a test: assume 32 bit flash mem --rp */
/*		mov	r2, #NETARM_MEM_OPT_32BIT */

		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS0_MASK) |	\
			       NETARM_MEM_OPT_WAIT_STATES(FLASH_90ns_WAIT_STATES) |		\
			       NETARM_MEM_OPT_BCYC_2 |			\
			       NETARM_MEM_OPT_BSIZE_4 | 		\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		orr	r1, r1, r2
		str	r1, [r4, #NETARM_MEM_CS0_OPTIONS]

@		mov	r0, #'F'
@		bl	_printch

#ifdef	CONFIG_NETARM_NET40_REV2
/* CS1 */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS1_MASK) |	\
			       NETARM_MEM_OPT_BCYC_2 |			\
			       NETARM_MEM_OPT_BSIZE_16 | 		\
			       NETARM_MEM_OPT_WAIT_STATES(0) | 		\
			       NETARM_MEM_OPT_32BIT | 			\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS1_OPTIONS]

@		mov	r0, #'G'
@		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS1_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_SYNC |		\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_UNBAL |		\
			       NETARM_MEM_BAR_DRAM_SEL |		\
			       NETARM_MEM_BAR_BURST_EN |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS1_BASE_ADDR]

@		mov	r0, #'H'
@		bl	_printch

/* CS2 */
		ldr	r1, =( 0 )
		str	r1, [r4, #NETARM_MEM_CS2_BASE_ADDR]

@		mov	r0, #'I'
@		bl	_printch

		ldr	r1, =( 0 )
		str	r1, [r4, #NETARM_MEM_CS2_OPTIONS]

@		mov	r0, #'J'
@		bl	_printch
#else
/* CS1 */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS1_MASK) |	\
			       NETARM_MEM_OPT_BCYC_3 |			\
			       NETARM_MEM_OPT_BSIZE_4 | 		\
			       NETARM_MEM_OPT_WAIT_STATES(0) | 		\
			       NETARM_MEM_OPT_32BIT | 			\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS1_OPTIONS]

@		mov	r0, #'G'
@		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS1_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |		\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_DRAM_SEL |		\
			       NETARM_MEM_BAR_BURST_EN |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS1_BASE_ADDR]

@		mov	r0, #'H'
@		bl	_printch
		
/* CS2 */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS2_MASK) |	\
			       NETARM_MEM_OPT_BCYC_3 |			\
			       NETARM_MEM_OPT_BSIZE_4 | 		\
			       NETARM_MEM_OPT_WAIT_STATES(0) | 		\
			       NETARM_MEM_OPT_32BIT | 			\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS2_OPTIONS]

@		mov	r0, #'I'
@		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS2_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |		\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_DRAM_SEL |		\
			       NETARM_MEM_BAR_BURST_EN |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS2_BASE_ADDR]

@		mov	r0, #'J'
@		bl	_printch
#endif

/* CS3 */
#ifdef CONFIG_NETARM_EEPROM
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS3_MASK) |	\
			       NETARM_MEM_OPT_BCYC_1 |\
			       NETARM_MEM_OPT_BSIZE_2 | \
			       NETARM_MEM_OPT_WAIT_STATES(10) | \
			       NETARM_MEM_OPT_8BIT | \
			       NETARM_MEM_OPT_READ_ASYNC | \
			       NETARM_MEM_OPT_WRITE_ASYNC )
#else
		ldr	r1, =( 0 )
#endif
		str	r1, [r4, #NETARM_MEM_CS3_OPTIONS]

@		mov	r0, #'K'
@		bl	_printch
		
#ifdef CONFIG_NETARM_EEPROM
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS3_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
#else
		ldr	r1, =( 0 )
#endif
		str	r1, [r4, #NETARM_MEM_CS3_BASE_ADDR]

@		mov	r0, #'L'
@		bl	_printch
		
/* CS4 */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(NETARM_MMAP_CS4_MASK) |	\
			       NETARM_MEM_OPT_32BIT_EXT_ACK | \
			       NETARM_MEM_OPT_READ_ASYNC | \
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS4_OPTIONS]

		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS4_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS4_BASE_ADDR]

#else
/* Settings for IMMS' EMLIN board */
/* mem config */
		ldr	r1, =( NETARM_MEM_REFR_PERIOD_USEC(15) | \
			       NETARM_MEM_CFG_REFRESH_EN | \
			       NETARM_MEM_CFG_REFR_CYCLE_8CLKS )
		str	r1, [r4, #NETARM_MEM_MODULE_CONFIG]
		
		mov	r0, #'D'
		bl	_printch
		
/* CS0 (Flash) */
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS0_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS0_BASE_ADDR]

		mov	r0, #'E'
		bl	_printch
		
		/* trust that the bus size for flash was strapped correctly */
		/* this saves the bus width in r2 and then ORs it back in */
		/* it's a pretty safe assumption, otherwise it wouldn't boot */

		ldr	r2, [r4, #NETARM_MEM_CS0_OPTIONS]
		and	r2, r2, #NETARM_MEM_OPT_BUS_SIZE_MASK

		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(0xFFC00000) |	\
			       NETARM_MEM_OPT_WAIT_STATES(FLASH_90ns_WAIT_STATES) |		\
			       NETARM_MEM_OPT_BCYC_2 |			\
			       NETARM_MEM_OPT_BSIZE_4 | 		\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		orr	r1, r1, r2
		str	r1, [r4, #NETARM_MEM_CS0_OPTIONS]

		mov	r0, #'F'
		bl	_printch

/* CS1 (SDRAM - optional) */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(0xFF000000) |	\
			       NETARM_MEM_OPT_BCYC_2 |			\
			       NETARM_MEM_OPT_BSIZE_8 | 		\
			       NETARM_MEM_OPT_WAIT_STATES(0) | 		\
			       NETARM_MEM_OPT_32BIT | 			\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS1_OPTIONS]

