1 /*
2  * Driver for the MDIO interface of Marvell network interfaces.
3  *
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
9  * mv643xx_eth drivers.
10  *
11  * Copyright (C) 2012 Marvell
12  *
13  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
14  *
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.
18  */
19 
20 #include <linux/acpi.h>
21 #include <linux/acpi_mdio.h>
22 #include <linux/clk.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/io.h>
26 #include <linux/kernel.h>
27 #include <linux/mod_devicetable.h>
28 #include <linux/module.h>
29 #include <linux/of_mdio.h>
30 #include <linux/phy.h>
31 #include <linux/platform_device.h>
32 #include <linux/sched.h>
33 #include <linux/wait.h>
34 
35 #define MVMDIO_SMI_DATA_SHIFT		0
36 #define MVMDIO_SMI_PHY_ADDR_SHIFT	16
37 #define MVMDIO_SMI_PHY_REG_SHIFT	21
38 #define MVMDIO_SMI_READ_OPERATION	BIT(26)
39 #define MVMDIO_SMI_WRITE_OPERATION	0
40 #define MVMDIO_SMI_READ_VALID		BIT(27)
41 #define MVMDIO_SMI_BUSY			BIT(28)
42 #define MVMDIO_ERR_INT_CAUSE		0x007C
43 #define  MVMDIO_ERR_INT_SMI_DONE	0x00000010
44 #define MVMDIO_ERR_INT_MASK		0x0080
45 
46 #define MVMDIO_XSMI_MGNT_REG		0x0
47 #define  MVMDIO_XSMI_PHYADDR_SHIFT	16
48 #define  MVMDIO_XSMI_DEVADDR_SHIFT	21
49 #define  MVMDIO_XSMI_WRITE_OPERATION	(0x5 << 26)
50 #define  MVMDIO_XSMI_READ_OPERATION	(0x7 << 26)
51 #define  MVMDIO_XSMI_READ_VALID		BIT(29)
52 #define  MVMDIO_XSMI_BUSY		BIT(30)
53 #define MVMDIO_XSMI_ADDR_REG		0x8
54 
55 /*
56  * SMI Timeout measurements:
57  * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
58  * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
59  */
60 #define MVMDIO_SMI_TIMEOUT		1000 /* 1000us = 1ms */
61 #define MVMDIO_SMI_POLL_INTERVAL_MIN	45
62 #define MVMDIO_SMI_POLL_INTERVAL_MAX	55
63 
64 #define MVMDIO_XSMI_POLL_INTERVAL_MIN	150
65 #define MVMDIO_XSMI_POLL_INTERVAL_MAX	160
66 
67 struct orion_mdio_dev {
68 	void __iomem *regs;
69 	struct clk *clk[4];
70 	/*
71 	 * If we have access to the error interrupt pin (which is
72 	 * somewhat misnamed as it not only reflects internal errors
73 	 * but also reflects SMI completion), use that to wait for
74 	 * SMI access completion instead of polling the SMI busy bit.
75 	 */
76 	int err_interrupt;
77 	wait_queue_head_t smi_busy_wait;
78 };
79 
80 enum orion_mdio_bus_type {
81 	BUS_TYPE_SMI,
82 	BUS_TYPE_XSMI
83 };
84 
85 struct orion_mdio_ops {
86 	int (*is_done)(struct orion_mdio_dev *);
87 	unsigned int poll_interval_min;
88 	unsigned int poll_interval_max;
89 };
90 
91 /* Wait for the SMI unit to be ready for another operation
92  */
93 static int orion_mdio_wait_ready(const struct orion_mdio_ops *ops,
94 				 struct mii_bus *bus)
95 {
96 	struct orion_mdio_dev *dev = bus->priv;
97 	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
98 	unsigned long end = jiffies + timeout;
99 	int timedout = 0;
100 
101 	while (1) {
102 	        if (ops->is_done(dev))
103 			return 0;
104 	        else if (timedout)
105 			break;
106 
107 	        if (dev->err_interrupt <= 0) {
108 			usleep_range(ops->poll_interval_min,
109 				     ops->poll_interval_max);
110 
111 			if (time_is_before_jiffies(end))
112 				++timedout;
113 	        } else {
114 			/* wait_event_timeout does not guarantee a delay of at
115 			 * least one whole jiffie, so timeout must be no less
116 			 * than two.
