drivers/net/mipsnet.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/io.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/netdevice.h>
  12 #include <linux/etherdevice.h>
  13 #include <linux/platform_device.h>
  14 #include <asm/mips-boards/simint.h>
  15
  16 #define MIPSNET_VERSION "2007-11-17"
  17
  18 /*
  19  * Net status/control block as seen by sw in the core.
  20  */
  21 struct mipsnet_regs {
  22         /*
  23          * Device info for probing, reads as MIPSNET%d where %d is some
  24          * form of version.
  25          */
  26         u64 devId;              /*0x00 */
  27
  28         /*
  29          * read only busy flag.
  30          * Set and cleared by the Net Device to indicate that an rx or a tx
  31          * is in progress.
  32          */
  33         u32 busy;               /*0x08 */
  34
  35         /*
  36          * Set by the Net Device.
  37          * The device will set it once data has been received.
  38          * The value is the number of bytes that should be read from
  39          * rxDataBuffer.  The value will decrease till 0 until all the data
  40          * from rxDataBuffer has been read.
  41          */
  42         u32 rxDataCount;        /*0x0c */
  43 #define MIPSNET_MAX_RXTX_DATACOUNT (1 << 16)
  44
  45         /*
  46          * Settable from the MIPS core, cleared by the Net Device.
  47          * The core should set the number of bytes it wants to send,
  48          * then it should write those bytes of data to txDataBuffer.
  49          * The device will clear txDataCount has been processed (not
  50          * necessarily sent).
  51          */
  52         u32 txDataCount;        /*0x10 */
  53
  54         /*
  55          * Interrupt control
  56          *
  57          * Used to clear the interrupted generated by this dev.
  58          * Write a 1 to clear the interrupt. (except bit31).
  59          *
  60          * Bit0 is set if it was a tx-done interrupt.
  61          * Bit1 is set when new rx-data is available.
  62          *    Until this bit is cleared there will be no other RXs.
  63          *
  64          * Bit31 is used for testing, it clears after a read.
  65          *    Writing 1 to this bit will cause an interrupt to be generated.
  66          *    To clear the test interrupt, write 0 to this register.
  67          */
  68         u32 interruptControl;   /*0x14 */
  69 #define MIPSNET_INTCTL_TXDONE     (1u << 0)
  70 #define MIPSNET_INTCTL_RXDONE     (1u << 1)
  71 #define MIPSNET_INTCTL_TESTBIT    (1u << 31)
  72
  73         /*
  74          * Readonly core-specific interrupt info for the device to signal
  75          * the core. The meaning of the contents of this field might change.
  76          */
  77         /* XXX: the whole memIntf interrupt scheme is messy: the device
  78          * should have no control what so ever of what VPE/register set is
  79          * being used.
  80          * The MemIntf should only expose interrupt lines, and something in
  81          * the config should be responsible for the line<->core/vpe bindings.
  82          */
  83         u32 interruptInfo;      /*0x18 */
  84
  85         /*
  86          * This is where the received data is read out.
  87          * There is more data to read until rxDataReady is 0.
  88          * Only 1 byte at this regs offset is used.
  89          */
  90         u32 rxDataBuffer;       /*0x1c */
  91
  92         /*
  93          * This is where the data to transmit is written.
  94          * Data should be written for the amount specified in the
  95          * txDataCount register.
  96          * Only 1 byte at this regs offset is used.
