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/clk.h>
21 #include <linux/delay.h>
22 #include <linux/interrupt.h>
23 #include <linux/io.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/of_device.h>
27 #include <linux/of_mdio.h>
28 #include <linux/phy.h>
29 #include <linux/platform_device.h>
30 #include <linux/sched.h>
31 #include <linux/wait.h>
32
33 #define MVMDIO_SMI_DATA_SHIFT 0
34 #define MVMDIO_SMI_PHY_ADDR_SHIFT 16
35 #define MVMDIO_SMI_PHY_REG_SHIFT 21
36 #define MVMDIO_SMI_READ_OPERATION BIT(26)
37 #define MVMDIO_SMI_WRITE_OPERATION 0
38 #define MVMDIO_SMI_READ_VALID BIT(27)
39 #define MVMDIO_SMI_BUSY BIT(28)
40 #define MVMDIO_ERR_INT_CAUSE 0x007C
41 #define MVMDIO_ERR_INT_SMI_DONE 0x00000010
42 #define MVMDIO_ERR_INT_MASK 0x0080
43
44 #define MVMDIO_XSMI_MGNT_REG 0x0
45 #define MVMDIO_XSMI_PHYADDR_SHIFT 16
46 #define MVMDIO_XSMI_DEVADDR_SHIFT 21
47 #define MVMDIO_XSMI_WRITE_OPERATION (0x5 << 26)
48 #define MVMDIO_XSMI_READ_OPERATION (0x7 << 26)
49 #define MVMDIO_XSMI_READ_VALID BIT(29)
50 #define MVMDIO_XSMI_BUSY BIT(30)
51 #define MVMDIO_XSMI_ADDR_REG 0x8
52
53 /*
54 * SMI Timeout measurements:
55 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
56 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
57 */
58 #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
59 #define MVMDIO_SMI_POLL_INTERVAL_MIN 45
60 #define MVMDIO_SMI_POLL_INTERVAL_MAX 55
61
62 #define MVMDIO_XSMI_POLL_INTERVAL_MIN 150
63 #define MVMDIO_XSMI_POLL_INTERVAL_MAX 160
64
65 struct orion_mdio_dev {
66 void __iomem *regs;
67 struct clk *clk[4];
68 /*
69 * If we have access to the error interrupt pin (which is
70 * somewhat misnamed as it not only reflects internal errors
71 * but also reflects SMI completion), use that to wait for
72 * SMI access completion instead of polling the SMI busy bit.
73 */
74 int err_interrupt;
75 wait_queue_head_t smi_busy_wait;
76 };
77
78 enum orion_mdio_bus_type {
79 BUS_TYPE_SMI,
80 BUS_TYPE_XSMI
81 };
82
83 struct orion_mdio_ops {
84 int (*is_done)(struct orion_mdio_dev *);
85 unsigned int poll_interval_min;
86 unsigned int poll_interval_max;
87 };
88
89 /* Wait for the SMI unit to be ready for another operation
90 */
orion_mdio_wait_ready(const struct orion_mdio_ops * ops,struct mii_bus * bus)91 static int orion_mdio_wait_ready(const struct orion_mdio_ops *ops,
92 struct mii_bus *bus)
93 {
94 struct orion_mdio_dev *dev = bus->priv;
95 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
96 unsigned long end = jiffies + timeout;
97 int timedout = 0;
98
99 while (1) {
100 if (ops->is_done(dev))
101 return 0;
102 else if (timedout)
103 break;
104
105 if (dev->err_interrupt <= 0) {
106 usleep_range(ops->poll_interval_min,
107 ops->poll_interval_max);
108
109 if (time_is_before_jiffies(end))
110 ++timedout;
111 } else {
112 /* wait_event_timeout does not guarantee a delay of at
113 * least one whole jiffie, so timeout must be no less
114 * than two.
