1 /* 2 * Driver for the MDIO interface of Marvell network interfaces. 3 * 4 * Since the MDIO interface of Marvell network interfaces is shared 5 * between all network interfaces, having a single driver allows to 6 * handle concurrent accesses properly (you may have four Ethernet 7 * ports, but they in fact share the same SMI interface to access 8 * the MDIO bus). This driver is currently used by the mvneta and 9 * mv643xx_eth drivers. 10 * 11 * Copyright (C) 2012 Marvell 12 * 13 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> 14 * 15 * This file is licensed under the terms of the GNU General Public 16 * License version 2. This program is licensed "as is" without any 17 * warranty of any kind, whether express or implied. 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/phy.h> 24 #include <linux/interrupt.h> 25 #include <linux/platform_device.h> 26 #include <linux/delay.h> 27 #include <linux/io.h> 28 #include <linux/clk.h> 29 #include <linux/of_mdio.h> 30 #include <linux/sched.h> 31 #include <linux/wait.h> 32 33 #define MVMDIO_SMI_DATA_SHIFT 0 34 #define MVMDIO_SMI_PHY_ADDR_SHIFT 16 35 #define MVMDIO_SMI_PHY_REG_SHIFT 21 36 #define MVMDIO_SMI_READ_OPERATION BIT(26) 37 #define MVMDIO_SMI_WRITE_OPERATION 0 38 #define MVMDIO_SMI_READ_VALID BIT(27) 39 #define MVMDIO_SMI_BUSY BIT(28) 40 #define MVMDIO_ERR_INT_CAUSE 0x007C 41 #define MVMDIO_ERR_INT_SMI_DONE 0x00000010 42 #define MVMDIO_ERR_INT_MASK 0x0080 43 44 /* 45 * SMI Timeout measurements: 46 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt) 47 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled) 48 */ 49 #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */ 50 #define MVMDIO_SMI_POLL_INTERVAL_MIN 45 51 #define MVMDIO_SMI_POLL_INTERVAL_MAX 55 52 53 struct orion_mdio_dev { 54 struct mutex lock; 55 void __iomem *regs; 56 struct clk *clk; 57 /* 58 * If we have access to the error interrupt pin (which is 59 * somewhat misnamed as it not only reflects internal errors 60 * but also reflects SMI completion), use that to wait for 61 * SMI access completion instead of polling the SMI busy bit. 62 */ 63 int err_interrupt; 64 wait_queue_head_t smi_busy_wait; 65 }; 66 67 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev) 68 { 69 return !(readl(dev->regs) & MVMDIO_SMI_BUSY); 70 } 71 72 /* Wait for the SMI unit to be ready for another operation 73 */ 74 static int orion_mdio_wait_ready(struct mii_bus *bus) 75 { 76 struct orion_mdio_dev *dev = bus->priv; 77 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); 78 unsigned long end = jiffies + timeout; 79 int timedout = 0; 80 81 while (1) { 82 if (orion_mdio_smi_is_done(dev)) 83 return 0; 84 else if (timedout) 85 break; 86 87 if (dev->err_interrupt <= 0) { 88 usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN, 89 MVMDIO_SMI_POLL_INTERVAL_MAX); 90 91 if (time_is_before_jiffies(end)) 92 ++timedout; 93 } else { 94 /* wait_event_timeout does not guarantee a delay of at 95 * least one whole jiffie, so timeout must be no less 96 * than two. 97 */ 98 if (timeout < 2) 99 timeout = 2; 100 wait_event_timeout(dev->smi_busy_wait, 101 orion_mdio_smi_is_done(dev), 102 timeout); 103 104 ++timedout; 105 } 106 } 107 108 dev_err(bus->parent, "Timeout: SMI busy for too long\n"); 109 return -ETIMEDOUT; 110 } 111 112 static int orion_mdio_read(struct mii_bus *bus, int mii_id, 113 int regnum) 114 { 115 struct orion_mdio_dev *dev = bus->priv; 116 u32 val; 117 int ret; 118 119 mutex_lock(&dev->lock); 120 121 ret = orion_mdio_wait_ready(bus); 122 if (ret < 0) 123 goto out; 124 125 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | 126 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | 127 MVMDIO_SMI_READ_OPERATION), 128 dev->regs); 129 130 ret = orion_mdio_wait_ready(bus); 131 if (ret < 0) 132 goto out; 133 134 val = readl(dev->regs); 135 if (!