[PATCH v2] of: Set the DMA mask to 64 bits when dma_addr_t is 64-bits

[Laura Abbott]

Currently, of_platform_device_create_pdata always sets the
coherent DMA mask to 32 bits. On ARM systems without CONFIG_ZONE_DMA,
arm_dma_limit gets set to ~0 or 0xFFFFFFFFFFFFFFFF on LPAE based
systems. Since arm_dma_limit represents the smallest dma_mask
on the system, the default of 32 bits prevents any dma_coherent
allocation from succeeding unless clients manually set the
dma mask first. Rather than make every client on an LPAE system set
the mask, set the mask to a 64 bit value on systems with 64-bit
dma addresses.

Signed-off-by: Laura Abbott <lauraa at codeaurora.org>
---
 drivers/of/platform.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 0970505..c669ab4 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -214,7 +214,11 @@ struct platform_device *of_platform_device_create_pdata(
 #if defined(CONFIG_MICROBLAZE)
 	dev->archdata.dma_mask = 0xffffffffUL;
 #endif
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
+#else
 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+#endif
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
 
-- 
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