PCI: apple: Reorder & improve link-up logic

Always re-check LINKSTS right before deciding whether to start the link
training and wait for it, just in case the link happened to come up
while we were setting up IRQs. Also, always do the clock-gate disable
even if the link is already up.

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

Author: marcan

drivers/pci/controller/pcie-apple.c

@@ -698,14 +698,14 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	ret = apple_pcie_port_register_irqs(port);
 	WARN_ON(ret);
 
-	if (link_stat & PORT_LINKSTS_UP)
-		return 0;
-
-	/* start link training */
-	writel_relaxed(PORT_LTSSMCTL_START, port->base + PORT_LTSSMCTL);
+	link_stat = readl_relaxed(port->base + PORT_LINKSTS);
+	if (!(link_stat & PORT_LINKSTS_UP)) {
+		/* start link training */
+		writel_relaxed(PORT_LTSSMCTL_START, port->base + PORT_LTSSMCTL);
 
-	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 (!wait_for_completion_timeout(&pcie->event, link_up_timeout * HZ / 1000))
+			dev_warn(pcie->dev, "%pOF link didn't come up\n", np);
+	}
 
 	return 0;
 }