2 * Driver for the MDIO interface of Marvell network interfaces.
4 * Since the MDIO interface of Marvell network interfaces is shared
5 * between all network interfaces, having a single driver allows to
6 * handle concurrent accesses properly (you may have four Ethernet
7 * ports, but they in fact share the same SMI interface to access the
8 * MDIO bus). Moreover, this MDIO interface code is similar between
9 * the mv643xx_eth driver and the mvneta driver. For now, it is only
10 * used by the mvneta driver, but it could later be used by the
11 * mv643xx_eth driver as well.
13 * Copyright (C) 2012 Marvell
15 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
17 * This file is licensed under the terms of the GNU General Public
18 * License version 2. This program is licensed "as is" without any
19 * warranty of any kind, whether express or implied.
22 #include <linux/init.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/mutex.h>
26 #include <linux/phy.h>
27 #include <linux/interrupt.h>
28 #include <linux/platform_device.h>
29 #include <linux/delay.h>
31 #include <linux/clk.h>
32 #include <linux/of_mdio.h>
33 #include <linux/sched.h>
34 #include <linux/wait.h>
36 #define MVMDIO_SMI_DATA_SHIFT 0
37 #define MVMDIO_SMI_PHY_ADDR_SHIFT 16
38 #define MVMDIO_SMI_PHY_REG_SHIFT 21
39 #define MVMDIO_SMI_READ_OPERATION BIT(26)
40 #define MVMDIO_SMI_WRITE_OPERATION 0
41 #define MVMDIO_SMI_READ_VALID BIT(27)
42 #define MVMDIO_SMI_BUSY BIT(28)
43 #define MVMDIO_ERR_INT_CAUSE 0x007C
44 #define MVMDIO_ERR_INT_SMI_DONE 0x00000010
45 #define MVMDIO_ERR_INT_MASK 0x0080
48 * SMI Timeout measurements:
49 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
50 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
52 #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
53 #define MVMDIO_SMI_POLL_INTERVAL_MIN 45
54 #define MVMDIO_SMI_POLL_INTERVAL_MAX 55
56 struct orion_mdio_dev {
61 * If we have access to the error interrupt pin (which is
62 * somewhat misnamed as it not only reflects internal errors
63 * but also reflects SMI completion), use that to wait for
64 * SMI access completion instead of polling the SMI busy bit.
67 wait_queue_head_t smi_busy_wait;
70 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
72 return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
75 /* Wait for the SMI unit to be ready for another operation
77 static int orion_mdio_wait_ready(struct mii_bus *bus)
79 struct orion_mdio_dev *dev = bus->priv;
80 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
81 unsigned long end = jiffies + timeout;
85 if (orion_mdio_smi_is_done(dev))
90 if (dev->err_interrupt <= 0) {
91 usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
92 MVMDIO_SMI_POLL_INTERVAL_MAX);
94 if (time_is_before_jiffies(end))
97 wait_event_timeout(dev->smi_busy_wait,
98 orion_mdio_smi_is_done(dev),
105 dev_err(bus->parent, "Timeout: SMI busy for too long\n");
109 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
112 struct orion_mdio_dev *dev = bus->priv;
116 mutex_lock(&dev->lock);
118 ret = orion_mdio_wait_ready(bus);
122 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
123 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
124 MVMDIO_SMI_READ_OPERATION),
127 ret = orion_mdio_wait_ready(bus);
131 val = readl(dev->regs);
132 if (!(val & MVMDIO_SMI_READ_VALID)) {
133 dev_err(bus->parent, "SMI bus read not valid\n");
140 mutex_unlock(&dev->lock);
144 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
145 int regnum, u16 value)
147 struct orion_mdio_dev *dev = bus->priv;
150 mutex_lock(&dev->lock);
152 ret = orion_mdio_wait_ready(bus);
156 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
157 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
158 MVMDIO_SMI_WRITE_OPERATION |
159 (value << MVMDIO_SMI_DATA_SHIFT)),
163 mutex_unlock(&dev->lock);
167 static int orion_mdio_reset(struct mii_bus *bus)
172 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
174 struct orion_mdio_dev *dev = dev_id;
176 if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
177 MVMDIO_ERR_INT_SMI_DONE) {
178 writel(~MVMDIO_ERR_INT_SMI_DONE,
179 dev->regs + MVMDIO_ERR_INT_CAUSE);
180 wake_up(&dev->smi_busy_wait);
187 static int orion_mdio_probe(struct platform_device *pdev)
191 struct orion_mdio_dev *dev;
194 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
196 dev_err(&pdev->dev, "No SMI register address given\n");
200 bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
202 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
206 bus->name = "orion_mdio_bus";
207 bus->read = orion_mdio_read;
208 bus->write = orion_mdio_write;
209 bus->reset = orion_mdio_reset;
210 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
211 dev_name(&pdev->dev));
212 bus->parent = &pdev->dev;
214 bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
220 for (i = 0; i < PHY_MAX_ADDR; i++)
221 bus->irq[i] = PHY_POLL;
224 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
226 dev_err(&pdev->dev, "Unable to remap SMI register\n");
231 init_waitqueue_head(&dev->smi_busy_wait);
233 dev->clk = devm_clk_get(&pdev->dev, NULL);
234 if (!IS_ERR(dev->clk))
235 clk_prepare_enable(dev->clk);
237 dev->err_interrupt = platform_get_irq(pdev, 0);
238 if (dev->err_interrupt != -ENXIO) {
239 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
241 IRQF_SHARED, pdev->name, dev);
245 writel(MVMDIO_ERR_INT_SMI_DONE,
246 dev->regs + MVMDIO_ERR_INT_MASK);
249 mutex_init(&dev->lock);
251 if (pdev->dev.of_node)
252 ret = of_mdiobus_register(bus, pdev->dev.of_node);
254 ret = mdiobus_register(bus);
256 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
260 platform_set_drvdata(pdev, bus);
265 if (!IS_ERR(dev->clk))
266 clk_disable_unprepare(dev->clk);
272 static int orion_mdio_remove(struct platform_device *pdev)
274 struct mii_bus *bus = platform_get_drvdata(pdev);
275 struct orion_mdio_dev *dev = bus->priv;
277 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
278 mdiobus_unregister(bus);
281 if (!IS_ERR(dev->clk))
282 clk_disable_unprepare(dev->clk);
287 static const struct of_device_id orion_mdio_match[] = {
288 { .compatible = "marvell,orion-mdio" },
291 MODULE_DEVICE_TABLE(of, orion_mdio_match);
293 static struct platform_driver orion_mdio_driver = {
294 .probe = orion_mdio_probe,
295 .remove = orion_mdio_remove,
297 .name = "orion-mdio",
298 .of_match_table = orion_mdio_match,
302 module_platform_driver(orion_mdio_driver);
304 MODULE_DESCRIPTION("Marvell MDIO interface driver");
305 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
306 MODULE_LICENSE("GPL");
307 MODULE_ALIAS("platform:orion-mdio");