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/of_mdio.h>
  32 #include <linux/sched.h>
  33 #include <linux/wait.h>
  34
  35 #define MVMDIO_SMI_DATA_SHIFT              0
  36 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
  37 #define MVMDIO_SMI_PHY_REG_SHIFT           21
  38 #define MVMDIO_SMI_READ_OPERATION          BIT(26)
  39 #define MVMDIO_SMI_WRITE_OPERATION         0
  40 #define MVMDIO_SMI_READ_VALID              BIT(27)
  41 #define MVMDIO_SMI_BUSY                    BIT(28)
  42 #define MVMDIO_ERR_INT_CAUSE               0x007C
  43 #define  MVMDIO_ERR_INT_SMI_DONE           0x00000010
  44 #define MVMDIO_ERR_INT_MASK                0x0080
  45
  46 struct orion_mdio_dev {
  47         struct mutex lock;
  48         void __iomem *regs;
  49         /*
  50          * If we have access to the error interrupt pin (which is
  51          * somewhat misnamed as it not only reflects internal errors
  52          * but also reflects SMI completion), use that to wait for
  53          * SMI access completion instead of polling the SMI busy bit.
  54          */
  55         int err_interrupt;
  56         wait_queue_head_t smi_busy_wait;
  57 };
  58
  59 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
  60 {
  61         return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
  62 }
  63
  64 /* Wait for the SMI unit to be ready for another operation
  65  */
  66 static int orion_mdio_wait_ready(struct mii_bus *bus)
  67 {
  68         struct orion_mdio_dev *dev = bus->priv;
  69         int count;
  70
  71         if (dev->err_interrupt <= 0) {
  72                 count = 0;
  73                 while (1) {
  74                         if (orion_mdio_smi_is_done(dev))
  75                                 break;
  76
  77                         if (count > 100) {
  78                                 dev_err(bus->parent,
  79                                         "Timeout: SMI busy for too long\n");
  80                                 return -ETIMEDOUT;
  81                         }
  82
  83                         udelay(10);
  84                         count++;
  85                 }
  86         } else {
  87                 if (!orion_mdio_smi_is_done(dev)) {
  88                         wait_event_timeout(dev->smi_busy_wait,
  89                                 orion_mdio_smi_is_done(dev),
  90                                 msecs_to_jiffies(100));
  91                         if (!orion_mdio_smi_is_done(dev))
  92                                 return -ETIMEDOUT;
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 100                            int regnum)
 101 {
 102         struct orion_mdio_dev *dev = bus->priv;
 103         int count;
 104         u32 val;
 105         int ret;
 106
 107         mutex_lock(&dev->lock);
 108
 109         ret = orion_mdio_wait_ready(bus);
 110         if (ret < 0) {
 111                 mutex_unlock(&dev->lock);
 112                 return ret;
 113         }
 114
 115         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 116                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 117                 MVMDIO_SMI_READ_OPERATION),
 118                dev->regs);
 119
 120         /* Wait for the value to become available */
 121         count = 0;
 122         while (1) {
 123                 val = readl(dev->regs);
 124                 if (val & MVMDIO_SMI_READ_VALID)
 125                         break;
 126
 127                 if (count > 100) {
 128                         dev_err(bus->parent, "Timeout when reading PHY\n");
 129                         mutex_unlock(&dev->lock);
 130                         return -ETIMEDOUT;
 131                 }
 132
 133                 udelay(10);
 134                 count++;
 135         }
 136
 137         mutex_unlock(&dev->lock);
 138
 139         return val & 0xFFFF;
 140 }
 141
 142 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 143                             int regnum, u16 value)
 144 {
 145         struct orion_mdio_dev *dev = bus->priv;
 146         int ret;
 147
 148         mutex_lock(&dev->lock);
 149
 150         ret = orion_mdio_wait_ready(bus);
 151         if (ret < 0) {
 152                 mutex_unlock(&dev->lock);
 153                 return ret;
 154         }
 155
 156         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 157                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 158                 MVMDIO_SMI_WRITE_OPERATION            |
 159                 (value << MVMDIO_SMI_DATA_SHIFT)),
