1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Copyright (C) 2019 IBM Corp. */ 3 4 #include <linux/bitfield.h> 5 #include <linux/delay.h> 6 #include <linux/reset.h> 7 #include <linux/iopoll.h> 8 #include <linux/mdio.h> 9 #include <linux/module.h> 10 #include <linux/of.h> 11 #include <linux/of_mdio.h> 12 #include <linux/phy.h> 13 #include <linux/platform_device.h> 14 15 #define DRV_NAME "mdio-aspeed" 16 17 #define ASPEED_MDIO_CTRL 0x0 18 #define ASPEED_MDIO_CTRL_FIRE BIT(31) 19 #define ASPEED_MDIO_CTRL_ST BIT(28) 20 #define ASPEED_MDIO_CTRL_ST_C45 0 21 #define ASPEED_MDIO_CTRL_ST_C22 1 22 #define ASPEED_MDIO_CTRL_OP GENMASK(27, 26) 23 #define MDIO_C22_OP_WRITE 0b01 24 #define MDIO_C22_OP_READ 0b10 25 #define MDIO_C45_OP_ADDR 0b00 26 #define MDIO_C45_OP_WRITE 0b01 27 #define MDIO_C45_OP_PREAD 0b10 28 #define MDIO_C45_OP_READ 0b11 29 #define ASPEED_MDIO_CTRL_PHYAD GENMASK(25, 21) 30 #define ASPEED_MDIO_CTRL_REGAD GENMASK(20, 16) 31 #define ASPEED_MDIO_CTRL_MIIWDATA GENMASK(15, 0) 32 33 #define ASPEED_MDIO_DATA 0x4 34 #define ASPEED_MDIO_DATA_MDC_THRES GENMASK(31, 24) 35 #define ASPEED_MDIO_DATA_MDIO_EDGE BIT(23) 36 #define ASPEED_MDIO_DATA_MDIO_LATCH GENMASK(22, 20) 37 #define ASPEED_MDIO_DATA_IDLE BIT(16) 38 #define ASPEED_MDIO_DATA_MIIRDATA GENMASK(15, 0) 39 40 #define ASPEED_MDIO_INTERVAL_US 100 41 #define ASPEED_MDIO_TIMEOUT_US (ASPEED_MDIO_INTERVAL_US * 10) 42 43 struct aspeed_mdio { 44 void __iomem *base; 45 struct reset_control *reset; 46 }; 47 48 static int aspeed_mdio_op(struct mii_bus *bus, u8 st, u8 op, u8 phyad, u8 regad, 49 u16 data) 50 { 51 struct aspeed_mdio *ctx = bus->priv; 52 u32 ctrl; 53 54 dev_dbg(&bus->dev, "%s: st: %u op: %u, phyad: %u, regad: %u, data: %u\n", 55 __func__, st, op, phyad, regad, data); 56 57 ctrl = ASPEED_MDIO_CTRL_FIRE 58 | FIELD_PREP(ASPEED_MDIO_CTRL_ST, st) 59 | FIELD_PREP(ASPEED_MDIO_CTRL_OP, op) 60 | FIELD_PREP(ASPEED_MDIO_CTRL_PHYAD, phyad) 61 | FIELD_PREP(ASPEED_MDIO_CTRL_REGAD, regad) 62 | FIELD_PREP(ASPEED_MDIO_DATA_MIIRDATA, data); 63 64 iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL); 65 66 /* Workaround for read-after-write issue. 67 * The controller may return stale data if a read follows immediately 68 * after a write. A dummy read forces the hardware to update its 69 * internal state, ensuring that the next real read returns correct data. 70 */ 71 ioread32(ctx->base + ASPEED_MDIO_CTRL); 72 73 return readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl, 74 !(ctrl & ASPEED_MDIO_CTRL_FIRE), 75 ASPEED_MDIO_INTERVAL_US, 76 ASPEED_MDIO_TIMEOUT_US); 77 } 78 79 static int aspeed_mdio_get_data(struct mii_bus *bus) 80 { 81 struct aspeed_mdio *ctx = bus->priv; 82 u32 data; 83 int rc; 84 85 rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data, 86 data & ASPEED_MDIO_DATA_IDLE, 87 ASPEED_MDIO_INTERVAL_US, 88 ASPEED_MDIO_TIMEOUT_US); 89 if (rc < 0) 90 return rc; 91 92 return FIELD_GET(ASPEED_MDIO_DATA_MIIRDATA, data); 93 } 94 95 static int aspeed_mdio_read_c22(struct mii_bus *bus, int addr, int regnum) 96 { 97 int rc; 98 99 rc = aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C22, MDIO_C22_OP_READ, 100 