summaryrefslogtreecommitdiff
path: root/arch/nios2/kernel/setup.c
blob: 6bbd4ae2beb01eab6386dc14f4c38f890558e056 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
/*
 * Nios2-specific parts of system setup
 *
 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2004 Microtronix Datacom Ltd.
 * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/console.h>
#include <linux/memblock.h>
#include <linux/initrd.h>
#include <linux/of_fdt.h>
#include <linux/screen_info.h>

#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/cpuinfo.h>

unsigned long memory_start;
EXPORT_SYMBOL(memory_start);

unsigned long memory_end;
EXPORT_SYMBOL(memory_end);

unsigned long memory_size;

static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
					0, 0, 0, 0, 0, 0,
					0};

#ifdef CONFIG_VT
struct screen_info screen_info;
#endif

/* Copy a short hook instruction sequence to the exception address */
static inline void copy_exception_handler(unsigned int addr)
{
	unsigned int start = (unsigned int) exception_handler_hook;
	volatile unsigned int tmp = 0;

	if (start == addr) {
		/* The CPU exception address already points to the handler. */
		return;
	}

	__asm__ __volatile__ (
		"ldw	%2,0(%0)\n"
		"stw	%2,0(%1)\n"
		"ldw	%2,4(%0)\n"
		"stw	%2,4(%1)\n"
		"ldw	%2,8(%0)\n"
		"stw	%2,8(%1)\n"
		"flushd	0(%1)\n"
		"flushd	4(%1)\n"
		"flushd	8(%1)\n"
		"flushi %1\n"
		"addi	%1,%1,4\n"
		"flushi %1\n"
		"addi	%1,%1,4\n"
		"flushi %1\n"
		"flushp\n"
		: /* no output registers */
		: "r" (start), "r" (addr), "r" (tmp)
		: "memory"
	);
}

/* Copy the fast TLB miss handler */
static inline void copy_fast_tlb_miss_handler(unsigned int addr)
{
	unsigned int start = (unsigned int) fast_handler;
	unsigned int end = (unsigned int) fast_handler_end;
	volatile unsigned int tmp = 0;

	__asm__ __volatile__ (
		"1:\n"
		"	ldw	%3,0(%0)\n"
		"	stw	%3,0(%1)\n"
		"	flushd	0(%1)\n"
		"	flushi	%1\n"
		"	flushp\n"
		"	addi	%0,%0,4\n"
		"	addi	%1,%1,4\n"
		"	bne	%0,%2,1b\n"
		: /* no output registers */
		: "r" (start), "r" (addr), "r" (end), "r" (tmp)
		: "memory"
	);
}

/*
 * save args passed from u-boot, called from head.S
 *
 * @r4: NIOS magic
 * @r5: initrd start
 * @r6: initrd end or fdt
 * @r7: kernel command line
 */
asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
				       unsigned r7)
{
	unsigned dtb_passed = 0;
	char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };

#if defined(CONFIG_NIOS2_PASS_CMDLINE)
	if (r4 == 0x534f494e) { /* r4 is magic NIOS */
#if defined(CONFIG_BLK_DEV_INITRD)
		if (r5) { /* initramfs */
			initrd_start = r5;
			initrd_end = r6;
		}
#endif /* CONFIG_BLK_DEV_INITRD */
		dtb_passed = r6;

		if (r7)
			strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
	}
#endif

	early_init_devtree((void *)dtb_passed);

#ifndef CONFIG_CMDLINE_FORCE
	if (cmdline_passed[0])
		strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
	else
		strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif
#endif

	parse_early_param();
}

void __init setup_arch(char **cmdline_p)
{
	int dram_start;

	console_verbose();

	dram_start = memblock_start_of_DRAM();
	memory_size = memblock_phys_mem_size();
	memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
	memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;

	init_mm.start_code = (unsigned long) _stext;
	init_mm.end_code = (unsigned long) _etext;
	init_mm.end_data = (unsigned long) _edata;
	init_mm.brk = (unsigned long) _end;
	init_task.thread.kregs = &fake_regs;

	/* Keep a copy of command line */
	*cmdline_p = boot_command_line;

	min_low_pfn = PFN_UP(memory_start);
	max_low_pfn = PFN_DOWN(memory_end);
	max_mapnr = max_low_pfn;

	memblock_reserve(dram_start, memory_start - dram_start);
#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start) {
		memblock_reserve(virt_to_phys((void *)initrd_start),
				initrd_end - initrd_start);
	}
#endif /* CONFIG_BLK_DEV_INITRD */

	early_init_fdt_reserve_self();
	early_init_fdt_scan_reserved_mem();

	unflatten_and_copy_device_tree();

	setup_cpuinfo();

	copy_exception_handler(cpuinfo.exception_addr);

	mmu_init();

	copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);

	/*
	 * Initialize MMU context handling here because data from cpuinfo is
	 * needed for this.
	 */
	mmu_context_init();

	/*
	 * get kmalloc into gear
	 */
	paging_init();

#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
	conswitchp = &dummy_con;
#endif
}