drivers/net/hamradio/dmascc.c

   1 /*
   2  * Driver for high-speed SCC boards (those with DMA support)
   3  * Copyright (C) 1997-2000 Klaus Kudielka
   4  *
   5  * S5SCC/DMA support by Janko Koleznik S52HI
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22
  23 #include <linux/module.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/in.h>
  28 #include <linux/init.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/ioport.h>
  31 #include <linux/kernel.h>
  32 #include <linux/mm.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/rtnetlink.h>
  35 #include <linux/sockios.h>
  36 #include <linux/workqueue.h>
  37 #include <asm/atomic.h>
  38 #include <asm/bitops.h>
  39 #include <asm/dma.h>
  40 #include <asm/io.h>
  41 #include <asm/irq.h>
  42 #include <asm/uaccess.h>
  43 #include <net/ax25.h>
  44 #include "z8530.h"
  45
  46
  47 /* Number of buffers per channel */
  48
  49 #define NUM_TX_BUF      2       /* NUM_TX_BUF >= 1 (min. 2 recommended) */
  50 #define NUM_RX_BUF      6       /* NUM_RX_BUF >= 1 (min. 2 recommended) */
  51 #define BUF_SIZE        1576    /* BUF_SIZE >= mtu + hard_header_len */
  52
  53
  54 /* Cards supported */
  55
  56 #define HW_PI           { "Ottawa PI", 0x300, 0x20, 0x10, 8, \
  57                             0, 8, 1843200, 3686400 }
  58 #define HW_PI2          { "Ottawa PI2", 0x300, 0x20, 0x10, 8, \
  59                             0, 8, 3686400, 7372800 }
  60 #define HW_TWIN         { "Gracilis PackeTwin", 0x200, 0x10, 0x10, 32, \
  61                             0, 4, 6144000, 6144000 }
  62 #define HW_S5           { "S5SCC/DMA", 0x200, 0x10, 0x10, 32, \
  63                           0, 8, 4915200, 9830400 }
  64
  65 #define HARDWARE        { HW_PI, HW_PI2, HW_TWIN, HW_S5 }
  66
  67 #define TMR_0_HZ        25600   /* Frequency of timer 0 */
  68
  69 #define TYPE_PI         0
  70 #define TYPE_PI2        1
  71 #define TYPE_TWIN       2
  72 #define TYPE_S5         3
  73 #define NUM_TYPES       4
  74
  75 #define MAX_NUM_DEVS    32
  76
  77
  78 /* SCC chips supported */
  79
  80 #define Z8530           0
  81 #define Z85C30          1
  82 #define Z85230          2
  83
  84 #define CHIPNAMES       { "Z8530", "Z85C30", "Z85230" }
  85
  86
  87 /* I/O registers */
  88
  89 /* 8530 registers relative to card base */
  90 #define SCCB_CMD        0x00
  91 #define SCCB_DATA       0x01
  92 #define SCCA_CMD        0x02
  93 #define SCCA_DATA       0x03
  94
  95 /* 8253/8254 registers relative to card base */
  96 #define TMR_CNT0        0x00
  97 #define TMR_CNT1        0x01
  98 #define TMR_CNT2        0x02
  99 #define TMR_CTRL        0x03
 100
 101 /* Additional PI/PI2 registers relative to card base */
 102 #define PI_DREQ_MASK    0x04
 103
 104 /* Additional PackeTwin registers relative to card base */
 105 #define TWIN_INT_REG    0x08
 106 #define TWIN_CLR_TMR1   0x09
 107 #define TWIN_CLR_TMR2   0x0a
 108 #define TWIN_SPARE_1    0x0b
 109 #define TWIN_DMA_CFG    0x08
 110 #define TWIN_SERIAL_CFG 0x09
 111 #define TWIN_DMA_CLR_FF 0x0a
 112 #define TWIN_SPARE_2    0x0b
 113
 114
 115 /* PackeTwin I/O register values */
 116
 117 /* INT_REG */
 118 #define TWIN_SCC_MSK       0x01
 119 #define TWIN_TMR1_MSK      0x02
 120 #define TWIN_TMR2_MSK      0x04
 121 #define TWIN_INT_MSK       0x07
 122
 123 /* SERIAL_CFG */
 124 #define TWIN_DTRA_ON       0x01
 125 #define TWIN_DTRB_ON       0x02
 126 #define TWIN_EXTCLKA       0x04
 127 #define TWIN_EXTCLKB       0x08
 128 #define TWIN_LOOPA_ON      0x10
 129 #define TWIN_LOOPB_ON      0x20
 130 #define TWIN_EI            0x80
 131
 132 /* DMA_CFG */
 133 #define TWIN_DMA_HDX_T1    0x08
 134 #define TWIN_DMA_HDX_R1    0x0a
 135 #define TWIN_DMA_HDX_T3    0x14
 136 #define TWIN_DMA_HDX_R3    0x16
 137 #define TWIN_DMA_FDX_T3R1  0x1b
 138 #define TWIN_DMA_FDX_T1R3  0x1d
 139
 140
 141 /* Status values */
 142
 143 #define IDLE      0
 144 #define TX_HEAD   1
 145 #define TX_DATA   2
 146 #define TX_PAUSE  3
 147 #define TX_TAIL   4
 148 #define RTS_OFF   5
 149 #define WAIT      6
 150 #define DCD_ON    7
 151 #define RX_ON     8
 152 #define DCD_OFF   9
 153
 154
 155 /* Ioctls */
 156
 157 #define SIOCGSCCPARAM SIOCDEVPRIVATE
