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/init.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/mutex.h> 24 #include <linux/phy.h> 25 #include <linux/interrupt.h> 26 #include <linux/platform_device.h> 27 #include <linux/delay.h> 28 #include <linux/io.h> 29 #include <linux/clk.h> 30 #include <linux/of_mdio.h> 31 #include <linux/sched.h> 32 #include <linux/wait.h> 33 34 #define MVMDIO_SMI_DATA_SHIFT 0 35 #define MVMDIO_SMI_PHY_ADDR_SHIFT 16 36 #define MVMDIO_SMI_PHY_REG_SHIFT 21 37 #define MVMDIO_SMI_READ_OPERATION BIT(26) 38 #define MVMDIO_SMI_WRITE_OPERATION 0 39 #define MVMDIO_SMI_READ_VALID BIT(27) 40 #define MVMDIO_SMI_BUSY BIT(28) 41 #define MVMDIO_ERR_INT_CAUSE 0x007C 42 #define MVMDIO_ERR_INT_SMI_DONE 0x00000010 43 #define MVMDIO_ERR_INT_MASK 0x0080 44 45 /* 46 * SMI Timeout measurements: 47 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt) 48 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled) 49 */ 50 #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */ 51 #define MVMDIO_SMI_POLL_INTERVAL_MIN 45 52 #define MVMDIO_SMI_POLL_INTERVAL_MAX 55 53 54 struct orion_mdio_dev { 55 struct mutex lock; 56 void __iomem *regs; 57 struct clk *clk; 58 /* 59 * If we have access to the error interrupt pin (which is 60 * somewhat misnamed as it not only reflects internal errors 61 * but also reflects SMI completion), use that to wait for 62 * SMI access completion instead of polling the SMI busy bit. 63 */ 64 int err_interrupt; 65 wait_queue_head_t smi_busy_wait; 66 }; 67 68 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev) 69 { 70 return !(readl(dev->regs) & MVMDIO_SMI_BUSY); 71 } 72 73 /* Wait for the SMI unit to be ready for another operation 74 */ 75 static int orion_mdio_wait_ready(struct mii_bus *bus) 76 { 77 struct orion_mdio_dev *dev = bus->priv; 78 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); 79 unsigned long end = jiffies + timeout; 80 int timedout = 0; 81 82 while (1) { 83 if (orion_mdio_smi_is_done(dev)) 84 return 0; 85 else if (timedout) 86 break; 87 88 if (dev->err_interrupt <= 0) { 89 usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN, 90 MVMDIO_SMI_POLL_INTERVAL_MAX); 91 92 if (time_is_before_jiffies(end)) 93 ++timedout; 94 } else { 95 wait_event_timeout(dev->smi_busy_wait, 96 orion_mdio_smi_is_done(dev), 97 timeout); 98 99 ++timedout; 100 } 101 } 102 103 dev_err(bus->parent, "Timeout: SMI busy for too long\n"); 104 return -ETIMEDOUT; 105 } 106 107 static int orion_mdio_read(struct mii_bus *bus, int mii_id, 108 int regnum) 109 { 110 struct orion_mdio_dev *dev = bus->priv; 111 u32 val; 112 int ret; 113 114 mutex_lock(&dev->lock); 115 116 ret = orion_mdio_wait_ready(bus); 117 if (ret < 0) 118 goto out; 119 120 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | 121 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | 122 MVMDIO_SMI_READ_OPERATION), 123 dev->regs); 124 125 ret = orion_mdio_wait_ready(bus); 126 if (ret < 0) 127 goto out; 128 129 val = readl(dev->regs); 130 if (!