From: dillon min <dillon.minfei@xxxxxxxxx>
Currently, we use dma direct to request coherent memory for driver on armv7m
platform if 'cacheid' is zero, but dma_direct_can_mmap() is return false,
dma_direct_mmap() return -ENXIO for CONFIG_MMU undefined platform.
so we have to back to use 'arm_nommu_dma_ops', add use_reserved_mem() to check
if device support global or device corherent memory. if yes, then call
set_dma_ops()
Signed-off-by: dillon min <dillon.minfei@xxxxxxxxx>
---
arch/arm/mm/dma-mapping-nommu.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index 287ef898a55e..e1c213fec152 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -14,6 +14,7 @@
#include <asm/cacheflush.h>
#include <asm/outercache.h>
#include <asm/cp15.h>
+#include <linux/of.h>
#include "dma.h"
@@ -188,6 +189,31 @@ const struct dma_map_ops arm_nommu_dma_ops = {
};
EXPORT_SYMBOL(arm_nommu_dma_ops);
+static bool use_reserved_mem(struct device *dev)
+{
+ struct device_node *np;
+
+ np = of_find_node_by_path("/reserved-memory/linux,dma");
+
+ if (np &&
+ of_device_is_compatible(np, "shared-dma-pool") &&
+ of_property_read_bool(np, "no-map") &&
+ of_property_read_bool(np, "linux,dma-default")) {
+ /* has global corherent mem support */
+ of_node_put(np);
+ return true;
+ }
+
+ np = of_parse_phandle(dev->of_node, "memory-region", 0);
+ if (np) {
+ /* has dev corherent mem support */
+ of_node_put(np);
+ return true;
+ }
+
+ return false;
+}
+
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
@@ -206,6 +232,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
dev->archdata.dma_coherent = (get_cr() & CR_M) ? coherent : true;
}
- if (!dev->archdata.dma_coherent)
+ if (!dev->archdata.dma_coherent || use_reserved_mem(dev))
set_dma_ops(dev, &arm_nommu_dma_ops);
}
--
2.7.4
