1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/init.h>
7 #include <asm/pgtable.h>
8 #include <asm/olpc_ofw.h>
10 /* address of OFW callback interface; will be NULL if OFW isn't found */
11 static int (*olpc_ofw_cif)(int *);
13 /* page dir entry containing OFW's pgdir table; filled in by head_32.S */
14 u32 olpc_ofw_pgd __initdata;
16 static DEFINE_SPINLOCK(ofw_lock);
20 void __init setup_olpc_ofw_pgd(void)
22 pgd_t *base, *ofw_pde;
28 base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
30 printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n");
34 ofw_pde = &base[OLPC_OFW_PDE_NR];
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 */
40 early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
43 int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res,
46 int ofw_args[MAXARGS + 3];
50 BUG_ON(nr_args + nr_res > MAXARGS);
55 ofw_args[0] = (int)name;
56 ofw_args[1] = nr_args;
60 for (i = 0; i < nr_args; i++, p++)
64 spin_lock_irqsave(&ofw_lock, flags);
65 ret = olpc_ofw_cif(ofw_args);
66 spin_unlock_irqrestore(&ofw_lock, flags);
69 for (i = 0; i < nr_res; i++, p++)
70 *((int *)res[i]) = *p;
75 EXPORT_SYMBOL_GPL(__olpc_ofw);
77 bool olpc_ofw_present(void)
79 return olpc_ofw_cif != NULL;
81 EXPORT_SYMBOL_GPL(olpc_ofw_present);
83 /* OFW cif _should_ be above this address */
84 #define OFW_MIN 0xff000000
86 /* OFW starts on a 1MB boundary */
87 #define OFW_BOUND (1<<20)
89 void __init olpc_ofw_detect(void)
91 struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
94 /* ensure OFW booted us by checking for "OFW " string */
95 if (hdr->ofw_magic != OLPC_OFW_SIG)
98 olpc_ofw_cif = (int (*)(int *))hdr->cif_handler;
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);
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);