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/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/mutex.h>
  24 #include <linux/phy.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/delay.h>
  28 #include <linux/io.h>
  29 #include <linux/clk.h>
  30 #include <linux/of_mdio.h>
  31 #include <linux/sched.h>
  32 #include <linux/wait.h>
  33
  34 #define MVMDIO_SMI_DATA_SHIFT              0
  35 #define MVMDIO_SMI_PHY_ADDR_SHIFT          16
  36 #define MVMDIO_SMI_PHY_REG_SHIFT           21
  37 #define MVMDIO_SMI_READ_OPERATION          BIT(26)
  38 #define MVMDIO_SMI_WRITE_OPERATION         0
  39 #define MVMDIO_SMI_READ_VALID              BIT(27)
  40 #define MVMDIO_SMI_BUSY                    BIT(28)
  41 #define MVMDIO_ERR_INT_CAUSE               0x007C
  42 #define  MVMDIO_ERR_INT_SMI_DONE           0x00000010
  43 #define MVMDIO_ERR_INT_MASK                0x0080
  44
  45 /*
  46  * SMI Timeout measurements:
  47  * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
  48  * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
  49  */
  50 #define MVMDIO_SMI_TIMEOUT                 1000 /* 1000us = 1ms */
  51 #define MVMDIO_SMI_POLL_INTERVAL_MIN       45
  52 #define MVMDIO_SMI_POLL_INTERVAL_MAX       55
  53
  54 struct orion_mdio_dev {
  55         struct mutex lock;
  56         void __iomem *regs;
  57         struct clk *clk;
  58         /*
  59          * If we have access to the error interrupt pin (which is
  60          * somewhat misnamed as it not only reflects internal errors
  61          * but also reflects SMI completion), use that to wait for
  62          * SMI access completion instead of polling the SMI busy bit.
  63          */
  64         int err_interrupt;
  65         wait_queue_head_t smi_busy_wait;
  66 };
  67
  68 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
  69 {
  70         return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
  71 }
  72
  73 /* Wait for the SMI unit to be ready for another operation
  74  */
  75 static int orion_mdio_wait_ready(struct mii_bus *bus)
  76 {
  77         struct orion_mdio_dev *dev = bus->priv;
  78         unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
  79         unsigned long end = jiffies + timeout;
  80         int timedout = 0;
  81
  82         while (1) {
  83                 if (orion_mdio_smi_is_done(dev))
  84                         return 0;
  85                 else if (timedout)
  86                         break;
  87
  88                 if (dev->err_interrupt <= 0) {
  89                         usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
  90                                      MVMDIO_SMI_POLL_INTERVAL_MAX);
  91
  92                         if (time_is_before_jiffies(end))
  93                                 ++timedout;
  94                 } else {
  95                         /* wait_event_timeout does not guarantee a delay of at
  96                          * least one whole jiffie, so timeout must be no less
  97                          * than two.
  98                          */
  99                         if (timeout < 2)
 100                                 timeout = 2;
 101                         wait_event_timeout(dev->smi_busy_wait,
 102                                            orion_mdio_smi_is_done(dev),
 103                                            timeout);
 104
 105                         ++timedout;
 106                 }
 107         }
 108
 109         dev_err(bus->parent, "Timeout: SMI busy for too long\n");
 110         return  -ETIMEDOUT;
 111 }
 112
 113 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 114                            int regnum)
 115 {
 116         struct orion_mdio_dev *dev = bus->priv;
 117         u32 val;
 118         int ret;
 119
 120         mutex_lock(&dev->lock);
 121
 122         ret = orion_mdio_wait_ready(bus);
 123         if (ret < 0)
 124                 goto out;
 125
 126         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 127                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 128                 MVMDIO_SMI_READ_OPERATION),
 129                dev->regs);
 130
 131         ret = orion_mdio_wait_ready(bus);
 132         if (ret < 0)
 133                 goto out;
 134
 135         val = readl(dev->regs);
 136         if (!(val & MVMDIO_SMI_READ_VALID)) {
 137                 dev_err(bus->parent, "SMI bus read not valid\n");
 138                 ret = -ENODEV;
 139                 goto out;
 140         }
 141
 142         ret = val & 0xFFFF;
 143 out:
 144         mutex_unlock(&dev->lock);
 145         return ret;
 146 }
 147
 148 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 149                             int regnum, u16 value)
 150 {
 151         struct orion_mdio_dev *dev = bus->priv;
 152         int ret;
 153
 154         mutex_lock(&dev->lock);
 155
 156         ret = orion_mdio_wait_ready(bus);
 157         if (ret < 0)
 158                 goto out;
 159
