net: mvmdio: enhance driver to support SMI error/done interrupts

This patch enhances the "mvmdio" to support a SMI error/done interrupt
line which can be used along with a wait queue instead of doing
busy-waiting on the registers. This is a feature which is available in
the mv643xx_eth SMI code and thus reduces again the gap between the two.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 83 insertions, 18 deletions

diff --git a/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt b/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt
index 34e7aafa321c..052b5f28a624 100644
--- a/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt
+++ b/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt
@@ -9,6 +9,9 @@ Required properties:
 - compatible: "marvell,orion-mdio"
 - reg: address and length of the SMI register
 
+Optional properties:
+- interrupts: interrupt line number for the SMI error/done interrupt
+
 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.
diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c
index 3e2711d22451..3472574602b2 100644
--- a/drivers/net/ethernet/marvell/mvmdio.c
+++ b/drivers/net/ethernet/marvell/mvmdio.c
@@ -24,10 +24,13 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/phy.h>
+#include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/of_mdio.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
 
 #define MVMDIO_SMI_DATA_SHIFT              0
 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
@@ -36,33 +39,58 @@
 #define MVMDIO_SMI_WRITE_OPERATION         0
 #define MVMDIO_SMI_READ_VALID              BIT(27)
 #define MVMDIO_SMI_BUSY                    BIT(28)
+#define MVMDIO_ERR_INT_CAUSE               0x007C
+#define  MVMDIO_ERR_INT_SMI_DONE           0x00000010
+#define MVMDIO_ERR_INT_MASK                0x0080
 
 struct orion_mdio_dev {
         struct mutex lock;
         void __iomem *regs;
+        /*
+         * If we have access to the error interrupt pin (which is
+         * somewhat misnamed as it not only reflects internal errors
+         * but also reflects SMI completion), use that to wait for
+         * SMI access completion instead of polling the SMI busy bit.
+         */
+        int err_interrupt;
+        wait_queue_head_t smi_busy_wait;
 };
 
+static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
+{
+        return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
+}
+
 /* Wait for the SMI unit to be ready for another operation
  */
 static int orion_mdio_wait_ready(struct mii_bus *bus)
 {
         struct orion_mdio_dev *dev = bus->priv;
         int count;
-        u32 val;
 
-        count = 0;
-        while (1) {
-                val = readl(dev->regs);
-                if (!(val & MVMDIO_SMI_BUSY))
-                        break;
+        if (dev->err_interrupt <= 0) {
+                count = 0;
+                while (1) {
+                        if (orion_mdio_smi_is_done(dev))
+                                break;
 
-                if (count > 100) {
-                        dev_err(bus->parent, "Timeout: SMI busy for too long\n");
-                        return -ETIMEDOUT;
-                }
+                        if (count > 100) {
+                                dev_err(bus->parent,
+                                        "Timeout: SMI busy for too long\n");
+                                return -ETIMEDOUT;
+                        }
 
-                udelay(10);
-                count++;
+                        udelay(10);
+                        count++;
+                }
+        } else {
+                if (!orion_mdio_smi_is_done(dev)) {
+                        wait_event_timeout(dev->smi_busy_wait,
+                                orion_mdio_smi_is_done(dev),
+                                msecs_to_jiffies(100));
+                        if (!orion_mdio_smi_is_done(dev))
+                                return -ETIMEDOUT;
+                }
         }
 
         return 0;
@@ -141,6 +169,21 @@ static int orion_mdio_reset(struct mii_bus *bus)
         return 0;
 }
 
+static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
+{
+        struct orion_mdio_dev *dev = dev_id;
+
+        if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
+                        MVMDIO_ERR_INT_SMI_DONE) {
+                writel(~MVMDIO_ERR_INT_SMI_DONE,
+                                dev->regs + MVMDIO_ERR_INT_CAUSE);
+                wake_up(&dev->smi_busy_wait);
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
 static int orion_mdio_probe(struct platform_device *pdev)
 {
         struct resource *r;
@@ -181,9 +224,22 @@ static int orion_mdio_probe(struct platform_device *pdev)
         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
         if (!dev->regs) {
                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
-                kfree(bus->irq);
-                mdiobus_free(bus);
-                return -ENODEV;
+                ret = -ENODEV;
+                goto out_mdio;
+        }
+
+        init_waitqueue_head(&dev->smi_busy_wait);
+
+        dev->err_interrupt = platform_get_irq(pdev, 0);
+        if (dev->err_interrupt != -ENXIO) {
+                ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
+                                        orion_mdio_err_irq,
+                                        IRQF_SHARED, pdev->name, dev);
+                if (ret)
+                        goto out_mdio;
+
+                writel(MVMDIO_ERR_INT_SMI_DONE,
+                        dev->regs + MVMDIO_ERR_INT_MASK);
         }
 
         mutex_init(&dev->lock);
@@ -194,19 +250,25 @@ static int orion_mdio_probe(struct platform_device *pdev)
                 ret = mdiobus_register(bus);
         if (ret < 0) {
                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
-                kfree(bus->irq);
-                mdiobus_free(bus);
-                return ret;
+                goto out_mdio;
         }
 
         platform_set_drvdata(pdev, bus);
 
         return 0;
+
+out_mdio:
+        kfree(bus->irq);
+        mdiobus_free(bus);
+        return ret;
 }
 
 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);
         mdiobus_unregister(bus);
         kfree(bus->irq);
         mdiobus_free(bus);