Merge patch series "Add PCIe Endpoint controller support for TI J784S4 SoC"

Hrushikesh Salunke <h-salunke@ti.com> says:

This series enables PCIe Endpoint mode on TI's J784S4 SoC. The J784S4
SoC features two Cadence PCIe controller instances (PCIe0 and PCIe1)
that can operate in endpoint mode. This series adds support for
configuring these controllers with up to 4 lanes.

Key changes include:
- Adding a stabilization delay after power domain reset to prevent
  timing-related initialization issues
- SERDES mux configuration support for proper lane routing, which is
  essential for SoCs where SERDES lanes are shared between multiple
  controllers (PCIe, USB, etc.) with different configurations across
  boot phases
- J784S4 SoC endpoint configuration with 4-lane support
- Disabling unconfigured endpoint functions to prevent enumeration
  issues on the Root Complex side

This series has been tested on J784S4 EVM with PCIe endpoint boot
configuration. Following are the corresponding test logs.

https://gist.github.com/hrushikesh221/331d65f45f43fd138f57e6adb61c4332

Link: https://lore.kernel.org/r/20251023114604.3655625-1-h-salunke@ti.com

configs/j784s4_evm_a72_defconfig

@@ -125,6 +125,8 @@ CONFIG_MUX_MMIO=y
 CONFIG_PHY_TI_DP83867=y
 CONFIG_PHY_FIXED=y
 CONFIG_TI_AM65_CPSW_NUSS=y
+CONFIG_PCI_ENDPOINT=y
+CONFIG_PCIE_CDNS_TI_EP=y
 CONFIG_PHY=y
 CONFIG_SPL_PHY=y
 CONFIG_PHY_CADENCE_TORRENT=y

drivers/pci_endpoint/pcie_cdns_ti_ep.c

@@ -20,6 +20,7 @@
 #include <regmap.h>
 #include <syscon.h>
 #include <pci_ep.h>
+#include <linux/delay.h>
 
 #include "pcie-cadence.h"
 
@@ -90,15 +91,26 @@ static int pcie_cdns_reset(struct udevice *dev, struct power_domain *pci_pwrdmn)
 		dev_err(dev, "failed to power on: %d\n", ret);
 		return ret;
 	}
-
+	mdelay(1);
 	return 0;
 }
 
 static int pcie_cdns_config_serdes(struct udevice *dev)
 {
+	int ret;
+
+	if (CONFIG_IS_ENABLED(MUX_MMIO)) {
+		struct udevice *mux;
+
+		ret = uclass_get_device_by_seq(UCLASS_MUX, 0, &mux);
+		if (ret) {
+			dev_err(dev, "unable to get mux\n");
+			return ret;
+		}
+	}
+
 	if (CONFIG_IS_ENABLED(PHY_CADENCE_TORRENT)) {
 		struct phy serdes;
-		int ret = 7;
 
 		ret = generic_phy_get_by_name(dev,  "pcie-phy", &serdes);
 		if (ret != 0 && ret != -EBUSY) {
@@ -263,9 +275,11 @@ static int pcie_cdns_ti_ep_probe(struct udevice *dev)
 	struct pcie_cdns_ti_ep *pcie = dev_get_priv(dev);
 	struct pcie_cdns_ti_ep_data *data;
 	struct power_domain pci_pwrdmn;
+	struct cdns_pcie pcie_dev;
 	struct clk *clk;
 	int ret;
 
+	pcie_dev.reg_base = pcie->reg_base;
 	pcie->dev = dev;
 	data = (struct pcie_cdns_ti_ep_data *)dev_get_driver_data(dev);
 	if (!data)
@@ -316,6 +330,13 @@ static int pcie_cdns_ti_ep_probe(struct udevice *dev)
 		return ret;
 	}
 
+	/*
+	 * Disable all the functions except function 0 (anyway BIT(0) is
+	 * hardwired to 1). This is required to avoid RC from enumerating
+	 * those functions which are not even configured.
+	 */
+	cdns_pcie_writel(&pcie_dev, CDNS_PCIE_LM_EP_FUNC_CFG, BIT(0));
+
 	return 0;
 }
 
@@ -377,11 +398,19 @@ static const struct pcie_cdns_ti_ep_data am64_pcie_ep_data = {
 	.max_lanes = 1,
 };
 
+static const struct pcie_cdns_ti_ep_data j784s4_pcie_ep_data = {
+	.max_lanes = 4,
+};
+
 static const struct udevice_id pcie_cdns_ti_ep_ids[] = {
 	{
 		.compatible = "ti,am64-pcie-ep",
 		.data = (ulong)&am64_pcie_ep_data,
 	},
+	{
+		.compatible = "ti,j784s4-pcie-ep",
+		.data = (ulong)&j784s4_pcie_ep_data,
+	},
 	{},
 };