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 */
11 static int (*olpc_ofw_cif)(int *);
12
13 /* page dir entry containing OFW's pgdir table; filled in by head_32.S */
14 u32 olpc_ofw_pgd __initdata;
15
16 static DEFINE_SPINLOCK(ofw_lock);
17
18 #define MAXARGS 10
19
setup_olpc_ofw_pgd(void)20 void __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
__olpc_ofw(const char * name,int nr_args,const void ** args,int nr_res,void ** res)43 int __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 }
75 EXPORT_SYMBOL_GPL(__olpc_ofw);
76
olpc_ofw_present(void)77 bool olpc_ofw_present(void)
78 {
79 return olpc_ofw_cif != NULL;
80 }
81 EXPORT_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
olpc_ofw_detect(void)89 void __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
olpc_ofw_is_installed(void)114 bool __init olpc_ofw_is_installed(void)
115 {
116 return olpc_ofw_cif != NULL;
117 }
118