With the help of of_dma_safe_phys_limit() we can get the topmost
physical address accessible for DMA to the whole system and use that
information to properly setup zone_dma_bits.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
---
arch/arm64/include/asm/processor.h | 1 +
arch/arm64/mm/init.c | 5 ++---
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index fce8cbecd6bc..c09d3f1a9a6b 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -97,6 +97,7 @@
extern phys_addr_t arm64_dma_phys_limit;
#define ARCH_LOW_ADDRESS_LIMIT (arm64_dma_phys_limit - 1)
+#define ZONE_DMA_BITS_DEFAULT 32
struct debug_info {
#ifdef CONFIG_HAVE_HW_BREAKPOINT
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 0eca5865dcb1..5934df93bf4d 100644
--- 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()
@@ -196,7 +194,8 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
#ifdef CONFIG_ZONE_DMA
- zone_dma_bits = ARM64_ZONE_DMA_BITS;
+ zone_dma_bits = min(zone_dma_bits,
+ (unsigned int)ilog2(of_dma_safe_phys_limit()));
if (IS_ENABLED(CONFIG_ACPI)) {
extern unsigned int acpi_iort_get_zone_dma_size(void);
--
2.28.0
