arm64: mm: fix DMA zone when dma-ranges is missing

Some platforms, like Rockchip RK3568 based Odroid M1, do not provide DMA
limits information in device-tree dma-ranges property. Still some device
drivers set DMA limit that relies on DMA zone at low 4GB memory area.
Until commit ba0fb44 ("dma-mapping: replace zone_dma_bits by
zone_dma_limit"), zone_sizes_init() restricted DMA zone to low 32-bit.

Restore DMA zone 32-bit limit when the platform provides no DMA bus
limit information.

Fixes: ba0fb44 ("dma-mapping: replace zone_dma_bits by zone_dma_limit")
Reported-by: Marek Szyprowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Suggested-by: Robin Murphy <[email protected]>
Signed-off-by: Baruch Siach <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

Author: baruchsiach

arch/arm64/mm/init.c

@@ -116,6 +116,9 @@ static void __init arch_reserve_crashkernel(void)
 
 static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit)
 {
+	if (zone_limit == PHYS_ADDR_MAX)
+		zone_limit = U32_MAX;
+
 	return min(zone_limit, memblock_end_of_DRAM() - 1) + 1;
 }