The of_dma_is_coherent() helper parses the given DT device
node to see if the "dma-coherent" property is supported and
returns true or false accordingly.
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
drivers/dma/of-dma.c | 22 ++++++++++++++++++++++
include/linux/of_dma.h | 5 +++++
2 files changed, 27 insertions(+)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 9b51768..c5958d1 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -304,3 +304,25 @@ out:
return ret;
}
EXPORT_SYMBOL_GPL(of_dma_get_range);
+
+/**
+ * of_dma_is_coherent - Check if device is coherent
+ * @np: device node
+ *
+ * It returns true if "dma-coherent" property was found
+ * for this device in DT.
+ */
+bool of_dma_is_coherent(struct device_node *np)
+{
+ struct device_node *node = np;
+
+ while (node) {
+ if (of_property_read_bool(node, "dma-coherent")) {
+ of_node_put(node);
+ return true;
+ }
+ node = of_get_next_parent(node);
+ }
+ return false;
+}
+EXPORT_SYMBOL_GPL(of_dma_is_coherent);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index f04171a..6191f02 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -44,6 +44,7 @@ extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
extern int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr,
phys_addr_t *paddr, phys_addr_t *size);
+extern bool of_dma_is_coherent(struct device_node *np);
#else
static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -74,6 +75,10 @@ static inline int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr,
{
return -ENODEV;
}
+static inline bool of_dma_is_coherent(struct device_node *np)
+{
+ return false;
+}
#endif
#endif /* __LINUX_OF_DMA_H */
--
1.7.9.5
--
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