 160                dev->regs);
 161
 162         mutex_unlock(&dev->lock);
 163
 164         return 0;
 165 }
 166
 167 static int orion_mdio_reset(struct mii_bus *bus)
 168 {
 169         return 0;
 170 }
 171
 172 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 173 {
 174         struct orion_mdio_dev *dev = dev_id;
 175
 176         if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 177                         MVMDIO_ERR_INT_SMI_DONE) {
 178                 writel(~MVMDIO_ERR_INT_SMI_DONE,
 179                                 dev->regs + MVMDIO_ERR_INT_CAUSE);
 180                 wake_up(&dev->smi_busy_wait);
 181                 return IRQ_HANDLED;
 182         }
 183
 184         return IRQ_NONE;
 185 }
 186
 187 static int orion_mdio_probe(struct platform_device *pdev)
 188 {
 189         struct resource *r;
 190         struct mii_bus *bus;
 191         struct orion_mdio_dev *dev;
 192         int i, ret;
 193
 194         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 195         if (!r) {
 196                 dev_err(&pdev->dev, "No SMI register address given\n");
 197                 return -ENODEV;
 198         }
 199
 200         bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
 201         if (!bus) {
 202                 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
 203                 return -ENOMEM;
 204         }
 205
 206         bus->name = "orion_mdio_bus";
 207         bus->read = orion_mdio_read;
 208         bus->write = orion_mdio_write;
 209         bus->reset = orion_mdio_reset;
 210         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 211                  dev_name(&pdev->dev));
 212         bus->parent = &pdev->dev;
 213
 214         bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
 215         if (!bus->irq) {
 216                 mdiobus_free(bus);
 217                 return -ENOMEM;
 218         }
 219
 220         for (i = 0; i < PHY_MAX_ADDR; i++)
 221                 bus->irq[i] = PHY_POLL;
 222
 223         dev = bus->priv;
 224         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 225         if (!dev->regs) {
 226                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
 227                 ret = -ENODEV;
 228                 goto out_mdio;
 229         }
 230
 231         init_waitqueue_head(&dev->smi_busy_wait);
 232
 233         dev->err_interrupt = platform_get_irq(pdev, 0);
 234         if (dev->err_interrupt != -ENXIO) {
 235                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 236                                         orion_mdio_err_irq,
 237                                         IRQF_SHARED, pdev->name, dev);
 238                 if (ret)
 239                         goto out_mdio;
 240
 241                 writel(MVMDIO_ERR_INT_SMI_DONE,
 242                         dev->regs + MVMDIO_ERR_INT_MASK);
 243         }
 244
 245         mutex_init(&dev->lock);
 246
 247         if (pdev->dev.of_node)
 248                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
 249         else
 250                 ret = mdiobus_register(bus);
 251         if (ret < 0) {
 252                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 253                 goto out_mdio;
 254         }
 255
 256         platform_set_drvdata(pdev, bus);
 257
 258         return 0;
 259
 260 out_mdio:
 261         kfree(bus->irq);
 262         mdiobus_free(bus);
 263         return ret;
 264 }
 265
 266 static int orion_mdio_remove(struct platform_device *pdev)
 267 {
 268         struct mii_bus *bus = platform_get_drvdata(pdev);
 269         struct orion_mdio_dev *dev = bus->priv;
 270
 271         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 272         mdiobus_unregister(bus);
 273         kfree(bus->irq);
 274         mdiobus_free(bus);
 275         return 0;
 276 }
 277
 278 static const struct of_device_id orion_mdio_match[] = {
 279         { .compatible = "marvell,orion-mdio" },
 280         { }
 281 };
 282 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 283
 284 static struct platform_driver orion_mdio_driver = {
 285         .probe = orion_mdio_probe,
 286         .remove = orion_mdio_remove,
 287         .driver = {
 288                 .name = "orion-mdio",
 289                 .of_match_table = orion_mdio_match,
 290         },
 291 };
 292
 293 module_platform_driver(orion_mdio_driver);
 294
 295 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 296 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 297 MODULE_LICENSE("GPL");
 298 MODULE_ALIAS("platform:orion-mdio");