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-rw-r--r--arch/x86/kernel/olpc_ofw.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/x86/kernel/olpc_ofw.c b/arch/x86/kernel/olpc_ofw.c
new file mode 100644
index 00000000000..469ee438429
--- /dev/null
+++ b/arch/x86/kernel/olpc_ofw.c
@@ -0,0 +1,104 @@
+#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);
+ early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
+}
+
+int __olpc_ofw(const char *name, int nr_args, 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);
+}