Fix orion-mdio resource/interrupt issues indentified while reviewing mvpp2

This patch series fixes some issues identified while reviewing the mvpp2 driver changes recently posted by Thomas. I've left the clock issue, and the question over whether this should be separate out of this series, concentrating on the resource size / interrupt issue.

This series updates the binding to reflect reality, and ensures that the driver will not try to access registers outside its binding. It also ensures that it doesn't leave the interrupt enabled in hardware on probe failure.

 .../devicetree/bindings/net/marvell-orion-mdio.txt      | 17 +++++++++++++++--
 drivers/net/ethernet/marvell/mvmdio.c                   | 11 ++++++++++-
 2 files changed, 25 insertions(+), 3 deletions(-)

RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

When the mvmdio driver has an interrupt, it enables the "done" interrupt after requesting its interrupt handler. However, probe failure results in the interrupt being left enabled. Disable it on the failure path.

---
 drivers/net/ethernet/marvell/mvmdio.c | 2 ++
 1 file changed, 2 insertions(+)

index a0d1b084ecec..7aea0beca56e 100644
@@ -251,6 +251,8 @@ static int orion_mdio_probe(struct platform_device *pdev)
 	return 0;
 
 out_mdio:
+	if (dev->err_interrupt > 0)
+		writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 	if (!IS_ERR(dev->clk))
 		clk_disable_unprepare(dev->clk);
 	return ret;

2.7.4

The pre-existing write to disable interrupts on the remove path happens whether we have an interrupt or not. While this may seem to be a good idea, this driver is re-used in many different implementations, some where the binding only specifies four bytes of register space. This access causes us to access registers outside of the binding.

Make it conditional on the interrupt being present, which is the same condition used when enabling the interrupt in the first place.

---
 drivers/net/ethernet/marvell/mvmdio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 7aea0beca56e..6ea5caddca62 100644
@@ -263,7 +263,8 @@ static int orion_mdio_remove(struct platform_device *pdev)
 	struct mii_bus *bus = platform_get_drvdata(pdev);
 	struct orion_mdio_dev *dev = bus->priv;
 
-	writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
+	if (dev->err_interrupt > 0)
+		writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 	mdiobus_unregister(bus);
 	if (!IS_ERR(dev->clk))
 		clk_disable_unprepare(dev->clk);

2.7.4

Correct the Marvell Orion MDIO binding document to properly reflect the cases where an interrupt is present. Augment the examples to show this.

---
 .../devicetree/bindings/net/marvell-orion-mdio.txt      | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

index 9417e54c26c0..ca733ff68ab9 100644
@@ -7,7 +7,10 @@ interface.
 
 Required properties:
 - compatible: "marvell,orion-mdio"
-- reg: address and length of the SMI register
+- reg: address and length of the MDIO registers.  When an interrupt is
+  not present, the length is the size of the SMI register (4 bytes)
+  otherwise it must be 0x84 bytes to cover the interrupt control
+  registers.
 
 Optional properties:
 - interrupts: interrupt line number for the SMI error/done interrupt

@@ -17,7 +20,7 @@ The child nodes of the MDIO driver are the individual PHY devices
 connected to this MDIO bus. They must have a "reg" property given the
 PHY address on the MDIO bus.
 
-Example at the SoC level:
+Example at the SoC level without an interrupt property:
 
 mdio {
 	#address-cells = <1>;

@@ -26,6 +29,16 @@ mdio {
 	reg = <0xd0072004 0x4>;
 };
 
+Example with an interrupt property:
+
+mdio {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	compatible = "marvell,orion-mdio";
+	reg = <0xd0072004 0x84>;
+	interrupts = <30>;
+};
+
 And at the board level:
 
 mdio {

2.7.4

This looks fine to me.

Mark.

Disable the MDIO interrupt, falling back to polled mode, if the resource size does not allow us to access the interrupt registers. All current DT bindings use a size of 0x84, which allows access, but verifying it is good practice.

---
 drivers/net/ethernet/marvell/mvmdio.c | 6 ++++++
 1 file changed, 6 insertions(+)

index 6ea5caddca62..614dfde657fe 100644
@@ -221,6 +221,12 @@ static int orion_mdio_probe(struct platform_device *pdev)
 		clk_prepare_enable(dev->clk);
 
 	dev->err_interrupt = platform_get_irq(pdev, 0);
+	if (dev->err_interrupt > 0 &&
+	    resource_size(r) < MVMDIO_ERR_INT_MASK + 4) {
+		dev_err(&pdev->dev,
+			"disabling interrupt, resource size is too small\n");
+		dev->err_interrupt = 0;
+	}
 	if (dev->err_interrupt > 0) {
 		ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 					orion_mdio_err_irq,

2.7.4