--- zzzz-none-000/linux-4.19.183/kernel/dma/swiotlb.c	2021-03-24 10:07:39.000000000 +0000
+++ bcm63-7530ax-756/linux-4.19.183/kernel/dma/swiotlb.c	2023-06-28 08:54:21.000000000 +0000
@@ -34,6 +34,9 @@
 #include <linux/scatterlist.h>
 #include <linux/mem_encrypt.h>
 #include <linux/set_memory.h>
+#if defined CONFIG_BCM_KF_ARM64_BCM963XX && defined(CONFIG_BCM94908) && defined(CONFIG_BCM_HND_EAP)
+#include <linux/memblock.h>
+#endif
 
 #include <asm/io.h>
 #include <asm/dma.h>
@@ -259,6 +262,23 @@
 	unsigned char *vstart;
 	unsigned long bytes;
 
+#if defined CONFIG_BCM_KF_ARM64_BCM963XX
+#if defined(CONFIG_BCM94908) && defined(CONFIG_BCM_HND_EAP)
+	/*
+	 * ZONE_DMA is restricted to 1GB due to a runner HW limitation. We
+	 * still don't need swiotlb in this case though so check against the
+	 * 4GB boundary here rather than zone_dma.
+	 */
+	if (!swiotlb_force &&
+		(max_pfn <= ((min((memblock_start_of_DRAM() & GENMASK_ULL(63, 32))
+				  + (1ULL << 32),
+				memblock_end_of_DRAM())) >> PAGE_SHIFT)))
+		return;
+#elif defined CONFIG_ARM64
+	if(!swiotlb_force && (max_pfn <= (arm64_dma_phys_limit >> PAGE_SHIFT)))
+		return;
+#endif
+#endif
 	if (!io_tlb_nslabs) {
 		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
 		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
@@ -1010,6 +1030,23 @@
 int
 swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
+#if defined CONFIG_BCM_KF_ARM64_BCM963XX
+#if defined(CONFIG_BCM94908) && defined(CONFIG_BCM_HND_EAP)
+	/*
+	 * ZONE_DMA is restricted to 1GB due to a runner HW limitation. We
+	 * still don't need swiotlb in this case though so check against the
+	 * 4GB boundary here rather than zone_dma.
+	 */
+	if (!swiotlb_force &&
+		(max_pfn <= ((min((memblock_start_of_DRAM() & GENMASK_ULL(63, 32))
+				  + (1ULL << 32),
+				memblock_end_of_DRAM())) >> PAGE_SHIFT)))
+		return 1;
+#elif defined CONFIG_ARM64
+	if(!swiotlb_force && (max_pfn <= (arm64_dma_phys_limit >> PAGE_SHIFT)))
+		return 1;
+#endif
+#endif
 	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
 }