1 // SPDX-License-Identifier: (GPL-2.0 OR MIT) 2 /* 3 * Driver for the MDIO interface of Microsemi network switches. 4 * 5 * Author: Alexandre Belloni <alexandre.belloni@bootlin.com> 6 * Copyright (c) 2017 Microsemi Corporation 7 */ 8 9 #include <linux/bitops.h> 10 #include <linux/io.h> 11 #include <linux/iopoll.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/of_mdio.h> 15 #include <linux/phy.h> 16 #include <linux/platform_device.h> 17 18 #define MSCC_MIIM_REG_STATUS 0x0 19 #define MSCC_MIIM_STATUS_STAT_PENDING BIT(2) 20 #define MSCC_MIIM_STATUS_STAT_BUSY BIT(3) 21 #define MSCC_MIIM_REG_CMD 0x8 22 #define MSCC_MIIM_CMD_OPR_WRITE BIT(1) 23 #define MSCC_MIIM_CMD_OPR_READ BIT(2) 24 #define MSCC_MIIM_CMD_WRDATA_SHIFT 4 25 #define MSCC_MIIM_CMD_REGAD_SHIFT 20 26 #define MSCC_MIIM_CMD_PHYAD_SHIFT 25 27 #define MSCC_MIIM_CMD_VLD BIT(31) 28 #define MSCC_MIIM_REG_DATA 0xC 29 #define MSCC_MIIM_DATA_ERROR (BIT(16) | BIT(17)) 30 31 #define MSCC_PHY_REG_PHY_CFG 0x0 32 #define PHY_CFG_PHY_ENA (BIT(0) | BIT(1) | BIT(2) | BIT(3)) 33 #define PHY_CFG_PHY_COMMON_RESET BIT(4) 34 #define PHY_CFG_PHY_RESET (BIT(5) | BIT(6) | BIT(7) | BIT(8)) 35 #define MSCC_PHY_REG_PHY_STATUS 0x4 36 37 struct mscc_miim_dev { 38 void __iomem *regs; 39 void __iomem *phy_regs; 40 }; 41 42 /* When high resolution timers aren't built-in: we can't use usleep_range() as 43 * we would sleep way too long. Use udelay() instead. 44 */ 45 #define mscc_readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 46 ({ \ 47 if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS)) \ 48 readl_poll_timeout_atomic(addr, val, cond, delay_us, \ 49 timeout_us); \ 50 readl_poll_timeout(addr, val, cond, delay_us, timeout_us); \ 51 }) 52 53 static int mscc_miim_wait_ready(struct mii_bus *bus) 54 { 55 struct mscc_miim_dev *miim = bus->priv; 56 u32 val; 57 58 return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val, 59 !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50, 60 10000); 61 } 62 63 static int mscc_miim_wait_pending(struct mii_bus *bus) 64 { 65 struct mscc_miim_dev *miim = bus->priv; 66 u32 val; 67 68 return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val, 69 !(val & MSCC_MIIM_STATUS_STAT_PENDING), 70 50, 10000); 71 } 72 73 static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum) 74 { 75 struct mscc_miim_dev *miim = bus->priv; 76 u32 val; 77 int ret; 78 79 ret = mscc_miim_wait_pending(bus); 80 if (ret) 81 goto out; 82 83 writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) | 84 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | MSCC_MIIM_CMD_OPR_READ, 85 miim->regs + MSCC_MIIM_REG_CMD); 86 87 ret = mscc_miim_wait_ready(bus); 88 if (ret) 89 goto out; 90 91 val = readl(miim->regs + MSCC_MIIM_REG_DATA); 92 if (val & MSCC_MIIM_DATA_ERROR) { 93 ret = -EIO; 94 goto out; 95 } 96 97 ret = val & 0xFFFF; 98 out: 99 return ret; 100 } 101 102 static int mscc_miim_write(struct mii_bus *bus, int mii_id, 103 int regnum, u16 value) 104 { 105 struct mscc_miim_dev *miim = bus->priv; 106 int ret; 107 108 ret = mscc_miim_wait_pending(bus); 109 if (ret < 0) 110 goto out; 111 112 writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) | 113 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | 114 (value << MSCC_MIIM_CMD_WRDATA_SHIFT) | 115 MSCC_MIIM_CMD_OPR_WRITE, 116 miim->regs + MSCC_MIIM_REG_CMD); 117 118 out: 119 return ret; 120 } 121 122 static int mscc_miim_reset(struct mii_bus *bus) 123 { 124 struct mscc_miim_dev *miim = bus->priv; 125 126 if (miim->phy_regs) { 127 writel(0, miim->phy_regs + MSCC_PHY_REG_PHY_CFG); 128 writel(0x1ff, miim->phy_regs + MSCC_PHY_REG_PHY_CFG); 129 mdelay(500); 130 } 131 132 return 0; 133 } 134 135 static int mscc_miim_probe(struct platform_device *pdev) 136 { 137 struct mscc_miim_dev *dev; 138 struct resource *res; 139 struct mii_bus *bus; 140 int ret; 141 142 bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*dev)); 143 if (!bus) 144 return -ENOMEM; 145 146 bus->name = "mscc_miim"; 147 bus->read = mscc_miim_read; 148 bus->write = mscc_miim_write; 149 bus->reset = mscc_miim_reset; 150 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev)); 151 bus->parent = &pdev->dev; 152 153 dev = bus->priv; 154 dev->regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); 155 if (IS_ERR(dev->regs)) { 156 dev_err(&pdev->dev, "Unable to map MIIM registers\n"); 157 return PTR_ERR(dev->regs); 158 } 159 160 /* This resource is optional */ 161 res = platform_get_resource(pdev, IORESOURCE_MEM, 1); 162 if (res) { 163 dev->phy_regs = devm_ioremap_resource(&pdev->dev, res); 164 if (IS_ERR(dev->phy_regs)) { 165 dev_err(&pdev->dev, "Unable to map internal phy registers\n"); 166 return PTR_ERR(dev->phy_regs); 167 } 168 } 169 170 ret = of_mdiobus_register(bus, pdev->dev.of_node); 171 if (ret < 0) { 172 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret); 173 return ret; 174 } 175 176 platform_set_drvdata(pdev, bus); 177 178 return 0; 179 } 180 181 static int mscc_miim_remove(struct platform_device *pdev) 182 { 183 struct mii_bus *bus = platform_get_drvdata(pdev); 184 185 mdiobus_unregister(bus); 186 187 return 0; 188 } 189 190 static const struct of_device_id mscc_miim_match[] = { 191 { .compatible = "mscc,ocelot-miim" }, 192 { } 193 }; 194 MODULE_DEVICE_TABLE(of, mscc_miim_match); 195 196 static struct platform_driver mscc_miim_driver = { 197 .probe = mscc_miim_probe, 198 .remove = mscc_miim_remove, 199 .driver = { 200 .name = "mscc-miim", 201 .of_match_table = mscc_miim_match, 202 }, 203 }; 204 205 module_platform_driver(mscc_miim_driver); 206 207 MODULE_DESCRIPTION("Microsemi MIIM driver"); 208 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>"); 209 MODULE_LICENSE("Dual MIT/GPL"); 210