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Linux/drivers/net/ethernet/ti/davinci_mdio.c

  1 /*
  2  * DaVinci MDIO Module driver
  3  *
  4  * Copyright (C) 2010 Texas Instruments.
  5  *
  6  * Shamelessly ripped out of davinci_emac.c, original copyrights follow:
  7  *
  8  * Copyright (C) 2009 Texas Instruments.
  9  *
 10  * ---------------------------------------------------------------------------
 11  *
 12  * This program is free software; you can redistribute it and/or modify
 13  * it under the terms of the GNU General Public License as published by
 14  * the Free Software Foundation; either version 2 of the License, or
 15  * (at your option) any later version.
 16  *
 17  * This program is distributed in the hope that it will be useful,
 18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 20  * GNU General Public License for more details.
 21  *
 22  * You should have received a copy of the GNU General Public License
 23  * along with this program; if not, write to the Free Software
 24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 25  * ---------------------------------------------------------------------------
 26  */
 27 #include <linux/module.h>
 28 #include <linux/kernel.h>
 29 #include <linux/platform_device.h>
 30 #include <linux/delay.h>
 31 #include <linux/sched.h>
 32 #include <linux/slab.h>
 33 #include <linux/phy.h>
 34 #include <linux/clk.h>
 35 #include <linux/err.h>
 36 #include <linux/io.h>
 37 #include <linux/pm_runtime.h>
 38 #include <linux/davinci_emac.h>
 39 #include <linux/of.h>
 40 #include <linux/of_device.h>
 41 #include <linux/pinctrl/consumer.h>
 42 
 43 /*
 44  * This timeout definition is a worst-case ultra defensive measure against
 45  * unexpected controller lock ups.  Ideally, we should never ever hit this
 46  * scenario in practice.
 47  */
 48 #define MDIO_TIMEOUT            100 /* msecs */
 49 
 50 #define PHY_REG_MASK            0x1f
 51 #define PHY_ID_MASK             0x1f
 52 
 53 #define DEF_OUT_FREQ            2200000         /* 2.2 MHz */
 54 
 55 struct davinci_mdio_regs {
 56         u32     version;
 57         u32     control;
 58 #define CONTROL_IDLE            BIT(31)
 59 #define CONTROL_ENABLE          BIT(30)
 60 #define CONTROL_MAX_DIV         (0xffff)
 61 
 62         u32     alive;
 63         u32     link;
 64         u32     linkintraw;
 65         u32     linkintmasked;
 66         u32     __reserved_0[2];
 67         u32     userintraw;
 68         u32     userintmasked;
 69         u32     userintmaskset;
 70         u32     userintmaskclr;
 71         u32     __reserved_1[20];
 72 
 73         struct {
 74                 u32     access;
 75 #define USERACCESS_GO           BIT(31)
 76 #define USERACCESS_WRITE        BIT(30)
 77 #define USERACCESS_ACK          BIT(29)
 78 #define USERACCESS_READ         (0)
 79 #define USERACCESS_DATA         (0xffff)
 80 
 81                 u32     physel;
 82         }       user[0];
 83 };
 84 
 85 static const struct mdio_platform_data default_pdata = {
 86         .bus_freq = DEF_OUT_FREQ,
 87 };
 88 
 89 struct davinci_mdio_data {
 90         struct mdio_platform_data pdata;
 91         struct davinci_mdio_regs __iomem *regs;
 92         spinlock_t      lock;
 93         struct clk      *clk;
 94         struct device   *dev;
 95         struct mii_bus  *bus;
 96         bool            suspended;
 97         unsigned long   access_time; /* jiffies */
 98 };
 99 
100 static void __davinci_mdio_reset(struct davinci_mdio_data *data)
101 {
102         u32 mdio_in, div, mdio_out_khz, access_time;
103 
104         mdio_in = clk_get_rate(data->clk);
105         div = (mdio_in / data->pdata.bus_freq) - 1;
106         if (div > CONTROL_MAX_DIV)
107                 div = CONTROL_MAX_DIV;
108 
109         /* set enable and clock divider */
110         __raw_writel(div | CONTROL_ENABLE, &data->regs->control);
111 
112         /*
113          * One mdio transaction consists of:
114          *      32 bits of preamble
115          *      32 bits of transferred data
116          *      24 bits of bus yield (not needed unless shared?)
