On 5/20/2015 5:28 AM, Will Deacon wrote:

On Fri, May 15, 2015 at 10:23:12PM +0100, Suravee Suthikulpanit wrote:

quoted

Currently, device drivers, which support both OF and ACPI,
need to call two separate APIs, of_dma_is_coherent() and
acpi_dma_is_coherent()) to determine device coherency attribute.

This patch simplifies this process by introducing a new device
property API, device_dma_is_coherent(), which calls the appropriate
interface based on the booting architecture.

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
CC: Rafael J. Wysocki <redacted>
---
  drivers/base/property.c  | 12 ++++++++++++
  include/linux/property.h |  2 ++
  2 files changed, 14 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 1d0b116..8123c6e 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c

@@ -14,6 +14,7 @@
  #include <linux/export.h>
  #include <linux/kernel.h>
  #include <linux/of.h>
+#include <linux/of_address.h>
  #include <linux/property.h>

  /**

@@ -519,3 +520,14 @@ unsigned int device_get_child_node_count(struct device *dev)
  	return count;
  }
  EXPORT_SYMBOL_GPL(device_get_child_node_count);
+
+bool device_dma_is_coherent(struct device *dev)
+{
+	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
+		return of_dma_is_coherent(dev->of_node);
+	else if (has_acpi_companion(dev))
+		return acpi_dma_is_coherent(acpi_node(dev->fwnode));

I don't think you need the has_acpi_companion check, as acpi_node handles
this and acpi_dma_is_coherent(NULL) returns false.

Will

You are right.

Thanks,

Suravee