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