drivers/net/phy/mdio-bcm-unimac.c

   1 /*
   2  * Broadcom UniMAC MDIO bus controller driver
   3  *
   4  * Copyright (C) 2014, Broadcom Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/phy.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/sched.h>
  16 #include <linux/module.h>
  17 #include <linux/io.h>
  18 #include <linux/delay.h>
  19
  20 #include <linux/of.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/of_mdio.h>
  23
  24 #define MDIO_CMD                0x00
  25 #define  MDIO_START_BUSY        (1 << 29)
  26 #define  MDIO_READ_FAIL         (1 << 28)
  27 #define  MDIO_RD                (2 << 26)
  28 #define  MDIO_WR                (1 << 26)
  29 #define  MDIO_PMD_SHIFT         21
  30 #define  MDIO_PMD_MASK          0x1F
  31 #define  MDIO_REG_SHIFT         16
  32 #define  MDIO_REG_MASK          0x1F
  33
  34 #define MDIO_CFG                0x04
  35 #define  MDIO_C22               (1 << 0)
  36 #define  MDIO_C45               0
  37 #define  MDIO_CLK_DIV_SHIFT     4
  38 #define  MDIO_CLK_DIV_MASK      0x3F
  39 #define  MDIO_SUPP_PREAMBLE     (1 << 12)
  40
  41 struct unimac_mdio_priv {
  42         struct mii_bus          *mii_bus;
  43         void __iomem            *base;
  44 };
  45
  46 static inline void unimac_mdio_start(struct unimac_mdio_priv *priv)
  47 {
  48         u32 reg;
  49
  50         reg = __raw_readl(priv->base + MDIO_CMD);
  51         reg |= MDIO_START_BUSY;
  52         __raw_writel(reg, priv->base + MDIO_CMD);
  53 }
  54
  55 static inline unsigned int unimac_mdio_busy(struct unimac_mdio_priv *priv)
  56 {
  57         return __raw_readl(priv->base + MDIO_CMD) & MDIO_START_BUSY;
  58 }
  59
  60 static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
  61 {
  62         struct unimac_mdio_priv *priv = bus->priv;
  63         unsigned int timeout = 1000;
  64         u32 cmd;
  65
  66         /* Prepare the read operation */
  67         cmd = MDIO_RD | (phy_id << MDIO_PMD_SHIFT) | (reg << MDIO_REG_SHIFT);
  68         __raw_writel(cmd, priv->base + MDIO_CMD);
  69
  70         /* Start MDIO transaction */
  71         unimac_mdio_start(priv);
  72
  73         do {
  74                 if (!unimac_mdio_busy(priv))
  75                         break;
  76
  77                 usleep_range(1000, 2000);
  78         } while (timeout--);
  79
  80         if (!timeout)
  81                 return -ETIMEDOUT;
  82
  83         cmd = __raw_readl(priv->base + MDIO_CMD);
  84
  85         /* Some broken devices are known not to release the line during
  86          * turn-around, e.g: Broadcom BCM53125 external switches, so check for
  87          * that condition here and ignore the MDIO controller read failure
  88          * indication.
  89          */
  90         if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (cmd & MDIO_READ_FAIL))
  91                 return -EIO;
  92
  93         return cmd & 0xffff;
  94 }
  95
  96 static int unimac_mdio_write(struct mii_bus *bus, int phy_id,
  97                              int reg, u16 val)
  98 {
  99         struct unimac_mdio_priv *priv = bus->priv;
 100         unsigned int timeout = 1000;
 101         u32 cmd;
 102
 103         /* Prepare the write operation */
 104         cmd = MDIO_WR | (phy_id << MDIO_PMD_SHIFT) |
 105                 (reg << MDIO_REG_SHIFT) | (0xffff & val);
 106         __raw_writel(cmd, priv->base + MDIO_CMD);
 107
 108         unimac_mdio_start(priv);
 109
 110         do {
 111                 if (!unimac_mdio_busy(priv))
 112                         break;
 113
 114                 usleep_range(1000, 2000);
 115         } while (timeout--);
 116
 117         if (!timeout)
 118                 return -ETIMEDOUT;
 119
 120         return 0;
 121 }
 122
 123 /* Workaround for integrated BCM7xxx Gigabit PHYs which have a problem with
 124  * their internal MDIO management controller making them fail to successfully
 125  * be read from or written to for the first transaction.  We insert a dummy
 126  * BMSR read here to make sure that phy_get_device() and get_phy_id() can
 127  * correctly read the PHY MII_PHYSID1/2 registers and successfully register a
 128  * PHY device for this peripheral.
