From: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com
[ 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 fancer.lancer@gmail.com Link: https://lore.kernel.org/linux-pci/20231018085631.1121289-4-yoshihiro.shimoda... Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Reviewed-by: Serge Semin fancer.lancer@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d14b4da700eaf..8e6f6ac42dc96 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)