powerpc/dma: Fix dma_iommu_dma_supported compare

The table offset is in entries, each of which imply a dma address of
an IOMMU page.

Also, we should check the device can reach the whole IOMMU table.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 10 deletions

diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index 37771a518119..6e54a0fd31aa 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -74,16 +74,17 @@ static int dma_iommu_dma_supported(struct device *dev, u64 mask)
 {
         struct iommu_table *tbl = get_iommu_table_base(dev);
 
-        if (!tbl || tbl->it_offset > mask) {
-                printk(KERN_INFO
-                       "Warning: IOMMU offset too big for device mask\n");
-                if (tbl)
-                        printk(KERN_INFO
-                               "mask: 0x%08llx, table offset: 0x%08lx\n",
-                                mask, tbl->it_offset);
-                else
-                        printk(KERN_INFO "mask: 0x%08llx, table unavailable\n",
-                                mask);
+        if (!tbl) {
+                dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
+                        ", table unavailable\n", mask);
+                return 0;
+        }
+
+        if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
+                dev_info(dev, "Warning: IOMMU window too big for device mask\n");
+                dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
+                                mask, (tbl->it_offset + tbl->it_size) <<
+                                IOMMU_PAGE_SHIFT);
                 return 0;
         } else
                 return 1;