1#include <linux/kernel.h>
2#include <linux/module.h>
3#include <linux/init.h>
4#include <asm/page.h>
5#include <asm/setup.h>
6#include <asm/io.h>
7#include <asm/pgtable.h>
8#include <asm/olpc_ofw.h>
9
10/* address of OFW callback interface; will be NULL if OFW isn't found */
11static int (*olpc_ofw_cif)(int *);
12
13/* page dir entry containing OFW's pgdir table; filled in by head_32.S */
14u32 olpc_ofw_pgd __initdata;
15
16static DEFINE_SPINLOCK(ofw_lock);
17
18#define MAXARGS 10
19
20void __init setup_olpc_ofw_pgd(void)
21{
22	pgd_t *base, *ofw_pde;
23
24	if (!olpc_ofw_cif)
25		return;
26
27	/* fetch OFW's PDE */
28	base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
29	if (!base) {
30		printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n");
31		olpc_ofw_cif = NULL;
32		return;
33	}
34	ofw_pde = &base[OLPC_OFW_PDE_NR];
35
36	/* install OFW's PDE permanently into the kernel's pgtable */
37	set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);
38	/* implicit optimization barrier here due to uninline function return */
39
40	early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
41}
42
43int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res,
44		void **res)
45{
46	int ofw_args[MAXARGS + 3];
47	unsigned long flags;
48	int ret, i, *p;
49
50	BUG_ON(nr_args + nr_res > MAXARGS);
51
52	if (!olpc_ofw_cif)
53		return -EIO;
54
55	ofw_args[0] = (int)name;
56	ofw_args[1] = nr_args;
57	ofw_args[2] = nr_res;
58
59	p = &ofw_args[3];
60	for (i = 0; i < nr_args; i++, p++)
61		*p = (int)args[i];
62
63	/* call into ofw */
64	spin_lock_irqsave(&ofw_lock, flags);
65	ret = olpc_ofw_cif(ofw_args);
66	spin_unlock_irqrestore(&ofw_lock, flags);
67
68	if (!ret) {
69		for (i = 0; i < nr_res; i++, p++)
70			*((int *)res[i]) = *p;
71	}
72
73	return ret;
74}
75EXPORT_SYMBOL_GPL(__olpc_ofw);
76
77bool olpc_ofw_present(void)
78{
79	return olpc_ofw_cif != NULL;
80}
81EXPORT_SYMBOL_GPL(olpc_ofw_present);
82
83/* OFW cif _should_ be above this address */
84#define OFW_MIN 0xff000000
85
86/* OFW starts on a 1MB boundary */
87#define OFW_BOUND (1<<20)
88
89void __init olpc_ofw_detect(void)
90{
91	struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
92	unsigned long start;
93
94	/* ensure OFW booted us by checking for "OFW " string */
95	if (hdr->ofw_magic != OLPC_OFW_SIG)
96		return;
97
98	olpc_ofw_cif = (int (*)(int *))hdr->cif_handler;
99
100	if ((unsigned long)olpc_ofw_cif < OFW_MIN) {
101		printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n",
102				(unsigned long)olpc_ofw_cif);
103		olpc_ofw_cif = NULL;
104		return;
105	}
106
107	/* determine where OFW starts in memory */
108	start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND);
109	printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n",
110			(unsigned long)olpc_ofw_cif, (-start) >> 20);
111	reserve_top_address(-start);
112}
113
114bool __init olpc_ofw_is_installed(void)
115{
116	return olpc_ofw_cif != NULL;
117}
118