117 			 */
118 			if (timeout < 2)
119 				timeout = 2;
120 			wait_event_timeout(dev->smi_busy_wait,
121 				           ops->is_done(dev), timeout);
122 
123 			++timedout;
124 	        }
125 	}
126 
127 	dev_err(bus->parent, "Timeout: SMI busy for too long\n");
128 	return  -ETIMEDOUT;
129 }
130 
131 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
132 {
133 	return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
134 }
135 
136 static const struct orion_mdio_ops orion_mdio_smi_ops = {
137 	.is_done = orion_mdio_smi_is_done,
138 	.poll_interval_min = MVMDIO_SMI_POLL_INTERVAL_MIN,
139 	.poll_interval_max = MVMDIO_SMI_POLL_INTERVAL_MAX,
140 };
141 
142 static int orion_mdio_smi_read(struct mii_bus *bus, int mii_id,
143 			       int regnum)
144 {
145 	struct orion_mdio_dev *dev = bus->priv;
146 	u32 val;
147 	int ret;
148 
149 	ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
150 	if (ret < 0)
151 		return ret;
152 
153 	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
154 		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
155 		MVMDIO_SMI_READ_OPERATION),
156 	       dev->regs);
157 
158 	ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
159 	if (ret < 0)
160 		return ret;
161 
162 	val = readl(dev->regs);
163 	if (!(val & MVMDIO_SMI_READ_VALID)) {
164 		dev_err(bus->parent, "SMI bus read not valid\n");
165 		return -ENODEV;
166 	}
167 
168 	return val & GENMASK(15, 0);
169 }
170 
171 static int orion_mdio_smi_write(struct mii_bus *bus, int mii_id,
172 				int regnum, u16 value)
173 {
174 	struct orion_mdio_dev *dev = bus->priv;
175 	int ret;
176 
177 	ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
178 	if (ret < 0)
179 		return ret;
180 
181 	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
182 		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
183 		MVMDIO_SMI_WRITE_OPERATION            |
184 		(value << MVMDIO_SMI_DATA_SHIFT)),
185 	       dev->regs);
186 
187 	return 0;
188 }
189 
190 static int orion_mdio_xsmi_is_done(struct orion_mdio_dev *dev)
191 {
192 	return !(readl(dev->regs + MVMDIO_XSMI_MGNT_REG) & MVMDIO_XSMI_BUSY);
193 }
194 
195 static const struct orion_mdio_ops orion_mdio_xsmi_ops = {
196 	.is_done = orion_mdio_xsmi_is_done,
197 	.poll_interval_min = MVMDIO_XSMI_POLL_INTERVAL_MIN,
198 	.poll_interval_max = MVMDIO_XSMI_POLL_INTERVAL_MAX,
199 };
200 
201 static int orion_mdio_xsmi_read_c45(struct mii_bus *bus, int mii_id,
202 				    int dev_addr, int regnum)
203 {
204 	struct orion_mdio_dev *dev = bus->priv;
205 	int ret;
206 
207 	ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
208 	if (ret < 0)
209 		return ret;
210 
211 	writel(regnum, dev->regs + MVMDIO_XSMI_ADDR_REG);
212 	writel((mii_id << MVMDIO_XSMI_PHYADDR_SHIFT) |
213 	       (dev_addr << MVMDIO_XSMI_DEVADDR_SHIFT) |
214 	       MVMDIO_XSMI_READ_OPERATION,
215 	       dev->regs + MVMDIO_XSMI_MGNT_REG);
216 
217 	ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
218 	if (ret < 0)
219 		return ret;
220 
221 	if (!(readl(dev->regs + MVMDIO_XSMI_MGNT_REG) &
222 	      MVMDIO_XSMI_READ_VALID)) {
223 		dev_err(bus->parent, "XSMI bus read not valid\n");
