drivers/net/ethernet/marvell/mvmdio.c

   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 the
   8  * MDIO bus). Moreover, this MDIO interface code is similar between
   9  * the mv643xx_eth driver and the mvneta driver. For now, it is only
  10  * used by the mvneta driver, but it could later be used by the
  11  * mv643xx_eth driver as well.
  12  *
  13  * Copyright (C) 2012 Marvell
  14  *
  15  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  16  *
  17  * This file is licensed under the terms of the GNU General Public
  18  * License version 2. This program is licensed "as is" without any
  19  * warranty of any kind, whether express or implied.
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/mutex.h>
  26 #include <linux/phy.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/delay.h>
  30 #include <linux/io.h>
  31 #include <linux/clk.h>
  32 #include <linux/of_mdio.h>
  33 #include <linux/sched.h>
  34 #include <linux/wait.h>
  35
  36 #define MVMDIO_SMI_DATA_SHIFT              0
  37 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
  38 #define MVMDIO_SMI_PHY_REG_SHIFT           21
  39 #define MVMDIO_SMI_READ_OPERATION          BIT(26)
  40 #define MVMDIO_SMI_WRITE_OPERATION         0
  41 #define MVMDIO_SMI_READ_VALID              BIT(27)
  42 #define MVMDIO_SMI_BUSY                    BIT(28)
  43 #define MVMDIO_ERR_INT_CAUSE               0x007C
  44 #define  MVMDIO_ERR_INT_SMI_DONE           0x00000010
  45 #define MVMDIO_ERR_INT_MASK                0x0080
  46
  47 struct orion_mdio_dev {
  48         struct mutex lock;
  49         void __iomem *regs;
  50         struct clk *clk;
  51         /*
  52          * If we have access to the error interrupt pin (which is
  53          * somewhat misnamed as it not only reflects internal errors
  54          * but also reflects SMI completion), use that to wait for
  55          * SMI access completion instead of polling the SMI busy bit.
  56          */
  57         int err_interrupt;
  58         wait_queue_head_t smi_busy_wait;
  59 };
  60
  61 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
  62 {
  63         return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
  64 }
  65
  66 /* Wait for the SMI unit to be ready for another operation
  67  */
  68 static int orion_mdio_wait_ready(struct mii_bus *bus)
  69 {
  70         struct orion_mdio_dev *dev = bus->priv;
  71         int count;
  72
  73         if (dev->err_interrupt <= 0) {
  74                 count = 0;
  75                 while (1) {
  76                         if (orion_mdio_smi_is_done(dev))
  77                                 break;
  78
  79                         if (count > 100) {
  80                                 dev_err(bus->parent,
  81                                         "Timeout: SMI busy for too long\n");
  82                                 return -ETIMEDOUT;
  83                         }
  84
  85                         udelay(10);
  86                         count++;
  87                 }
  88         } else {
  89                 if (!orion_mdio_smi_is_done(dev)) {
  90                         wait_event_timeout(dev->smi_busy_wait,
  91                                 orion_mdio_smi_is_done(dev),
  92                                 msecs_to_jiffies(100));
  93                         if (!orion_mdio_smi_is_done(dev))
  94                                 return -ETIMEDOUT;
  95                 }
  96         }
  97
  98         return 0;
  99 }
 100
 101 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 102                            int regnum)
 103 {
 104         struct orion_mdio_dev *dev = bus->priv;
 105         int count;
 106         u32 val;
 107         int ret;
 108
 109         mutex_lock(&dev->lock);
 110
 111         ret = orion_mdio_wait_ready(bus);
 112         if (ret < 0) {
 113                 mutex_unlock(&dev->lock);
 114                 return ret;
 115         }
 116
 117         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 118                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 119                 MVMDIO_SMI_READ_OPERATION),
 120                dev->regs);
 121
 122         /* Wait for the value to become available */
 123         count = 0;
 124         while (1) {
 125                 val = readl(dev->regs);
 126                 if (val & MVMDIO_SMI_READ_VALID)
 127                         break;
 128
 129                 if (count > 100) {
 130                         dev_err(bus->parent, "Timeout when reading PHY\n");
 131                         mutex_unlock(&dev->lock);
 132                         return -ETIMEDOUT;
 133                 }
 134
 135                 udelay(10);
 136                 count++;
 137         }
 138
 139         mutex_unlock(&dev->lock);
 140
 141         return val & 0xFFFF;
 142 }
 143
 144 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 145                             int regnum, u16 value)
 146 {
 147         struct orion_mdio_dev *dev = bus->priv;
 148         int ret;
 149
 150         mutex_lock(&dev->lock);
 151
 152         ret = orion_mdio_wait_ready(bus);
 153         if (ret < 0) {
 154                 mutex_unlock(&dev->lock);