 158 #define SIOCSSCCPARAM (SIOCDEVPRIVATE+1)
 159
 160
 161 /* Data types */
 162
 163 struct scc_param {
 164         int pclk_hz;            /* frequency of BRG input (don't change) */
 165         int brg_tc;             /* BRG terminal count; BRG disabled if < 0 */
 166         int nrzi;               /* 0 (nrz), 1 (nrzi) */
 167         int clocks;             /* see dmascc_cfg documentation */
 168         int txdelay;            /* [1/TMR_0_HZ] */
 169         int txtimeout;          /* [1/HZ] */
 170         int txtail;             /* [1/TMR_0_HZ] */
 171         int waittime;           /* [1/TMR_0_HZ] */
 172         int slottime;           /* [1/TMR_0_HZ] */
 173         int persist;            /* 1 ... 256 */
 174         int dma;                /* -1 (disable), 0, 1, 3 */
 175         int txpause;            /* [1/TMR_0_HZ] */
 176         int rtsoff;             /* [1/TMR_0_HZ] */
 177         int dcdon;              /* [1/TMR_0_HZ] */
 178         int dcdoff;             /* [1/TMR_0_HZ] */
 179 };
 180
 181 struct scc_hardware {
 182         char *name;
 183         int io_region;
 184         int io_delta;
 185         int io_size;
 186         int num_devs;
 187         int scc_offset;
 188         int tmr_offset;
 189         int tmr_hz;
 190         int pclk_hz;
 191 };
 192
 193 struct scc_priv {
 194         int type;
 195         int chip;
 196         struct net_device *dev;
 197         struct scc_info *info;
 198         struct net_device_stats stats;
 199         int channel;
 200         int card_base, scc_cmd, scc_data;
 201         int tmr_cnt, tmr_ctrl, tmr_mode;
 202         struct scc_param param;
 203         char rx_buf[NUM_RX_BUF][BUF_SIZE];
 204         int rx_len[NUM_RX_BUF];
 205         int rx_ptr;
 206         struct work_struct rx_work;
 207         int rx_head, rx_tail, rx_count;
 208         int rx_over;
 209         char tx_buf[NUM_TX_BUF][BUF_SIZE];
 210         int tx_len[NUM_TX_BUF];
 211         int tx_ptr;
 212         int tx_head, tx_tail, tx_count;
 213         int state;
 214         unsigned long tx_start;
 215         int rr0;
 216         spinlock_t *register_lock;      /* Per scc_info */
 217         spinlock_t ring_lock;
 218 };
 219
 220 struct scc_info {
 221         int irq_used;
 222         int twin_serial_cfg;
 223         struct net_device *dev[2];
 224         struct scc_priv priv[2];
 225         struct scc_info *next;
 226         spinlock_t register_lock;       /* Per device register lock */
 227 };
 228
 229
 230 /* Function declarations */
 231 static int setup_adapter(int card_base, int type, int n) __init;
 232
 233 static void write_scc(struct scc_priv *priv, int reg, int val);
 234 static void write_scc_data(struct scc_priv *priv, int val, int fast);
 235 static int read_scc(struct scc_priv *priv, int reg);
 236 static int read_scc_data(struct scc_priv *priv);
 237
 238 static int scc_open(struct net_device *dev);
 239 static int scc_close(struct net_device *dev);
 240 static int scc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 241 static int scc_send_packet(struct sk_buff *skb, struct net_device *dev);
 242 static struct net_device_stats *scc_get_stats(struct net_device *dev);
 243 static int scc_set_mac_address(struct net_device *dev, void *sa);
 244
 245 static inline void tx_on(struct scc_priv *priv);
 246 static inline void rx_on(struct scc_priv *priv);
 247 static inline void rx_off(struct scc_priv *priv);
 248 static void start_timer(struct scc_priv *priv, int t, int r15);
 249 static inline unsigned char random(void);
 250
 251 static inline void z8530_isr(struct scc_info *info);
 252 static irqreturn_t scc_isr(int irq, void *dev_id, struct pt_regs *regs);
 253 static void rx_isr(struct scc_priv *priv);
 254 static void special_condition(struct scc_priv *priv, int rc);
 255 static void rx_bh(void *arg);
 256 static void tx_isr(struct scc_priv *priv);
 257 static void es_isr(struct scc_priv *priv);
 258 static void tm_isr(struct scc_priv *priv);
 259
 260
 261 /* Initialization variables */
 262
 263 static int io[MAX_NUM_DEVS] __initdata = { 0, };
 264
 265 /* Beware! hw[] is also used in cleanup_module(). */
