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Linux/drivers/net/ethernet/marvell/mvmdio.c

  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 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         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
208                  dev_name(&pdev->dev));
209         bus->parent = &pdev->dev;
210 
211         bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
212         if (!bus->irq) {
213                 mdiobus_free(bus);
214                 return -ENOMEM;
215         }
216 
217         for (i = 0; i < PHY_MAX_ADDR; i++)
218                 bus->irq[i] = PHY_POLL;
219 
220         dev = bus->priv;
221         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
222         if (!dev->regs) {
223                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
224                 ret = -ENODEV;
225                 goto out_mdio;
226         }
227 
228         init_waitqueue_head(&dev->smi_busy_wait);
229 
230         dev->clk = devm_clk_get(&pdev->dev, NULL);
231         if (!IS_ERR(dev->clk))
232                 clk_prepare_enable(dev->clk);
233 
234         dev->err_interrupt = platform_get_irq(pdev, 0);
235         if (dev->err_interrupt > 0) {
236                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
237                                         orion_mdio_err_irq,
238                                         IRQF_SHARED, pdev->name, dev);
239                 if (ret)
240                         goto out_mdio;
241 
242                 writel(MVMDIO_ERR_INT_SMI_DONE,
243                         dev->regs + MVMDIO_ERR_INT_MASK);
244 
245         } else if (dev->err_interrupt == -EPROBE_DEFER) {
246                 return -EPROBE_DEFER;
247         }
248 
249         mutex_init(&dev->lock);
250 
251         if (pdev->dev.of_node)
252                 ret = of_mdiobus_register(bus, pdev->dev.of_node);
253         else
254                 ret = mdiobus_register(bus);
255         if (ret < 0) {
256                 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
257                 goto out_mdio;
258         }
259 
260         platform_set_drvdata(pdev, bus);
261 
262         return 0;
263 
264 out_mdio:
265         if (!IS_ERR(dev->clk))
266                 clk_disable_unprepare(dev->clk);
267         kfree(bus->irq);
268         mdiobus_free(bus);
269         return ret;
270 }
271 
272 static int orion_mdio_remove(struct platform_device *pdev)
273 {
274         struct mii_bus *bus = platform_get_drvdata(pdev);
275         struct orion_mdio_dev *dev = bus->priv;
276 
277         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
278         mdiobus_unregister(bus);
279         kfree(bus->irq);
280         mdiobus_free(bus);
281         if (!IS_ERR(dev->clk))
282                 clk_disable_unprepare(dev->clk);
283 
284         return 0;
285 }
286 
287 static const struct of_device_id orion_mdio_match[] = {
288         { .compatible = "marvell,orion-mdio" },
289         { }
290 };
291 MODULE_DEVICE_TABLE(of, orion_mdio_match);
292 
293 static struct platform_driver orion_mdio_driver = {
294         .probe = orion_mdio_probe,
295         .remove = orion_mdio_remove,
296         .driver = {
297                 .name = "orion-mdio",
298                 .of_match_table = orion_mdio_match,
299         },
300 };
301 
302 module_platform_driver(orion_mdio_driver);
303 
304 MODULE_DESCRIPTION("Marvell MDIO interface driver");
305 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
306 MODULE_LICENSE("GPL");
307 MODULE_ALIAS("platform:orion-mdio");
308 

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