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/of_address.h>
  28 #include <linux/of_mdio.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/delay.h>
  31
  32 #define MVMDIO_SMI_DATA_SHIFT              0
  33 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
  34 #define MVMDIO_SMI_PHY_REG_SHIFT           21
  35 #define MVMDIO_SMI_READ_OPERATION          BIT(26)
  36 #define MVMDIO_SMI_WRITE_OPERATION         0
  37 #define MVMDIO_SMI_READ_VALID              BIT(27)
  38 #define MVMDIO_SMI_BUSY                    BIT(28)
  39
  40 struct orion_mdio_dev {
  41         struct mutex lock;
  42         void __iomem *smireg;
  43 };
  44
  45 /*
  46  * Wait for the SMI unit to be ready for another operation
  47  */
  48 static int orion_mdio_wait_ready(struct mii_bus *bus)
  49 {
  50         struct orion_mdio_dev *dev = bus->priv;
  51         int count;
  52         u32 val;
  53
  54         count = 0;
  55         while (1) {
  56                 val = readl(dev->smireg);
  57                 if (!(val & MVMDIO_SMI_BUSY))
  58                         break;
  59
  60                 if (count > 100) {
  61                         dev_err(bus->parent, "Timeout: SMI busy for too long\n");
  62                         return -ETIMEDOUT;
  63                 }
  64
  65                 udelay(10);
  66                 count++;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
  73                            int regnum)
  74 {
  75         struct orion_mdio_dev *dev = bus->priv;
  76         int count;
  77         u32 val;
  78         int ret;
  79
  80         mutex_lock(&dev->lock);
  81
  82         ret = orion_mdio_wait_ready(bus);
  83         if (ret < 0) {
  84                 mutex_unlock(&dev->lock);
  85                 return ret;
  86         }
  87
  88         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
  89                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
  90                 MVMDIO_SMI_READ_OPERATION),
  91                dev->smireg);
  92
  93         /* Wait for the value to become available */
  94         count = 0;
  95         while (1) {
  96                 val = readl(dev->smireg);
  97                 if (val & MVMDIO_SMI_READ_VALID)
  98                         break;
  99
 100                 if (count > 100) {
 101                         dev_err(bus->parent, "Timeout when reading PHY\n");
 102                         mutex_unlock(&dev->lock);
 103                         return -ETIMEDOUT;
 104                 }
 105
 106                 udelay(10);
 107                 count++;
 108         }
 109
 110         mutex_unlock(&dev->lock);
 111
 112         return val & 0xFFFF;
 113 }
 114
 115 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 116                             int regnum, u16 value)
 117 {
 118         struct orion_mdio_dev *dev = bus->priv;
 119         int ret;
 120
 121         mutex_lock(&dev->lock);
 122
 123         ret = orion_mdio_wait_ready(bus);
 124         if (ret < 0) {
 125                 mutex_unlock(&dev->lock);
 126                 return ret;
 127         }
 128
 129         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 130                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 131                 MVMDIO_SMI_WRITE_OPERATION            |
 132                 (value << MVMDIO_SMI_DATA_SHIFT)),
 133                dev->smireg);
 134
 135         mutex_unlock(&dev->lock);
 136
 137         return 0;
 138 }
 139
 140 static int orion_mdio_reset(struct mii_bus *bus)
 141 {
 142         return 0;
 143 }
 144
 145 static int __devinit orion_mdio_probe(struct platform_device *pdev)
 146 {
 147         struct device_node *np = pdev->dev.of_node;
 148         struct mii_bus *bus;
 149         struct orion_mdio_dev *dev;
 150         int i, ret;
 151
 152         bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
 153         if (!bus) {
 154                 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
 155                 return -ENOMEM;
 156         }
 157
 158         bus->name = "orion_mdio_bus";
 159         bus->read = orion_mdio_read;
 160         bus->write = orion_mdio_write;
 161         bus->reset = orion_mdio_reset;
 162         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 163                  dev_name(&pdev->dev));
 164         bus->parent = &pdev->dev;
 165
 166         bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
 167         if (!bus->irq) {
 168                 dev_err(&pdev->dev, "Cannot allocate PHY IRQ array\n");
 169                 mdiobus_free(bus);
 170                 return -ENOMEM;
 171         }
 172
 173         for (i = 0; i < PHY_MAX_ADDR; i++)
 174                 bus->irq[i] = PHY_POLL;
 175
 176         dev = bus->priv;
 177         dev->smireg = of_iomap(pdev->dev.of_node, 0);
 178         if (!dev->smireg) {
 179                 dev_err(&pdev->dev, "No SMI register address given in DT\n");
 180                 kfree(bus->irq);
 181                 mdiobus_free(bus);
 182                 return -ENODEV;
 183         }
 184
 185         mutex_init(&dev->lock);
 186
 187         ret = of_mdiobus_register(bus, np);
 188         if (ret < 0) {
 189                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 190                 iounmap(dev->smireg);
 191                 kfree(bus->irq);
 192                 mdiobus_free(bus);
 193                 return ret;
 194         }
 195
 196         platform_set_drvdata(pdev, bus);
 197
 198         return 0;
 199 }
 200
 201 static int __devexit orion_mdio_remove(struct platform_device *pdev)
 202 {
 203         struct mii_bus *bus = platform_get_drvdata(pdev);
 204         mdiobus_unregister(bus);
 205         kfree(bus->irq);
 206         mdiobus_free(bus);
 207         return 0;
 208 }
 209
 210 static const struct of_device_id orion_mdio_match[] = {
 211         { .compatible = "marvell,orion-mdio" },
 212         { }
 213 };
 214 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 215
 216 static struct platform_driver orion_mdio_driver = {
 217         .probe = orion_mdio_probe,
 218         .remove = __devexit_p(orion_mdio_remove),
 219         .driver = {
 220                 .name = "orion-mdio",
 221                 .of_match_table = orion_mdio_match,
 222         },
 223 };
 224
 225 module_platform_driver(orion_mdio_driver);
 226
 227 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 228 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 229 MODULE_LICENSE("GPL");