common/main.c


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

/*
 * main.c - the C entry. console up first, then load the payload and
 * jump. called from start.S with x0 = whatever the firmware passed.
 *
 * the osdev model, arm64: the firmware services do the work, the
 * kernel goes at a fixed known address, whatever x0 we were handed
 * goes straight through to the payload.
 *
 * Copyright (c) 2026 Bradley Morgan <brads@mainlining.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <stdint.h>
#include <debug.h>
#include <semihosting.h>
#include <boot.h>

#define TB_VERSION "0.1"
#define TB_INITRD_ADDR	0x46000000ULL
#define TB_INITRD_FILE	"initrd.cpio.gz"

extern int tb_console_init(void);

/*
 * fixed load address, the osdev way. past the bootloader at the
 * bottom of RAM, the image header decides its final resting place.
 */
#define TB_LOAD_ADDR	0x40200000

/* the file semihosting serves as the payload */
#define TB_BOOTFILE	"Image"

extern void __NO_RETURN tb_boot_linux(uintptr_t ep, uintptr_t fw_arg);

void tashaboot_main(uintptr_t fw_arg)
{
	struct tb_image img;
	int ret;

	if (tb_console_init())
		return;

	dprintf(ALWAYS, "tashaboot " TB_VERSION "\n");

#ifdef TB_ENABLE_MMU
	{
		extern int tb_mmu_enable(void);
		extern int tb_mmu_selftest(void);
		extern void tb_mmu_disable(void);

		if (tb_mmu_enable() == 0) {
			if (tb_mmu_selftest() == 0)
				dprintf(ALWAYS, "mmu: identity map on\n");
			else
				dprintf(ALWAYS, "mmu: self test failed, "
					 "running unmapped\n");
			tb_mmu_disable();
		}
	}
#endif

	{
		/* spin table gates into the dtb, one per cpu node */
		extern unsigned long *tb_spin_gates_ptr;
		extern int tb_dtb_patch_spin_table(uintptr_t dtb,
						  uintptr_t *gates,
						  int ngates);
		int n;

		if (tb_spin_gates_ptr) {
			extern unsigned char tb_pen_stamps[8];
			int c;

			n = tb_dtb_patch_spin_table(fw_arg,
						    tb_spin_gates_ptr, 8);
			dprintf(ALWAYS, "dtb: %d release addrs patched\n", n);

			/* who made it to the pen */
			for (c = 1; c < 8; c++) {
				if (tb_pen_stamps[c])
					break;
			}
			dprintf(ALWAYS, "pen: %s\n",
				c < 8 ? "secondaries waiting" :
					"no secondaries parked");
		}
	}

	ret = tb_load_semihosting(TB_BOOTFILE, TB_LOAD_ADDR, &img);
	if (ret) {
		dprintf(ALWAYS, "load failed (%d), halting\n", ret);
		platform_halt();
	}

	/*
	 * the initrd rides after the kernel, the dtb /chosen carries
	 * linux,initrd-start and -end, both already patched in place
	 * with this layout.
	 */
	{
		extern int tb_load_raw(const char *fname,
				       uintptr_t load_addr);
		int r = tb_load_raw(TB_INITRD_FILE, TB_INITRD_ADDR);

		if (r == 0)
			dprintf(ALWAYS, "initrd at %lx\n",
				(unsigned long)TB_INITRD_ADDR);
		else
			dprintf(ALWAYS, "no initrd (%d)\n", r);
	}

	dprintf(ALWAYS, "loaded %llu bytes at %lx, entry %lx\n",
		(unsigned long long)img.size, img.load, img.ep);
	dprintf(ALWAYS, "jumping\n");

	tb_boot_linux(img.ep, fw_arg);
}