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authorStephen Warren <swarren@wwwdotorg.org>2015-03-24 20:07:33 -0600
committerMarek Vasut <marex@denx.de>2015-04-14 05:47:59 +0200
commit927c1fa266ead17acb09e9397dbd33578f3ee267 (patch)
tree58a8b23869008d8a1b99bb2e33969095bbf4e53e /include/phys2bus.h
parentfc909c0563da20f3a564aa598dbe5966defabdcc (diff)
Create API to map between CPU physical and bus addresses
On some SoCs, DMA-capable peripherals see a different address space to the CPU's physical address space. Create an API to allow platform-agnostic drivers to convert between the two address spaces when programming DMA operations. This API will exist on all platforms, but will have a dummy implementation when this feature is not required. Other platforms will enable CONFIG_PHYS_TO_BUS and provide the required implementation. Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Diffstat (limited to 'include/phys2bus.h')
-rw-r--r--include/phys2bus.h25
1 files changed, 25 insertions, 0 deletions
diff --git a/include/phys2bus.h b/include/phys2bus.h
new file mode 100644
index 00000000000..87b6d69aa61
--- /dev/null
+++ b/include/phys2bus.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2015 Stephen Warren
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef _BUS_ADDR_H
+#define _BUS_ADDR_H
+
+#ifdef CONFIG_PHYS_TO_BUS
+unsigned long phys_to_bus(unsigned long phys);
+unsigned long bus_to_phys(unsigned long bus);
+#else
+static inline unsigned long phys_to_bus(unsigned long phys)
+{
+ return phys;
+}
+
+static inline unsigned long bus_to_phys(unsigned long bus)
+{
+ return bus;
+}
+#endif
+
+#endif