diff options
Diffstat (limited to 'arch/x86/platform/olpc/olpc_ofw.c')
-rw-r--r-- | arch/x86/platform/olpc/olpc_ofw.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/x86/platform/olpc/olpc_ofw.c b/arch/x86/platform/olpc/olpc_ofw.c new file mode 100644 index 00000000000..78732046437 --- /dev/null +++ b/arch/x86/platform/olpc/olpc_ofw.c @@ -0,0 +1,112 @@ +#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!\n"); + 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.\n", + (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)\n", + (unsigned long)olpc_ofw_cif, (-start) >> 20); + reserve_top_address(-start); +} |