of: device: Fix overflow of coherent_dma_mask

Size of the dma-range is calculated as coherent_dma_mask + 1
and passed to arch_setup_dma_ops further. It overflows when
the coherent_dma_mask is set for full 64 bits 0xFFFFFFFFFFFFFFFF,
resulting in size getting passed as 0 wrongly. Fix this by
passsing in max(mask, mask + 1). Note that in this case
when the mask is set to full 64bits, we will be passing the mask
itself to arch_setup_dma_ops instead of the size. The real fix
for this should be to make arch_setup_dma_ops receive the
mask and handle it, to be done in the future.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 0d378c0..e1ae9e7 100644 (file)
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -107,7 +107,7 @@ 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 + 1;
+               size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
        } else {
                offset = PFN_DOWN(paddr - dma_addr);