224 		return -ENODEV;
225 	}
226 
227 	return readl(dev->regs + MVMDIO_XSMI_MGNT_REG) & GENMASK(15, 0);
228 }
229 
230 static int orion_mdio_xsmi_write_c45(struct mii_bus *bus, int mii_id,
231 				     int dev_addr, int regnum, u16 value)
232 {
233 	struct orion_mdio_dev *dev = bus->priv;
234 	int ret;
235 
236 	ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
237 	if (ret < 0)
238 		return ret;
239 
240 	writel(regnum, dev->regs + MVMDIO_XSMI_ADDR_REG);
241 	writel((mii_id << MVMDIO_XSMI_PHYADDR_SHIFT) |
242 	       (dev_addr << MVMDIO_XSMI_DEVADDR_SHIFT) |
243 	       MVMDIO_XSMI_WRITE_OPERATION | value,
244 	       dev->regs + MVMDIO_XSMI_MGNT_REG);
245 
246 	return 0;
247 }
248 
249 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
250 {
251 	struct orion_mdio_dev *dev = dev_id;
252 
253 	if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
254 			MVMDIO_ERR_INT_SMI_DONE) {
255 		writel(~MVMDIO_ERR_INT_SMI_DONE,
256 				dev->regs + MVMDIO_ERR_INT_CAUSE);
257 		wake_up(&dev->smi_busy_wait);
258 		return IRQ_HANDLED;
259 	}
260 
261 	return IRQ_NONE;
262 }
263 
264 static int orion_mdio_probe(struct platform_device *pdev)
265 {
266 	enum orion_mdio_bus_type type;
267 	struct resource *r;
268 	struct mii_bus *bus;
269 	struct orion_mdio_dev *dev;
270 	int i, ret;
271 
272 	type = (enum orion_mdio_bus_type)device_get_match_data(&pdev->dev);
273 
274 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
275 	if (!r) {
276 		dev_err(&pdev->dev, "No SMI register address given\n");
277 		return -ENODEV;
278 	}
279 
280 	bus = devm_mdiobus_alloc_size(&pdev->dev,
281 				      sizeof(struct orion_mdio_dev));
282 	if (!bus)
283 		return -ENOMEM;
284 
285 	switch (type) {
286 	case BUS_TYPE_SMI:
287 		bus->read = orion_mdio_smi_read;
288 		bus->write = orion_mdio_smi_write;
289 		break;
290 	case BUS_TYPE_XSMI:
291 		bus->read_c45 = orion_mdio_xsmi_read_c45;
292 		bus->write_c45 = orion_mdio_xsmi_write_c45;
293 		break;
294 	}
295 
296 	bus->name = "orion_mdio_bus";
297 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
298 		 dev_name(&pdev->dev));
299 	bus->parent = &pdev->dev;
300 
301 	dev = bus->priv;
302 	dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
303 	if (!dev->regs) {
304 		dev_err(&pdev->dev, "Unable to remap SMI register\n");
305 		return -ENODEV;
306 	}
307 
308 	init_waitqueue_head(&dev->smi_busy_wait);
309 
310 	if (pdev->dev.of_node) {
311 		for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
312 			dev->clk[i] = of_clk_get(pdev->dev.of_node, i);
313 			if (PTR_ERR(dev->clk[i]) == -EPROBE_DEFER) {
314 				ret = -EPROBE_DEFER;
315 				goto out_clk;
316 			}
317 			if (IS_ERR(dev->clk[i]))
318 				break;
319 			clk_prepare_enable(dev->clk[i]);
320 		}
321 
322 		if (!IS_ERR(of_clk_get(pdev->dev.of_node,
323 				       ARRAY_SIZE(dev->clk))))
324 			dev_warn(&pdev->dev,
325 				 "unsupported number of clocks, limiting to the first "
326 				 __stringify(ARRAY_SIZE(dev->clk)) "\n");
327 	} else {
328 		dev->clk[0] = clk_get(&pdev->dev, NULL);
329 		if (PTR_ERR(dev->clk[0]) == -EPROBE_DEFER) {
330 			ret = -EPROBE_DEFER;
331 			goto out_clk;
332 		}
