On 02/06/2015 09:38 AM, Catalin Marinas wrote:
On Thu, Feb 05, 2015 at 09:52:55PM +0000, Murali Karicheri wrote:
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. Also add
code to check invalid values of size configured in DT and log error.

Cc: Joerg Roedel<[email protected]>
Cc: Grant Likely<[email protected]>
Cc: Rob Herring<[email protected]>
Cc: Bjorn Helgaas<[email protected]>
Cc: Will Deacon<[email protected]>
Cc: Russell King<[email protected]>
Cc: Arnd Bergmann<[email protected]>
Cc: Suravee Suthikulpanit<[email protected]>

Signed-off-by: Murali Karicheri<[email protected]>
---
  drivers/of/device.c |   17 ++++++++++++++++-
  1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 2de320d..314c8a9 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -105,9 +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) {
+                       dev_warn(dev, "Invalid size 0x%llx for dma-range\n",
+                                size);
+                       size = size + 1;
+               }
+
+               if (!size) {
+                       dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
+                       return;
+               }

Would it make sense to set coherent_dma_mask to 0 here to make this more
noticeable? It can be done together with the mask calculation from size.

I guess you are the following in the code.

if (!size) {
                dev->coherent_dma_mask = 0;
                dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
                return;
}

Not sure how this is going to help and how this get handled by the caller and subsequent logic. Probably it will cause probe to fail, with some helpful error code. Need to try this out. Will do before sending my size based dma mask patch later today.

Murali

--
Murali Karicheri
Linux Kernel, Texas Instruments
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