Since commit e72323f3b09f ("scsi: ufs: core: Configure only active lanes during link"), the following error is observed on R-Car S4: ufshcd-renesas e6860000.ufs: Tx lane mismatch [config,reported] [2,1] ufshcd-renesas e6860000.ufs: link startup failed -67 ufshcd-renesas e6860000.ufs: error -ENOLINK: Initialization failed with error -67 ufshcd-renesas e6860000.ufs: probe with driver ufshcd-renesas failed with error -67 R-Car S4 has one UFS lane per direction, as described in section 152.1 of its hardware manual. Without lanes-per-direction, the UFS platform driver defaults to two lanes. Previously, the core used PA_CONNECTEDRXDATALANES and PA_CONNECTEDTXDATALANES to configure the link without checking them against lanes-per-direction, so the missing property did not prevent initialization. While fixing the R-Car S4 DTS is the proper solution, doing only that would still break backwards compatibility with existing DTBs. Hence add a quirk to let lanes-per-direction default to one on R-Car S4. Fixes: e72323f3b09f9c89 ("scsi: ufs: core: Configure only active lanes during link") Reported-by: Koichiro Den Closes: https://lore.kernel.org/20260911073058.253000-1-den@valinux.co.jp Cc: stable@vger.kernel.org # 7.2+ Signed-off-by: Geert Uytterhoeven --- Tested on S4SK. drivers/ufs/host/ufshcd-pltfrm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/ufs/host/ufshcd-pltfrm.c b/drivers/ufs/host/ufshcd-pltfrm.c index 5ac7afe759346deb..169dbc1a75fe5734 100644 --- a/drivers/ufs/host/ufshcd-pltfrm.c +++ b/drivers/ufs/host/ufshcd-pltfrm.c @@ -206,7 +206,11 @@ static void ufshcd_init_lanes_per_dir(struct ufs_hba *hba) dev_dbg(hba->dev, "%s: failed to read lanes-per-direction, ret=%d\n", __func__, ret); - hba->lanes_per_direction = UFSHCD_DEFAULT_LANES_PER_DIRECTION; + /* Old R-Car S4 DTBs lack "lanes-per-direction = <1>" */ + if (of_device_is_compatible(dev->of_node, "renesas,r8a779f0-ufs")) + hba->lanes_per_direction = 1; + else + hba->lanes_per_direction = UFSHCD_DEFAULT_LANES_PER_DIRECTION; } } -- 2.43.0