1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/kernel.h> |
3 | #include <linux/export.h> |
4 | #include <linux/spinlock_types.h> |
5 | #include <linux/init.h> |
6 | #include <linux/pgtable.h> |
7 | #include <asm/page.h> |
8 | #include <asm/setup.h> |
9 | #include <asm/io.h> |
10 | #include <asm/cpufeature.h> |
11 | #include <asm/special_insns.h> |
12 | #include <asm/olpc_ofw.h> |
13 | |
14 | /* address of OFW callback interface; will be NULL if OFW isn't found */ |
15 | static int (*olpc_ofw_cif)(int *); |
16 | |
17 | /* page dir entry containing OFW's pgdir table; filled in by head_32.S */ |
18 | u32 olpc_ofw_pgd __initdata; |
19 | |
20 | static DEFINE_SPINLOCK(ofw_lock); |
21 | |
22 | #define MAXARGS 10 |
23 | |
24 | void __init setup_olpc_ofw_pgd(void) |
25 | { |
26 | pgd_t *base, *ofw_pde; |
27 | |
28 | if (!olpc_ofw_cif) |
29 | return; |
30 | |
31 | /* fetch OFW's PDE */ |
32 | base = early_ioremap(phys_addr: olpc_ofw_pgd, size: sizeof(olpc_ofw_pgd) * PTRS_PER_PGD); |
33 | if (!base) { |
34 | printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n" ); |
35 | olpc_ofw_cif = NULL; |
36 | return; |
37 | } |
38 | ofw_pde = &base[OLPC_OFW_PDE_NR]; |
39 | |
40 | /* install OFW's PDE permanently into the kernel's pgtable */ |
41 | set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde); |
42 | /* implicit optimization barrier here due to uninline function return */ |
43 | |
44 | early_iounmap(addr: base, size: sizeof(olpc_ofw_pgd) * PTRS_PER_PGD); |
45 | } |
46 | |
47 | int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res, |
48 | void **res) |
49 | { |
50 | int ofw_args[MAXARGS + 3]; |
51 | unsigned long flags; |
52 | int ret, i, *p; |
53 | |
54 | BUG_ON(nr_args + nr_res > MAXARGS); |
55 | |
56 | if (!olpc_ofw_cif) |
57 | return -EIO; |
58 | |
59 | ofw_args[0] = (int)name; |
60 | ofw_args[1] = nr_args; |
61 | ofw_args[2] = nr_res; |
62 | |
63 | p = &ofw_args[3]; |
64 | for (i = 0; i < nr_args; i++, p++) |
65 | *p = (int)args[i]; |
66 | |
67 | /* call into ofw */ |
68 | spin_lock_irqsave(&ofw_lock, flags); |
69 | ret = olpc_ofw_cif(ofw_args); |
70 | spin_unlock_irqrestore(lock: &ofw_lock, flags); |
71 | |
72 | if (!ret) { |
73 | for (i = 0; i < nr_res; i++, p++) |
74 | *((int *)res[i]) = *p; |
75 | } |
76 | |
77 | return ret; |
78 | } |
79 | EXPORT_SYMBOL_GPL(__olpc_ofw); |
80 | |
81 | bool olpc_ofw_present(void) |
82 | { |
83 | return olpc_ofw_cif != NULL; |
84 | } |
85 | EXPORT_SYMBOL_GPL(olpc_ofw_present); |
86 | |
87 | /* OFW cif _should_ be above this address */ |
88 | #define OFW_MIN 0xff000000 |
89 | |
90 | /* OFW starts on a 1MB boundary */ |
91 | #define OFW_BOUND (1<<20) |
92 | |
93 | void __init olpc_ofw_detect(void) |
94 | { |
95 | struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header; |
96 | unsigned long start; |
97 | |
98 | /* ensure OFW booted us by checking for "OFW " string */ |
99 | if (hdr->ofw_magic != OLPC_OFW_SIG) |
100 | return; |
101 | |
102 | olpc_ofw_cif = (int (*)(int *))hdr->cif_handler; |
103 | |
104 | if ((unsigned long)olpc_ofw_cif < OFW_MIN) { |
105 | printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n" , |
106 | (unsigned long)olpc_ofw_cif); |
107 | olpc_ofw_cif = NULL; |
108 | return; |
109 | } |
110 | |
111 | /* determine where OFW starts in memory */ |
112 | start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND); |
113 | printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n" , |
114 | (unsigned long)olpc_ofw_cif, (-start) >> 20); |
115 | reserve_top_address(reserve: -start); |
116 | } |
117 | |
118 | bool __init olpc_ofw_is_installed(void) |
119 | { |
120 | return olpc_ofw_cif != NULL; |
121 | } |
122 | |