[PATCH 3.12 04/72] PCI: mvebu: move clock enable before register access

[Jiri Slaby]

From: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit b42285f66f871a9898a0e79e2d74bc7e7a101995 upstream.

The clock passed to PCI controller found on MVEBU SoCs may come from a
clock gate. This requires the clock to be enabled before any registers
are accessed. Therefore, move the clock enable before register iomap to
ensure it is enabled.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
Signed-off-by: Jason Cooper <jason@xxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/pci/host/pci-mvebu.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index 1953c1680986..8efd11dafd44 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -866,11 +866,23 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
 			continue;
 		}
 
+		port->clk = of_clk_get_by_name(child, NULL);
+		if (IS_ERR(port->clk)) {
+			dev_err(&pdev->dev, "PCIe%d.%d: cannot get clock\n",
+			       port->port, port->lane);
+			continue;
+		}
+
+		ret = clk_prepare_enable(port->clk);
+		if (ret)
+			continue;
+
 		port->base = mvebu_pcie_map_registers(pdev, child, port);
 		if (IS_ERR(port->base)) {
 			dev_err(&pdev->dev, "PCIe%d.%d: cannot map registers\n",
 				port->port, port->lane);
 			port->base = NULL;
+			clk_disable_unprepare(port->clk);
 			continue;
 		}
 
@@ -886,22 +898,9 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
 				 port->port, port->lane);
 		}
 
-		port->clk = of_clk_get_by_name(child, NULL);
-		if (IS_ERR(port->clk)) {
-			dev_err(&pdev->dev, "PCIe%d.%d: cannot get clock\n",
-			       port->port, port->lane);
-			iounmap(port->base);
-			port->haslink = 0;
-			continue;
-		}
-
 		port->dn = child;
-
-		clk_prepare_enable(port->clk);
 		spin_lock_init(&port->conf_lock);
-
 		mvebu_sw_pci_bridge_init(port);
-
 		i++;
 	}
 
-- 
1.9.2

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