 160         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 161                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 162                 MVMDIO_SMI_WRITE_OPERATION            |
 163                 (value << MVMDIO_SMI_DATA_SHIFT)),
 164                dev->regs);
 165
 166 out:
 167         mutex_unlock(&dev->lock);
 168         return ret;
 169 }
 170
 171 static int orion_mdio_reset(struct mii_bus *bus)
 172 {
 173         return 0;
 174 }
 175
 176 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 177 {
 178         struct orion_mdio_dev *dev = dev_id;
 179
 180         if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 181                         MVMDIO_ERR_INT_SMI_DONE) {
 182                 writel(~MVMDIO_ERR_INT_SMI_DONE,
 183                                 dev->regs + MVMDIO_ERR_INT_CAUSE);
 184                 wake_up(&dev->smi_busy_wait);
 185                 return IRQ_HANDLED;
 186         }
 187
 188         return IRQ_NONE;
 189 }
 190
 191 static int orion_mdio_probe(struct platform_device *pdev)
 192 {
 193         struct resource *r;
 194         struct mii_bus *bus;
 195         struct orion_mdio_dev *dev;
 196         int i, ret;
 197
 198         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 199         if (!r) {
 200                 dev_err(&pdev->dev, "No SMI register address given\n");
 201                 return -ENODEV;
 202         }
 203
 204         bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
 205         if (!bus) {
 206                 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
 207                 return -ENOMEM;
 208         }
 209
 210         bus->name = "orion_mdio_bus";
 211         bus->read = orion_mdio_read;
 212         bus->write = orion_mdio_write;
 213         bus->reset = orion_mdio_reset;
 214         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 215                  dev_name(&pdev->dev));
 216         bus->parent = &pdev->dev;
 217
 218         bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
 219         if (!bus->irq) {
 220                 mdiobus_free(bus);
 221                 return -ENOMEM;
 222         }
 223
 224         for (i = 0; i < PHY_MAX_ADDR; i++)
 225                 bus->irq[i] = PHY_POLL;
 226
 227         dev = bus->priv;
 228         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 229         if (!dev->regs) {
 230                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
 231                 ret = -ENODEV;
 232                 goto out_mdio;
 233         }
 234
 235         init_waitqueue_head(&dev->smi_busy_wait);
 236
 237         dev->clk = devm_clk_get(&pdev->dev, NULL);
 238         if (!IS_ERR(dev->clk))
 239                 clk_prepare_enable(dev->clk);
 240
 241         dev->err_interrupt = platform_get_irq(pdev, 0);
 242         if (dev->err_interrupt != -ENXIO) {
 243                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 244                                         orion_mdio_err_irq,
 245                                         IRQF_SHARED, pdev->name, dev);
 246                 if (ret)
 247                         goto out_mdio;
 248
 249                 writel(MVMDIO_ERR_INT_SMI_DONE,
 250                         dev->regs + MVMDIO_ERR_INT_MASK);
 251         }
 252
 253         mutex_init(&dev->lock);
 254
 255         if (pdev->dev.of_node)
 256                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
 257         else
 258                 ret = mdiobus_register(bus);
 259         if (ret < 0) {
 260                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 261                 goto out_mdio;
 262         }
 263
 264         platform_set_drvdata(pdev, bus);
 265
 266         return 0;
 267
 268 out_mdio:
 269         if (!IS_ERR(dev->clk))
 270                 clk_disable_unprepare(dev->clk);
 271         kfree(bus->irq);
 272         mdiobus_free(bus);
 273         return ret;
 274 }
 275
 276 static int orion_mdio_remove(struct platform_device *pdev)
 277 {
 278         struct mii_bus *bus = platform_get_drvdata(pdev);
 279         struct orion_mdio_dev *dev = bus->priv;
 280
 281         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 282         mdiobus_unregister(bus);
 283         kfree(bus->irq);
 284         mdiobus_free(bus);
 285         if (!IS_ERR(dev->clk))
 286                 clk_disable_unprepare(dev->clk);
 287
 288         return 0;
 289 }
 290
 291 static const struct of_device_id orion_mdio_match[] = {
 292         { .compatible = "marvell,orion-mdio" },
 293         { }
 294 };
 295 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 296
 297 static struct platform_driver orion_mdio_driver = {
 298         .probe = orion_mdio_probe,
 299         .remove = orion_mdio_remove,
 300         .driver = {
 301                 .name = "orion-mdio",
 302                 .of_match_table = orion_mdio_match,
 303         },
 304 };
 305
 306 module_platform_driver(orion_mdio_driver);
 307
 308 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 309 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 310 MODULE_LICENSE("GPL");
 311 MODULE_ALIAS("platform:orion-mdio");