addr, regnum, 0); 101 if (rc < 0) 102 return rc; 103 104 return aspeed_mdio_get_data(bus); 105 } 106 107 static int aspeed_mdio_write_c22(struct mii_bus *bus, int addr, int regnum, 108 u16 val) 109 { 110 return aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C22, MDIO_C22_OP_WRITE, 111 addr, regnum, val); 112 } 113 114 static int aspeed_mdio_read_c45(struct mii_bus *bus, int addr, int devad, 115 int regnum) 116 { 117 int rc; 118 119 rc = aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C45, MDIO_C45_OP_ADDR, 120 addr, devad, regnum); 121 if (rc < 0) 122 return rc; 123 124 rc = aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C45, MDIO_C45_OP_READ, 125 addr, devad, 0); 126 if (rc < 0) 127 return rc; 128 129 return aspeed_mdio_get_data(bus); 130 } 131 132 static int aspeed_mdio_write_c45(struct mii_bus *bus, int addr, int devad, 133 int regnum, u16 val) 134 { 135 int rc; 136 137 rc = aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C45, MDIO_C45_OP_ADDR, 138 addr, devad, regnum); 139 if (rc < 0) 140 return rc; 141 142 return aspeed_mdio_op(bus, ASPEED_MDIO_CTRL_ST_C45, MDIO_C45_OP_WRITE, 143 addr, devad, val); 144 } 145 146 static int aspeed_mdio_probe(struct platform_device *pdev) 147 { 148 struct aspeed_mdio *ctx; 149 struct mii_bus *bus; 150 int rc; 151 152 bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*ctx)); 153 if (!bus) 154 return -ENOMEM; 155 156 ctx = bus->priv; 157 ctx->base = devm_platform_ioremap_resource(pdev, 0); 158 if (IS_ERR(ctx->base)) 159 return PTR_ERR(ctx->base); 160 161 ctx->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL); 162 if (IS_ERR(ctx->reset)) 163 return PTR_ERR(ctx->reset); 164 165 reset_control_deassert(ctx->reset); 166 167 bus->name = DRV_NAME; 168 snprintf(bus->id, MII_BUS_ID_SIZE, "%s%d", pdev->name, pdev->id); 169 bus->parent = &pdev->dev; 170 bus->read = aspeed_mdio_read_c22; 171 bus->write = aspeed_mdio_write_c22; 172 bus->read_c45 = aspeed_mdio_read_c45; 173 bus->write_c45 = aspeed_mdio_write_c45; 174 175 rc = of_mdiobus_register(bus, pdev->dev.of_node); 176 if (rc) { 177 dev_err(&pdev->dev, "Cannot register MDIO bus!\n"); 178 reset_control_assert(ctx->reset); 179 return rc; 180 } 181 182 platform_set_drvdata(pdev, bus); 183 184 return 0; 185 } 186 187 static void aspeed_mdio_remove(struct platform_device *pdev) 188 { 189 struct mii_bus *bus = (struct mii_bus *)platform_get_drvdata(pdev); 190 struct aspeed_mdio *ctx = bus->priv; 191 192 reset_control_assert(ctx->reset); 193 mdiobus_unregister(bus); 194 } 195 196 static const struct of_device_id aspeed_mdio_of_match[] = { 197 { .compatible = "aspeed,ast2600-mdio", }, 198 { }, 199 }; 200 MODULE_DEVICE_TABLE(of, aspeed_mdio_of_match); 201 202 static struct platform_driver aspeed_mdio_driver = { 203 .driver = { 204 .name = DRV_NAME, 205 .of_match_table = aspeed_mdio_of_match, 206 }, 207 .probe = aspeed_mdio_probe, 208 .remove = aspeed_mdio_remove, 209 }; 210 211 module_platform_driver(aspeed_mdio_driver); 212 213 MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>"); 214 MODULE_LICENSE("GPL"); 215 MODULE_DESCRIPTION("ASPEED MDIO bus controller"); 216