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
   8  * the MDIO bus). This driver is currently used by the mvneta and
   9  * mv643xx_eth drivers.
  10  *
  11  * Copyright (C) 2012 Marvell
  12  *
  13  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  14  *
  15  * This file is licensed under the terms of the GNU General Public
  16  * License version 2. This program is licensed "as is" without any
  17  * warranty of any kind, whether express or implied.
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/mutex.h>
  23 #include <linux/phy.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/delay.h>
  27 #include <linux/io.h>
  28 #include <linux/clk.h>
  29 #include <linux/of_mdio.h>
  30 #include <linux/sched.h>
  31 #include <linux/wait.h>
  32
  33 #define MVMDIO_SMI_DATA_SHIFT              0
  34 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
  35 #define MVMDIO_SMI_PHY_REG_SHIFT           21
  36 #define MVMDIO_SMI_READ_OPERATION          BIT(26)
  37 #define MVMDIO_SMI_WRITE_OPERATION         0
  38 #define MVMDIO_SMI_READ_VALID              BIT(27)
  39 #define MVMDIO_SMI_BUSY                    BIT(28)
  40 #define MVMDIO_ERR_INT_CAUSE               0x007C
  41 #define  MVMDIO_ERR_INT_SMI_DONE           0x00000010
  42 #define MVMDIO_ERR_INT_MASK                0x0080
  43
  44 /*
  45  * SMI Timeout measurements:
  46  * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
  47  * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
  48  */
  49 #define MVMDIO_SMI_TIMEOUT                 1000 /* 1000us = 1ms */
  50 #define MVMDIO_SMI_POLL_INTERVAL_MIN       45
  51 #define MVMDIO_SMI_POLL_INTERVAL_MAX       55
  52
  53 struct orion_mdio_dev {
  54         struct mutex lock;
  55         void __iomem *regs;
  56         struct clk *clk;
  57         /*
  58          * If we have access to the error interrupt pin (which is
  59          * somewhat misnamed as it not only reflects internal errors
  60          * but also reflects SMI completion), use that to wait for
  61          * SMI access completion instead of polling the SMI busy bit.
  62          */
  63         int err_interrupt;
  64         wait_queue_head_t smi_busy_wait;
  65 };
  66
  67 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
  68 {
  69         return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
  70 }
  71
  72 /* Wait for the SMI unit to be ready for another operation
  73  */
  74 static int orion_mdio_wait_ready(struct mii_bus *bus)
  75 {
  76         struct orion_mdio_dev *dev = bus->priv;
  77         unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
  78         unsigned long end = jiffies + timeout;
  79         int timedout = 0;
  80
  81         while (1) {
  82                 if (orion_mdio_smi_is_done(dev))
  83                         return 0;
  84                 else if (timedout)
  85                         break;
  86
  87                 if (dev->err_interrupt <= 0) {
  88                         usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
  89                                      MVMDIO_SMI_POLL_INTERVAL_MAX);
  90
  91                         if (time_is_before_jiffies(end))
  92                                 ++timedout;
  93                 } else {
  94                         /* wait_event_timeout does not guarantee a delay of at
  95                          * least one whole jiffie, so timeout must be no less
  96                          * than two.
  97                          */
  98                         if (timeout < 2)
  99                                 timeout = 2;
 100                         wait_event_timeout(dev->smi_busy_wait,
 101                                            orion_mdio_smi_is_done(dev),
 102                                            timeout);
 103
 104                         ++timedout;
 105                 }
 106         }
 107
 108         dev_err(bus->parent, "Timeout: SMI busy for too long\n");
 109         return  -ETIMEDOUT;
 110 }
 111
 112 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 113                            int regnum)
 114 {
 115         struct orion_mdio_dev *dev = bus->priv;
 116         u32 val;
 117         int ret;
 118
 119         mutex_lock(&dev->lock);
 120
 121         ret = orion_mdio_wait_ready(bus);
 122         if (ret < 0)
 123                 goto out;
 124
 125         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 126                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 127                 MVMDIO_SMI_READ_OPERATION),
 128                dev->regs);
 129
 130         ret = orion_mdio_wait_ready(bus);
 131         if (ret < 0)
 132                 goto out;
 133
 134         val = readl(dev->regs);
 135         if (!(val & MVMDIO_SMI_READ_VALID)) {
 136                 dev_err(bus->parent, "SMI bus read not valid\n");
 137                 ret = -ENODEV;
 138                 goto out;
 139         }
 140
 141         ret = val & 0xFFFF;
 142 out:
 143         mutex_unlock(&dev->lock);
