1 // SPDX-License-Identifier: GPL-2.0
4 * linux/arch/cris/kernel/setup.c
6 * Copyright (C) 1995 Linus Torvalds
7 * Copyright (c) 2001 Axis Communications AB
11 * This file handles the architecture-dependent parts of initialization
14 #include <linux/init.h>
16 #include <linux/bootmem.h>
17 #include <asm/pgtable.h>
18 #include <linux/seq_file.h>
19 #include <linux/screen_info.h>
20 #include <linux/utsname.h>
21 #include <linux/pfn.h>
22 #include <linux/cpu.h>
24 #include <linux/of_fdt.h>
25 #include <asm/setup.h>
26 #include <arch/system.h>
31 struct screen_info screen_info
;
33 extern int root_mountflags
;
34 extern char _etext
, _edata
, _end
;
36 char __initdata cris_command_line
[COMMAND_LINE_SIZE
] = { 0, };
38 extern const unsigned long text_start
, edata
; /* set by the linker script */
39 extern unsigned long dram_start
, dram_end
;
41 extern unsigned long romfs_start
, romfs_length
, romfs_in_flash
; /* from head.S */
43 static struct cpu cpu_devices
[NR_CPUS
];
45 extern void show_etrax_copyright(void); /* arch-vX/kernel/setup.c */
47 /* This mainly sets up the memory area, and can be really confusing.
49 * The physical DRAM is virtually mapped into dram_start to dram_end
50 * (usually c0000000 to c0000000 + DRAM size). The physical address is
51 * given by the macro __pa().
53 * In this DRAM, the kernel code and data is loaded, in the beginning.
54 * It really starts at c0004000 to make room for some special pages -
55 * the start address is text_start. The kernel data ends at _end. After
56 * this the ROM filesystem is appended (if there is any).
58 * Between this address and dram_end, we have RAM pages usable to the
59 * boot code and the system.
63 void __init
setup_arch(char **cmdline_p
)
65 extern void init_etrax_debug(void);
66 unsigned long bootmap_size
;
67 unsigned long start_pfn
, max_pfn
;
68 unsigned long memory_start
;
71 early_init_dt_scan(__dtb_start
);
74 /* register an initial console printing routine for printk's */
78 /* we should really poll for DRAM size! */
80 high_memory
= &dram_end
;
82 if(romfs_in_flash
|| !romfs_length
) {
83 /* if we have the romfs in flash, or if there is no rom filesystem,
84 * our free area starts directly after the BSS
86 memory_start
= (unsigned long) &_end
;
88 /* otherwise the free area starts after the ROM filesystem */
89 printk("ROM fs in RAM, size %lu bytes\n", romfs_length
);
90 memory_start
= romfs_start
+ romfs_length
;
93 /* process 1's initial memory region is the kernel code/data */
95 init_mm
.start_code
= (unsigned long) &text_start
;
96 init_mm
.end_code
= (unsigned long) &_etext
;
97 init_mm
.end_data
= (unsigned long) &_edata
;
98 init_mm
.brk
= (unsigned long) &_end
;
100 /* min_low_pfn points to the start of DRAM, start_pfn points
101 * to the first DRAM pages after the kernel, and max_low_pfn
102 * to the end of DRAM.
106 * partially used pages are not usable - thus
107 * we are rounding upwards:
110 start_pfn
= PFN_UP(memory_start
); /* usually c0000000 + kernel + romfs */
111 max_pfn
= PFN_DOWN((unsigned long)high_memory
); /* usually c0000000 + dram size */
114 * Initialize the boot-time allocator (start, end)
116 * We give it access to all our DRAM, but we could as well just have
117 * given it a small slice. No point in doing that though, unless we
118 * have non-contiguous memory and want the boot-stuff to be in, say,
121 * It will put a bitmap of the allocated pages in the beginning
122 * of the range we give it, but it won't mark the bitmaps pages
123 * as reserved. We have to do that ourselves below.
125 * We need to use init_bootmem_node instead of init_bootmem
126 * because our map starts at a quite high address (min_low_pfn).
129 max_low_pfn
= max_pfn
;
130 min_low_pfn
= PAGE_OFFSET
>> PAGE_SHIFT
;
132 bootmap_size
= init_bootmem_node(NODE_DATA(0), start_pfn
,
136 /* And free all memory not belonging to the kernel (addr, size) */
138 free_bootmem(PFN_PHYS(start_pfn
), PFN_PHYS(max_pfn
- start_pfn
));
141 * Reserve the bootmem bitmap itself as well. We do this in two
142 * steps (first step was init_bootmem()) because this catches
143 * the (very unlikely) case of us accidentally initializing the
144 * bootmem allocator with an invalid RAM area.
146 * Arguments are start, size
149 reserve_bootmem(PFN_PHYS(start_pfn
), bootmap_size
, BOOTMEM_DEFAULT
);
151 unflatten_and_copy_device_tree();
153 /* paging_init() sets up the MMU and marks all pages as reserved */
157 *cmdline_p
= cris_command_line
;
159 #ifdef CONFIG_ETRAX_CMDLINE
160 if (!strcmp(cris_command_line
, "")) {
161 strlcpy(cris_command_line
, CONFIG_ETRAX_CMDLINE
, COMMAND_LINE_SIZE
);
162 cris_command_line
[COMMAND_LINE_SIZE
- 1] = '\0';
166 /* Save command line for future references. */
167 memcpy(boot_command_line
, cris_command_line
, COMMAND_LINE_SIZE
);
168 boot_command_line
[COMMAND_LINE_SIZE
- 1] = '\0';
170 /* give credit for the CRIS port */
171 show_etrax_copyright();
174 strcpy(init_utsname()->machine
, cris_machine_name
);
177 #ifdef CONFIG_PROC_FS
178 static void *c_start(struct seq_file
*m
, loff_t
*pos
)
180 return *pos
< nr_cpu_ids
? (void *)(int)(*pos
+ 1) : NULL
;
183 static void *c_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
186 return c_start(m
, pos
);
189 static void c_stop(struct seq_file
*m
, void *v
)
193 extern int show_cpuinfo(struct seq_file
*m
, void *v
);
195 const struct seq_operations cpuinfo_op
= {
199 .show
= show_cpuinfo
,
201 #endif /* CONFIG_PROC_FS */
203 static int __init
topology_init(void)
207 for_each_possible_cpu(i
) {
208 return register_cpu(&cpu_devices
[i
], i
);
214 subsys_initcall(topology_init
);