drivers/net/ethernet/qualcomm/emac/emac-phy.c

   1 /* Copyright (c) 2013-2016, The Linux Foundation. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 /* Qualcomm Technologies, Inc. EMAC PHY Controller driver.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/of_net.h>
  19 #include <linux/of_mdio.h>
  20 #include <linux/phy.h>
  21 #include <linux/iopoll.h>
  22 #include <linux/acpi.h>
  23 #include "emac.h"
  24 #include "emac-mac.h"
  25 #include "emac-phy.h"
  26 #include "emac-sgmii.h"
  27
  28 /* EMAC base register offsets */
  29 #define EMAC_MDIO_CTRL                                        0x001414
  30 #define EMAC_PHY_STS                                          0x001418
  31 #define EMAC_MDIO_EX_CTRL                                     0x001440
  32
  33 /* EMAC_MDIO_CTRL */
  34 #define MDIO_MODE                                              BIT(30)
  35 #define MDIO_PR                                                BIT(29)
  36 #define MDIO_AP_EN                                             BIT(28)
  37 #define MDIO_BUSY                                              BIT(27)
  38 #define MDIO_CLK_SEL_BMSK                                    0x7000000
  39 #define MDIO_CLK_SEL_SHFT                                           24
  40 #define MDIO_START                                             BIT(23)
  41 #define SUP_PREAMBLE                                           BIT(22)
  42 #define MDIO_RD_NWR                                            BIT(21)
  43 #define MDIO_REG_ADDR_BMSK                                    0x1f0000
  44 #define MDIO_REG_ADDR_SHFT                                          16
  45 #define MDIO_DATA_BMSK                                          0xffff
  46 #define MDIO_DATA_SHFT                                               0
  47
  48 /* EMAC_PHY_STS */
  49 #define PHY_ADDR_BMSK                                         0x1f0000
  50 #define PHY_ADDR_SHFT                                               16
  51
  52 #define MDIO_CLK_25_4                                                0
  53 #define MDIO_CLK_25_28                                               7
  54
  55 #define MDIO_WAIT_TIMES                                           1000
  56
  57 #define EMAC_LINK_SPEED_DEFAULT (\
  58                 EMAC_LINK_SPEED_10_HALF  |\
  59                 EMAC_LINK_SPEED_10_FULL  |\
  60                 EMAC_LINK_SPEED_100_HALF |\
  61                 EMAC_LINK_SPEED_100_FULL |\
  62                 EMAC_LINK_SPEED_1GB_FULL)
  63
  64 /**
  65  * emac_phy_mdio_autopoll_disable() - disable mdio autopoll
  66  * @adpt: the emac adapter
  67  *
  68  * The autopoll feature takes over the MDIO bus.  In order for
  69  * the PHY driver to be able to talk to the PHY over the MDIO
  70  * bus, we need to temporarily disable the autopoll feature.
  71  */
  72 static int emac_phy_mdio_autopoll_disable(struct emac_adapter *adpt)
  73 {
  74         u32 val;
  75
  76         /* disable autopoll */
  77         emac_reg_update32(adpt->base + EMAC_MDIO_CTRL, MDIO_AP_EN, 0);
  78
  79         /* wait for any mdio polling to complete */
  80         if (!readl_poll_timeout(adpt->base + EMAC_MDIO_CTRL, val,
  81                                 !(val & MDIO_BUSY), 100, MDIO_WAIT_TIMES * 100))
  82                 return 0;
  83
  84         /* failed to disable; ensure it is enabled before returning */
  85         emac_reg_update32(adpt->base + EMAC_MDIO_CTRL, 0, MDIO_AP_EN);
  86
  87         return -EBUSY;
  88 }
  89
  90 /**
  91  * emac_phy_mdio_autopoll_disable() - disable mdio autopoll
  92  * @adpt: the emac adapter
  93  *
  94  * The EMAC has the ability to poll the external PHY on the MDIO
  95  * bus for link state changes.  This eliminates the need for the
  96  * driver to poll the phy.  If if the link state does change,
  97  * the EMAC issues an interrupt on behalf of the PHY.
