1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun #include <linux/kernel.h>
3*4882a593Smuzhiyun #include <linux/export.h>
4*4882a593Smuzhiyun #include <linux/spinlock_types.h>
5*4882a593Smuzhiyun #include <linux/init.h>
6*4882a593Smuzhiyun #include <linux/pgtable.h>
7*4882a593Smuzhiyun #include <asm/page.h>
8*4882a593Smuzhiyun #include <asm/setup.h>
9*4882a593Smuzhiyun #include <asm/io.h>
10*4882a593Smuzhiyun #include <asm/cpufeature.h>
11*4882a593Smuzhiyun #include <asm/special_insns.h>
12*4882a593Smuzhiyun #include <asm/olpc_ofw.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun /* address of OFW callback interface; will be NULL if OFW isn't found */
15*4882a593Smuzhiyun static int (*olpc_ofw_cif)(int *);
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun /* page dir entry containing OFW's pgdir table; filled in by head_32.S */
18*4882a593Smuzhiyun u32 olpc_ofw_pgd __initdata;
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun static DEFINE_SPINLOCK(ofw_lock);
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun #define MAXARGS 10
23*4882a593Smuzhiyun
setup_olpc_ofw_pgd(void)24*4882a593Smuzhiyun void __init setup_olpc_ofw_pgd(void)
25*4882a593Smuzhiyun {
26*4882a593Smuzhiyun pgd_t *base, *ofw_pde;
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun if (!olpc_ofw_cif)
29*4882a593Smuzhiyun return;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun /* fetch OFW's PDE */
32*4882a593Smuzhiyun base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
33*4882a593Smuzhiyun if (!base) {
34*4882a593Smuzhiyun printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n");
35*4882a593Smuzhiyun olpc_ofw_cif = NULL;
36*4882a593Smuzhiyun return;
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun ofw_pde = &base[OLPC_OFW_PDE_NR];
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* install OFW's PDE permanently into the kernel's pgtable */
41*4882a593Smuzhiyun set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);
42*4882a593Smuzhiyun /* implicit optimization barrier here due to uninline function return */
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
__olpc_ofw(const char * name,int nr_args,const void ** args,int nr_res,void ** res)47*4882a593Smuzhiyun int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res,
48*4882a593Smuzhiyun void **res)
49*4882a593Smuzhiyun {
50*4882a593Smuzhiyun int ofw_args[MAXARGS + 3];
51*4882a593Smuzhiyun unsigned long flags;
52*4882a593Smuzhiyun int ret, i, *p;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun BUG_ON(nr_args + nr_res > MAXARGS);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun if (!olpc_ofw_cif)
57*4882a593Smuzhiyun return -EIO;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun ofw_args[0] = (int)name;
60*4882a593Smuzhiyun ofw_args[1] = nr_args;
61*4882a593Smuzhiyun ofw_args[2] = nr_res;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun p = &ofw_args[3];
64*4882a593Smuzhiyun for (i = 0; i < nr_args; i++, p++)
65*4882a593Smuzhiyun *p = (int)args[i];
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun /* call into ofw */
68*4882a593Smuzhiyun spin_lock_irqsave(&ofw_lock, flags);
69*4882a593Smuzhiyun ret = olpc_ofw_cif(ofw_args);
70*4882a593Smuzhiyun spin_unlock_irqrestore(&ofw_lock, flags);
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun if (!ret) {
73*4882a593Smuzhiyun for (i = 0; i < nr_res; i++, p++)
74*4882a593Smuzhiyun *((int *)res[i]) = *p;
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun return ret;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(__olpc_ofw);
80*4882a593Smuzhiyun
olpc_ofw_present(void)81*4882a593Smuzhiyun bool olpc_ofw_present(void)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun return olpc_ofw_cif != NULL;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(olpc_ofw_present);
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun /* OFW cif _should_ be above this address */
88*4882a593Smuzhiyun #define OFW_MIN 0xff000000
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun /* OFW starts on a 1MB boundary */
91*4882a593Smuzhiyun #define OFW_BOUND (1<<20)
92*4882a593Smuzhiyun
olpc_ofw_detect(void)93*4882a593Smuzhiyun void __init olpc_ofw_detect(void)
94*4882a593Smuzhiyun {
95*4882a593Smuzhiyun struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
96*4882a593Smuzhiyun unsigned long start;
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun /* ensure OFW booted us by checking for "OFW " string */
99*4882a593Smuzhiyun if (hdr->ofw_magic != OLPC_OFW_SIG)
100*4882a593Smuzhiyun return;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun olpc_ofw_cif = (int (*)(int *))hdr->cif_handler;
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun if ((unsigned long)olpc_ofw_cif < OFW_MIN) {
105*4882a593Smuzhiyun printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n",
106*4882a593Smuzhiyun (unsigned long)olpc_ofw_cif);
107*4882a593Smuzhiyun olpc_ofw_cif = NULL;
108*4882a593Smuzhiyun return;
109*4882a593Smuzhiyun }
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun /* determine where OFW starts in memory */
112*4882a593Smuzhiyun start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND);
113*4882a593Smuzhiyun printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n",
114*4882a593Smuzhiyun (unsigned long)olpc_ofw_cif, (-start) >> 20);
115*4882a593Smuzhiyun reserve_top_address(-start);
116*4882a593Smuzhiyun }
117*4882a593Smuzhiyun
olpc_ofw_is_installed(void)118*4882a593Smuzhiyun bool __init olpc_ofw_is_installed(void)
119*4882a593Smuzhiyun {
120*4882a593Smuzhiyun return olpc_ofw_cif != NULL;
121*4882a593Smuzhiyun }
122