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authorAndres Salomon <dilinger@queued.net>2010-06-18 17:46:53 -0400
committerH. Peter Anvin <hpa@linux.intel.com>2010-06-18 14:54:36 -0700
commitfd699c76552bbfa66631f019be415a87dbb08237 (patch)
tree49f136f22fc94230af214f9c9c21a6fc0b7180e1 /arch/x86/include/asm/olpc_ofw.h
parent7e27d6e778cd87b6f2415515d7127eba53fe5d02 (diff)
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x86, olpc: Add support for calling into OpenFirmware
Add support for saving OFW's cif, and later calling into it to run OFW commands. OFW remains resident in memory, living within virtual range 0xff800000 - 0xffc00000. A single page directory entry points to the pgdir that OFW actually uses, so rather than saving the entire page table, we grab and install that one entry permanently in the kernel's page table. This is currently only used by the OLPC XO. Note that this particular calling convention breaks PAE and PAT, and so cannot be used on newer x86 hardware. Signed-off-by: Andres Salomon <dilinger@queued.net> LKML-Reference: <20100618174653.7755a39a@dev.queued.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/olpc_ofw.h')
-rw-r--r--arch/x86/include/asm/olpc_ofw.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/x86/include/asm/olpc_ofw.h b/arch/x86/include/asm/olpc_ofw.h
new file mode 100644
index 00000000000..3e63d857c48
--- /dev/null
+++ b/arch/x86/include/asm/olpc_ofw.h
@@ -0,0 +1,31 @@
+#ifndef _ASM_X86_OLPC_OFW_H
+#define _ASM_X86_OLPC_OFW_H
+
+/* index into the page table containing the entry OFW occupies */
+#define OLPC_OFW_PDE_NR 1022
+
+#define OLPC_OFW_SIG 0x2057464F /* aka "OFW " */
+
+#ifdef CONFIG_OLPC_OPENFIRMWARE
+
+/* run an OFW command by calling into the firmware */
+#define olpc_ofw(name, args, res) \
+ __olpc_ofw((name), ARRAY_SIZE(args), args, ARRAY_SIZE(res), res)
+
+extern int __olpc_ofw(const char *name, int nr_args, void **args, int nr_res,
+ void **res);
+
+/* determine whether OFW is available and lives in the proper memory */
+extern void olpc_ofw_detect(void);
+
+/* install OFW's pde permanently into the kernel's pgtable */
+extern void setup_olpc_ofw_pgd(void);
+
+#else /* !CONFIG_OLPC_OPENFIRMWARE */
+
+static inline void olpc_ofw_detect(void) { }
+static inline void setup_olpc_ofw_pgd(void) { }
+
+#endif /* !CONFIG_OLPC_OPENFIRMWARE */
+
+#endif /* _ASM_X86_OLPC_OFW_H */