LXR linux/arch/x86/platform/olpc/olpc

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