[PATCH] PCI: mediatek-gen3: Fix 64-bit type truncation in mtk_pcie_set_trans_table()

From: Sreeraj S Kurup

Date: Tue Jul 28 2026 - 06:37:57 EST


The variables cpu_addr, pci_addr, and remaining in
mtk_pcie_set_trans_table() are of type resource_size_t, which is 64-bit
on 64-bit architectures.

Using 32-bit helpers fls(), ffs(), and BIT() causes 64-bit integer
truncation when computing window sizes and address alignments above
4GB.

Replace them with fls64(), ffs64(), and BIT_ULL() to ensure correct
64-bit types are used across the address space.

Signed-off-by: Sreeraj S Kurup <sreekuttan2156239@xxxxxxxxx>
---
drivers/pci/controller/pcie-mediatek-gen3.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index bcbd08c82a5c..b1dc18f851d2 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -334,10 +334,10 @@ static int mtk_pcie_set_trans_table(struct mtk_gen3_pcie *pcie,

while (remaining && (*num < PCIE_MAX_TRANS_TABLES)) {
/* Table size needs to be a power of 2 */
- table_size = BIT(fls(remaining) - 1);
+ table_size = BIT_ULL(fls64(remaining) - 1);

if (cpu_addr > 0) {
- addr_align = BIT(ffs(cpu_addr) - 1);
+ addr_align = BIT_ULL(ffs64(cpu_addr) - 1);
table_size = min(table_size, addr_align);
}

@@ -349,7 +349,8 @@ static int mtk_pcie_set_trans_table(struct mtk_gen3_pcie *pcie,
}

table = pcie->base + PCIE_TRANS_TABLE_BASE_REG + *num * PCIE_ATR_TLB_SET_OFFSET;
- writel_relaxed(lower_32_bits(cpu_addr) | PCIE_ATR_SIZE(fls(table_size) - 1), table);
+ writel_relaxed(lower_32_bits(cpu_addr) |
+ PCIE_ATR_SIZE(fls64(table_size) - 1), table);
writel_relaxed(upper_32_bits(cpu_addr), table + PCIE_ATR_SRC_ADDR_MSB_OFFSET);
writel_relaxed(lower_32_bits(pci_addr), table + PCIE_ATR_TRSL_ADDR_LSB_OFFSET);
writel_relaxed(upper_32_bits(pci_addr), table + PCIE_ATR_TRSL_ADDR_MSB_OFFSET);
--
2.54.0