6.5-stable review patch. If anyone has any objections, please let me know.
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From: Xiaowei Bao xiaowei.bao@nxp.com
[ Upstream commit 17cf8661ee0f065c08152e611a568dd1fb0285f1 ]
The endpoint controller loses the Maximum Link Width and Supported Link Speed value from the Link Capabilities Register - initially configured by the Reset Configuration Word (RCW) - during a link-down or hot reset event.
Address this issue in the endpoint event handler.
Link: https://lore.kernel.org/r/20230720135834.1977616-2-Frank.Li@nxp.com Fixes: a805770d8a22 ("PCI: layerscape: Add EP mode support") Signed-off-by: Xiaowei Bao xiaowei.bao@nxp.com Signed-off-by: Hou Zhiqiang Zhiqiang.Hou@nxp.com Signed-off-by: Frank Li Frank.Li@nxp.com Signed-off-by: Lorenzo Pieralisi lpieralisi@kernel.org Acked-by: Manivannan Sadhasivam mani@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../pci/controller/dwc/pci-layerscape-ep.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c index de4c1758a6c33..19595e93dd4b6 100644 --- a/drivers/pci/controller/dwc/pci-layerscape-ep.c +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c @@ -45,6 +45,7 @@ struct ls_pcie_ep { struct pci_epc_features *ls_epc; const struct ls_pcie_ep_drvdata *drvdata; int irq; + u32 lnkcap; bool big_endian; };
@@ -73,6 +74,7 @@ static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id) struct ls_pcie_ep *pcie = dev_id; struct dw_pcie *pci = pcie->pci; u32 val, cfg; + u8 offset;
val = ls_lut_readl(pcie, PEX_PF0_PME_MES_DR); ls_lut_writel(pcie, PEX_PF0_PME_MES_DR, val); @@ -81,6 +83,19 @@ static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id) return IRQ_NONE;
if (val & PEX_PF0_PME_MES_DR_LUD) { + + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + + /* + * The values of the Maximum Link Width and Supported Link + * Speed from the Link Capabilities Register will be lost + * during link down or hot reset. Restore initial value + * that configured by the Reset Configuration Word (RCW). + */ + dw_pcie_dbi_ro_wr_en(pci); + dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, pcie->lnkcap); + dw_pcie_dbi_ro_wr_dis(pci); + cfg = ls_lut_readl(pcie, PEX_PF0_CONFIG); cfg |= PEX_PF0_CFG_READY; ls_lut_writel(pcie, PEX_PF0_CONFIG, cfg); @@ -215,6 +230,7 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev) struct ls_pcie_ep *pcie; struct pci_epc_features *ls_epc; struct resource *dbi_base; + u8 offset; int ret;
pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); @@ -251,6 +267,9 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, pcie);
+ offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + pcie->lnkcap = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP); + ret = dw_pcie_ep_init(&pci->ep); if (ret) return ret;