117          */
118         mdio_out_khz = mdio_in / (1000 * (div + 1));
119         access_time  = (88 * 1000) / mdio_out_khz;
120 
121         /*
122          * In the worst case, we could be kicking off a user-access immediately
123          * after the mdio bus scan state-machine triggered its own read.  If
124          * so, our request could get deferred by one access cycle.  We
125          * defensively allow for 4 access cycles.
126          */
127         data->access_time = usecs_to_jiffies(access_time * 4);
128         if (!data->access_time)
129                 data->access_time = 1;
130 }
131 
132 static int davinci_mdio_reset(struct mii_bus *bus)
133 {
134         struct davinci_mdio_data *data = bus->priv;
135         u32 phy_mask, ver;
136 
137         __davinci_mdio_reset(data);
138 
139         /* wait for scan logic to settle */
140         msleep(PHY_MAX_ADDR * data->access_time);
141 
142         /* dump hardware version info */
143         ver = __raw_readl(&data->regs->version);
144         dev_info(data->dev, "davinci mdio revision %d.%d\n",
145                  (ver >> 8) & 0xff, ver & 0xff);
146 
147         /* get phy mask from the alive register */
148         phy_mask = __raw_readl(&data->regs->alive);
149         if (phy_mask) {
150                 /* restrict mdio bus to live phys only */
151                 dev_info(data->dev, "detected phy mask %x\n", ~phy_mask);
152                 phy_mask = ~phy_mask;
153         } else {
154                 /* desperately scan all phys */
155                 dev_warn(data->dev, "no live phy, scanning all\n");
156                 phy_mask = 0;
157         }
158         data->bus->phy_mask = phy_mask;
159 
160         return 0;
161 }
162 
163 /* wait until hardware is ready for another user access */
164 static inline int wait_for_user_access(struct davinci_mdio_data *data)
165 {
166         struct davinci_mdio_regs __iomem *regs = data->regs;
167         unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);
168         u32 reg;
169 
170         while (time_after(timeout, jiffies)) {
171                 reg = __raw_readl(&regs->user[0].access);
172                 if ((reg & USERACCESS_GO) == 0)
173                         return 0;
174 
175                 reg = __raw_readl(&regs->control);
176                 if ((reg & CONTROL_IDLE) == 0)
177                         continue;
178 
179                 /*
180                  * An emac soft_reset may have clobbered the mdio controller's
181                  * state machine.  We need to reset and retry the current
182                  * operation
183                  */
184                 dev_warn(data->dev, "resetting idled controller\n");
185                 __davinci_mdio_reset(data);
186                 return -EAGAIN;
187         }
188 
189         reg = __raw_readl(&regs->user[0].access);
190         if ((reg & USERACCESS_GO) == 0)
191                 return 0;
192 
193         dev_err(data->dev, "timed out waiting for user access\n");
194         return -ETIMEDOUT;
195 }
196 
197 /* wait until hardware state machine is idle */
198 static inline int wait_for_idle(struct davinci_mdio_data *data)
199 {
200         struct davinci_mdio_regs __iomem *regs = data->regs;
201         unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);
202 
203         while (time_after(timeout, jiffies)) {
204                 if (__raw_readl(&regs->control) & CONTROL_IDLE)
205                         return 0;
206         }
207         dev_err(data->dev, "timed out waiting for idle\n");
208         return -ETIMEDOUT;
209 }
210 
211 static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)
212 {
213         struct davinci_mdio_data *data = bus->priv;
214         u32 reg;
215         int ret;
216 
217         if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
218                 return -EINVAL;
219 
220         spin_lock(&data->lock);
221 
222         if (data->suspended) {
223                 spin_unlock(&data->lock);
224                 return -ENODEV;
225         }
226 
227         reg = (USERACCESS_GO | USERACCESS_READ | (phy_reg << 21) |
228                (phy_id << 16));
229 
230         while (1) {
