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 41struct unimac_mdio_priv { 42 struct mii_bus *mii_bus; 43 void __iomem *base; 44}; 45 46static 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 55static 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 60static 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 96static 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 */ 138static 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 165static 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 bus->irq = kcalloc(PHY_MAX_ADDR, sizeof(int), GFP_KERNEL); 204 if (!bus->irq) { 205 ret = -ENOMEM; 206 goto out_mdio_free; 207 } 208 209 ret = of_mdiobus_register(bus, np); 210 if (ret) { 211 dev_err(&pdev->dev, "MDIO bus registration failed\n"); 212 goto out_mdio_irq; 213 } 214 215 platform_set_drvdata(pdev, priv); 216 217 dev_info(&pdev->dev, "Broadcom UniMAC MDIO bus at 0x%p\n", priv->base); 218 219 return 0; 220 221out_mdio_irq: 222 kfree(bus->irq); 223out_mdio_free: 224 mdiobus_free(bus); 225 return ret; 226} 227 228static int unimac_mdio_remove(struct platform_device *pdev) 229{ 230 struct unimac_mdio_priv *priv = platform_get_drvdata(pdev); 231 232 mdiobus_unregister(priv->mii_bus); 233 kfree(priv->mii_bus->irq); 234 mdiobus_free(priv->mii_bus); 235 236 return 0; 237} 238 239static const struct of_device_id unimac_mdio_ids[] = { 240 { .compatible = "brcm,genet-mdio-v4", }, 241 { .compatible = "brcm,genet-mdio-v3", }, 242 { .compatible = "brcm,genet-mdio-v2", }, 243 { .compatible = "brcm,genet-mdio-v1", }, 244 { .compatible = "brcm,unimac-mdio", }, 245 { /* sentinel */ }, 246}; 247MODULE_DEVICE_TABLE(of, unimac_mdio_ids); 248 249static struct platform_driver unimac_mdio_driver = { 250 .driver = { 251 .name = "unimac-mdio", 252 .of_match_table = unimac_mdio_ids, 253 }, 254 .probe = unimac_mdio_probe, 255 .remove = unimac_mdio_remove, 256}; 257module_platform_driver(unimac_mdio_driver); 258 259MODULE_AUTHOR("Broadcom Corporation"); 260MODULE_DESCRIPTION("Broadcom UniMAC MDIO bus controller"); 261MODULE_LICENSE("GPL"); 262MODULE_ALIAS("platform:unimac-mdio"); 263