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authorIngo Molnar <mingo@elte.hu>2009-01-10 23:56:42 +0100
committerIngo Molnar <mingo@elte.hu>2009-01-10 23:56:42 +0100
commit1de8cd3cb9f61e854e743c7210df43db517d4832 (patch)
tree2b69c5ba5e4094037fa04d0fcb6c4537c222cde8 /arch/xtensa/include/asm/dma.h
parent1eb1b3b65dc3e3ffcc6a60e115c085c0c11c1077 (diff)
parent3d14bdad40315b54470cb7812293d14c8af2bf7d (diff)
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Merge branch 'linus' into x86/cleanups
Diffstat (limited to 'arch/xtensa/include/asm/dma.h')
-rw-r--r--arch/xtensa/include/asm/dma.h61
1 files changed, 61 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/dma.h b/arch/xtensa/include/asm/dma.h
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+++ b/arch/xtensa/include/asm/dma.h
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+/*
+ * include/asm-xtensa/dma.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2003 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_DMA_H
+#define _XTENSA_DMA_H
+
+#include <asm/io.h> /* need byte IO */
+
+/*
+ * This is only to be defined if we have PC-like DMA.
+ * By default this is not true on an Xtensa processor,
+ * however on boards with a PCI bus, such functionality
+ * might be emulated externally.
+ *
+ * NOTE: there still exists driver code that assumes
+ * this is defined, eg. drivers/sound/soundcard.c (as of 2.4).
+ */
+#define MAX_DMA_CHANNELS 8
+
+/*
+ * The maximum virtual address to which DMA transfers
+ * can be performed on this platform.
+ *
+ * NOTE: This is board (platform) specific, not processor-specific!
+ *
+ * NOTE: This assumes DMA transfers can only be performed on
+ * the section of physical memory contiguously mapped in virtual
+ * space for the kernel. For the Xtensa architecture, this
+ * means the maximum possible size of this DMA area is
+ * the size of the statically mapped kernel segment
+ * (XCHAL_KSEG_{CACHED,BYPASS}_SIZE), ie. 128 MB.
+ *
+ * NOTE: When the entire KSEG area is DMA capable, we substract
+ * one from the max address so that the virt_to_phys() macro
+ * works correctly on the address (otherwise the address
+ * enters another area, and virt_to_phys() may not return
+ * the value desired).
+ */
+
+#define MAX_DMA_ADDRESS (PAGE_OFFSET + XCHAL_KIO_SIZE - 1)
+
+
+/* Reserve and release a DMA channel */
+extern int request_dma(unsigned int dmanr, const char * device_id);
+extern void free_dma(unsigned int dmanr);
+
+#ifdef CONFIG_PCI
+extern int isa_dma_bridge_buggy;
+#else
+#define isa_dma_bridge_buggy (0)
+#endif
+
+
+#endif