Subject: [PATCH v2 10/11] arm64: edit zone_dma_bits to fine tune dma-direct min mask

From: Nicolas Saenz Julienne <[email-masked]>
Date: Tue, 20 Aug 2019 16:58:18 +0200

With the introduction of ZONE_DMA in arm64 devices are not forced to
support 32 bit DMA masks. We have to inform dma-direct of this
limitation whenever it happens.

Signed-off-by: Nicolas Saenz Julienne <[email-masked]>
---

Changes in v2:
- Make sure to filter the higher part of arm64_dma_phys_limit
- Rename variable to zone_dma_bits

 arch/arm64/mm/init.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index c51ce79b692b..c5e619f21ad8 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -22,6 +22,7 @@
 #include <linux/of_fdt.h>
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
+#include <linux/dma-direct.h>
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
 #include <linux/vmalloc.h>
@@ -437,8 +438,10 @@ void __init arm64_memblock_init(void)
 
 	early_init_fdt_scan_reserved_mem();
 
-	if (IS_ENABLED(CONFIG_ZONE_DMA))
+	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
 		arm64_dma_phys_limit = max_zone_dma_phys();
+		zone_dma_bits = ilog2((arm64_dma_phys_limit - 1) & GENMASK_ULL(31, 0)) + 1;
+	}
 
 	if (IS_ENABLED(CONFIG_ZONE_DMA32))
 		arm64_dma32_phys_limit = max_zone_dma32_phys();
-- 
2.22.0

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