115 */
116 if (timeout < 2)
117 timeout = 2;
118 wait_event_timeout(dev->smi_busy_wait,
119 ops->is_done(dev), timeout);
120
121 ++timedout;
122 }
123 }
124
125 dev_err(bus->parent, "Timeout: SMI busy for too long\n");
126 return -ETIMEDOUT;
127 }
128
orion_mdio_smi_is_done(struct orion_mdio_dev * dev)129 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
130 {
131 return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
132 }
133
134 static const struct orion_mdio_ops orion_mdio_smi_ops = {
135 .is_done = orion_mdio_smi_is_done,
136 .poll_interval_min = MVMDIO_SMI_POLL_INTERVAL_MIN,
137 .poll_interval_max = MVMDIO_SMI_POLL_INTERVAL_MAX,
138 };
139
orion_mdio_smi_read(struct mii_bus * bus,int mii_id,int regnum)140 static int orion_mdio_smi_read(struct mii_bus *bus, int mii_id,
141 int regnum)
142 {
143 struct orion_mdio_dev *dev = bus->priv;
144 u32 val;
145 int ret;
146
147 if (regnum & MII_ADDR_C45)
148 return -EOPNOTSUPP;
149
150 ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
151 if (ret < 0)
152 return ret;
153
154 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
155 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
156 MVMDIO_SMI_READ_OPERATION),
157 dev->regs);
158
159 ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
160 if (ret < 0)
161 return ret;
162
163 val = readl(dev->regs);
164 if (!(val & MVMDIO_SMI_READ_VALID)) {
165 dev_err(bus->parent, "SMI bus read not valid\n");
166 return -ENODEV;
167 }
168
169 return val & GENMASK(15, 0);
170 }
171
orion_mdio_smi_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)172 static int orion_mdio_smi_write(struct mii_bus *bus, int mii_id,
173 int regnum, u16 value)
174 {
175 struct orion_mdio_dev *dev = bus->priv;
176 int ret;
177
178 if (regnum & MII_ADDR_C45)
179 return -EOPNOTSUPP;
180
181 ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
182 if (ret < 0)
183 return ret;
184
185 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
186 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
187 MVMDIO_SMI_WRITE_OPERATION |
188 (value << MVMDIO_SMI_DATA_SHIFT)),
189 dev->regs);
190
191 return 0;
192 }
193
orion_mdio_xsmi_is_done(struct orion_mdio_dev * dev)194 static int orion_mdio_xsmi_is_done(struct orion_mdio_dev *dev)
195 {
196 return !(readl(dev->regs + MVMDIO_XSMI_MGNT_REG) & MVMDIO_XSMI_BUSY);
197 }
198
199 static const struct orion_mdio_ops orion_mdio_xsmi_ops = {
200 .is_done = orion_mdio_xsmi_is_done,
201 .poll_interval_min = MVMDIO_XSMI_POLL_INTERVAL_MIN,
202 .poll_interval_max = MVMDIO_XSMI_POLL_INTERVAL_MAX,
203 };
204
orion_mdio_xsmi_read(struct mii_bus * bus,int mii_id,int regnum)205 static int orion_mdio_xsmi_read(struct mii_bus *bus, int mii_id,
206 int regnum)
207 {
208 struct orion_mdio_dev *dev = bus->priv;
209 u16 dev_addr = (regnum >> 16) & GENMASK(4, 0);
210 int ret;
211
212 if (!(regnum & MII_ADDR_C45))
213 return -EOPNOTSUPP;
214
215 ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
216 if (ret < 0)
217 return ret;
218
219 writel(regnum & GENMASK(15, 0), dev->regs + MVMDIO_XSMI_ADDR_REG);
220 writel((mii_id << MVMDIO_XSMI_PHYADDR_SHIFT) |
221 (dev_addr << MVMDIO_XSMI_DEVADDR_SHIFT) |
222 MVMDIO_XSMI_READ_OPERATION,
223 dev->regs + MVMDIO_XSMI_MGNT_REG);
224
225 ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
226 if (ret < 0)
227 return ret;
228
229 if (!(readl(dev->regs + MVMDIO_XSMI_MGNT_REG) &
230 MVMDIO_XSMI_READ_VALID)) {
231 dev_err(bus->parent, "XSMI bus read not valid\n");
232 return -ENODEV;
233 }
234
235 return readl(dev->regs + MVMDIO_XSMI_MGNT_REG) & GENMASK(15, 0);
236 }
237
orion_mdio_xsmi_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)238 static int orion_mdio_xsmi_write(struct mii_bus *bus, int mii_id,
239 int regnum, u16 value)
240 {
241 struct orion_mdio_dev *dev = bus->priv;
242 u16 dev_addr = (regnum >> 16) & GENMASK(4, 0);
243 int ret;
244
245 if (!(regnum & MII_ADDR_C45))
246 return -EOPNOTSUPP;
247
248 ret = orion_mdio_wait_ready(&orion_mdio_xsmi_ops, bus);
249 if (ret < 0)
250 return ret;
251
252 writel(regnum & GENMASK(15, 0), dev->regs + MVMDIO_XSMI_ADDR_REG);
253 writel((mii_id << MVMDIO_XSMI_PHYADDR_SHIFT) |
254 (dev_addr << MVMDIO_XSMI_DEVADDR_SHIFT) |
255 MVMDIO_XSMI_WRITE_OPERATION | value,
256 dev->regs + MVMDIO_XSMI_MGNT_REG);
257
258 return 0;
259 }
260
orion_mdio_err_irq(int irq,void * dev_id)261 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
262 {
263 struct orion_mdio_dev *dev = dev_id;
264
265 if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
266 MVMDIO_ERR_INT_SMI_DONE) {
267 writel(~MVMDIO_ERR_INT_SMI_DONE,
268 dev->regs + MVMDIO_ERR_INT_CAUSE);