 129  *
 130  * Once the PHY driver is registered, we can workaround subsequent reads from
 131  * there (e.g: during system-wide power management).
 132  *
 133  * bus->reset is invoked before mdiobus_scan during mdiobus_register and is
 134  * therefore the right location to stick that workaround. Since we do not want
 135  * to read from non-existing PHYs, we either use bus->phy_mask or do a manual
 136  * Device Tree scan to limit the search area.
 137  */
 138 static int unimac_mdio_reset(struct mii_bus *bus)
 139 {
 140         struct device_node *np = bus->dev.of_node;
 141         struct device_node *child;
 142         u32 read_mask = 0;
 143         int addr;
 144
 145         if (!np) {
 146                 read_mask = ~bus->phy_mask;
 147         } else {
 148                 for_each_available_child_of_node(np, child) {
 149                         addr = of_mdio_parse_addr(&bus->dev, child);
 150                         if (addr < 0)
 151                                 continue;
 152
 153                         read_mask |= 1 << addr;
 154                 }
 155         }
 156
 157         for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
 158                 if (read_mask & 1 << addr)
 159                         mdiobus_read(bus, addr, MII_BMSR);
 160         }
 161
 162         return 0;
 163 }
 164
 165 static int unimac_mdio_probe(struct platform_device *pdev)
 166 {
 167         struct unimac_mdio_priv *priv;
 168         struct device_node *np;
 169         struct mii_bus *bus;
 170         struct resource *r;
 171         int ret;
 172
 173         np = pdev->dev.of_node;
 174
 175         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 176         if (!priv)
 177                 return -ENOMEM;
 178
 179         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 180
 181         /* Just ioremap, as this MDIO block is usually integrated into an
 182          * Ethernet MAC controller register range
 183          */
 184         priv->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 185         if (!priv->base) {
 186                 dev_err(&pdev->dev, "failed to remap register\n");
 187                 return -ENOMEM;
 188         }
 189
 190         priv->mii_bus = mdiobus_alloc();
 191         if (!priv->mii_bus)
 192                 return -ENOMEM;
 193
 194         bus = priv->mii_bus;
 195         bus->priv = priv;
 196         bus->name = "unimac MII bus";
 197         bus->parent = &pdev->dev;
 198         bus->read = unimac_mdio_read;
 199         bus->write = unimac_mdio_write;
 200         bus->reset = unimac_mdio_reset;
 201         snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
 202
 203         ret = of_mdiobus_register(bus, np);
 204         if (ret) {
 205                 dev_err(&pdev->dev, "MDIO bus registration failed\n");
 206                 goto out_mdio_free;
 207         }
 208
 209         platform_set_drvdata(pdev, priv);
 210
 211         dev_info(&pdev->dev, "Broadcom UniMAC MDIO bus at 0x%p\n", priv->base);
 212
 213         return 0;
 214
 215 out_mdio_free:
 216         mdiobus_free(bus);
 217         return ret;
 218 }
 219
 220 static int unimac_mdio_remove(struct platform_device *pdev)
 221 {
 222         struct unimac_mdio_priv *priv = platform_get_drvdata(pdev);
 223
 224         mdiobus_unregister(priv->mii_bus);
 225         mdiobus_free(priv->mii_bus);
 226
 227         return 0;
 228 }
 229
 230 static const struct of_device_id unimac_mdio_ids[] = {
 231         { .compatible = "brcm,genet-mdio-v4", },
 232         { .compatible = "brcm,genet-mdio-v3", },
 233         { .compatible = "brcm,genet-mdio-v2", },
 234         { .compatible = "brcm,genet-mdio-v1", },
 235         { .compatible = "brcm,unimac-mdio", },
 236         { /* sentinel */ },
 237 };
 238 MODULE_DEVICE_TABLE(of, unimac_mdio_ids);
 239
 240 static struct platform_driver unimac_mdio_driver = {
 241         .driver = {
 242                 .name = "unimac-mdio",
 243                 .of_match_table = unimac_mdio_ids,
 244         },
 245         .probe  = unimac_mdio_probe,
 246         .remove = unimac_mdio_remove,
 247 };
 248 module_platform_driver(unimac_mdio_driver);
 249
 250 MODULE_AUTHOR("Broadcom Corporation");
 251 MODULE_DESCRIPTION("Broadcom UniMAC MDIO bus controller");
 252 MODULE_LICENSE("GPL");
 253 MODULE_ALIAS("platform:unimac-mdio");