 266 static struct scc_hardware hw[NUM_TYPES] __initdata_or_module = HARDWARE;
 267 static char ax25_broadcast[7] __initdata =
 268     { 'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1,
 269 '0' << 1 };
 270 static char ax25_test[7] __initdata =
 271     { 'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1,
 272 '1' << 1 };
 273
 274
 275 /* Global variables */
 276
 277 static struct scc_info *first;
 278 static unsigned long rand;
 279
 280
 281 MODULE_AUTHOR("Klaus Kudielka");
 282 MODULE_DESCRIPTION("Driver for high-speed SCC boards");
 283 MODULE_PARM(io, "1-" __MODULE_STRING(MAX_NUM_DEVS) "i");
 284 MODULE_LICENSE("GPL");
 285
 286 static void __exit dmascc_exit(void)
 287 {
 288         int i;
 289         struct scc_info *info;
 290
 291         while (first) {
 292                 info = first;
 293
 294                 /* Unregister devices */
 295                 for (i = 0; i < 2; i++)
 296                         unregister_netdev(info->dev[i]);
 297
 298                 /* Reset board */
 299                 if (info->priv[0].type == TYPE_TWIN)
 300                         outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 301                 write_scc(&info->priv[0], R9, FHWRES);
 302                 release_region(info->dev[0]->base_addr,
 303                                hw[info->priv[0].type].io_size);
 304
 305                 for (i = 0; i < 2; i++)
 306                         free_netdev(info->dev[i]);
 307
 308                 /* Free memory */
 309                 first = info->next;
 310                 kfree(info);
 311         }
 312 }
 313
 314 #ifndef MODULE
 315 void __init dmascc_setup(char *str, int *ints)
 316 {
 317         int i;
 318
 319         for (i = 0; i < MAX_NUM_DEVS && i < ints[0]; i++)
 320                 io[i] = ints[i + 1];
 321 }
 322 #endif
 323
 324 static int __init dmascc_init(void)
 325 {
 326         int h, i, j, n;
 327         int base[MAX_NUM_DEVS], tcmd[MAX_NUM_DEVS], t0[MAX_NUM_DEVS],
 328             t1[MAX_NUM_DEVS];
 329         unsigned t_val;
 330         unsigned long time, start[MAX_NUM_DEVS], delay[MAX_NUM_DEVS],
 331             counting[MAX_NUM_DEVS];
 332
 333         /* Initialize random number generator */
 334         rand = jiffies;
 335         /* Cards found = 0 */
 336         n = 0;
 337         /* Warning message */
 338         if (!io[0])
 339                 printk(KERN_INFO "dmascc: autoprobing (dangerous)\n");
 340
 341         /* Run autodetection for each card type */
 342         for (h = 0; h < NUM_TYPES; h++) {
 343
 344                 if (io[0]) {
 345                         /* User-specified I/O address regions */
 346                         for (i = 0; i < hw[h].num_devs; i++)
 347                                 base[i] = 0;
 348                         for (i = 0; i < MAX_NUM_DEVS && io[i]; i++) {
 349                                 j = (io[i] -
 350                                      hw[h].io_region) / hw[h].io_delta;
 351                                 if (j >= 0 && j < hw[h].num_devs
 352                                     && hw[h].io_region +
 353                                     j * hw[h].io_delta == io[i]) {
 354                                         base[j] = io[i];
 355                                 }
 356                         }
 357                 } else {
 358                         /* Default I/O address regions */
 359                         for (i = 0; i < hw[h].num_devs; i++) {
 360                                 base[i] =
 361                                     hw[h].io_region + i * hw[h].io_delta;
 362                         }
 363                 }
 364
 365                 /* Check valid I/O address regions */
 366                 for (i = 0; i < hw[h].num_devs; i++)
 367                         if (base[i]) {
 368                                 if (!request_region
 369                                     (base[i], hw[h].io_size, "dmascc"))
 370                                         base[i] = 0;
 371                                 else {
 372                                         tcmd[i] =
 373                                             base[i] + hw[h].tmr_offset +
 374                                             TMR_CTRL;
