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1/*
2 * Nios2-specific parts of system setup
3 *
4 * Copyright (C) 2010 Tobias Klauser <[email protected]>
5 * Copyright (C) 2004 Microtronix Datacom Ltd.
6 * Copyright (C) 2001 Vic Phillips <[email protected]>
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
23#include <asm/mmu_context.h>
24#include <asm/sections.h>
25#include <asm/setup.h>
26#include <asm/cpuinfo.h>
27
28unsigned long memory_start;
29EXPORT_SYMBOL(memory_start);
30
31unsigned long memory_end;
32EXPORT_SYMBOL(memory_end);
33
34static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
35 0, 0, 0, 0, 0, 0,
36 0};
37
38/* Copy a short hook instruction sequence to the exception address */
39static inline void copy_exception_handler(unsigned int addr)
40{
41 unsigned int start = (unsigned int) exception_handler_hook;
42 volatile unsigned int tmp = 0;
43
44 if (start == addr) {
45 /* The CPU exception address already points to the handler. */
46 return;
47 }
48
49 __asm__ __volatile__ (
50 "ldw %2,0(%0)\n"
51 "stw %2,0(%1)\n"
52 "ldw %2,4(%0)\n"
53 "stw %2,4(%1)\n"
54 "ldw %2,8(%0)\n"
55 "stw %2,8(%1)\n"
56 "flushd 0(%1)\n"
57 "flushd 4(%1)\n"
58 "flushd 8(%1)\n"
59 "flushi %1\n"
60 "addi %1,%1,4\n"
61 "flushi %1\n"
62 "addi %1,%1,4\n"
63 "flushi %1\n"
64 "flushp\n"
65 : /* no output registers */
66 : "r" (start), "r" (addr), "r" (tmp)
67 : "memory"
68 );
69}
70
71/* Copy the fast TLB miss handler */
72static inline void copy_fast_tlb_miss_handler(unsigned int addr)
73{
74 unsigned int start = (unsigned int) fast_handler;
75 unsigned int end = (unsigned int) fast_handler_end;
76 volatile unsigned int tmp = 0;
77
78 __asm__ __volatile__ (
79 "1:\n"
80 " ldw %3,0(%0)\n"
81 " stw %3,0(%1)\n"
82 " flushd 0(%1)\n"
83 " flushi %1\n"
84 " flushp\n"
85 " addi %0,%0,4\n"
86 " addi %1,%1,4\n"
87 " bne %0,%2,1b\n"
88 : /* no output registers */
89 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
90 : "memory"
91 );
92}
93
94/*
95 * save args passed from u-boot, called from head.S
96 *
97 * @r4: NIOS magic
98 * @r5: initrd start
99 * @r6: initrd end or fdt
100 * @r7: kernel command line
101 */
102asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
103 unsigned r7)
104{
105 unsigned dtb_passed = 0;
106 char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
107
108#if defined(CONFIG_NIOS2_PASS_CMDLINE)
109 if (r4 == 0x534f494e) { /* r4 is magic NIOS */
110#if defined(CONFIG_BLK_DEV_INITRD)
111 if (r5) { /* initramfs */
112 initrd_start = r5;
113 initrd_end = r6;
114 }
115#endif /* CONFIG_BLK_DEV_INITRD */
116 dtb_passed = r6;
117
118 if (r7)
119 strscpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
120 }
121#endif
122
123 early_init_devtree((void *)dtb_passed);
124
125#ifndef CONFIG_CMDLINE_FORCE
126 if (cmdline_passed[0])
127 strscpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
128#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
129 else
130 strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
131#endif
132#endif
133
134 parse_early_param();
135}
136
137static void __init find_limits(unsigned long *min, unsigned long *max_low,
138 unsigned long *max_high)
139{
140 *max_low = PFN_DOWN(memblock_get_current_limit());
141 *min = PFN_UP(memblock_start_of_DRAM());
142 *max_high = PFN_DOWN(memblock_end_of_DRAM());
143}
144
145static void __init adjust_lowmem_bounds(void)
146{
147 phys_addr_t block_start, block_end;
148 u64 i;
149 phys_addr_t memblock_limit = 0;
150
151 for_each_mem_range(i, &block_start, &block_end) {
152 if (block_end > memblock_limit)
153 memblock_limit = block_end;
154 }
155
156 memblock_set_current_limit(memblock_limit);
157}
158
159void __init setup_arch(char **cmdline_p)
160{
161 console_verbose();
162
163 memory_start = memblock_start_of_DRAM();
164 memory_end = memblock_end_of_DRAM();
165
166 pr_debug("%s: start=%lx, end=%lx\n", __func__, memory_start, memory_end);
167
168 setup_initial_init_mm(_stext, _etext, _edata, _end);
169 init_task.thread.kregs = &fake_regs;
170
171 /* Keep a copy of command line */
172 *cmdline_p = boot_command_line;
173
174 adjust_lowmem_bounds();
175 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
176
177 memblock_reserve(__pa_symbol(_stext), _end - _stext);
178#ifdef CONFIG_BLK_DEV_INITRD
179 if (initrd_start) {
180 memblock_reserve(virt_to_phys((void *)initrd_start),
181 initrd_end - initrd_start);
182 }
183#endif /* CONFIG_BLK_DEV_INITRD */
184
185 early_init_fdt_reserve_self();
186 early_init_fdt_scan_reserved_mem();
187
188 unflatten_and_copy_device_tree();
189
190 setup_cpuinfo();
191
192 copy_exception_handler(cpuinfo.exception_addr);
193
194 mmu_init();
195
196 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
197
198 /*
199 * Initialize MMU context handling here because data from cpuinfo is
200 * needed for this.
201 */
202 mmu_context_init();
203
204 /*
205 * get kmalloc into gear
206 */
207 paging_init();
208}