[v6,04/14] PCI: cadence: Add support to start link and verify link status

diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index c6eb2db94680..034cb3cf726e 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -357,8 +357,10 @@  static int cdns_pcie_ep_start(struct pci_epc *epc)
 {
 	struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
 	struct cdns_pcie *pcie = &ep->pcie;
+	struct device *dev = pcie->dev;
 	struct pci_epf *epf;
 	u32 cfg;
+	int ret;
 
 	/*
 	 * BIT(0) is hardwired to 1, hence function 0 is always enabled
@@ -369,6 +371,12 @@  static int cdns_pcie_ep_start(struct pci_epc *epc)
 		cfg |= BIT(epf->func_no);
 	cdns_pcie_writel(pcie, CDNS_PCIE_LM_EP_FUNC_CFG, cfg);
 
+	ret = cdns_pcie_start_link(pcie);
+	if (ret) {
+		dev_err(dev, "Failed to start link\n");
+		return ret;
+	}
+
 	return 0;
 }
 
diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
index 030e828bfd4c..de02fadc4809 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -3,6 +3,7 @@ 
 // Cadence PCIe host controller driver.
 // Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
 
+#include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/list_sort.h>
 #include <linux/of_address.h>
@@ -419,6 +420,23 @@  static int cdns_pcie_host_init(struct device *dev,
 	return err;
 }
 
+static int cdns_pcie_host_wait_for_link(struct cdns_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	int retries;
+
+	/* Check if the link is up or not */
+	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+		if (cdns_pcie_link_up(pcie)) {
+			dev_info(dev, "Link up\n");
+			return 0;
+		}
+		usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
+	}
+
+	return -ETIMEDOUT;
+}
+
 int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 {
 	struct device *dev = rc->pcie.dev;
@@ -467,6 +485,16 @@  int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 
 	pcie->mem_res = res;
 
+	ret = cdns_pcie_start_link(pcie);
+	if (ret) {
+		dev_err(dev, "Failed to start link\n");
+		return ret;
+	}
+
+	ret = cdns_pcie_host_wait_for_link(pcie);
+	if (ret)
+		dev_dbg(dev, "PCIe link never came up\n");
+
 	for (bar = RP_BAR0; bar <= RP_NO_BAR; bar++)
 		rc->avail_ib_bar[bar] = true;
 
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index a45c11158f49..54e10caf2d4b 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -10,6 +10,11 @@ 
 #include <linux/pci.h>
 #include <linux/phy/phy.h>
 
+/* Parameters for the waiting for link up routine */
+#define LINK_WAIT_MAX_RETRIES	10
+#define LINK_WAIT_USLEEP_MIN	90000
+#define LINK_WAIT_USLEEP_MAX	100000
+
 /*
  * Local Management Registers
  */
@@ -245,12 +250,20 @@  enum cdns_pcie_msg_routing {
 	MSG_ROUTING_GATHER,
 };
 
+struct cdns_pcie_ops {
+	int	(*start_link)(struct cdns_pcie *pcie);
+	void	(*stop_link)(struct cdns_pcie *pcie);
+	bool	(*link_up)(struct cdns_pcie *pcie);
+};
+
 /**
  * struct cdns_pcie - private data for Cadence PCIe controller drivers
  * @reg_base: IO mapped register base
  * @mem_res: start/end offsets in the physical system memory to map PCI accesses
  * @is_rc: tell whether the PCIe controller mode is Root Complex or Endpoint.
  * @bus: In Root Complex mode, the bus number
+ * @ops: Platform specific ops to control various inputs from Cadence PCIe
+ *       wrapper
  */
 struct cdns_pcie {
 	void __iomem		*reg_base;
@@ -261,7 +274,7 @@  struct cdns_pcie {
 	int			phy_count;
 	struct phy		**phy;
 	struct device_link	**link;
-	const struct cdns_pcie_common_ops *ops;
+	const struct cdns_pcie_ops *ops;
 };
 
 /**
@@ -426,6 +439,28 @@  static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
 	return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
 }
 
+static inline int cdns_pcie_start_link(struct cdns_pcie *pcie)
+{
+	if (pcie->ops->start_link)
+		return pcie->ops->start_link(pcie);
+
+	return 0;
+}
+
+static inline void cdns_pcie_stop_link(struct cdns_pcie *pcie)
+{
+	if (pcie->ops->stop_link)
+		pcie->ops->stop_link(pcie);
+}
+
+static inline bool cdns_pcie_link_up(struct cdns_pcie *pcie)
+{
+	if (pcie->ops->link_up)
+		return pcie->ops->link_up(pcie);
+
+	return true;
+}
+
 #ifdef CONFIG_PCIE_CADENCE_HOST
 int cdns_pcie_host_setup(struct cdns_pcie_rc *rc);
 #else