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kernel add
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#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <asm/page.h>
#include <asm/setup.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/olpc_ofw.h>
/* address of OFW callback interface; will be NULL if OFW isn't found */
static int (*olpc_ofw_cif)(int *);
/* page dir entry containing OFW's pgdir table; filled in by head_32.S */
u32 olpc_ofw_pgd __initdata;
static DEFINE_SPINLOCK(ofw_lock);
#define MAXARGS 10
void __init setup_olpc_ofw_pgd(void)
{
pgd_t *base, *ofw_pde;
if (!olpc_ofw_cif)
return;
/* fetch OFW's PDE */
base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
if (!base) {
printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!
");
olpc_ofw_cif = NULL;
return;
}
ofw_pde = &base[OLPC_OFW_PDE_NR];
/* install OFW's PDE permanently into the kernel's pgtable */
set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);
/* implicit optimization barrier here due to uninline function return */
early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
}
int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res,
void **res)
{
int ofw_args[MAXARGS + 3];
unsigned long flags;
int ret, i, *p;
BUG_ON(nr_args + nr_res > MAXARGS);
if (!olpc_ofw_cif)
return -EIO;
ofw_args[0] = (int)name;
ofw_args[1] = nr_args;
ofw_args[2] = nr_res;
p = &ofw_args[3];
for (i = 0; i < nr_args; i++, p++)
*p = (int)args[i];
/* call into ofw */
spin_lock_irqsave(&ofw_lock, flags);
ret = olpc_ofw_cif(ofw_args);
spin_unlock_irqrestore(&ofw_lock, flags);
if (!ret) {
for (i = 0; i < nr_res; i++, p++)
*((int *)res[i]) = *p;
}
return ret;
}
EXPORT_SYMBOL_GPL(__olpc_ofw);
bool olpc_ofw_present(void)
{
return olpc_ofw_cif != NULL;
}
EXPORT_SYMBOL_GPL(olpc_ofw_present);
/* OFW cif _should_ be above this address */
#define OFW_MIN 0xff000000
/* OFW starts on a 1MB boundary */
#define OFW_BOUND (1<<20)
void __init olpc_ofw_detect(void)
{
struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
unsigned long start;
/* ensure OFW booted us by checking for "OFW " string */
if (hdr->ofw_magic != OLPC_OFW_SIG)
return;
olpc_ofw_cif = (int (*)(int *))hdr->cif_handler;
if ((unsigned long)olpc_ofw_cif < OFW_MIN) {
printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.
",
(unsigned long)olpc_ofw_cif);
olpc_ofw_cif = NULL;
return;
}
/* determine where OFW starts in memory */
start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND);
printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)
",
(unsigned long)olpc_ofw_cif, (-start) >> 20);
reserve_top_address(-start);
}
bool __init olpc_ofw_is_installed(void)
{
return olpc_ofw_cif != NULL;
}
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