net: davinci_emac: separate out davinci mdio

Davinci's MDIO controller is present on other TI devices, without an
accompanying EMAC.  For example, on tnetv107x, the same MDIO module is used in
conjunction with a 3-port switch hardware.

By separating the MDIO controller code into its own platform driver, this
patch allows common logic to be reused on such platforms.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Tested-by: Michael Williamson <michael.williamson@criticallink.com>
Tested-by: Caglar Akyuz <caglarakyuz@gmail.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 475 insertions, 0 deletions

diff --git a/drivers/net/davinci_mdio.c b/drivers/net/davinci_mdio.c
new file mode 100644
index 00000000000..7615040df75
--- /dev/null
+++ b/drivers/net/davinci_mdio.c
@@ -0,0 +1,475 @@
+/*
+ * DaVinci MDIO Module driver
+ *
+ * Copyright (C) 2010 Texas Instruments.
+ *
+ * Shamelessly ripped out of davinci_emac.c, original copyrights follow:
+ *
+ * Copyright (C) 2009 Texas Instruments.
+ *
+ * ---------------------------------------------------------------------------
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ---------------------------------------------------------------------------
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/phy.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/davinci_emac.h>
+
+/*
+ * This timeout definition is a worst-case ultra defensive measure against
+ * unexpected controller lock ups.  Ideally, we should never ever hit this
+ * scenario in practice.
+ */
+#define MDIO_TIMEOUT            100 /* msecs */
+
+#define PHY_REG_MASK            0x1f
+#define PHY_ID_MASK             0x1f
+
+#define DEF_OUT_FREQ            2200000         /* 2.2 MHz */
+
+struct davinci_mdio_regs {
+        u32     version;
+        u32     control;
+#define CONTROL_IDLE            BIT(31)
+#define CONTROL_ENABLE          BIT(30)
+#define CONTROL_MAX_DIV         (0xff)
+
+        u32     alive;
+        u32     link;
+        u32     linkintraw;
+        u32     linkintmasked;
+        u32     __reserved_0[2];
+        u32     userintraw;
+        u32     userintmasked;
+        u32     userintmaskset;
+        u32     userintmaskclr;
+        u32     __reserved_1[20];
+
+        struct {
+                u32     access;
+#define USERACCESS_GO           BIT(31)
+#define USERACCESS_WRITE        BIT(30)
+#define USERACCESS_ACK          BIT(29)
+#define USERACCESS_READ         (0)
+#define USERACCESS_DATA         (0xffff)
+
+                u32     physel;
+        }       user[0];
+};
+
+struct mdio_platform_data default_pdata = {
+        .bus_freq = DEF_OUT_FREQ,
+};
+
+struct davinci_mdio_data {
+        struct mdio_platform_data pdata;
+        struct davinci_mdio_regs __iomem *regs;
+        spinlock_t      lock;
+        struct clk      *clk;
+        struct device   *dev;
+        struct mii_bus  *bus;
+        bool            suspended;
+        unsigned long   access_time; /* jiffies */
+};
+
+static void __davinci_mdio_reset(struct davinci_mdio_data *data)
+{
+        u32 mdio_in, div, mdio_out_khz, access_time;
+
+        mdio_in = clk_get_rate(data->clk);
+        div = (mdio_in / data->pdata.bus_freq) - 1;
+        if (div > CONTROL_MAX_DIV)
+                div = CONTROL_MAX_DIV;
+
+        /* set enable and clock divider */
+        __raw_writel(div | CONTROL_ENABLE, &data->regs->control);
+
+        /*
+         * One mdio transaction consists of:
+         *      32 bits of preamble
+         *      32 bits of transferred data
+         *      24 bits of bus yield (not needed unless shared?)
+         */
+        mdio_out_khz = mdio_in / (1000 * (div + 1));
+        access_time  = (88 * 1000) / mdio_out_khz;
+
+        /*
+         * In the worst case, we could be kicking off a user-access immediately
+         * after the mdio bus scan state-machine triggered its own read.  If
+         * so, our request could get deferred by one access cycle.  We
+         * defensively allow for 4 access cycles.