  97          */
  98         u32 txDataBuffer;       /*0x20 */
  99 };
 100
 101 #define regaddr(dev, field) \
 102   (dev->base_addr + offsetof(struct mipsnet_regs, field))
 103
 104 static char mipsnet_string[] = "mipsnet";
 105
 106 /*
 107  * Copy data from the MIPSNET rx data port
 108  */
 109 static int ioiocpy_frommipsnet(struct net_device *dev, unsigned char *kdata,
 110                         int len)
 111 {
 112         for (; len > 0; len--, kdata++)
 113                 *kdata = inb(regaddr(dev, rxDataBuffer));
 114
 115         return inl(regaddr(dev, rxDataCount));
 116 }
 117
 118 static inline void mipsnet_put_todevice(struct net_device *dev,
 119         struct sk_buff *skb)
 120 {
 121         int count_to_go = skb->len;
 122         char *buf_ptr = skb->data;
 123
 124         outl(skb->len, regaddr(dev, txDataCount));
 125
 126         for (; count_to_go; buf_ptr++, count_to_go--)
 127                 outb(*buf_ptr, regaddr(dev, txDataBuffer));
 128
 129         dev->stats.tx_packets++;
 130         dev->stats.tx_bytes += skb->len;
 131
 132         dev_kfree_skb(skb);
 133 }
 134
 135 static int mipsnet_xmit(struct sk_buff *skb, struct net_device *dev)
 136 {
 137         /*
 138          * Only one packet at a time. Once TXDONE interrupt is serviced, the
 139          * queue will be restarted.
 140          */
 141         netif_stop_queue(dev);
 142         mipsnet_put_todevice(dev, skb);
 143
 144         return 0;
 145 }
 146
 147 static inline ssize_t mipsnet_get_fromdev(struct net_device *dev, size_t len)
 148 {
 149         struct sk_buff *skb;
 150
 151         if (!len)
 152                 return len;
 153
 154         skb = dev_alloc_skb(len + NET_IP_ALIGN);
 155         if (!skb) {
 156                 dev->stats.rx_dropped++;
 157                 return -ENOMEM;
 158         }
 159
 160         skb_reserve(skb, NET_IP_ALIGN);
 161         if (ioiocpy_frommipsnet(dev, skb_put(skb, len), len))
 162                 return -EFAULT;
 163
 164         skb->protocol = eth_type_trans(skb, dev);
 165         skb->ip_summed = CHECKSUM_UNNECESSARY;
 166
 167         netif_rx(skb);
 168
 169         dev->stats.rx_packets++;
 170         dev->stats.rx_bytes += len;
 171
 172         return len;
 173 }
 174
 175 static irqreturn_t mipsnet_interrupt(int irq, void *dev_id)
 176 {
 177         struct net_device *dev = dev_id;
 178         u32 int_flags;
 179         irqreturn_t ret = IRQ_NONE;
 180
 181         if (irq != dev->irq)
 182                 goto out_badirq;
 183
 184         /* TESTBIT is cleared on read. */
 185         int_flags = inl(regaddr(dev, interruptControl));
 186         if (int_flags & MIPSNET_INTCTL_TESTBIT) {
 187                 /* TESTBIT takes effect after a write with 0. */
 188                 outl(0, regaddr(dev, interruptControl));
 189                 ret = IRQ_HANDLED;
 190         } else if (int_flags & MIPSNET_INTCTL_TXDONE) {
 191                 /* Only one packet at a time, we are done. */
 192                 dev->stats.tx_packets++;
 193                 netif_wake_queue(dev);
 194                 outl(MIPSNET_INTCTL_TXDONE,
 195                      regaddr(dev, interruptControl));
 196                 ret = IRQ_HANDLED;
 197         } else if (int_flags & MIPSNET_INTCTL_RXDONE) {
 198                 mipsnet_get_fromdev(dev, inl(regaddr(dev, rxDataCount)));
 199                 outl(MIPSNET_INTCTL_RXDONE, regaddr(dev, interruptControl));
 200                 ret = IRQ_HANDLED;
 201         }
 202         return ret;
 203
 204 out_badirq:
 205         printk(KERN_INFO "%s: %s(): irq %d for unknown device\n",
 206                dev->name, __FUNCTION__, irq);
 207         return ret;
 208 }
 209
 210 static int mipsnet_open(struct net_device *dev)
 211 {
 212         int err;
