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/clk.h>
  21 #include <linux/delay.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/io.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/of_mdio.h>
  27 #include <linux/phy.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/sched.h>
  30 #include <linux/wait.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 #define MVMDIO_ERR_INT_CAUSE            0x007C
  40 #define  MVMDIO_ERR_INT_SMI_DONE        0x00000010
  41 #define MVMDIO_ERR_INT_MASK             0x0080
  42
  43 /*
  44  * SMI Timeout measurements:
  45  * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
  46  * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
  47  */
  48 #define MVMDIO_SMI_TIMEOUT              1000 /* 1000us = 1ms */
  49 #define MVMDIO_SMI_POLL_INTERVAL_MIN    45
  50 #define MVMDIO_SMI_POLL_INTERVAL_MAX    55
  51
  52 struct orion_mdio_dev {
  53         void __iomem *regs;
  54         struct clk *clk[3];
  55         /*
  56          * If we have access to the error interrupt pin (which is
  57          * somewhat misnamed as it not only reflects internal errors
  58          * but also reflects SMI completion), use that to wait for
  59          * SMI access completion instead of polling the SMI busy bit.
  60          */
  61         int err_interrupt;
  62         wait_queue_head_t smi_busy_wait;
  63 };
  64
  65 struct orion_mdio_ops {
  66         int (*is_done)(struct orion_mdio_dev *);
  67         unsigned int poll_interval_min;
  68         unsigned int poll_interval_max;
  69 };
  70
  71 /* Wait for the SMI unit to be ready for another operation
  72  */
  73 static int orion_mdio_wait_ready(const struct orion_mdio_ops *ops,
  74                                  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 (ops->is_done(dev))
  83                         return 0;
  84                 else if (timedout)
  85                         break;
  86
  87                 if (dev->err_interrupt <= 0) {
  88                         usleep_range(ops->poll_interval_min,
  89                                      ops->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                                            ops->is_done(dev), timeout);
 102
 103                         ++timedout;
 104                 }
 105         }
 106
 107         dev_err(bus->parent, "Timeout: SMI busy for too long\n");
 108         return  -ETIMEDOUT;
 109 }
 110
 111 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
 112 {
 113         return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
 114 }
 115
 116 static const struct orion_mdio_ops orion_mdio_smi_ops = {
 117         .is_done = orion_mdio_smi_is_done,
 118         .poll_interval_min = MVMDIO_SMI_POLL_INTERVAL_MIN,
 119         .poll_interval_max = MVMDIO_SMI_POLL_INTERVAL_MAX,
 120 };
 121
 122 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 123                            int regnum)
 124 {
 125         struct orion_mdio_dev *dev = bus->priv;
 126         u32 val;
 127         int ret;
 128
 129         if (regnum & MII_ADDR_C45)
 130                 return -EOPNOTSUPP;
 131
 132         ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
 133         if (ret < 0)
 134                 goto out;
 135
 136         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 137                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 138                 MVMDIO_SMI_READ_OPERATION),
 139                dev->regs);
 140
 141         ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
 142         if (ret < 0)
 143                 goto out;
 144
 145         val = readl(dev->regs);
 146         if (!(val & MVMDIO_SMI_READ_VALID)) {
 147                 dev_err(bus->parent, "SMI bus read not valid\n");
 148                 ret = -ENODEV;
 149                 goto out;
 150         }
 151
 152         ret = val & GENMASK(15, 0);
 153 out:
 154         return ret;
 155 }
 156
 157 static int orion_mdio_write(struct mii_bus *bus, int mii_id,
 158                             int regnum, u16 value)
 159 {
 160         struct orion_mdio_dev *dev = bus->priv;
 161         int ret;
 162
 163         if (regnum & MII_ADDR_C45)
 164                 return -EOPNOTSUPP;
 165
 166         ret = orion_mdio_wait_ready(&orion_mdio_smi_ops, bus);
 167         if (ret < 0)
 168                 goto out;
 169
 170         writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 171                 (regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 172                 MVMDIO_SMI_WRITE_OPERATION            |
 173                 (value << MVMDIO_SMI_DATA_SHIFT)),
 174                dev->regs);
 175
 176 out:
 177         return ret;
 178 }
 179
 180 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 181 {
 182         struct orion_mdio_dev *dev = dev_id;
 183
 184         if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 185                         MVMDIO_ERR_INT_SMI_DONE) {