(val & MVMDIO_SMI_READ_VALID)) { 136 dev_err(bus->parent, "SMI bus read not valid\n"); 137 ret = -ENODEV; 138 goto out; 139 } 140 141 ret = val & 0xFFFF; 142 out: 143 mutex_unlock(&dev->lock); 144 return ret; 145 } 146 147 static int orion_mdio_write(struct mii_bus *bus, int mii_id, 148 int regnum, u16 value) 149 { 150 struct orion_mdio_dev *dev = bus->priv; 151 int ret; 152 153 mutex_lock(&dev->lock); 154 155 ret = orion_mdio_wait_ready(bus); 156 if (ret < 0) 157 goto out; 158 159 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | 160 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | 161 MVMDIO_SMI_WRITE_OPERATION | 162 (value << MVMDIO_SMI_DATA_SHIFT)), 163 dev->regs); 164 165 out: 166 mutex_unlock(&dev->lock); 167 return ret; 168 } 169 170 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id) 171 { 172 struct orion_mdio_dev *dev = dev_id; 173 174 if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) & 175 MVMDIO_ERR_INT_SMI_DONE) { 176 writel(~MVMDIO_ERR_INT_SMI_DONE, 177 dev->regs + MVMDIO_ERR_INT_CAUSE); 178 wake_up(&dev->smi_busy_wait); 179 return IRQ_HANDLED; 180 } 181 182 return IRQ_NONE; 183 } 184 185 static int orion_mdio_probe(struct platform_device *pdev) 186 { 187 struct resource *r; 188 struct mii_bus *bus; 189 struct orion_mdio_dev *dev; 190 int ret; 191 192 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 193 if (!r) { 194 dev_err(&pdev->dev, "No SMI register address given\n"); 195 return -ENODEV; 196 } 197 198 bus = devm_mdiobus_alloc_size(&pdev->dev, 199 sizeof(struct orion_mdio_dev)); 200 if (!bus) 201 return -ENOMEM; 202 203 bus->name = "orion_mdio_bus"; 204 bus->read = orion_mdio_read; 205 bus->write = orion_mdio_write; 206 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", 207 dev_name(&pdev->dev)); 208 bus->parent = &pdev->dev; 209 210 dev = bus->priv; 211 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r)); 212 if (!dev->regs) { 213 dev_err(&pdev->dev, "Unable to remap SMI register\n"); 214 return -ENODEV; 215 } 216 217 init_waitqueue_head(&dev->smi_busy_wait); 218 219 dev->clk = devm_clk_get(&pdev->dev, NULL); 220 if (!IS_ERR(dev->clk)) 221 clk_prepare_enable(dev->clk); 222 223 dev->err_interrupt = platform_get_irq(pdev, 0); 224 if (dev->err_interrupt > 0) { 225 ret = devm_request_irq(&pdev->dev, dev->err_interrupt, 226 orion_mdio_err_irq, 227 IRQF_SHARED, pdev->name, dev); 228 if (ret) 229 goto out_mdio; 230 231 writel(MVMDIO_ERR_INT_SMI_DONE, 232 dev->regs + MVMDIO_ERR_INT_MASK); 233 234 } else if (dev->err_interrupt == -EPROBE_DEFER) { 235 return -EPROBE_DEFER; 236 } 237 238 mutex_init(&dev->lock); 239 240 if (pdev->dev.of_node) 241 ret = of_mdiobus_register(bus, pdev->dev.of_node); 242 else 243 ret = mdiobus_register(bus); 244 if (ret < 0) { 245 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret); 246 goto out_mdio; 247 } 248 249 platform_set_drvdata(pdev, bus); 250 251 return 0; 252 253 out_mdio: 254 if (!IS_ERR(dev->clk)) 255 clk_disable_unprepare(dev->clk); 256 return ret; 257 } 258 259 static int orion_mdio_remove(struct platform_device *pdev) 260 { 261 struct mii_bus *bus = platform_get_drvdata(pdev); 262 struct orion_mdio_dev *dev = bus->priv; 263 264 writel(0, dev->regs + MVMDIO_ERR_INT_MASK); 265 mdiobus_unregister(bus); 266 if (!IS_ERR(dev->clk)) 267 clk_disable_unprepare(dev->clk); 268 269 return 0; 270 } 271 272 static const struct of_device_id orion_mdio_match[] = { 273 { .compatible = "marvell,orion-mdio" }, 274 { } 275 }; 276 MODULE_DEVICE_TABLE(of, orion_mdio_match); 277 278 static struct platform_driver orion_mdio_driver = { 279 .probe = orion_mdio_probe, 280 .remove = orion_mdio_remove, 281 .driver = { 282 .name = "orion-mdio", 283 .of_match_table = orion_mdio_match, 284 }, 285 }; 286 287 module_platform_driver(orion_mdio_driver); 288 289 MODULE_DESCRIPTION("Marvell MDIO interface driver"); 290 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>"); 291 MODULE_LICENSE("GPL"); 292 MODULE_ALIAS("platform:orion-mdio"); 293