Merge tag 'mediatek-drm-fixes-5.5' of https://github.com/ckhu-mediatek/linux.git...

[linux.git] / arch / powerpc / mm / mem.c

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 9488b63dfc872d2bb7fc3350e1adf22251581f58..617c2777926fc15344937701d9d02f2bbc09c962 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -289,6 +289,14 @@ void __init mem_init(void)
        BUILD_BUG_ON(MMU_PAGE_COUNT > 16);
 
 #ifdef CONFIG_SWIOTLB
+       /*
+        * Some platforms (e.g. 85xx) limit DMA-able memory way below
+        * 4G. We force memblock to bottom-up mode to ensure that the
+        * memory allocated in swiotlb_init() is DMA-able.
+        * As it's the last memblock allocation, no need to reset it
+        * back to to-down.
+        */
+       memblock_set_bottom_up(true);
        swiotlb_init(0);
 #endif