arm64: Replace ZONE_DMA32 with ZONE_DMA

On arm64 we do not have two DMA zones, so it does not make sense to
implement ZONE_DMA32. This patch changes ZONE_DMA32 with ZONE_DMA, the
latter covering 32-bit dma address space to honour GFP_DMA allocations.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

2 files changed, 18 insertions, 17 deletions

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 985fc075c0f3..26b2512c1fcd 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -39,9 +39,9 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
                 return NULL;
         }
 
-        if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
+        if (IS_ENABLED(CONFIG_ZONE_DMA) &&
             dev->coherent_dma_mask <= DMA_BIT_MASK(32))
-                flags |= GFP_DMA32;
+                flags |= GFP_DMA;
         if (IS_ENABLED(CONFIG_DMA_CMA)) {
                 struct page *page;
 
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d0b4c2efda90..a61a4d560d12 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -30,6 +30,7 @@
 #include <linux/memblock.h>
 #include <linux/sort.h>
 #include <linux/of_fdt.h>
+#include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
 
 #include <asm/sections.h>
@@ -59,22 +60,22 @@ static int __init early_initrd(char *p)
 early_param("initrd", early_initrd);
 #endif
 
-#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT)
-
 static void __init zone_sizes_init(unsigned long min, unsigned long max)
 {
         struct memblock_region *reg;
         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
-        unsigned long max_dma32 = min;
+        unsigned long max_dma = min;
 
         memset(zone_size, 0, sizeof(zone_size));
 
-#ifdef CONFIG_ZONE_DMA32
         /* 4GB maximum for 32-bit only capable devices */
-        max_dma32 = max(min, min(max, MAX_DMA32_PFN));
-        zone_size[ZONE_DMA32] = max_dma32 - min;
-#endif
-        zone_size[ZONE_NORMAL] = max - max_dma32;
+        if (IS_ENABLED(CONFIG_ZONE_DMA)) {
+                unsigned long max_dma_phys =
+                        (unsigned long)dma_to_phys(NULL, DMA_BIT_MASK(32) + 1);
+                max_dma = max(min, min(max, max_dma_phys >> PAGE_SHIFT));
+                zone_size[ZONE_DMA] = max_dma - min;
+        }
+        zone_size[ZONE_NORMAL] = max - max_dma;
 
         memcpy(zhole_size, zone_size, sizeof(zhole_size));
 
@@ -84,15 +85,15 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
 
                 if (start >= max)
                         continue;
-#ifdef CONFIG_ZONE_DMA32
-                if (start < max_dma32) {
-                        unsigned long dma_end = min(end, max_dma32);
-                        zhole_size[ZONE_DMA32] -= dma_end - start;
+
+                if (IS_ENABLED(CONFIG_ZONE_DMA) && start < max_dma) {
+                        unsigned long dma_end = min(end, max_dma);
+                        zhole_size[ZONE_DMA] -= dma_end - start;
                 }
-#endif
-                if (end > max_dma32) {
+
+                if (end > max_dma) {
                         unsigned long normal_end = min(end, max);
-                        unsigned long normal_start = max(start, max_dma32);
+                        unsigned long normal_start = max(start, max_dma);
                         zhole_size[ZONE_NORMAL] -= normal_end - normal_start;
                 }
         }