+         */
+        data->access_time = usecs_to_jiffies(access_time * 4);
+        if (!data->access_time)
+                data->access_time = 1;
+}
+
+static int davinci_mdio_reset(struct mii_bus *bus)
+{
+        struct davinci_mdio_data *data = bus->priv;
+        u32 phy_mask, ver;
+
+        __davinci_mdio_reset(data);
+
+        /* wait for scan logic to settle */
+        msleep(PHY_MAX_ADDR * data->access_time);
+
+        /* dump hardware version info */
+        ver = __raw_readl(&data->regs->version);
+        dev_info(data->dev, "davinci mdio revision %d.%d\n",
+                 (ver >> 8) & 0xff, ver & 0xff);
+
+        /* get phy mask from the alive register */
+        phy_mask = __raw_readl(&data->regs->alive);
+        if (phy_mask) {
+                /* restrict mdio bus to live phys only */
+                dev_info(data->dev, "detected phy mask %x\n", ~phy_mask);
+                phy_mask = ~phy_mask;
+        } else {
+                /* desperately scan all phys */
+                dev_warn(data->dev, "no live phy, scanning all\n");
+                phy_mask = 0;
+        }
+        data->bus->phy_mask = phy_mask;
+
+        return 0;
+}
+
+/* wait until hardware is ready for another user access */
+static inline int wait_for_user_access(struct davinci_mdio_data *data)
+{
+        struct davinci_mdio_regs __iomem *regs = data->regs;
+        unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);
+        u32 reg;
+
+        while (time_after(timeout, jiffies)) {
+                reg = __raw_readl(&regs->user[0].access);
+                if ((reg & USERACCESS_GO) == 0)
+                        return 0;
+
+                reg = __raw_readl(&regs->control);
+                if ((reg & CONTROL_IDLE) == 0)
+                        continue;
+
+                /*
+                 * An emac soft_reset may have clobbered the mdio controller's
+                 * state machine.  We need to reset and retry the current
+                 * operation
+                 */
+                dev_warn(data->dev, "resetting idled controller\n");
+                __davinci_mdio_reset(data);
+                return -EAGAIN;
+        }
+        dev_err(data->dev, "timed out waiting for user access\n");
+        return -ETIMEDOUT;
+}
+
+/* wait until hardware state machine is idle */
+static inline int wait_for_idle(struct davinci_mdio_data *data)
+{
+        struct davinci_mdio_regs __iomem *regs = data->regs;
+        unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);
+
+        while (time_after(timeout, jiffies)) {
+                if (__raw_readl(&regs->control) & CONTROL_IDLE)
+                        return 0;
+        }
+        dev_err(data->dev, "timed out waiting for idle\n");
+        return -ETIMEDOUT;
+}
+
+static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)
+{
+        struct davinci_mdio_data *data = bus->priv;
+        u32 reg;
+        int ret;
+
+        if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
+                return -EINVAL;
+
+        spin_lock(&data->lock);
+
+        if (data->suspended) {
+                spin_unlock(&data->lock);
+                return -ENODEV;
+        }
+
+        reg = (USERACCESS_GO | USERACCESS_READ | (phy_reg << 21) |
+               (phy_id << 16));
+
+        while (1) {
+                ret = wait_for_user_access(data);
+                if (ret == -EAGAIN)
+                        continue;
+                if (ret < 0)
+                        break;
+
+                __raw_writel(reg, &data->regs->user[0].access);
+
+                ret = wait_for_user_access(data);
+                if (ret == -EAGAIN)
+                        continue;
+                if (ret < 0)
+                        break;
+
+                reg = __raw_readl(&data->regs->user[0].access);
+                ret = (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -EIO;
+                break;
+        }
+
+        spin_unlock(&data->lock);
+
+        return ret;
+}
+
+static int davinci_mdio_write(struct mii_bus *bus, int phy_id,
+                              int phy_reg, u16 phy_data)
+{
+        struct davinci_mdio_data *data = bus->priv;
+        u32 reg;
+        int ret;
+
+        if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
+                return -EINVAL;
+
+        spin_lock(&data->lock);
+
+        if (data->suspended) {
+                spin_unlock(&data->lock);
+                return -ENODEV;
+        }
+
+        reg = (USERACCESS_GO | USERACCESS_WRITE | (phy_reg << 21) |
+                   (phy_id << 16) | (phy_data & USERACCESS_DATA));
+
+        while (1) {
+                ret = wait_for_user_access(data);
+                if (ret == -EAGAIN)
+                        continue;
+                if (ret < 0)
+                        break;
+
+                __raw_writel(reg, &data->regs->user[0].access);
+
+                ret = wait_for_user_access(data);
+                if (ret == -EAGAIN)
+                        continue;
+                break;
+        }
+
+        spin_unlock(&data->lock);
+
+        return 0;
+}
+
+static int __devinit davinci_mdio_probe(struct platform_device *pdev)
+{
+        struct mdio_platform_data *pdata = pdev->dev.platform_data;
