--- /dev/null
+/*
+ * Driver for the MDIO interface of Marvell network interfaces.
+ *
+ * Since the MDIO interface of Marvell network interfaces is shared
+ * between all network interfaces, having a single driver allows to
+ * handle concurrent accesses properly (you may have four Ethernet
+ * ports, but they in fact share the same SMI interface to access
+ * the MDIO bus). This driver is currently used by the mvneta and
+ * mv643xx_eth drivers.
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#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/clk.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
+#define MVMDIO_SMI_PHY_REG_SHIFT 21
+#define MVMDIO_SMI_READ_OPERATION BIT(26)
+#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
+
+/*
+ * SMI Timeout measurements:
+ * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
+ * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
+ */
+#define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
+#define MVMDIO_SMI_POLL_INTERVAL_MIN 45
+#define MVMDIO_SMI_POLL_INTERVAL_MAX 55
+
+struct orion_mdio_dev {
+ struct mutex lock;
+ void __iomem *regs;
+ struct clk *clk;
+ /*
+ * 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;
+ unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
+ unsigned long end = jiffies + timeout;
+ int timedout = 0;
+
+ while (1) {
+ if (orion_mdio_smi_is_done(dev))
+ return 0;
+ else if (timedout)
+ break;
+
+ if (dev->err_interrupt <= 0) {
+ usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
+ MVMDIO_SMI_POLL_INTERVAL_MAX);
+
+ if (time_is_before_jiffies(end))
+ ++timedout;
+ } else {
+ /* wait_event_timeout does not guarantee a delay of at
+ * least one whole jiffie, so timeout must be no less
+ * than two.
+ */
+ if (timeout < 2)
+ timeout = 2;
+ wait_event_timeout(dev->smi_busy_wait,
+ orion_mdio_smi_is_done(dev),
+ timeout);
+
+ ++timedout;
+ }
+ }
+
+ dev_err(bus->parent, "Timeout: SMI busy for too long\n");
+ return -ETIMEDOUT;
+}
+
+static int orion_mdio_read(struct mii_bus *bus, int mii_id,
+ int regnum)
+{
+ struct orion_mdio_dev *dev = bus->priv;
+ u32 val;
+ int ret;
+
+ mutex_lock(&dev->lock);
+
+ ret = orion_mdio_wait_ready(bus);
+ if (ret < 0)
+ goto out;
+
+ writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
+ (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
+ MVMDIO_SMI_READ_OPERATION),
+ dev->regs);
+
+ ret = orion_mdio_wait_ready(bus);
+ if (ret < 0)
+ goto out;
+
+ val = readl(dev->regs);
+ if (!(val & MVMDIO_SMI_READ_VALID)) {
+ dev_err(bus->parent, "SMI bus read not valid\n");
+ ret = -ENODEV;
+ goto out;
+ }
+
+ ret = val & 0xFFFF;
+out:
+ mutex_unlock(&dev->lock);
+ return ret;
+}
+
+static int orion_mdio_write(struct mii_bus *bus, int mii_id,
+ int regnum, u16 value)
+{
+ struct orion_mdio_dev *dev = bus->priv;
+ int ret;
+
+ mutex_lock(&dev->lock);
+
+ ret = orion_mdio_wait_ready(bus);
+ if (ret < 0)
+ goto out;
+
+ writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
+ (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
+ MVMDIO_SMI_WRITE_OPERATION |
+ (value << MVMDIO_SMI_DATA_SHIFT)),
+ dev->regs);
+
+out:
+ mutex_unlock(&dev->lock);
+ return ret;
+}
+
+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;
+ struct mii_bus *bus;
+ struct orion_mdio_dev *dev;
+ int i, ret;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "No SMI register address given\n");
+ return -ENODEV;
+ }
+
+ bus = devm_mdiobus_alloc_size(&pdev->dev,
+ sizeof(struct orion_mdio_dev));
+ if (!bus)
+ return -ENOMEM;
+
+ bus->name = "orion_mdio_bus";
+ bus->read = orion_mdio_read;
+ bus->write = orion_mdio_write;
+ snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
+ dev_name(&pdev->dev));
+ bus->parent = &pdev->dev;
+
+ bus->irq = devm_kmalloc_array(&pdev->dev, PHY_MAX_ADDR, sizeof(int),
+ GFP_KERNEL);
+ if (!bus->irq)
+ return -ENOMEM;
+
+ for (i = 0; i < PHY_MAX_ADDR; i++)
+ bus->irq[i] = PHY_POLL;
+
+ dev = bus->priv;
+ dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+ if (!dev->regs) {
+ dev_err(&pdev->dev, "Unable to remap SMI register\n");
+ ret = -ENODEV;
+ goto out_mdio;
+ }
+
+ init_waitqueue_head(&dev->smi_busy_wait);
+
+ dev->clk = devm_clk_get(&pdev->dev, NULL);
+ if (!IS_ERR(dev->clk))
+ clk_prepare_enable(dev->clk);
+
+ dev->err_interrupt = platform_get_irq(pdev, 0);
+ if (dev->err_interrupt > 0) {
+ 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);
+
+ } else if (dev->err_interrupt == -EPROBE_DEFER) {
+ return -EPROBE_DEFER;
+ }
+
+ mutex_init(&dev->lock);
+
+ if (pdev->dev.of_node)
+ ret = of_mdiobus_register(bus, pdev->dev.of_node);
+ else
+ ret = mdiobus_register(bus);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
+ goto out_mdio;
+ }
+
+ platform_set_drvdata(pdev, bus);
+
+ return 0;
+
+out_mdio:
+ if (!IS_ERR(dev->clk))
+ clk_disable_unprepare(dev->clk);
+ 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);
+ if (!IS_ERR(dev->clk))
+ clk_disable_unprepare(dev->clk);
+
+ return 0;
+}
+
+static const struct of_device_id orion_mdio_match[] = {
+ { .compatible = "marvell,orion-mdio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, orion_mdio_match);
+
+static struct platform_driver orion_mdio_driver = {
+ .probe = orion_mdio_probe,
+ .remove = orion_mdio_remove,
+ .driver = {
+ .name = "orion-mdio",
+ .of_match_table = orion_mdio_match,
+ },
+};
+
+module_platform_driver(orion_mdio_driver);
+
+MODULE_DESCRIPTION("Marvell MDIO interface driver");
+MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:orion-mdio");
Code Review / kvmfornfv.git / blobdiff