powerpc/powernv: Add PIO accessors for Power8 LPC bus
This uses the hooks provided by CONFIG_PPC_INDIRECT_PIO to
implement a set of hooks for IO port access to use the LPC
bus via OPAL calls for the first 64K of IO space
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 6cc61a3..5a64757 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -69,6 +69,14 @@
extern resource_size_t isa_mem_base;
+/* Boolean set by platform if PIO accesses are suppored while _IO_BASE
+ * is not set or addresses cannot be translated to MMIO. This is typically
+ * set when the platform supports "special" PIO accesses via a non memory
+ * mapped mechanism, and allows things like the early udbg UART code to
+ * function.
+ */
+extern bool isa_io_special;
+
#ifdef CONFIG_PPC32
#if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
#error CONFIG_PPC_INDIRECT_{PIO,MMIO} are not yet supported on 32 bits