+        struct device *dev = &pdev->dev;
+        struct davinci_mdio_data *data;
+        struct resource *res;
+        struct phy_device *phy;
+        int ret, addr;
+
+        data = kzalloc(sizeof(*data), GFP_KERNEL);
+        if (!data) {
+                dev_err(dev, "failed to alloc device data\n");
+                return -ENOMEM;
+        }
+
+        data->pdata = pdata ? (*pdata) : default_pdata;
+
+        data->bus = mdiobus_alloc();
+        if (!data->bus) {
+                dev_err(dev, "failed to alloc mii bus\n");
+                ret = -ENOMEM;
+                goto bail_out;
+        }
+
+        data->bus->name         = dev_name(dev);
+        data->bus->read         = davinci_mdio_read,
+        data->bus->write        = davinci_mdio_write,
+        data->bus->reset        = davinci_mdio_reset,
+        data->bus->parent       = dev;
+        data->bus->priv         = data;
+        snprintf(data->bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);
+
+        data->clk = clk_get(dev, NULL);
+        if (IS_ERR(data->clk)) {
+                data->clk = NULL;
+                dev_err(dev, "failed to get device clock\n");
+                ret = PTR_ERR(data->clk);
+                goto bail_out;
+        }
+
+        clk_enable(data->clk);
+
+        dev_set_drvdata(dev, data);
+        data->dev = dev;
+        spin_lock_init(&data->lock);
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(dev, "could not find register map resource\n");
+                ret = -ENOENT;
+                goto bail_out;
+        }
+
+        res = devm_request_mem_region(dev, res->start, resource_size(res),
+                                            dev_name(dev));
+        if (!res) {
+                dev_err(dev, "could not allocate register map resource\n");
+                ret = -ENXIO;
+                goto bail_out;
+        }
+
+        data->regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
+        if (!data->regs) {
+                dev_err(dev, "could not map mdio registers\n");
+                ret = -ENOMEM;
+                goto bail_out;
+        }
+
+        /* register the mii bus */
+        ret = mdiobus_register(data->bus);
+        if (ret)
+                goto bail_out;
+
+        /* scan and dump the bus */
+        for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
+                phy = data->bus->phy_map[addr];
+                if (phy) {
+                        dev_info(dev, "phy[%d]: device %s, driver %s\n",
+                                 phy->addr, dev_name(&phy->dev),
+                                 phy->drv ? phy->drv->name : "unknown");
+                }
+        }
+
+        return 0;
+
+bail_out:
+        if (data->bus)
+                mdiobus_free(data->bus);
+
+        if (data->clk) {
+                clk_disable(data->clk);
+                clk_put(data->clk);
+        }
+
+        kfree(data);
+
+        return ret;
+}
+
+static int __devexit davinci_mdio_remove(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct davinci_mdio_data *data = dev_get_drvdata(dev);
+
+        if (data->bus)
+                mdiobus_free(data->bus);
+
+        if (data->clk) {
+                clk_disable(data->clk);
+                clk_put(data->clk);
+        }
+
+        dev_set_drvdata(dev, NULL);
+
+        kfree(data);
+
+        return 0;
+}
+
+static int davinci_mdio_suspend(struct device *dev)
+{
+        struct davinci_mdio_data *data = dev_get_drvdata(dev);
+        u32 ctrl;
+
+        spin_lock(&data->lock);
+
+        /* shutdown the scan state machine */
+        ctrl = __raw_readl(&data->regs->control);
+        ctrl &= ~CONTROL_ENABLE;
+        __raw_writel(ctrl, &data->regs->control);
+        wait_for_idle(data);
+
+        if (data->clk)
+                clk_disable(data->clk);
+
+        data->suspended = true;
+        spin_unlock(&data->lock);
+
+        return 0;
+}
+
+static int davinci_mdio_resume(struct device *dev)
+{
+        struct davinci_mdio_data *data = dev_get_drvdata(dev);
+        u32 ctrl;
+
+        spin_lock(&data->lock);
+        if (data->clk)
+                clk_enable(data->clk);
+
+        /* restart the scan state machine */
+        ctrl = __raw_readl(&data->regs->control);
+        ctrl |= CONTROL_ENABLE;
+        __raw_writel(ctrl, &data->regs->control);
+
+        data->suspended = false;
+        spin_unlock(&data->lock);
+
+        return 0;
+}
+
+static const struct dev_pm_ops davinci_mdio_pm_ops = {
+        .suspend        = davinci_mdio_suspend,
+        .resume         = davinci_mdio_resume,
+};
+
+static struct platform_driver davinci_mdio_driver = {
+        .driver = {
+                .name    = "davinci_mdio",
+                .owner   = THIS_MODULE,
+                .pm      = &davinci_mdio_pm_ops,
+        },
+        .probe = davinci_mdio_probe,
+        .remove = __devexit_p(davinci_mdio_remove),
+};
+
+static int __init davinci_mdio_init(void)
+{
+        return platform_driver_register(&davinci_mdio_driver);
+}
+device_initcall(davinci_mdio_init);
+
+static void __exit davinci_mdio_exit(void)
+{
+        platform_driver_unregister(&davinci_mdio_driver);
+}
+module_exit(davinci_mdio_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DaVinci MDIO driver");