231                 ret = wait_for_user_access(data);
232                 if (ret == -EAGAIN)
233                         continue;
234                 if (ret < 0)
235                         break;
236 
237                 __raw_writel(reg, &data->regs->user[0].access);
238 
239                 ret = wait_for_user_access(data);
240                 if (ret == -EAGAIN)
241                         continue;
242                 if (ret < 0)
243                         break;
244 
245                 reg = __raw_readl(&data->regs->user[0].access);
246                 ret = (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -EIO;
247                 break;
248         }
249 
250         spin_unlock(&data->lock);
251 
252         return ret;
253 }
254 
255 static int davinci_mdio_write(struct mii_bus *bus, int phy_id,
256                               int phy_reg, u16 phy_data)
257 {
258         struct davinci_mdio_data *data = bus->priv;
259         u32 reg;
260         int ret;
261 
262         if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
263                 return -EINVAL;
264 
265         spin_lock(&data->lock);
266 
267         if (data->suspended) {
268                 spin_unlock(&data->lock);
269                 return -ENODEV;
270         }
271 
272         reg = (USERACCESS_GO | USERACCESS_WRITE | (phy_reg << 21) |
273                    (phy_id << 16) | (phy_data & USERACCESS_DATA));
274 
275         while (1) {
276                 ret = wait_for_user_access(data);
277                 if (ret == -EAGAIN)
278                         continue;
279                 if (ret < 0)
280                         break;
281 
282                 __raw_writel(reg, &data->regs->user[0].access);
283 
284                 ret = wait_for_user_access(data);
285                 if (ret == -EAGAIN)
286                         continue;
287                 break;
288         }
289 
290         spin_unlock(&data->lock);
291 
292         return 0;
293 }
294 
295 #if IS_ENABLED(CONFIG_OF)
296 static int davinci_mdio_probe_dt(struct mdio_platform_data *data,
297                          struct platform_device *pdev)
298 {
299         struct device_node *node = pdev->dev.of_node;
300         u32 prop;
301 
302         if (!node)
303                 return -EINVAL;
304 
305         if (of_property_read_u32(node, "bus_freq", &prop)) {
306                 dev_err(&pdev->dev, "Missing bus_freq property in the DT.\n");
307                 return -EINVAL;
308         }
309         data->bus_freq = prop;
310 
311         return 0;
312 }
313 #endif
314 
315 static int davinci_mdio_probe(struct platform_device *pdev)
316 {
317         struct mdio_platform_data *pdata = dev_get_platdata(&pdev->dev);
318         struct device *dev = &pdev->dev;
319         struct davinci_mdio_data *data;
320         struct resource *res;
321         struct phy_device *phy;
322         int ret, addr;
323 
324         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
325         if (!data)
326                 return -ENOMEM;
327 
328         data->bus = devm_mdiobus_alloc(dev);
329         if (!data->bus) {
330                 dev_err(dev, "failed to alloc mii bus\n");
331                 return -ENOMEM;
332         }
333 
334         if (dev->of_node) {
335                 if (davinci_mdio_probe_dt(&data->pdata, pdev))
336                         data->pdata = default_pdata;
337                 snprintf(data->bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
338         } else {
339                 data->pdata = pdata ? (*pdata) : default_pdata;
340                 snprintf(data->bus->id, MII_BUS_ID_SIZE, "%s-%x",
341                          pdev->name, pdev->id);
342         }
343 
344         data->bus->name         = dev_name(dev);
345         data->bus->read         = davinci_mdio_read,
346         data->bus->write        = davinci_mdio_write,
347         data->bus->reset        = davinci_mdio_reset,
348         data->bus->parent       = dev;
349         data->bus->priv         = data;
350 
351         pm_runtime_enable(&pdev->dev);
352         pm_runtime_get_sync(&pdev->dev);
353         data->clk = devm_clk_get(dev, "fck");
354         if (IS_ERR(data->clk)) {