 186                 writel(~MVMDIO_ERR_INT_SMI_DONE,
 187                                 dev->regs + MVMDIO_ERR_INT_CAUSE);
 188                 wake_up(&dev->smi_busy_wait);
 189                 return IRQ_HANDLED;
 190         }
 191
 192         return IRQ_NONE;
 193 }
 194
 195 static int orion_mdio_probe(struct platform_device *pdev)
 196 {
 197         struct resource *r;
 198         struct mii_bus *bus;
 199         struct orion_mdio_dev *dev;
 200         int i, ret;
 201
 202         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 203         if (!r) {
 204                 dev_err(&pdev->dev, "No SMI register address given\n");
 205                 return -ENODEV;
 206         }
 207
 208         bus = devm_mdiobus_alloc_size(&pdev->dev,
 209                                       sizeof(struct orion_mdio_dev));
 210         if (!bus)
 211                 return -ENOMEM;
 212
 213         bus->name = "orion_mdio_bus";
 214         bus->read = orion_mdio_read;
 215         bus->write = orion_mdio_write;
 216         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 217                  dev_name(&pdev->dev));
 218         bus->parent = &pdev->dev;
 219
 220         dev = bus->priv;
 221         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 222         if (!dev->regs) {
 223                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
 224                 return -ENODEV;
 225         }
 226
 227         init_waitqueue_head(&dev->smi_busy_wait);
 228
 229         for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
 230                 dev->clk[i] = of_clk_get(pdev->dev.of_node, i);
 231                 if (IS_ERR(dev->clk[i]))
 232                         break;
 233                 clk_prepare_enable(dev->clk[i]);
 234         }
 235
 236         dev->err_interrupt = platform_get_irq(pdev, 0);
 237         if (dev->err_interrupt > 0 &&
 238             resource_size(r) < MVMDIO_ERR_INT_MASK + 4) {
 239                 dev_err(&pdev->dev,
 240                         "disabling interrupt, resource size is too small\n");
 241                 dev->err_interrupt = 0;
 242         }
 243         if (dev->err_interrupt > 0) {
 244                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 245                                         orion_mdio_err_irq,
 246                                         IRQF_SHARED, pdev->name, dev);
 247                 if (ret)
 248                         goto out_mdio;
 249
 250                 writel(MVMDIO_ERR_INT_SMI_DONE,
 251                         dev->regs + MVMDIO_ERR_INT_MASK);
 252
 253         } else if (dev->err_interrupt == -EPROBE_DEFER) {
 254                 return -EPROBE_DEFER;
 255         }
 256
 257         if (pdev->dev.of_node)
 258                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
 259         else
 260                 ret = mdiobus_register(bus);
 261         if (ret < 0) {
 262                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 263                 goto out_mdio;
 264         }
 265
 266         platform_set_drvdata(pdev, bus);
 267
 268         return 0;
 269
 270 out_mdio:
 271         if (dev->err_interrupt > 0)
 272                 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 273
 274         for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
 275                 if (IS_ERR(dev->clk[i]))
 276                         break;
 277                 clk_disable_unprepare(dev->clk[i]);
 278                 clk_put(dev->clk[i]);
 279         }
 280
 281         return ret;
 282 }
 283
 284 static int orion_mdio_remove(struct platform_device *pdev)
 285 {
 286         struct mii_bus *bus = platform_get_drvdata(pdev);
 287         struct orion_mdio_dev *dev = bus->priv;
 288         int i;
 289
 290         if (dev->err_interrupt > 0)
 291                 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 292         mdiobus_unregister(bus);
 293
 294         for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
 295                 if (IS_ERR(dev->clk[i]))
 296                         break;
 297                 clk_disable_unprepare(dev->clk[i]);
 298                 clk_put(dev->clk[i]);
 299         }
 300
 301         return 0;
 302 }
 303
 304 static const struct of_device_id orion_mdio_match[] = {
 305         { .compatible = "marvell,orion-mdio" },
 306         { }
 307 };
 308 MODULE_DEVICE_TABLE(of, orion_mdio_match);
 309
 310 static struct platform_driver orion_mdio_driver = {
 311         .probe = orion_mdio_probe,
 312         .remove = orion_mdio_remove,
 313         .driver = {
 314                 .name = "orion-mdio",
 315                 .of_match_table = orion_mdio_match,
 316         },
 317 };
 318
 319 module_platform_driver(orion_mdio_driver);
 320
 321 MODULE_DESCRIPTION("Marvell MDIO interface driver");
 322 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
 323 MODULE_LICENSE("GPL");
 324 MODULE_ALIAS("platform:orion-mdio");