  98  */
  99 static void emac_phy_mdio_autopoll_enable(struct emac_adapter *adpt)
 100 {
 101         emac_reg_update32(adpt->base + EMAC_MDIO_CTRL, 0, MDIO_AP_EN);
 102 }
 103
 104 static int emac_mdio_read(struct mii_bus *bus, int addr, int regnum)
 105 {
 106         struct emac_adapter *adpt = bus->priv;
 107         u32 reg;
 108         int ret;
 109
 110         ret = emac_phy_mdio_autopoll_disable(adpt);
 111         if (ret)
 112                 return ret;
 113
 114         emac_reg_update32(adpt->base + EMAC_PHY_STS, PHY_ADDR_BMSK,
 115                           (addr << PHY_ADDR_SHFT));
 116
 117         reg = SUP_PREAMBLE |
 118               ((MDIO_CLK_25_4 << MDIO_CLK_SEL_SHFT) & MDIO_CLK_SEL_BMSK) |
 119               ((regnum << MDIO_REG_ADDR_SHFT) & MDIO_REG_ADDR_BMSK) |
 120               MDIO_START | MDIO_RD_NWR;
 121
 122         writel(reg, adpt->base + EMAC_MDIO_CTRL);
 123
 124         if (readl_poll_timeout(adpt->base + EMAC_MDIO_CTRL, reg,
 125                                !(reg & (MDIO_START | MDIO_BUSY)),
 126                                100, MDIO_WAIT_TIMES * 100))
 127                 ret = -EIO;
 128         else
 129                 ret = (reg >> MDIO_DATA_SHFT) & MDIO_DATA_BMSK;
 130
 131         emac_phy_mdio_autopoll_enable(adpt);
 132
 133         return ret;
 134 }
 135
 136 static int emac_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 137 {
 138         struct emac_adapter *adpt = bus->priv;
 139         u32 reg;
 140         int ret;
 141
 142         ret = emac_phy_mdio_autopoll_disable(adpt);
 143         if (ret)
 144                 return ret;
 145
 146         emac_reg_update32(adpt->base + EMAC_PHY_STS, PHY_ADDR_BMSK,
 147                           (addr << PHY_ADDR_SHFT));
 148
 149         reg = SUP_PREAMBLE |
 150                 ((MDIO_CLK_25_4 << MDIO_CLK_SEL_SHFT) & MDIO_CLK_SEL_BMSK) |
 151                 ((regnum << MDIO_REG_ADDR_SHFT) & MDIO_REG_ADDR_BMSK) |
 152                 ((val << MDIO_DATA_SHFT) & MDIO_DATA_BMSK) |
 153                 MDIO_START;
 154
 155         writel(reg, adpt->base + EMAC_MDIO_CTRL);
 156
 157         if (readl_poll_timeout(adpt->base + EMAC_MDIO_CTRL, reg,
 158                                !(reg & (MDIO_START | MDIO_BUSY)), 100,
 159                                MDIO_WAIT_TIMES * 100))
 160                 ret = -EIO;
 161
 162         emac_phy_mdio_autopoll_enable(adpt);
 163
 164         return ret;
 165 }
 166
 167 /* Configure the MDIO bus and connect the external PHY */
 168 int emac_phy_config(struct platform_device *pdev, struct emac_adapter *adpt)
 169 {
 170         struct device_node *np = pdev->dev.of_node;
 171         struct mii_bus *mii_bus;
 172         int ret;
 173
 174         /* Create the mii_bus object for talking to the MDIO bus */
 175         adpt->mii_bus = mii_bus = devm_mdiobus_alloc(&pdev->dev);
 176         if (!mii_bus)
 177                 return -ENOMEM;
 178
 179         mii_bus->name = "emac-mdio";
 180         snprintf(mii_bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
 181         mii_bus->read = emac_mdio_read;
 182         mii_bus->write = emac_mdio_write;
 183         mii_bus->parent = &pdev->dev;
 184         mii_bus->priv = adpt;
 185
 186         if (has_acpi_companion(&pdev->dev)) {
 187                 u32 phy_addr;
 188
 189                 ret = mdiobus_register(mii_bus);
 190                 if (ret) {
 191                         dev_err(&pdev->dev, "could not register mdio bus\n");
 192                         return ret;
 193                 }
 194                 ret = device_property_read_u32(&pdev->dev, "phy-channel",
 195                                                &phy_addr);
 196                 if (ret)
 197                         /* If we can't read a valid phy address, then assume
 198                          * that there is only one phy on this mdio bus.
 199                          */
 200                         adpt->phydev = phy_find_first(mii_bus);
 201                 else
 202                         adpt->phydev = mdiobus_get_phy(mii_bus, phy_addr);
 203
 204                 /* of_phy_find_device() claims a reference to the phydev,
 205                  * so we do that here manually as well. When the driver
 206                  * later unloads, it can unilaterally drop the reference
 207                  * without worrying about ACPI vs DT.
 208                  */
 209                 if (adpt->phydev)
 210                         get_device(&adpt->phydev->mdio.dev);
 211         } else {
 212                 struct device_node *phy_np;
 213
 214                 ret = of_mdiobus_register(mii_bus, np);
 215                 if (ret) {
 216                         dev_err(&pdev->dev, "could not register mdio bus\n");
 217                         return ret;
 218                 }
 219
 220                 phy_np = of_parse_phandle(np, "phy-handle", 0);
 221                 adpt->phydev = of_phy_find_device(phy_np);
 222                 of_node_put(phy_np);
 223         }
 224
 225         if (!adpt->phydev) {
 226                 dev_err(&pdev->dev, "could not find external phy\n");
 227                 mdiobus_unregister(mii_bus);
 228                 return -ENODEV;
 229         }
 230
 231         if (adpt->phydev->drv)
 232                 phy_attached_print(adpt->phydev, NULL);
 233
 234         return 0;
 235 }