Add support for handling the AMD Versal Gen 2 MDB PCIe Root Port PERST# signal via a GPIO by parsing the new PCIe bridge node to acquire the reset GPIO. As part of this, update the interrupt controller node parsing to use of_get_child_by_name() instead of of_get_next_child(), since the PCIe node now has multiple children. This ensures the correct node is selected during initialization. Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202506241020.rPD1a2Vr-lkp@xxxxxxxxx/ Signed-off-by: Sai Krishna Musham <sai.krishna.musham@xxxxxxx> --- Changes in v4: - Resolve kernel test robot warning. https://lore.kernel.org/oe-kbuild-all/202506241020.rPD1a2Vr-lkp@xxxxxxxxx/ - Update commit message. Changes in v3: - Implement amd_mdb_parse_pcie_port to parse bridge node for reset-gpios property. Changes in v2: - Change delay to PCIE_T_PVPERL_MS v3 https://lore.kernel.org/r/20250618080931.2472366-1-sai.krishna.musham@xxxxxxx/ v2 https://lore.kernel.org/r/20250429090046.1512000-1-sai.krishna.musham@xxxxxxx/ v1 https://lore.kernel.org/r/20250326041507.98232-1-sai.krishna.musham@xxxxxxx/ --- drivers/pci/controller/dwc/pcie-amd-mdb.c | 46 ++++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pcie-amd-mdb.c b/drivers/pci/controller/dwc/pcie-amd-mdb.c index 9f7251a16d32..f011a83550b9 100644 --- a/drivers/pci/controller/dwc/pcie-amd-mdb.c +++ b/drivers/pci/controller/dwc/pcie-amd-mdb.c @@ -18,6 +18,7 @@ #include <linux/resource.h> #include <linux/types.h> +#include "../../pci.h" #include "pcie-designware.h" #define AMD_MDB_TLP_IR_STATUS_MISC 0x4C0 @@ -56,6 +57,7 @@ * @slcr: MDB System Level Control and Status Register (SLCR) base * @intx_domain: INTx IRQ domain pointer * @mdb_domain: MDB IRQ domain pointer + * @perst_gpio: GPIO descriptor for PERST# signal handling * @intx_irq: INTx IRQ interrupt number */ struct amd_mdb_pcie { @@ -63,6 +65,7 @@ struct amd_mdb_pcie { void __iomem *slcr; struct irq_domain *intx_domain; struct irq_domain *mdb_domain; + struct gpio_desc *perst_gpio; int intx_irq; }; @@ -284,7 +287,7 @@ static int amd_mdb_pcie_init_irq_domains(struct amd_mdb_pcie *pcie, struct device_node *pcie_intc_node; int err; - pcie_intc_node = of_get_next_child(node, NULL); + pcie_intc_node = of_get_child_by_name(node, "interrupt-controller"); if (!pcie_intc_node) { dev_err(dev, "No PCIe Intc node found\n"); return -ENODEV; @@ -402,6 +405,34 @@ static int amd_mdb_setup_irq(struct amd_mdb_pcie *pcie, return 0; } +static int amd_mdb_parse_pcie_port(struct amd_mdb_pcie *pcie) +{ + struct device *dev = pcie->pci.dev; + struct device_node *pcie_port_node; + + pcie_port_node = of_get_next_child_with_prefix(dev->of_node, NULL, "pcie"); + if (!pcie_port_node) { + dev_err(dev, "No PCIe Bridge node found\n"); + return -ENODEV; + } + + /* Request the GPIO for PCIe reset signal and assert */ + pcie->perst_gpio = devm_fwnode_gpiod_get(dev, of_fwnode_handle(pcie_port_node), + "reset", GPIOD_OUT_HIGH, NULL); + if (IS_ERR(pcie->perst_gpio)) { + if (PTR_ERR(pcie->perst_gpio) != -ENOENT) { + of_node_put(pcie_port_node); + return dev_err_probe(dev, PTR_ERR(pcie->perst_gpio), + "Failed to request reset GPIO\n"); + } + pcie->perst_gpio = NULL; + } + + of_node_put(pcie_port_node); + + return 0; +} + static int amd_mdb_add_pcie_port(struct amd_mdb_pcie *pcie, struct platform_device *pdev) { @@ -426,6 +457,14 @@ static int amd_mdb_add_pcie_port(struct amd_mdb_pcie *pcie, pp->ops = &amd_mdb_pcie_host_ops; + if (pcie->perst_gpio) { + mdelay(PCIE_T_PVPERL_MS); + + /* Deassert the reset signal */ + gpiod_set_value_cansleep(pcie->perst_gpio, 0); + mdelay(PCIE_T_RRS_READY_MS); + } + err = dw_pcie_host_init(pp); if (err) { dev_err(dev, "Failed to initialize host, err=%d\n", err); @@ -444,6 +483,7 @@ static int amd_mdb_pcie_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct amd_mdb_pcie *pcie; struct dw_pcie *pci; + int ret; pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); if (!pcie) @@ -454,6 +494,10 @@ static int amd_mdb_pcie_probe(struct platform_device *pdev) platform_set_drvdata(pdev, pcie); + ret = amd_mdb_parse_pcie_port(pcie); + if (ret) + return ret; + return amd_mdb_add_pcie_port(pcie, pdev); } -- 2.44.1
