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 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 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 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 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 } 113 114 bool __init olpc_ofw_is_installed(void) 115 { 116 return olpc_ofw_cif != NULL; 117 } 118