ARM: 9323/1: mm: Fix ARCH_LOW_ADDRESS_LIMIT when CONFIG_ZONE_DMA

Configuring VMSPLIT_2G + LPAE on Raspberry Pi 4 leads to SWIOTLB
buffer allocation beyond platform dma_zone_size of SZ_1G, which
results in broken SD card boot.

So fix this be setting ARCH_LOW_ADDRESS_LIMIT in CONFIG_ZONE_DMA
case.

Suggested-by: Russell King <[email protected]>
Fixes: e9faf9b ("ARM: add multi_v7_lpae_defconfig")
Signed-off-by: Stefan Wahren <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

Author: lategoodbye

arch/arm/include/asm/dma.h

@@ -12,6 +12,9 @@
 	extern phys_addr_t arm_dma_zone_size; \
 	arm_dma_zone_size && arm_dma_zone_size < (0x100000000ULL - PAGE_OFFSET) ? \
 		(PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
+
+extern phys_addr_t arm_dma_limit;
+#define ARCH_LOW_ADDRESS_LIMIT arm_dma_limit
 #endif
 
 #ifdef CONFIG_ISA_DMA_API