 213
 214         err = request_irq(dev->irq, &mipsnet_interrupt,
 215                           IRQF_SHARED, dev->name, (void *) dev);
 216         if (err) {
 217                 release_region(dev->base_addr, sizeof(struct mipsnet_regs));
 218                 return err;
 219         }
 220
 221         netif_start_queue(dev);
 222
 223         /* test interrupt handler */
 224         outl(MIPSNET_INTCTL_TESTBIT, regaddr(dev, interruptControl));
 225
 226         return 0;
 227 }
 228
 229 static int mipsnet_close(struct net_device *dev)
 230 {
 231         netif_stop_queue(dev);
 232         free_irq(dev->irq, dev);
 233         return 0;
 234 }
 235
 236 static void mipsnet_set_mclist(struct net_device *dev)
 237 {
 238 }
 239
 240 static int __init mipsnet_probe(struct device *dev)
 241 {
 242         struct net_device *netdev;
 243         int err;
 244
 245         netdev = alloc_etherdev(0);
 246         if (!netdev) {
 247                 err = -ENOMEM;
 248                 goto out;
 249         }
 250
 251         dev_set_drvdata(dev, netdev);
 252
 253         netdev->open                    = mipsnet_open;
 254         netdev->stop                    = mipsnet_close;
 255         netdev->hard_start_xmit         = mipsnet_xmit;
 256         netdev->set_multicast_list      = mipsnet_set_mclist;
 257
 258         /*
 259          * TODO: probe for these or load them from PARAM
 260          */
 261         netdev->base_addr = 0x4200;
 262         netdev->irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_MB0 +
 263                       inl(regaddr(netdev, interruptInfo));
 264
 265         /* Get the io region now, get irq on open() */
 266         if (!request_region(netdev->base_addr, sizeof(struct mipsnet_regs),
 267                             "mipsnet")) {
 268                 err = -EBUSY;
 269                 goto out_free_netdev;
 270         }
 271
 272         /*
 273          * Lacking any better mechanism to allocate a MAC address we use a
 274          * random one ...
 275          */
 276         random_ether_addr(netdev->dev_addr);
 277
 278         err = register_netdev(netdev);
 279         if (err) {
 280                 printk(KERN_ERR "MIPSNet: failed to register netdev.\n");
 281                 goto out_free_region;
 282         }
 283
 284         return 0;
 285
 286 out_free_region:
 287         release_region(netdev->base_addr, sizeof(struct mipsnet_regs));
 288
 289 out_free_netdev:
 290         free_netdev(netdev);
 291
 292 out:
 293         return err;
 294 }
 295
 296 static int __devexit mipsnet_device_remove(struct device *device)
 297 {
 298         struct net_device *dev = dev_get_drvdata(device);
 299
 300         unregister_netdev(dev);
 301         release_region(dev->base_addr, sizeof(struct mipsnet_regs));
 302         free_netdev(dev);
 303         dev_set_drvdata(device, NULL);
 304
 305         return 0;
 306 }
 307
 308 static struct device_driver mipsnet_driver = {
 309         .name   = mipsnet_string,
 310         .bus    = &platform_bus_type,
 311         .probe  = mipsnet_probe,
 312         .remove = __devexit_p(mipsnet_device_remove),
 313 };
 314
 315 static int __init mipsnet_init_module(void)
 316 {
 317         int err;
 318
 319         printk(KERN_INFO "MIPSNet Ethernet driver. Version: %s. "
 320                "(c)2005 MIPS Technologies, Inc.\n", MIPSNET_VERSION);
 321
 322         err = driver_register(&mipsnet_driver);
 323         if (err)
 324                 printk(KERN_ERR "Driver registration failed\n");
 325
 326         return err;
 327 }
 328
 329 static void __exit mipsnet_exit_module(void)
 330 {
 331         driver_unregister(&mipsnet_driver);
 332 }
 333
 334 module_init(mipsnet_init_module);
 335 module_exit(mipsnet_exit_module);