 155                 return ret;
 156         }
 157
 158         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 159                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 160                 MVMDIO_SMI_WRITE_OPERATION            |
 161                 (value << MVMDIO_SMI_DATA_SHIFT)),
 162                dev->regs);
 163
 164         mutex_unlock(&dev->lock);
 165
 166         return 0;
 167 }
 168
 169 static int orion_mdio_reset(struct mii_bus *bus)
 170 {
 171         return 0;
 172 }
 173
 174 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 175 {
 176         struct orion_mdio_dev *dev = dev_id;
 177
 178         if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 179                         MVMDIO_ERR_INT_SMI_DONE) {
 180                 writel(~MVMDIO_ERR_INT_SMI_DONE,
 181                                 dev->regs + MVMDIO_ERR_INT_CAUSE);
 182                 wake_up(&dev->smi_busy_wait);
 183                 return IRQ_HANDLED;
 184         }
 185
 186         return IRQ_NONE;
 187 }
 188
 189 static int orion_mdio_probe(struct platform_device *pdev)
 190 {
 191         struct resource *r;
 192         struct mii_bus *bus;
 193         struct orion_mdio_dev *dev;
 194         int i, ret;
 195
 196         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 197         if (!r) {
 198                 dev_err(&pdev->dev, "No SMI register address given\n");
 199                 return -ENODEV;
 200         }
 201
 202         bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
 203         if (!bus) {
 204                 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
 205                 return -ENOMEM;
 206         }
 207
 208         bus->name = "orion_mdio_bus";
 209         bus->read = orion_mdio_read;
 210         bus->write = orion_mdio_write;
 211         bus->reset = orion_mdio_reset;
 212         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 213                  dev_name(&pdev->dev));
 214         bus->parent = &pdev->dev;
 215
 216         bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
 217         if (!bus->irq) {
 218                 mdiobus_free(bus);
 219                 return -ENOMEM;
 220         }
 221
 222         for (i = 0; i < PHY_MAX_ADDR; i++)
 223                 bus->irq[i] = PHY_POLL;
 224
 225         dev = bus->priv;
 226         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 227         if (!dev->regs) {
 228                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
 229                 ret = -ENODEV;
 230                 goto out_mdio;
 231         }
 232
 233         init_waitqueue_head(&dev->smi_busy_wait);
 234
 235         dev->clk = devm_clk_get(&pdev->dev, NULL);
 236         if (!IS_ERR(dev->clk))
 237                 clk_prepare_enable(dev->clk);
 238
 239         dev->err_interrupt = platform_get_irq(pdev, 0);
 240         if (dev->err_interrupt != -ENXIO) {
 241                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 242                                         orion_mdio_err_irq,
 243                                         IRQF_SHARED, pdev->name, dev);
 244                 if (ret)
 245                         goto out_mdio;
 246
 247                 writel(MVMDIO_ERR_INT_SMI_DONE,
 248                         dev->regs + MVMDIO_ERR_INT_MASK);
 249         }
 250
 251         mutex_init(&dev->lock);
 252
 253         if (pdev->dev.of_node)
 254                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
 255         else
 256                 ret = mdiobus_register(bus);
 257         if (ret < 0) {
 258                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 259                 goto out_mdio;
 260         }
 261
 262         platform_set_drvdata(pdev, bus);
 263
 264         return 0;
 265
 266 out_mdio:
 267         if (!IS_ERR(dev->clk))
 268                 clk_disable_unprepare(dev->clk);
 269         kfree(bus->irq);
 270         mdiobus_free(bus);
 271         return ret;
 272 }
 273
 274 static int orion_mdio_remove(struct platform_device *pdev)
 275 {
 276         struct mii_bus *bus = platform_get_drvdata(pdev);
 277         struct orion_mdio_dev *dev = bus->priv;
 278
 279         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 280         mdiobus_unregister(bus);
 281         kfree(bus->irq);
 282         mdiobus_free(bus);
 283         if (!IS_ERR(dev->clk))
 284                 clk_disable_unprepare(dev->clk);
 285
 286         return 0;
 287 }
 288
 289 static const struct of_device_id orion_mdio_match[] = {
 290         { .compatible = "marvell,orion-mdio" },
 291         { }
 292 };
 293 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 294
 295 static struct platform_driver orion_mdio_driver = {
 296         .probe = orion_mdio_probe,
 297         .remove = orion_mdio_remove,
 298         .driver = {
 299                 .name = "orion-mdio",
 300                 .of_match_table = orion_mdio_match,
 301         },
 302 };
 303
 304 module_platform_driver(orion_mdio_driver);
 305
 306 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 307 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 308 MODULE_LICENSE("GPL");
 309 MODULE_ALIAS("platform:orion-mdio");