PCI: designware: Add generic dw_pcie_wait_for_link()

Several DesignWare-based drivers (dra7xx, exynos, imx6, keystone, qcom, and
spear13xx) had similar loops waiting for the link to come up.

Add a generic dw_pcie_wait_for_link() for use by all these drivers so the
waiting is done consistently, e.g., always using usleep_range() rather than
mdelay() and using similar timeouts and retry counts.

Note that this changes the Keystone link training/wait for link strategy,
so we initiate link training, then wait longer for the link to come up
before re-initiating link training.

[bhelgaas: changelog, split into its own patch, update pci-keystone.c, pcie-qcom.c]
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Pratyush Anand <pratyush.anand@gmail.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
index 0aa81bd3de12..9a91487d6ecb 100644
--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -97,17 +97,15 @@ static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
 		return 0;
 	}
 
-	ks_dw_pcie_initiate_link_train(ks_pcie);
 	/* check if the link is up or not */
-	for (retries = 0; retries < 200; retries++) {
-		if (dw_pcie_link_up(pp))
-			return 0;
-		usleep_range(100, 1000);
+	for (retries = 0; retries < 5; retries++) {
 		ks_dw_pcie_initiate_link_train(ks_pcie);
+		if (!dw_pcie_wait_for_link(pp))
+			return 0;
 	}
 
 	dev_err(pp->dev, "phy link never came up\n");
-	return -EINVAL;
+	return -ETIMEDOUT;
 }
 
 static void ks_pcie_msi_irq_handler(struct irq_desc *desc)