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