333 		if (!IS_ERR(dev->clk[0]))
334 			clk_prepare_enable(dev->clk[0]);
335 	}
336 
337 
338 	dev->err_interrupt = platform_get_irq_optional(pdev, 0);
339 	if (dev->err_interrupt > 0 &&
340 	    resource_size(r) < MVMDIO_ERR_INT_MASK + 4) {
341 		dev_err(&pdev->dev,
342 			"disabling interrupt, resource size is too small\n");
343 		dev->err_interrupt = 0;
344 	}
345 	if (dev->err_interrupt > 0) {
346 		ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
347 					orion_mdio_err_irq,
348 					IRQF_SHARED, pdev->name, dev);
349 		if (ret)
350 			goto out_mdio;
351 
352 		writel(MVMDIO_ERR_INT_SMI_DONE,
353 			dev->regs + MVMDIO_ERR_INT_MASK);
354 
355 	} else if (dev->err_interrupt == -EPROBE_DEFER) {
356 		ret = -EPROBE_DEFER;
357 		goto out_mdio;
358 	}
359 
360 	/* For the platforms not supporting DT/ACPI fall-back
361 	 * to mdiobus_register via of_mdiobus_register.
362 	 */
363 	if (is_acpi_node(pdev->dev.fwnode))
364 		ret = acpi_mdiobus_register(bus, pdev->dev.fwnode);
365 	else
366 		ret = of_mdiobus_register(bus, pdev->dev.of_node);
367 	if (ret < 0) {
368 		dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
369 		goto out_mdio;
370 	}
371 
372 	platform_set_drvdata(pdev, bus);
373 
374 	return 0;
375 
376 out_mdio:
377 	if (dev->err_interrupt > 0)
378 		writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
379 
380 out_clk:
381 	for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
382 		if (IS_ERR(dev->clk[i]))
383 			break;
384 		clk_disable_unprepare(dev->clk[i]);
385 		clk_put(dev->clk[i]);
386 	}
387 
388 	return ret;
389 }
390 
391 static int orion_mdio_remove(struct platform_device *pdev)
392 {
393 	struct mii_bus *bus = platform_get_drvdata(pdev);
394 	struct orion_mdio_dev *dev = bus->priv;
395 	int i;
396 
397 	if (dev->err_interrupt > 0)
398 		writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
399 	mdiobus_unregister(bus);
400 
401 	for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
402 		if (IS_ERR(dev->clk[i]))
403 			break;
404 		clk_disable_unprepare(dev->clk[i]);
405 		clk_put(dev->clk[i]);
406 	}
407 
408 	return 0;
409 }
410 
411 static const struct of_device_id orion_mdio_match[] = {
412 	{ .compatible = "marvell,orion-mdio", .data = (void *)BUS_TYPE_SMI },
413 	{ .compatible = "marvell,xmdio", .data = (void *)BUS_TYPE_XSMI },
414 	{ }
415 };
416 MODULE_DEVICE_TABLE(of, orion_mdio_match);
417 
418 #ifdef CONFIG_ACPI
419 static const struct acpi_device_id orion_mdio_acpi_match[] = {
420 	{ "MRVL0100", BUS_TYPE_SMI },
421 	{ "MRVL0101", BUS_TYPE_XSMI },
422 	{ },
423 };
424 MODULE_DEVICE_TABLE(acpi, orion_mdio_acpi_match);
425 #endif
426 
427 static struct platform_driver orion_mdio_driver = {
428 	.probe = orion_mdio_probe,
429 	.remove = orion_mdio_remove,
430 	.driver = {
431 		.name = "orion-mdio",
432 		.of_match_table = orion_mdio_match,
433 		.acpi_match_table = ACPI_PTR(orion_mdio_acpi_match),
434 	},
435 };
436 
437 module_platform_driver(orion_mdio_driver);
438 
439 MODULE_DESCRIPTION("Marvell MDIO interface driver");
440 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
441 MODULE_LICENSE("GPL");
442 MODULE_ALIAS("platform:orion-mdio");
443