arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges

[linux-2.6-microblaze.git] / arch / arm64 / mm / init.c

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 1609b61..b736890 100644 (file)
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -42,8 +42,6 @@
 #include <asm/tlb.h>
 #include <asm/alternative.h>
 
-#define ARM64_ZONE_DMA_BITS    30
-
 /*
  * We need to be able to catch inadvertent references to memstart_addr
  * that occur (potentially in generic code) before arm64_memblock_init()
@@ -195,9 +193,11 @@ static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
 static void __init zone_sizes_init(unsigned long min, unsigned long max)
 {
        unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
+       unsigned int __maybe_unused dt_zone_dma_bits;
 
 #ifdef CONFIG_ZONE_DMA
-       zone_dma_bits = ARM64_ZONE_DMA_BITS;
+       dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
+       zone_dma_bits = min(32U, dt_zone_dma_bits);
        arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
        max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
 #endif