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-rw-r--r--arch/powerpc/include/asm/io.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 6cc61a3c43ee..5a64757dc0d1 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -69,6 +69,14 @@ extern unsigned long pci_dram_offset;
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