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authorDavid S. Miller <davem@davemloft.net>2009-01-08 11:05:59 -0800
committerDavid S. Miller <davem@davemloft.net>2009-01-08 11:05:59 -0800
commit7f46b1343f723f98634a5dcee47856b2000079ed (patch)
treeed22b6298c8dd2f687890a0d79abcd1d273b5f81 /arch/xtensa/include/asm/dma.h
parentb8c31da64165b8566fc6e1c9c826f76e7b98ff02 (diff)
parent9e42d0cf5020aaf217433cad1a224745241d212a (diff)
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
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
new file mode 100644
index 00000000000..e30f3abf48f
--- /dev/null
+++ b/arch/xtensa/include/asm/dma.h
@@ -0,0 +1,61 @@
+/*
+ * 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