File: /usr/src/linux/arch/ppc/boot/tree/main.c
1 /*
2 * BK Id: SCCS/s.main.c 1.9 06/15/01 13:16:10 paulus
3 */
4 /*
5 * Copyright (c) 1997 Paul Mackerras <paulus@cs.anu.edu.au>
6 * Initial Power Macintosh COFF version.
7 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
8 * Modifications for an ELF-based IBM evaluation board version.
9 * Copyright 2000-2001 MontaVista Software Inc.
10 * PPC405GP modifications
11 * Author: MontaVista Software, Inc.
12 * frank_rowand@mvista.com or source@mvista.com
13 * debbie_chu@mvista.com
14 *
15 * Module name: main.c
16 *
17 * Description:
18 * This module does most of the real work for the boot loader. It
19 * checks the variables holding the absolute start address and size
20 * of the Linux kernel "image" and initial RAM disk "initrd" sections
21 * and if they are present, moves them to their "proper" locations.
22 *
23 * For the Linux kernel, "proper" is physical address 0x00000000.
24 * For the RAM disk, "proper" is the image's size below the top
25 * of physical memory. The Linux kernel may be in either raw
26 * binary form or compressed with GNU zip (aka gzip).
27 *
28 * This program is free software; you can redistribute it and/or
29 * modify it under the terms of the GNU General Public License
30 * as published by the Free Software Foundation; either version
31 * 2 of the License, or (at your option) any later version.
32 *
33 */
34
35 #include <linux/config.h>
36 #include <asm/ppc4xx.h>
37
38 #include "nonstdio.h"
39 #include "irSect.h"
40 #if defined(CONFIG_SERIAL_CONSOLE)
41 #include "ns16550.h"
42 #endif /* CONFIG_SERIAL_CONSOLE */
43
44
45 /* Preprocessor Defines */
46
47 /*
48 * Location of the IBM boot ROM function pointer address for retrieving
49 * the board information structure.
50 */
51
52 #define BOARD_INFO_VECTOR 0xFFFE0B50
53
54 /*
55 * Warning: the board_info doesn't contain valid data until get_board_info()
56 * gets called in start().
57 */
58 #define RAM_SIZE board_info.bi_memsize
59
60 #define RAM_PBASE 0x00000000
61 #define RAM_PEND (RAM_PBASE + RAM_SIZE)
62
63 #define RAM_VBASE 0xC0000000
64 #define RAM_VEND (RAM_VBASE + RAM_SIZE)
65
66 #define RAM_START RAM_PBASE
67 #define RAM_END RAM_PEND
68 #define RAM_FREE (imageSect_start + imageSect_size + initrdSect_size)
69
70 #define PROG_START RAM_START
71
72
73 /* Function Macros */
74
75 #define ALIGN_UP(x, align) (((x) + ((align) - 1)) & ~((align) - 1))
76
77 /* Global Variables */
78
79 /* Needed by zalloc and zfree for allocating memory */
80
81 char *avail_ram; /* Indicates start of RAM available for heap */
82 char *end_avail; /* Indicates end of RAM available for heap */
83
84 /* Needed for serial I/O.
85 */
86 extern unsigned long *com_port;
87
88 bd_t board_info;
89
90 /*
91 ** The bootrom may change bootrom_cmdline to point to a buffer in the
92 ** bootrom.
93 */
94 char *bootrom_cmdline = "";
95 char treeboot_bootrom_cmdline[512];
96
97 #ifdef CONFIG_CMDLINE
98 char *cmdline = CONFIG_CMDLINE;
99 #else
100 char *cmdline = "";
101 #endif
102
103 /* Function Prototypes */
104
105 extern void gunzip(void *dst, int dstlen, unsigned char *src, int *lenp);
106
107 void
108 kick_watchdog(void)
109 {
110 #ifdef CONFIG_405GP
111 mtspr(SPRN_TSR, (TSR_ENW | TSR_WIS));
112 #endif
113 }
114
115 void start(void)
116 {
117 void *options;
118 int ns, oh, i;
119 unsigned long sa, len;
120 void *dst;
121 unsigned char *im;
122 unsigned long initrd_start, initrd_size;
123 bd_t *(*get_board_info)(void) =
124 (bd_t *(*)(void))(*(unsigned long *)BOARD_INFO_VECTOR);
125 bd_t *bip = NULL;
126
127
128 com_port = (struct NS16550 *)serial_init(0);
129
130 #ifdef CONFIG_405GP
131 /* turn off on-chip ethernet */
132 /* This is to fix a problem with early walnut bootrom. */
133
134 {
135 /* Physical mapping of ethernet register space. */
136 static struct ppc405_enet_regs *ppc405_enet_regp =
137 (struct ppc405_enet_regs *)PPC405_EM0_REG_ADDR;
138
139 mtdcr(DCRN_MALCR, MALCR_MMSR); /* 1st reset MAL */
140
141 while (mfdcr(DCRN_MALCR) & MALCR_MMSR) {}; /* wait for the reset */
142
143 ppc405_enet_regp->em0mr0 = 0x20000000; /* then reset EMAC */
144 }
145 #endif
146
147 if ((bip = get_board_info()) != NULL)
148 memcpy(&board_info, bip, sizeof(bd_t));
149
150 /* Init RAM disk (initrd) section */
151
152 kick_watchdog();
153
154 if (initrdSect_start != 0 && (initrd_size = initrdSect_size) != 0) {
155 initrd_start = (RAM_END - initrd_size) & ~0xFFF;
156
157 _printk("Initial RAM disk at 0x%08x (%u bytes)\n",
158 initrd_start, initrd_size);
159
160 memcpy((char *)initrd_start,
161 (char *)(initrdSect_start),
162 initrdSect_size);
163
164 end_avail = (char *)initrd_start;
165 } else {
166 initrd_start = initrd_size = 0;
167 end_avail = (char *)RAM_END;
168 }
169
170 /* Linux kernel image section */
171
172 kick_watchdog();
173
174 im = (unsigned char *)(imageSect_start);
175 len = imageSect_size;
176 dst = (void *)PROG_START;
177
178 /* Check for the gzip archive magic numbers */
179
180 if (im[0] == 0x1f && im[1] == 0x8b) {
181
182 /* The gunzip routine needs everything nice and aligned */
183
184 void *cp = (void *)ALIGN_UP(RAM_FREE, 8);
185 avail_ram = (void *)(cp + ALIGN_UP(len, 8)); /* used by zalloc() */
186 memcpy(cp, im, len);
187
188 /* I'm not sure what the 0x200000 parameter is for, but it works. */
189 /* It tells gzip the end of the area you wish to reserve, and it
190 * can use data past that point....unfortunately, this value
191 * isn't big enough (luck ran out). -- Dan
192 */
193
194 gunzip(dst, 0x400000, cp, (int *)&len);
195 } else {
196 memmove(dst, im, len);
197 }
198
199 kick_watchdog();
200
201 flush_cache(dst, len);
202
203 sa = (unsigned long)dst;
204
205 (*(void (*)())sa)(&board_info,
206 initrd_start,
207 initrd_start + initrd_size,
208 cmdline,
209 cmdline + strlen(cmdline));
210
211 pause();
212 }
213