(val & MVMDIO_SMI_READ_VALID)) { 131 dev_err(bus->parent, "SMI bus read not valid\n"); 132 ret = -ENODEV; 133 goto out; 134 } 135 136 ret = val & 0xFFFF; 137 out: 138 mutex_unlock(&dev->lock); 139 return ret; 140 } 141 142 static int orion_mdio_write(struct mii_bus *bus, int mii_id, 143 int regnum, u16 value) 144 { 145 struct orion_mdio_dev *dev = bus->priv; 146 int ret; 147 148 mutex_lock(&dev->lock); 149 150 ret = orion_mdio_wait_ready(bus); 151 if (ret < 0) 152 goto out; 153 154 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | 155 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | 156 MVMDIO_SMI_WRITE_OPERATION | 157 (value << MVMDIO_SMI_DATA_SHIFT)), 158 dev->regs); 159 160 out: 161 mutex_unlock(&dev->lock); 162 return ret; 163 } 164 165 static int orion_mdio_reset(struct mii_bus *bus) 166 { 167 return 0; 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 i, 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 = mdiobus_alloc_size(sizeof(struct orion_mdio_dev)); 199 if (!bus) { 200 dev_err(&pdev->dev, "Cannot allocate MDIO bus\n"); 201 return -ENOMEM; 202 } 203 204 bus->name = "orion_mdio_bus"; 205 bus->read = orion_mdio_read; 206 bus->write = orion_mdio_write; 207 bus->reset = orion_mdio_reset; 208 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", 209 dev_name(&pdev->dev)); 210 bus->parent = &pdev->dev; 211 212 bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL); 213 if (!bus->irq) { 214 mdiobus_free(bus); 215 return -ENOMEM; 216 } 217 218 for (i = 0; i < PHY_MAX_ADDR; i++) 219 bus->irq[i] = PHY_POLL; 220 221 dev = bus->priv; 222 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r)); 223 if (!dev->regs) { 224 dev_err(&pdev->dev, "Unable to remap SMI register\n"); 225 ret = -ENODEV; 226 goto out_mdio; 227 } 228 229 init_waitqueue_head(&dev->smi_busy_wait); 230 231 dev->clk = devm_clk_get(&pdev->dev, NULL); 232 if (!IS_ERR(dev->clk)) 233 clk_prepare_enable(dev->clk); 234 235 dev->err_interrupt = platform_get_irq(pdev, 0); 236 if (dev->err_interrupt != -ENXIO) { 237 ret = devm_request_irq(&pdev->dev, dev->err_interrupt, 238 orion_mdio_err_irq, 239 IRQF_SHARED, pdev->name, dev); 240 if (ret) 241 goto out_mdio; 242 243 writel(MVMDIO_ERR_INT_SMI_DONE, 244 dev->regs + MVMDIO_ERR_INT_MASK); 245 } 246 247 mutex_init(&dev->lock); 248 249 if (pdev->dev.of_node) 250 ret = of_mdiobus_register(bus, pdev->dev.of_node); 251 else 252 ret = mdiobus_register(bus); 253 if (ret < 0) { 254 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret); 255 goto out_mdio; 256 } 257 258 platform_set_drvdata(pdev, bus); 259 260 return 0; 261 262 out_mdio: 263 if (!IS_ERR(dev->clk)) 264 clk_disable_unprepare(dev->clk); 265 kfree(bus->irq); 266 mdiobus_free(bus); 267 return ret; 268 } 269 270 static int orion_mdio_remove(struct platform_device *pdev) 271 { 272 struct mii_bus *bus = platform_get_drvdata(pdev); 273 struct orion_mdio_dev *dev = bus->priv; 274 275 writel(0, dev->regs + MVMDIO_ERR_INT_MASK); 276 mdiobus_unregister(bus); 277 kfree(bus->irq); 278 mdiobus_free(bus); 279 if (!IS_ERR(dev->clk)) 280 clk_disable_unprepare(dev->clk); 281 282 return 0; 283 } 284 285 static const struct of_device_id orion_mdio_match[] = { 286 { .compatible = "marvell,orion-mdio" }, 287 { } 288 }; 289 MODULE_DEVICE_TABLE(of, orion_mdio_match); 290 291 static struct platform_driver orion_mdio_driver = { 292 .probe = orion_mdio_probe, 293 .remove = orion_mdio_remove, 294 .driver = { 295 .name = "orion-mdio", 296 .of_match_table = orion_mdio_match, 297 }, 298 }; 299 300 module_platform_driver(orion_mdio_driver); 301 302 MODULE_DESCRIPTION("Marvell MDIO interface driver"); 303 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>"); 304 MODULE_LICENSE("GPL"); 305 MODULE_ALIAS("platform:orion-mdio"); 306