[PATCH v4 3/6] of: fix size when dma-range is not used

[Murali Karicheri]

Fix the dma-range size when the DT attribute is missing. i.e  set size to
dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
overflow when mask is set to max of u64, add a check, log error and return.
Some platform use mask format for size in DTS. So add a work around to
catch this and fix.

Cc: Joerg Roedel <joro at 8bytes.org>
Cc: Grant Likely <grant.likely at linaro.org>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Will Deacon <will.deacon at arm.com>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com>

Signed-off-by: Murali Karicheri <m-karicheri2 at ti.com>
---
 drivers/of/device.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 2de320d..0a5ff54 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct device_node *np)
 	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
 	if (ret < 0) {
 		dma_addr = offset = 0;
-		size = dev->coherent_dma_mask;
+		size = dev->coherent_dma_mask + 1;
 	} else {
 		offset = PFN_DOWN(paddr - dma_addr);
+		/*
+		 * Add a work around to treat the size as mask + 1 in case
+		 * it is defined in DT as a mask.
+		 */
+		if (size & 1)
+			size = size + 1;
 		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
 	}
 
+	/* if size is 0, we have an overflow of u64 */
+	if (!size) {
+		dev_err(dev, "invalid size\n");
+		return;
+	}
+
 	dev->dma_pfn_offset = offset;
 
 	coherent = of_dma_is_coherent(np);
-- 
1.7.9.5