355                 dev_err(dev, "failed to get device clock\n");
356                 ret = PTR_ERR(data->clk);
357                 data->clk = NULL;
358                 goto bail_out;
359         }
360 
361         dev_set_drvdata(dev, data);
362         data->dev = dev;
363         spin_lock_init(&data->lock);
364 
365         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366         data->regs = devm_ioremap_resource(dev, res);
367         if (IS_ERR(data->regs)) {
368                 ret = PTR_ERR(data->regs);
369                 goto bail_out;
370         }
371 
372         /* register the mii bus */
373         ret = mdiobus_register(data->bus);
374         if (ret)
375                 goto bail_out;
376 
377         /* scan and dump the bus */
378         for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
379                 phy = data->bus->phy_map[addr];
380                 if (phy) {
381                         dev_info(dev, "phy[%d]: device %s, driver %s\n",
382                                  phy->addr, dev_name(&phy->dev),
383                                  phy->drv ? phy->drv->name : "unknown");
384                 }
385         }
386 
387         return 0;
388 
389 bail_out:
390         pm_runtime_put_sync(&pdev->dev);
391         pm_runtime_disable(&pdev->dev);
392 
393         return ret;
394 }
395 
396 static int davinci_mdio_remove(struct platform_device *pdev)
397 {
398         struct davinci_mdio_data *data = platform_get_drvdata(pdev);
399 
400         if (data->bus)
401                 mdiobus_unregister(data->bus);
402 
403         pm_runtime_put_sync(&pdev->dev);
404         pm_runtime_disable(&pdev->dev);
405 
406         return 0;
407 }
408 
409 static int davinci_mdio_suspend(struct device *dev)
410 {
411         struct davinci_mdio_data *data = dev_get_drvdata(dev);
412         u32 ctrl;
413 
414         spin_lock(&data->lock);
415 
416         /* shutdown the scan state machine */
417         ctrl = __raw_readl(&data->regs->control);
418         ctrl &= ~CONTROL_ENABLE;
419         __raw_writel(ctrl, &data->regs->control);
420         wait_for_idle(data);
421 
422         data->suspended = true;
423         spin_unlock(&data->lock);
424         pm_runtime_put_sync(data->dev);
425 
426         /* Select sleep pin state */
427         pinctrl_pm_select_sleep_state(dev);
428 
429         return 0;
430 }
431 
432 static int davinci_mdio_resume(struct device *dev)
433 {
434         struct davinci_mdio_data *data = dev_get_drvdata(dev);
435 
436         /* Select default pin state */
437         pinctrl_pm_select_default_state(dev);
438 
439         pm_runtime_get_sync(data->dev);
440 
441         spin_lock(&data->lock);
442         /* restart the scan state machine */
443         __davinci_mdio_reset(data);
444 
445         data->suspended = false;
446         spin_unlock(&data->lock);
447 
448         return 0;
449 }
450 
451 static const struct dev_pm_ops davinci_mdio_pm_ops = {
452         .suspend_late   = davinci_mdio_suspend,
453         .resume_early   = davinci_mdio_resume,
454 };
455 
456 #if IS_ENABLED(CONFIG_OF)
457 static const struct of_device_id davinci_mdio_of_mtable[] = {
458         { .compatible = "ti,davinci_mdio", },
459         { /* sentinel */ },
460 };
461 MODULE_DEVICE_TABLE(of, davinci_mdio_of_mtable);
462 #endif
463 
464 static struct platform_driver davinci_mdio_driver = {
465         .driver = {
466                 .name    = "davinci_mdio",
467                 .owner   = THIS_MODULE,
468                 .pm      = &davinci_mdio_pm_ops,
469                 .of_match_table = of_match_ptr(davinci_mdio_of_mtable),
470         },
471         .probe = davinci_mdio_probe,
472         .remove = davinci_mdio_remove,
473 };
474 
475 static int __init davinci_mdio_init(void)
476 {
477         return platform_driver_register(&davinci_mdio_driver);
478 }
479 device_initcall(davinci_mdio_init);
480 
481 static void __exit davinci_mdio_exit(void)
482 {
483         platform_driver_unregister(&davinci_mdio_driver);
484 }
485 module_exit(davinci_mdio_exit);
486 
487 MODULE_LICENSE("GPL");
488 MODULE_DESCRIPTION("DaVinci MDIO driver");
489 

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