From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Vitalij Borissow <250549977+vitalijborissow@users.noreply.github.com> Date: Sat, 15 Feb 2026 21:30:00 +0100 Subject: iommu/rockchip: Force GFP_DMA32 for rk3568-iommu v2 On systems with >4GB RAM, the RK3568 IOMMU v2 allocates page tables from high memory (above 4GB). While the IOMMU claims 40-bit address support, some devices like the NPU cannot properly handle page tables located above 4GB, resulting in DMA mapping failures and NPU timeouts. This patch forces GFP_DMA32 allocation for IOMMU v2 page tables, ensuring all allocations are within the first 4GB of physical memory. Tested on ODROID-M1 with 8GB RAM running kernel 6.18.9-current-rockchip64. Without this patch, NPU inference fails with IOMMU page table access errors. With this patch, NPU operates correctly with full IOMMU support enabled. Signed-off-by: Vitalij Borissow <250549977+vitalijborissow@users.noreply.github.com> --- drivers/iommu/rockchip-iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c index 111111111111..222222222222 100644 --- a/drivers/iommu/rockchip-iommu.c +++ b/drivers/iommu/rockchip-iommu.c @@ -1349,7 +1349,7 @@ static struct rk_iommu_ops iommu_data_ops_v2 = { .mk_dtentries = &rk_mk_dte_v2, .mk_ptentries = &rk_mk_pte_v2, .dma_bit_mask = DMA_BIT_MASK(40), - .gfp_flags = 0, + .gfp_flags = GFP_DMA32, }; static const struct of_device_id rk_iommu_dt_ids[] = { -- Armbian