1 files changed, 25 insertions, 16 deletions

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 20ea0e118f24..d75ccded7f10 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -802,17 +802,24 @@ static int __init cell_iommu_init_disabled(void)
 
 static u64 cell_iommu_get_fixed_address(struct device *dev)
 {
-        u64 cpu_addr, size, best_size, pci_addr = OF_BAD_ADDR;
+        u64 cpu_addr, size, best_size, dev_addr = OF_BAD_ADDR;
         struct device_node *np;
         const u32 *ranges = NULL;
-        int i, len, best;
+        int i, len, best, naddr, nsize, pna, range_size;
 
         np = of_node_get(dev->archdata.of_node);
-        while (np) {
+        while (1) {
+                naddr = of_n_addr_cells(np);
+                nsize = of_n_size_cells(np);
+                np = of_get_next_parent(np);
+                if (!np)
+                        break;
+
                 ranges = of_get_property(np, "dma-ranges", &len);
-                if (ranges)
+
+                /* Ignore empty ranges, they imply no translation required */
+                if (ranges && len > 0)
                         break;
-                np = of_get_next_parent(np);
         }
 
         if (!ranges) {
@@ -822,15 +829,17 @@ static u64 cell_iommu_get_fixed_address(struct device *dev)
 
         len /= sizeof(u32);
 
+        pna = of_n_addr_cells(np);
+        range_size = naddr + nsize + pna;
+
         /* dma-ranges format:
-         * 1 cell:  pci space
-         * 2 cells: pci address
-         * 2 cells: parent address
-         * 2 cells: size
+         * child addr   : naddr cells
+         * parent addr  : pna cells
+         * size         : nsize cells
          */
-        for (i = 0, best = -1, best_size = 0; i < len; i += 7) {
-                cpu_addr = of_translate_dma_address(np, ranges +i + 3);
-                size = of_read_number(ranges + i + 5, 2);
+        for (i = 0, best = -1, best_size = 0; i < len; i += range_size) {
+                cpu_addr = of_translate_dma_address(np, ranges + i + naddr);
+                size = of_read_number(ranges + i + naddr + pna, nsize);
 
                 if (cpu_addr == 0 && size > best_size) {
                         best = i;
@@ -838,15 +847,15 @@ static u64 cell_iommu_get_fixed_address(struct device *dev)
                 }
         }
 
-        if (best >= 0)
-                pci_addr = of_read_number(ranges + best + 1, 2);
-        else
+        if (best >= 0) {
+                dev_addr = of_read_number(ranges + best, naddr);
+        } else
                 dev_dbg(dev, "iommu: no suitable range found!\n");
 
 out:
         of_node_put(np);
 
-        return pci_addr;
+        return dev_addr;
 }
 
 static int dma_set_mask_and_switch(struct device *dev, u64 dma_mask)