boot.S revision 12271:fcd15e59fcd5 
110447Snilay@cs.wisc.edu/*
210447Snilay@cs.wisc.edu * Copyright (c) 2012 ARM Limited
310447Snilay@cs.wisc.edu * All rights reserved
410447Snilay@cs.wisc.edu *
510447Snilay@cs.wisc.edu * The license below extends only to copyright in the software and shall
610447Snilay@cs.wisc.edu * not be construed as granting a license to any other intellectual
710447Snilay@cs.wisc.edu * property including but not limited to intellectual property relating
810447Snilay@cs.wisc.edu * to a hardware implementation of the functionality of the software
910447Snilay@cs.wisc.edu * licensed hereunder.  You may use the software subject to the license
1010447Snilay@cs.wisc.edu * terms below provided that you ensure that this notice is replicated
1110447Snilay@cs.wisc.edu * unmodified and in its entirety in all distributions of the software,
1210447Snilay@cs.wisc.edu * modified or unmodified, in source code or in binary form.
1310447Snilay@cs.wisc.edu *
1410447Snilay@cs.wisc.edu * Redistribution and use in source and binary forms, with or without
1510447Snilay@cs.wisc.edu * modification, are permitted provided that the following conditions are
1610447Snilay@cs.wisc.edu * met: redistributions of source code must retain the above copyright
1710447Snilay@cs.wisc.edu * notice, this list of conditions and the following disclaimer;
1810447Snilay@cs.wisc.edu * redistributions in binary form must reproduce the above copyright
1910447Snilay@cs.wisc.edu * notice, this list of conditions and the following disclaimer in the
2010447Snilay@cs.wisc.edu * documentation and/or other materials provided with the distribution;
2110447Snilay@cs.wisc.edu * neither the name of the copyright holders nor the names of its
2210447Snilay@cs.wisc.edu * contributors may be used to endorse or promote products derived from
2310447Snilay@cs.wisc.edu * this software without specific prior written permission.
2410447Snilay@cs.wisc.edu *
2510447Snilay@cs.wisc.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
2610447Snilay@cs.wisc.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
2710447Snilay@cs.wisc.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
2810447Snilay@cs.wisc.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
2910447Snilay@cs.wisc.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
3010447Snilay@cs.wisc.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
3110447Snilay@cs.wisc.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
3210447Snilay@cs.wisc.edu * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
3310447Snilay@cs.wisc.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
3410447Snilay@cs.wisc.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
3510447Snilay@cs.wisc.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
3610447Snilay@cs.wisc.edu *
3710447Snilay@cs.wisc.edu */
38
39        .text
40
41        .globl	_start
42_start:
43        /*
44         * EL3 initialisation
45         */
46        mrs	x0, CurrentEL
47        cmp	x0, #0xc			// EL3?
48        b.ne	start_ns			// skip EL3 initialisation
49
50        mov	x0, #0x30			// RES1
51        orr	x0, x0, #(1 << 0)		// Non-secure EL1
52        orr	x0, x0, #(1 << 8)		// HVC enable
53        orr	x0, x0, #(1 << 10)		// 64-bit EL2
54        msr	scr_el3, x0
55
56        msr	cptr_el3, xzr			// Disable copro. traps to EL3
57
58        ldr	x0, =CNTFRQ
59        msr	cntfrq_el0, x0
60
61        /*
62         * Check for the primary CPU to avoid a race on the distributor
63         * registers.
64         */
65        mrs	x0, mpidr_el1
66        // ARM MPIDR_EL1 bytes: Aff3 (AArch64), Stuff, Aff2, Aff1, Aff0
67        // Test the the MPIDR_EL1 register against 0xff00ffffff to
68        // extract the primary CPU.
69        ldr x1, =0xff00ffffff
70        tst x0, x1                    // check for cpuid==zero
71        b.ne	1f				      // secondary CPU
72
73        ldr	x1, =GIC_DIST_BASE		// GICD_CTLR
74        mov	w0, #3				// EnableGrp0 | EnableGrp1
75        str	w0, [x1]
76
771:	ldr	x1, =GIC_DIST_BASE + 0x80	// GICD_IGROUPR
78        mov	w0, #~0				// Grp1 interrupts
79        str	w0, [x1], #4
80        b.ne	2f				// Only local interrupts for secondary CPUs
81        str	w0, [x1], #4
82        str	w0, [x1], #4
83
842:	ldr	x1, =GIC_CPU_BASE		// GICC_CTLR
85        ldr	w0, [x1]
86        mov	w0, #3				// EnableGrp0 | EnableGrp1
87        str	w0, [x1]
88
89        mov	w0, #1 << 7			// allow NS access to GICC_PMR
90        str	w0, [x1, #4]			// GICC_PMR
91
92        msr	sctlr_el2, xzr
93
94        /*
95         * Prepare the switch to the EL2_SP1 mode from EL3
96         */
97        ldr	x0, =start_ns			// Return after mode switch
98        mov	x1, #0x3c9			// EL2_SP1 | D | A | I | F
99        msr	elr_el3, x0
100        msr	spsr_el3, x1
101        eret
102
103start_ns:
104        /*
105         * Kernel parameters
106         */
107        mov	x0, xzr
108        mov	x1, xzr
109        mov	x2, xzr
110        mov	x3, xzr
111
112        mrs	x4, mpidr_el1
113        // ARM MPIDR_EL1 bytes: Aff3 (AArch64), Stuff, Aff2, Aff1, Aff0
114        // Test the the MPIDR_EL1 register against 0xff00ffffff to
115        // extract the primary CPU.
116        ldr x1, =0xff00ffffff
117        tst x4, x1                    // check for cpuid==zero
118        mov x1, xzr                   // load previous 'xzr' value back to x1
119        b.eq	2f				      // secondary CPU
120
121        /*
122         * Secondary CPUs
123         */
1241:	wfe
125        ldr	x4, =PHYS_OFFSET + 0xfff8
126        ldr     x4, [x4]
127        cbz	x4, 1b
128        br	x4				// branch to the given address
129
1302:
131        /*
132         * UART initialisation (38400 8N1)
133         */
134        ldr	x4, =UART_BASE			// UART base
135        mov	w5, #0x10			// ibrd
136        str	w5, [x4, #0x24]
137        mov	w5, #0xc300
138        orr	w5, w5, #0x0001			// cr
139        str	w5, [x4, #0x30]
140
141        /*
142         * CLCD output site MB
143         */
144        ldr	x4, =SYSREGS_BASE
145        ldr	w5, =(1 << 31) | (1 << 30) | (7 << 20) | (0 << 16)	// START|WRITE|MUXFPGA|SITE_MB
146        str	wzr, [x4, #0xa0]		// V2M_SYS_CFGDATA
147        str	w5, [x4, #0xa4]			// V2M_SYS_CFGCTRL
148
149        // set up the arch timer frequency
150        //ldr	x0, =CNTFRQ
151        //msr	cntfrq_el0, x0
152
153        /*
154         * Primary CPU
155         */
156        ldr	x0, =PHYS_OFFSET + 0x8000000	 // device tree blob
157        ldr     x6, =PHYS_OFFSET + 0x80000       // kernel start address
158        br	x6
159
160        .ltorg
161
162        .org	0x200
163