1 /*
2 * Nios2-specific parts of system setup
3 *
4 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
5 * Copyright (C) 2004 Microtronix Datacom Ltd.
6 * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12
13 #include <linux/export.h>
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/sched.h>
17 #include <linux/sched/task.h>
18 #include <linux/console.h>
19 #include <linux/memblock.h>
20 #include <linux/initrd.h>
21 #include <linux/of_fdt.h>
22 #include <linux/screen_info.h>
23
24 #include <asm/mmu_context.h>
25 #include <asm/sections.h>
26 #include <asm/setup.h>
27 #include <asm/cpuinfo.h>
28
29 unsigned long memory_start;
30 EXPORT_SYMBOL(memory_start);
31
32 unsigned long memory_end;
33 EXPORT_SYMBOL(memory_end);
34
35 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
36 0, 0, 0, 0, 0, 0,
37 0};
38
39 #ifdef CONFIG_VT
40 struct screen_info screen_info;
41 #endif
42
43 /* Copy a short hook instruction sequence to the exception address */
copy_exception_handler(unsigned int addr)44 static inline void copy_exception_handler(unsigned int addr)
45 {
46 unsigned int start = (unsigned int) exception_handler_hook;
47 volatile unsigned int tmp = 0;
48
49 if (start == addr) {
50 /* The CPU exception address already points to the handler. */
51 return;
52 }
53
54 __asm__ __volatile__ (
55 "ldw %2,0(%0)\n"
56 "stw %2,0(%1)\n"
57 "ldw %2,4(%0)\n"
58 "stw %2,4(%1)\n"
59 "ldw %2,8(%0)\n"
60 "stw %2,8(%1)\n"
61 "flushd 0(%1)\n"
62 "flushd 4(%1)\n"
63 "flushd 8(%1)\n"
64 "flushi %1\n"
65 "addi %1,%1,4\n"
66 "flushi %1\n"
67 "addi %1,%1,4\n"
68 "flushi %1\n"
69 "flushp\n"
70 : /* no output registers */
71 : "r" (start), "r" (addr), "r" (tmp)
72 : "memory"
73 );
74 }
75
76 /* Copy the fast TLB miss handler */
copy_fast_tlb_miss_handler(unsigned int addr)77 static inline void copy_fast_tlb_miss_handler(unsigned int addr)
78 {
79 unsigned int start = (unsigned int) fast_handler;
80 unsigned int end = (unsigned int) fast_handler_end;
81 volatile unsigned int tmp = 0;
82
83 __asm__ __volatile__ (
84 "1:\n"
85 " ldw %3,0(%0)\n"
86 " stw %3,0(%1)\n"
87 " flushd 0(%1)\n"
88 " flushi %1\n"
89 " flushp\n"
90 " addi %0,%0,4\n"
91 " addi %1,%1,4\n"
92 " bne %0,%2,1b\n"
93 : /* no output registers */
94 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
95 : "memory"
96 );
97 }
98
99 /*
100 * save args passed from u-boot, called from head.S
101 *
102 * @r4: NIOS magic
103 * @r5: initrd start
104 * @r6: initrd end or fdt
105 * @r7: kernel command line
106 */
nios2_boot_init(unsigned r4,unsigned r5,unsigned r6,unsigned r7)107 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
108 unsigned r7)
109 {
110 unsigned dtb_passed = 0;
111 char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
112
113 #if defined(CONFIG_NIOS2_PASS_CMDLINE)
114 if (r4 == 0x534f494e) { /* r4 is magic NIOS */
115 #if defined(CONFIG_BLK_DEV_INITRD)
116 if (r5) { /* initramfs */
117 initrd_start = r5;
118 initrd_end = r6;
119 }
120 #endif /* CONFIG_BLK_DEV_INITRD */
121 dtb_passed = r6;
122
123 if (r7)
124 strlcpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
125 }
126 #endif
127
128 early_init_devtree((void *)dtb_passed);
129
130 #ifndef CONFIG_CMDLINE_FORCE
131 if (cmdline_passed[0])
132 strlcpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
133 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
134 else
135 strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
136 #endif
137 #endif
138
139 parse_early_param();
140 }
141
find_limits(unsigned long * min,unsigned long * max_low,unsigned long * max_high)142 static void __init find_limits(unsigned long *min, unsigned long *max_low,
143 unsigned long *max_high)
144 {
145 *max_low = PFN_DOWN(memblock_get_current_limit());
146 *min = PFN_UP(memblock_start_of_DRAM());
147 *max_high = PFN_DOWN(memblock_end_of_DRAM());
148 }
149
setup_arch(char ** cmdline_p)150 void __init setup_arch(char **cmdline_p)
151 {
152 console_verbose();
153
154 memory_start = memblock_start_of_DRAM();
155 memory_end = memblock_end_of_DRAM();
156
157 setup_initial_init_mm(_stext, _etext, _edata, _end);
158 init_task.thread.kregs = &fake_regs;
159
160 /* Keep a copy of command line */
161 *cmdline_p = boot_command_line;
162
163 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
164 max_mapnr = max_low_pfn;
165
166 memblock_reserve(__pa_symbol(_stext), _end - _stext);
167 #ifdef CONFIG_BLK_DEV_INITRD
168 if (initrd_start) {
169 memblock_reserve(virt_to_phys((void *)initrd_start),
170 initrd_end - initrd_start);
171 }
172 #endif /* CONFIG_BLK_DEV_INITRD */
173
174 early_init_fdt_reserve_self();
175 early_init_fdt_scan_reserved_mem();
176
177 unflatten_and_copy_device_tree();
178
179 setup_cpuinfo();
180
181 copy_exception_handler(cpuinfo.exception_addr);
182
183 mmu_init();
184
185 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
186
187 /*
188 * Initialize MMU context handling here because data from cpuinfo is
189 * needed for this.
190 */
191 mmu_context_init();
192
193 /*
194 * get kmalloc into gear
195 */
196 paging_init();
197 }
198