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

Nicolas Saenz Julienne
2019-08-20T14:59:11Z

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 <nsaenzjulienne@suse.de>
---

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