1 files changed, 106 insertions, 0 deletions

diff --git a/arch/x86/kernel/olpc_ofw.c b/arch/x86/kernel/olpc_ofw.c
new file mode 100644
index 000000000000..3218aa71ab5e
--- /dev/null
+++ b/arch/x86/kernel/olpc_ofw.c
@@ -0,0 +1,106 @@
+#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);
+
+/* 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);
+}