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 000000000000..7615040df756
--- /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");