 144         return ret;
 145 }
 146
 147 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 148                             int regnum, u16 value)
 149 {
 150         struct orion_mdio_dev *dev = bus->priv;
 151         int ret;
 152
 153         mutex_lock(&dev->lock);
 154
 155         ret = orion_mdio_wait_ready(bus);
 156         if (ret < 0)
 157                 goto out;
 158
 159         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 160                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 161                 MVMDIO_SMI_WRITE_OPERATION            |
 162                 (value << MVMDIO_SMI_DATA_SHIFT)),
 163                dev->regs);
 164
 165 out:
 166         mutex_unlock(&dev->lock);
 167         return ret;
 168 }
 169
 170 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 171 {
 172         struct orion_mdio_dev *dev = dev_id;
 173
 174         if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 175                         MVMDIO_ERR_INT_SMI_DONE) {
 176                 writel(~MVMDIO_ERR_INT_SMI_DONE,
 177                                 dev->regs + MVMDIO_ERR_INT_CAUSE);
 178                 wake_up(&dev->smi_busy_wait);
 179                 return IRQ_HANDLED;
 180         }
 181
 182         return IRQ_NONE;
 183 }
 184
 185 static int orion_mdio_probe(struct platform_device *pdev)
 186 {
 187         struct resource *r;
 188         struct mii_bus *bus;
 189         struct orion_mdio_dev *dev;
 190         int ret;
 191
 192         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 193         if (!r) {
 194                 dev_err(&pdev->dev, "No SMI register address given\n");
 195                 return -ENODEV;
 196         }
 197
 198         bus = devm_mdiobus_alloc_size(&pdev->dev,
 199                                       sizeof(struct orion_mdio_dev));
 200         if (!bus)
 201                 return -ENOMEM;
 202
 203         bus->name = "orion_mdio_bus";
 204         bus->read = orion_mdio_read;
 205         bus->write = orion_mdio_write;
 206         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 207                  dev_name(&pdev->dev));
 208         bus->parent = &pdev->dev;
 209
 210         dev = bus->priv;
 211         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 212         if (!dev->regs) {
 213                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
 214                 return -ENODEV;
 215         }
 216
 217         init_waitqueue_head(&dev->smi_busy_wait);
 218
 219         dev->clk = devm_clk_get(&pdev->dev, NULL);
 220         if (!IS_ERR(dev->clk))
 221                 clk_prepare_enable(dev->clk);
 222
 223         dev->err_interrupt = platform_get_irq(pdev, 0);
 224         if (dev->err_interrupt > 0) {
 225                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 226                                         orion_mdio_err_irq,
 227                                         IRQF_SHARED, pdev->name, dev);
 228                 if (ret)
 229                         goto out_mdio;
 230
 231                 writel(MVMDIO_ERR_INT_SMI_DONE,
 232                         dev->regs + MVMDIO_ERR_INT_MASK);
 233
 234         } else if (dev->err_interrupt == -EPROBE_DEFER) {
 235                 return -EPROBE_DEFER;
 236         }
 237
 238         mutex_init(&dev->lock);
 239
 240         if (pdev->dev.of_node)
 241                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
 242         else
 243                 ret = mdiobus_register(bus);
 244         if (ret < 0) {
 245                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 246                 goto out_mdio;
 247         }
 248
 249         platform_set_drvdata(pdev, bus);
 250
 251         return 0;
 252
 253 out_mdio:
 254         if (!IS_ERR(dev->clk))
 255                 clk_disable_unprepare(dev->clk);
 256         return ret;
 257 }
 258
 259 static int orion_mdio_remove(struct platform_device *pdev)
 260 {
 261         struct mii_bus *bus = platform_get_drvdata(pdev);
 262         struct orion_mdio_dev *dev = bus->priv;
 263
 264         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 265         mdiobus_unregister(bus);
 266         if (!IS_ERR(dev->clk))
 267                 clk_disable_unprepare(dev->clk);
 268
 269         return 0;
 270 }
 271
 272 static const struct of_device_id orion_mdio_match[] = {
 273         { .compatible = "marvell,orion-mdio" },
 274         { }
 275 };
 276 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 277
 278 static struct platform_driver orion_mdio_driver = {
 279         .probe = orion_mdio_probe,
 280         .remove = orion_mdio_remove,
 281         .driver = {
 282                 .name = "orion-mdio",
 283                 .of_match_table = orion_mdio_match,
 284         },
 285 };
 286
 287 module_platform_driver(orion_mdio_driver);
 288
 289 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 290 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 291 MODULE_LICENSE("GPL");
 292 MODULE_ALIAS("platform:orion-mdio");