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
8 * the MDIO bus). This driver is currently used by the mvneta and
11 * Copyright (C) 2012 Marvell
13 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
15 * This file is licensed under the terms of the GNU General Public
16 * License version 2. This program is licensed "as is" without any
17 * warranty of any kind, whether express or implied.
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/phy.h>
25 #include <linux/interrupt.h>
26 #include <linux/platform_device.h>
27 #include <linux/delay.h>
29 #include <linux/clk.h>
30 #include <linux/of_mdio.h>
31 #include <linux/sched.h>
32 #include <linux/wait.h>
34 #define MVMDIO_SMI_DATA_SHIFT 0
35 #define MVMDIO_SMI_PHY_ADDR_SHIFT 16
36 #define MVMDIO_SMI_PHY_REG_SHIFT 21
37 #define MVMDIO_SMI_READ_OPERATION BIT(26)
38 #define MVMDIO_SMI_WRITE_OPERATION 0
39 #define MVMDIO_SMI_READ_VALID BIT(27)
40 #define MVMDIO_SMI_BUSY BIT(28)
41 #define MVMDIO_ERR_INT_CAUSE 0x007C
42 #define MVMDIO_ERR_INT_SMI_DONE 0x00000010
43 #define MVMDIO_ERR_INT_MASK 0x0080
46 * SMI Timeout measurements:
47 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
48 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
50 #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
51 #define MVMDIO_SMI_POLL_INTERVAL_MIN 45
52 #define MVMDIO_SMI_POLL_INTERVAL_MAX 55
54 struct orion_mdio_dev {
59 * If we have access to the error interrupt pin (which is
60 * somewhat misnamed as it not only reflects internal errors
61 * but also reflects SMI completion), use that to wait for
62 * SMI access completion instead of polling the SMI busy bit.
65 wait_queue_head_t smi_busy_wait;
68 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
70 return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
73 /* Wait for the SMI unit to be ready for another operation
75 static int orion_mdio_wait_ready(struct mii_bus *bus)
77 struct orion_mdio_dev *dev = bus->priv;
78 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
79 unsigned long end = jiffies + timeout;
83 if (orion_mdio_smi_is_done(dev))
88 if (dev->err_interrupt <= 0) {
89 usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
90 MVMDIO_SMI_POLL_INTERVAL_MAX);
92 if (time_is_before_jiffies(end))
95 wait_event_timeout(dev->smi_busy_wait,
96 orion_mdio_smi_is_done(dev),
103 dev_err(bus->parent, "Timeout: SMI busy for too long\n");
107 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
110 struct orion_mdio_dev *dev = bus->priv;
114 mutex_lock(&dev->lock);
116 ret = orion_mdio_wait_ready(bus);
120 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
121 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
122 MVMDIO_SMI_READ_OPERATION),
125 ret = orion_mdio_wait_ready(bus);
129 val = readl(dev->regs);
130 if (!(val & MVMDIO_SMI_READ_VALID)) {
131 dev_err(bus->parent, "SMI bus read not valid\n");
138 mutex_unlock(&dev->lock);
142 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
143 int regnum, u16 value)
145 struct orion_mdio_dev *dev = bus->priv;
148 mutex_lock(&dev->lock);
150 ret = orion_mdio_wait_ready(bus);
154 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
155 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
156 MVMDIO_SMI_WRITE_OPERATION |
157 (value << MVMDIO_SMI_DATA_SHIFT)),
161 mutex_unlock(&dev->lock);
165 static int orion_mdio_reset(struct mii_bus *bus)
170 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
172 struct orion_mdio_dev *dev = dev_id;
174 if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
175 MVMDIO_ERR_INT_SMI_DONE) {
176 writel(~MVMDIO_ERR_INT_SMI_DONE,
177 dev->regs + MVMDIO_ERR_INT_CAUSE);
178 wake_up(&dev->smi_busy_wait);
185 static int orion_mdio_probe(struct platform_device *pdev)
189 struct orion_mdio_dev *dev;
192 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194 dev_err(&pdev->dev, "No SMI register address given\n");
198 bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
200 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
204 bus->name = "orion_mdio_bus";
205 bus->read = orion_mdio_read;
206 bus->write = orion_mdio_write;
207 bus->reset = orion_mdio_reset;
208 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
209 dev_name(&pdev->dev));
210 bus->parent = &pdev->dev;
212 bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
218 for (i = 0; i < PHY_MAX_ADDR; i++)
219 bus->irq[i] = PHY_POLL;
222 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
224 dev_err(&pdev->dev, "Unable to remap SMI register\n");
229 init_waitqueue_head(&dev->smi_busy_wait);
231 dev->clk = devm_clk_get(&pdev->dev, NULL);
232 if (!IS_ERR(dev->clk))
233 clk_prepare_enable(dev->clk);
235 dev->err_interrupt = platform_get_irq(pdev, 0);
236 if (dev->err_interrupt != -ENXIO) {
237 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
239 IRQF_SHARED, pdev->name, dev);
243 writel(MVMDIO_ERR_INT_SMI_DONE,
244 dev->regs + MVMDIO_ERR_INT_MASK);
247 mutex_init(&dev->lock);
249 if (pdev->dev.of_node)
250 ret = of_mdiobus_register(bus, pdev->dev.of_node);
252 ret = mdiobus_register(bus);
254 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
258 platform_set_drvdata(pdev, bus);
263 if (!IS_ERR(dev->clk))
264 clk_disable_unprepare(dev->clk);
270 static int orion_mdio_remove(struct platform_device *pdev)
272 struct mii_bus *bus = platform_get_drvdata(pdev);
273 struct orion_mdio_dev *dev = bus->priv;
275 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
276 mdiobus_unregister(bus);
279 if (!IS_ERR(dev->clk))
280 clk_disable_unprepare(dev->clk);
285 static const struct of_device_id orion_mdio_match[] = {
286 { .compatible = "marvell,orion-mdio" },
289 MODULE_DEVICE_TABLE(of, orion_mdio_match);
291 static struct platform_driver orion_mdio_driver = {
292 .probe = orion_mdio_probe,
293 .remove = orion_mdio_remove,
295 .name = "orion-mdio",
296 .of_match_table = orion_mdio_match,
300 module_platform_driver(orion_mdio_driver);
302 MODULE_DESCRIPTION("Marvell MDIO interface driver");
303 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
304 MODULE_LICENSE("GPL");
305 MODULE_ALIAS("platform:orion-mdio");