Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

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 = 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         bus->irq = devm_kmalloc_array(&pdev->dev, PHY_MAX_ADDR, sizeof(int),
211                                       GFP_KERNEL);
212         if (!bus->irq)
213                 return -ENOMEM;
214 
215         for (i = 0; i < PHY_MAX_ADDR; i++)
216                 bus->irq[i] = PHY_POLL;
217 
218         dev = bus->priv;
219         dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
220         if (!dev->regs) {
221                 dev_err(&pdev->dev, "Unable to remap SMI register\n");
222                 ret = -ENODEV;
223                 goto out_mdio;
224         }
225 
226         init_waitqueue_head(&dev->smi_busy_wait);
227 
228         dev->clk = devm_clk_get(&pdev->dev, NULL);
229         if (!IS_ERR(dev->clk))
230                 clk_prepare_enable(dev->clk);
231 
232         dev->err_interrupt = platform_get_irq(pdev, 0);
233         if (dev->err_interrupt > 0) {
234                 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
235                                         orion_mdio_err_irq,
236                                         IRQF_SHARED, pdev->name, dev);
237                 if (ret)
238                         goto out_mdio;
239 
240                 writel(MVMDIO_ERR_INT_SMI_DONE,
241                         dev->regs + MVMDIO_ERR_INT_MASK);
242 
243         } else if (dev->err_interrupt == -EPROBE_DEFER) {
244                 return -EPROBE_DEFER;
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         return ret;
266 }
267 
268 static int orion_mdio_remove(struct platform_device *pdev)
269 {
270         struct mii_bus *bus = platform_get_drvdata(pdev);
271         struct orion_mdio_dev *dev = bus->priv;
272 
273         writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
274         mdiobus_unregister(bus);
275         if (!IS_ERR(dev->clk))
276                 clk_disable_unprepare(dev->clk);
277 
278         return 0;
279 }
280 
281 static const struct of_device_id orion_mdio_match[] = {
282         { .compatible = "marvell,orion-mdio" },
283         { }
284 };
285 MODULE_DEVICE_TABLE(of, orion_mdio_match);
286 
287 static struct platform_driver orion_mdio_driver = {
288         .probe = orion_mdio_probe,
289         .remove = orion_mdio_remove,
290         .driver = {
291                 .name = "orion-mdio",
292                 .of_match_table = orion_mdio_match,
293         },
294 };
295 
296 module_platform_driver(orion_mdio_driver);
297 
298 MODULE_DESCRIPTION("Marvell MDIO interface driver");
299 MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
300 MODULE_LICENSE("GPL");
301 MODULE_ALIAS("platform:orion-mdio");
302 

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