asm-generic: add legacy I/O header files

The dma.h, hw_irq.h, serial.h and timex.h files originally
described PC-style i8237, i8259A, i8250, i8253 and i8255 chips
as well as the VGA style text mode graphics.

Modern architectures live happily without these specific
interfaces, but a few definitions from these headers keep
getting used in common code.

The new generic headers are what most architectures use
anyway nowadays, just implementing the minimal definitions.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/asm-generic/dma.h b/include/asm-generic/dma.h
new file mode 100644
index 000000000000..9dfc3a7f36d2
--- /dev/null
+++ b/include/asm-generic/dma.h
@@ -0,0 +1,15 @@
+#ifndef __ASM_GENERIC_DMA_H
+#define __ASM_GENERIC_DMA_H
+/*
+ * This file traditionally describes the i8237 PC style DMA controller.
+ * Most architectures don't have these any more and can get the minimal
+ * implementation from kernel/dma.c by not defining MAX_DMA_CHANNELS.
+ *
+ * Some code relies on seeing MAX_DMA_ADDRESS though.
+ */
+#define MAX_DMA_ADDRESS PAGE_OFFSET
+
+extern int request_dma(unsigned int dmanr, const char *device_id);
+extern void free_dma(unsigned int dmanr);
+
+#endif /* __ASM_GENERIC_DMA_H */