269 wake_up(&dev->smi_busy_wait);
270 return IRQ_HANDLED;
271 }
272
273 return IRQ_NONE;
274 }
275
orion_mdio_probe(struct platform_device * pdev)276 static int orion_mdio_probe(struct platform_device *pdev)
277 {
278 enum orion_mdio_bus_type type;
279 struct resource *r;
280 struct mii_bus *bus;
281 struct orion_mdio_dev *dev;
282 int i, ret;
283
284 type = (enum orion_mdio_bus_type)of_device_get_match_data(&pdev->dev);
285
286 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
287 if (!r) {
288 dev_err(&pdev->dev, "No SMI register address given\n");
289 return -ENODEV;
290 }
291
292 bus = devm_mdiobus_alloc_size(&pdev->dev,
293 sizeof(struct orion_mdio_dev));
294 if (!bus)
295 return -ENOMEM;
296
297 switch (type) {
298 case BUS_TYPE_SMI:
299 bus->read = orion_mdio_smi_read;
300 bus->write = orion_mdio_smi_write;
301 break;
302 case BUS_TYPE_XSMI:
303 bus->read = orion_mdio_xsmi_read;
304 bus->write = orion_mdio_xsmi_write;
305 break;
306 }
307
308 bus->name = "orion_mdio_bus";
309 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
310 dev_name(&pdev->dev));
311 bus->parent = &pdev->dev;
312
313 dev = bus->priv;
314 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
315 if (!dev->regs) {
316 dev_err(&pdev->dev, "Unable to remap SMI register\n");
317 return -ENODEV;
318 }
319
320 init_waitqueue_head(&dev->smi_busy_wait);
321
322 if (pdev->dev.of_node) {
323 for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
324 dev->clk[i] = of_clk_get(pdev->dev.of_node, i);
325 if (PTR_ERR(dev->clk[i]) == -EPROBE_DEFER) {
326 ret = -EPROBE_DEFER;
327 goto out_clk;
328 }
329 if (IS_ERR(dev->clk[i]))
330 break;
331 clk_prepare_enable(dev->clk[i]);
332 }
333
334 if (!IS_ERR(of_clk_get(pdev->dev.of_node,
335 ARRAY_SIZE(dev->clk))))
336 dev_warn(&pdev->dev,
337 "unsupported number of clocks, limiting to the first "
338 __stringify(ARRAY_SIZE(dev->clk)) "\n");
339 } else {
340 dev->clk[0] = clk_get(&pdev->dev, NULL);
341 if (PTR_ERR(dev->clk[0]) == -EPROBE_DEFER) {
342 ret = -EPROBE_DEFER;
343 goto out_clk;
344 }
345 if (!IS_ERR(dev->clk[0]))
346 clk_prepare_enable(dev->clk[0]);
347 }
348
349
350 dev->err_interrupt = platform_get_irq_optional(pdev, 0);
351 if (dev->err_interrupt > 0 &&
352 resource_size(r) < MVMDIO_ERR_INT_MASK + 4) {
353 dev_err(&pdev->dev,
354 "disabling interrupt, resource size is too small\n");
355 dev->err_interrupt = 0;
356 }
357 if (dev->err_interrupt > 0) {
358 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
359 orion_mdio_err_irq,
360 IRQF_SHARED, pdev->name, dev);
361 if (ret)
362 goto out_mdio;
363
364 writel(MVMDIO_ERR_INT_SMI_DONE,
365 dev->regs + MVMDIO_ERR_INT_MASK);
366
367 } else if (dev->err_interrupt == -EPROBE_DEFER) {
368 ret = -EPROBE_DEFER;
369 goto out_mdio;
370 }
371
372 ret = of_mdiobus_register(bus, pdev->dev.of_node);
373 if (ret < 0) {
374 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
375 goto out_mdio;
376 }
377
378 platform_set_drvdata(pdev, bus);
379
380 return 0;
381
382 out_mdio:
383 if (dev->err_interrupt > 0)
384 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
385
386 out_clk:
387 for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
388 if (IS_ERR(dev->clk[i]))
389 break;
390 clk_disable_unprepare(dev->clk[i]);
391 clk_put(dev->clk[i]);
392 }
393
394 return ret;
395 }
396
orion_mdio_remove(struct platform_device * pdev)397 static int orion_mdio_remove(struct platform_device *pdev)
398 {
399 struct mii_bus *bus = platform_get_drvdata(pdev);
400 struct orion_mdio_dev *dev = bus->priv;
401 int i;
402
403 if (dev->err_interrupt > 0)
404 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
405 mdiobus_unregister(bus);
406
407 for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
408 if (IS_ERR(dev->clk[i]))
409 break;
410 clk_disable_unprepare(dev->clk[i]);
411 clk_put(dev->clk[i]);
412 }
413
414 return 0;
415 }
416
417 static const struct of_device_id orion_mdio_match[] = {
418 { .compatible = "marvell,orion-mdio", .data = (void *)BUS_TYPE_SMI },
419 { .compatible = "marvell,xmdio", .data = (void *)BUS_TYPE_XSMI },
420 { }
421 };
422 MODULE_DEVICE_TABLE(of, orion_mdio_match);
423
424 static struct platform_driver orion_mdio_driver = {
425 .probe = orion_mdio_probe,
426 .remove = orion_mdio_remove,
427 .driver = {
428 .name = "orion-mdio",
429 .of_match_table = orion_mdio_match,
430 },
431 };
432
433 module_platform_driver(orion_mdio_driver);
434
435 MODULE_DESCRIPTION("Marvell MDIO interface driver");
436 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
437 MODULE_LICENSE("GPL");
438 MODULE_ALIAS("platform:orion-mdio");
439
