1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3
4#include <linux/console.h>
5#include <linux/memblock.h>
6#include <linux/initrd.h>
7#include <linux/of.h>
8#include <linux/of_fdt.h>
9#include <linux/start_kernel.h>
10#include <linux/dma-map-ops.h>
11#include <asm/sections.h>
12#include <asm/mmu_context.h>
13#include <asm/pgalloc.h>
14
15#ifdef CONFIG_BLK_DEV_INITRD
16static void __init setup_initrd(void)
17{
18 unsigned long size;
19
20 if (initrd_start >= initrd_end) {
21 pr_err("initrd not found or empty");
22 goto disable;
23 }
24
25 if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
26 pr_err("initrd extends beyond end of memory");
27 goto disable;
28 }
29
30 size = initrd_end - initrd_start;
31
32 if (memblock_is_region_reserved(__pa(initrd_start), size)) {
33 pr_err("INITRD: 0x%08lx+0x%08lx overlaps in-use memory region",
34 __pa(initrd_start), size);
35 goto disable;
36 }
37
38 memblock_reserve(__pa(initrd_start), size);
39
40 pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
41 (void *)(initrd_start), size);
42
43 initrd_below_start_ok = 1;
44
45 return;
46
47disable:
48 initrd_start = initrd_end = 0;
49
50 pr_err(" - disabling initrd\n");
51}
52#endif
53
54static void __init csky_memblock_init(void)
55{
56 unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
57 unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
58 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
59 signed long size;
60
61 memblock_reserve(__pa(_start), _end - _start);
62
63 early_init_fdt_reserve_self();
64 early_init_fdt_scan_reserved_mem();
65
66 memblock_dump_all();
67
68 min_low_pfn = PFN_UP(memblock_start_of_DRAM());
69 max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM());
70
71 size = max_pfn - min_low_pfn;
72
73 if (size >= lowmem_size) {
74 max_low_pfn = min_low_pfn + lowmem_size;
75#ifdef CONFIG_PAGE_OFFSET_80000000
76 write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);
77#endif
78 } else if (size > sseg_size) {
79 max_low_pfn = min_low_pfn + sseg_size;
80 }
81
82#ifdef CONFIG_BLK_DEV_INITRD
83 setup_initrd();
84#endif
85
86 max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
87
88 mmu_init(min_low_pfn, max_low_pfn);
89
90#ifdef CONFIG_HIGHMEM
91 max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
92
93 highstart_pfn = max_low_pfn;
94 highend_pfn = max_pfn;
95#endif
96 memblock_set_current_limit(PFN_PHYS(max_low_pfn));
97
98 dma_contiguous_reserve(addr_limit: 0);
99
100 free_area_init(max_zone_pfn);
101}
102
103void __init setup_arch(char **cmdline_p)
104{
105 *cmdline_p = boot_command_line;
106
107 console_verbose();
108
109 pr_info("Phys. mem: %ldMB\n",
110 (unsigned long) memblock_phys_mem_size()/1024/1024);
111
112 setup_initial_init_mm(start_code: _start, end_code: _etext, end_data: _edata, brk: _end);
113
114 parse_early_param();
115
116 csky_memblock_init();
117
118 unflatten_and_copy_device_tree();
119
120#ifdef CONFIG_SMP
121 setup_smp();
122#endif
123
124 sparse_init();
125
126 fixaddr_init();
127
128#ifdef CONFIG_HIGHMEM
129 kmap_init();
130#endif
131}
132
133unsigned long va_pa_offset;
134EXPORT_SYMBOL(va_pa_offset);
135
136static inline unsigned long read_mmu_msa(void)
137{
138#ifdef CONFIG_PAGE_OFFSET_80000000
139 return read_mmu_msa0();
140#endif
141
142#ifdef CONFIG_PAGE_OFFSET_A0000000
143 return read_mmu_msa1();
144#endif
145}
146
147asmlinkage __visible void __init csky_start(unsigned int unused,
148 void *dtb_start)
149{
150 /* Clean up bss section */
151 memset(__bss_start, 0, __bss_stop - __bss_start);
152
153 va_pa_offset = read_mmu_msa() & ~(SSEG_SIZE - 1);
154
155 pre_trap_init();
156
157 if (dtb_start == NULL)
158 early_init_dt_scan(dt_virt: __dtb_start, __pa(dtb_start));
159 else
160 early_init_dt_scan(dt_virt: dtb_start, __pa(dtb_start));
161
162 start_kernel();
163
164 asm volatile("br .\n");
165}
166

source code of linux/arch/csky/kernel/setup.c