PCI: apple: Make link up timeout configurable, default to 500ms

We're seeing link up timeouts and it looks like devices are just too
slow. Let's just increase this.

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/pci/controller/pcie-apple.c

@@ -31,6 +31,10 @@
 #include <linux/of_irq.h>
 #include <linux/pci-ecam.h>
 
+static int link_up_timeout = 500;
+module_param(link_up_timeout, int, 0644);
+MODULE_PARM_DESC(link_up_timeout, "PCIe link training timeout in milliseconds");
+
 #define CORE_RC_PHYIF_CTL		0x00024
 #define   CORE_RC_PHYIF_CTL_RUN		BIT(0)
 #define CORE_RC_PHYIF_STAT		0x00028
@@ -739,7 +743,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	/* start link training */
 	writel_relaxed(PORT_LTSSMCTL_START, port->base + PORT_LTSSMCTL);
 
-	if (!wait_for_completion_timeout(&pcie->event, HZ / 10))
+	if (!wait_for_completion_timeout(&pcie->event, link_up_timeout * HZ / 1000))
 		dev_warn(pcie->dev, "%pOF link didn't come up\n", np);
 
 	if (pcie->hw->port_refclk)