powerpc/warp: Fix ISA_DMA_THRESHOLD default

If no device is passed to __dma_alloc_coherent, it defaults to using ISA_DMA_THRESHOLD
for the mask. This patch provides a reasonable default rather than 0.

Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/44x/warp.c b/arch/powerpc/platforms/44x/warp.c
index c5118802a281..42e09a9f77e2 100644
--- a/arch/powerpc/platforms/44x/warp.c
+++ b/arch/powerpc/platforms/44x/warp.c
@@ -43,7 +43,13 @@ static int __init warp_probe(void)
 {
         unsigned long root = of_get_flat_dt_root();
 
-        return of_flat_dt_is_compatible(root, "pika,warp");
+        if (!of_flat_dt_is_compatible(root, "pika,warp"))
+                return 0;
+
+        /* For __dma_alloc_coherent */
+        ISA_DMA_THRESHOLD = ~0L;
+
+        return 1;
 }
 
 define_machine(warp) {