From f3dda1cf33b481c22412002e5ee361aa6dbcbd75 Mon Sep 17 00:00:00 2001 From: Yoshihiro Shimoda Date: Wed, 18 Oct 2023 17:56:19 +0900 Subject: [PATCH] PCI: dwc: Add missing PCI_EXP_LNKCAP_MLW handling MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 89db0793c9f2da265ecb6c1681f899d9af157f37 ] Update dw_pcie_link_set_max_link_width() to set PCI_EXP_LNKCAP_MLW. In accordance with the DW PCIe RC/EP HW manuals [1,2,3,...] aside with the PORT_LINK_CTRL_OFF.LINK_CAPABLE and GEN2_CTRL_OFF.NUM_OF_LANES[8:0] field there is another one which needs to be updated. It's LINK_CAPABILITIES_REG.PCIE_CAP_MAX_LINK_WIDTH. If it isn't done at the very least the maximum link-width capability CSR won't expose the actual maximum capability. [1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.60a, March 2015, p.1032 [2] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.70a, March 2016, p.1065 [3] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 4.90a, March 2016, p.1057 ... [X] DesignWare Cores PCI Express Controller Databook - DWC PCIe Endpoint, Version 5.40a, March 2019, p.1396 [X+1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port, Version 5.40a, March 2019, p.1266 Suggested-by: Serge Semin Link: https://lore.kernel.org/linux-pci/20231018085631.1121289-4-yoshihiro.shimoda.uh@renesas.com Signed-off-by: Yoshihiro Shimoda Signed-off-by: Krzysztof Wilczyński Reviewed-by: Manivannan Sadhasivam Reviewed-by: Serge Semin Signed-off-by: Sasha Levin --- drivers/pci/controller/dwc/pcie-designware.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index da4aba4..2b60d20 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -734,7 +734,8 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen) static void dw_pcie_link_set_max_link_width(struct dw_pcie *pci, u32 num_lanes) { - u32 lwsc, plc; + u32 lnkcap, lwsc, plc; + u8 cap; if (!num_lanes) return; @@ -770,6 +771,12 @@ static void dw_pcie_link_set_max_link_width(struct dw_pcie *pci, u32 num_lanes) } dw_pcie_writel_dbi(pci, PCIE_PORT_LINK_CONTROL, plc); dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, lwsc); + + cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + lnkcap = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP); + lnkcap &= ~PCI_EXP_LNKCAP_MLW; + lnkcap |= FIELD_PREP(PCI_EXP_LNKCAP_MLW, num_lanes); + dw_pcie_writel_dbi(pci, cap + PCI_EXP_LNKCAP, lnkcap); } void dw_pcie_iatu_detect(struct dw_pcie *pci) -- 2.7.4