dm: core: Introduce xxx_translate_dma_address()

Add the following functions to translate DMA address to CPU address:
- dev_translate_dma_address()
- ofnode_translate_dma_address()
- of_translate_dma_address()
- fdt_translate_dma_address()
These functions work the same way as xxx_translate_address(), with the
difference that the translation relies on the "dma-ranges" property
instead of the "ranges" property.

Add related test. Test report:
=> ut dm fdt_translation
Test: dm_test_fdt_translation: test-fdt.c
Test: dm_test_fdt_translation: test-fdt.c (flat tree)
Failures: 0

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/dm/of_addr.h b/include/dm/of_addr.h
index 12b1a99a80..3fa1ffce81 100644
--- a/include/dm/of_addr.h
+++ b/include/dm/of_addr.h
@@ -27,6 +27,24 @@
 u64 of_translate_address(const struct device_node *no, const __be32 *in_addr);
 
 /**
+ * of_translate_dma_address() - translate a device-tree DMA address to a CPU
+ *				address
+ *
+ * Translate a DMA address from the device-tree into a CPU physical address,
+ * this walks up the tree and applies the various bus mappings on the way.
+ *
+ * Note: We consider that crossing any level with #size-cells == 0 to mean
+ * that translation is impossible (that is we are not dealing with a value
+ * that can be mapped to a cpu physical address). This is not really specified
+ * that way, but this is traditionally the way IBM at least do things
+ *
+ * @np: node to check
+ * @in_addr: pointer to input DMA address
+ * @return translated DMA address or OF_BAD_ADDR on error
+ */
+u64 of_translate_dma_address(const struct device_node *no, const __be32 *in_addr);
+
+/**
  * of_get_address() - obtain an address from a node
  *
  * Extract an address from a node, returns the region size and the address