PCI: designware: Wait for iATU enable

Add a loop with timeout to make sure the iATU is really enabled before
subsequent config and I/O accesses.

[bhelgaas: split to separate patch, use dev_err() instead of dev_dbg()]
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index e99f56ecd61d..947fac37cf1b 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -31,7 +31,12 @@
 #define LINK_WAIT_USLEEP_MIN            90000
 #define LINK_WAIT_USLEEP_MAX            100000
 
-/* Synopsis specific PCIE configuration registers */
+/* Parameters for the waiting for iATU enabled routine */
+#define LINK_WAIT_MAX_IATU_RETRIES      5
+#define LINK_WAIT_IATU_MIN              9000
+#define LINK_WAIT_IATU_MAX              10000
+
+/* Synopsys-specific PCIe configuration registers */
 #define PCIE_PORT_LINK_CONTROL          0x710
 #define PORT_LINK_MODE_MASK             (0x3f << 16)
 #define PORT_LINK_MODE_1_LANES          (0x1 << 16)
@@ -157,7 +162,7 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size,
 static void dw_pcie_prog_outbound_atu(struct pcie_port *pp, int index,
                 int type, u64 cpu_addr, u64 pci_addr, u32 size)
 {
-        u32 val;
+        u32 retries, val;
 
         dw_pcie_writel_rc(pp, PCIE_ATU_REGION_OUTBOUND | index,
                           PCIE_ATU_VIEWPORT);
@@ -174,7 +179,14 @@ static void dw_pcie_prog_outbound_atu(struct pcie_port *pp, int index,
          * Make sure ATU enable takes effect before any subsequent config
          * and I/O accesses.
          */
-        val = dw_pcie_readl_rc(pp, PCIE_ATU_CR2);
+        for (retries = 0; retries < LINK_WAIT_MAX_IATU_RETRIES; retries++) {
+                val = dw_pcie_readl_rc(pp, PCIE_ATU_CR2);
+                if (val == PCIE_ATU_ENABLE)
+                        return;
+
+                usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+        }
+        dev_err(pp->dev, "iATU is not being enabled\n");
 }
 
 static struct irq_chip dw_msi_irq_chip = {