		mov	r0, #'G'
		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS2_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_SYNC |		\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_UNBAL |		\
			       NETARM_MEM_BAR_DRAM_SEL )
		str	r1, [r4, #NETARM_MEM_CS1_BASE_ADDR]

		mov	r0, #'H'
		bl	_printch

/* CS2 (mainboard SDRAM) */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(0xFF000000) |	\
			       NETARM_MEM_OPT_BCYC_2 |			\
			       NETARM_MEM_OPT_BSIZE_8 | 		\
			       NETARM_MEM_OPT_WAIT_STATES(0) | 		\
			       NETARM_MEM_OPT_32BIT | 			\
			       NETARM_MEM_OPT_READ_ASYNC | 		\
			       NETARM_MEM_OPT_WRITE_ASYNC )
		str	r1, [r4, #NETARM_MEM_CS2_OPTIONS]

		mov	r0, #'I'
		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS1_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_SYNC |		\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_DRAM_MUX_UNBAL |		\
			       NETARM_MEM_BAR_DRAM_SEL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS2_BASE_ADDR]

		mov	r0, #'J'
		bl	_printch

/* CS3 (Peripherals) */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(0xFFF00000) |	\
			       NETARM_MEM_OPT_BCYC_4 |\
			       NETARM_MEM_OPT_BSIZE_2 | \
			       NETARM_MEM_OPT_WAIT_STATES(15) | \
			       NETARM_MEM_OPT_16BIT | \
			       NETARM_MEM_OPT_READ_SYNC | \
			       NETARM_MEM_OPT_WRITE_SYNC )
		str	r1, [r4, #NETARM_MEM_CS3_OPTIONS]

		mov	r0, #'K'
		bl	_printch
		
		ldr	r1, =( NETARM_MEM_BAR_BASE(NETARM_MMAP_CS3_BASE) | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_1BCLK_IDLE |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS3_BASE_ADDR]

		mov	r0, #'L'
		bl	_printch

/* CS4 (FPGA) */
		ldr	r1, =( NETARM_MEM_OPT_BASE_USE(0xFFFFF000) |	\
			       NETARM_MEM_OPT_WAIT_STATES(15) | \
			       NETARM_MEM_OPT_32BIT | \
			       NETARM_MEM_OPT_READ_SYNC | \
			       NETARM_MEM_OPT_WRITE_SYNC )
		str	r1, [r4, #NETARM_MEM_CS4_OPTIONS]

		ldr	r1, =( 0x30000000 | 	\
			       NETARM_MEM_BAR_DRAM_FP |			\
			       NETARM_MEM_BAR_DRAM_MUX_INT |		\
			       NETARM_MEM_BAR_1BCLK_IDLE |		\
			       NETARM_MEM_BAR_DRAM_MUX_BAL |		\
			       NETARM_MEM_BAR_VALID )
		str	r1, [r4, #NETARM_MEM_CS4_BASE_ADDR]

#endif

/* copy to RAM */

		mov	r0, #'M'
		bl	_printch

		mov	r3, #NETARM_MMAP_RAM_BASE;
		mov	r4, #NETARM_MMAP_FLASH_BASE;
		mov	r0, #NETARM_MMAP_FLASH_COPY_SIZE;
1:
		ldr	r1, [r4], #4
		str	r1, [r3], #4
		subs	r0, r0, #4
		bgt	1b


_exec_in_RAM:
		mov	r0, #'N'
		bl	_printch
		
 		ldr	pc, =(__zentry)
__zentry:

/*
 * print bootloaded hello and current PC
 */

		mov	r0, #'@'
		bl	_printch

		mov	r0, pc
		bl 	_printhex8

		mov	r0, #'\n'
		bl	_printch
		
		ldr	r0, =_hello_world
		bl 	_printascii

		mov	r0, #'\n'
		bl	_printch

/*
 * dump serial and memory control registers
 */

		bl	_netarm_debug_serial_dump
		bl	_netarm_debug_mem_ctl_dump		
	
/*
 * count down to boot...
 */

		mov	r8, #15

1:		
		mov	r0, r8
		bl 	_printhex2

		mov	r0, #'\r'
		bl	_printch

		mov	r2, #0x20000
2:
		subs	r2, r2, #1
		bgt	2b
		
		subs	r8, r8, #1
		bgt	1b

/*
 * test point - jump to blink
 */

/*		b	_netarm_led_blink */

/*
 * set up initial stack 
 */

		ldr	r5, =LC0
		ldmia	r5, {r5, r6, r8, r9, sp}

/* clear BSS segment */
		mov	r4, #0
1:		cmp	r5, r8
		strcc	r4, [r5], #4
		bcc	1b

        /*  Put initial values into stack.  This would normally be done
        by sched_init() in kernel/sched.c, but that would overwrite the
        stack we're already using.  That would be bad.
        (code from the DSC21 head file by Steve Johnson) 
	Only fill half the task_union area, because the task list starts
	in the lower part. --rp */
        	mov r5, sp
        	sub r5, r5, #0x1000
        	ldr r4, L_STACK_MAGIC
        	str r4, [r5], #4
        	ldr r4, L_STACK_UNTOUCHED_MAGIC
1:      	cmp r5, sp
        	strcc r4, [r5], #4
        	bcc 1b

/*
 * Stob in the ARMID - since we don't have CP15 to query... 
 */

		ldr	r2, =0x41007700
		str	r2, [r6]
/*  Pretend we know what our processor code is (for arm_id)   */
		mov     r2, #MACH_TYPE_NETARM
		str     r2, [r9]

/*