 375                                         t0[i] =
 376                                             base[i] + hw[h].tmr_offset +
 377                                             TMR_CNT0;
 378                                         t1[i] =
 379                                             base[i] + hw[h].tmr_offset +
 380                                             TMR_CNT1;
 381                                 }
 382                         }
 383
 384                 /* Start timers */
 385                 for (i = 0; i < hw[h].num_devs; i++)
 386                         if (base[i]) {
 387                                 /* Timer 0: LSB+MSB, Mode 3, TMR_0_HZ */
 388                                 outb(0x36, tcmd[i]);
 389                                 outb((hw[h].tmr_hz / TMR_0_HZ) & 0xFF,
 390                                      t0[i]);
 391                                 outb((hw[h].tmr_hz / TMR_0_HZ) >> 8,
 392                                      t0[i]);
 393                                 /* Timer 1: LSB+MSB, Mode 0, HZ/10 */
 394                                 outb(0x70, tcmd[i]);
 395                                 outb((TMR_0_HZ / HZ * 10) & 0xFF, t1[i]);
 396                                 outb((TMR_0_HZ / HZ * 10) >> 8, t1[i]);
 397                                 start[i] = jiffies;
 398                                 delay[i] = 0;
 399                                 counting[i] = 1;
 400                                 /* Timer 2: LSB+MSB, Mode 0 */
 401                                 outb(0xb0, tcmd[i]);
 402                         }
 403                 time = jiffies;
 404                 /* Wait until counter registers are loaded */
 405                 udelay(2000000 / TMR_0_HZ);
 406
 407                 /* Timing loop */
 408                 while (jiffies - time < 13) {
 409                         for (i = 0; i < hw[h].num_devs; i++)
 410                                 if (base[i] && counting[i]) {
 411                                         /* Read back Timer 1: latch; read LSB; read MSB */
 412                                         outb(0x40, tcmd[i]);
 413                                         t_val =
 414                                             inb(t1[i]) + (inb(t1[i]) << 8);
 415                                         /* Also check whether counter did wrap */
 416                                         if (t_val == 0
 417                                             || t_val > TMR_0_HZ / HZ * 10)
 418                                                 counting[i] = 0;
 419                                         delay[i] = jiffies - start[i];
 420                                 }
 421                 }
 422
 423                 /* Evaluate measurements */
 424                 for (i = 0; i < hw[h].num_devs; i++)
 425                         if (base[i]) {
 426                                 if ((delay[i] >= 9 && delay[i] <= 11) &&
 427                                     /* Ok, we have found an adapter */
 428                                     (setup_adapter(base[i], h, n) == 0))
 429                                         n++;
 430                                 else
 431                                         release_region(base[i],
 432                                                        hw[h].io_size);
 433                         }
 434
 435         }                       /* NUM_TYPES */
 436
 437         /* If any adapter was successfully initialized, return ok */
 438         if (n)
 439                 return 0;
 440
 441         /* If no adapter found, return error */
 442         printk(KERN_INFO "dmascc: no adapters found\n");
 443         return -EIO;
 444 }
 445
 446 module_init(dmascc_init);
 447 module_exit(dmascc_exit);
 448
 449 static void dev_setup(struct net_device *dev)
 450 {
 451         dev->type = ARPHRD_AX25;
 452         dev->hard_header_len = 73;
 453         dev->mtu = 1500;
 454         dev->addr_len = 7;
 455         dev->tx_queue_len = 64;
 456         memcpy(dev->broadcast, ax25_broadcast, 7);
 457         memcpy(dev->dev_addr, ax25_test, 7);
 458 }
 459
 460 static int __init setup_adapter(int card_base, int type, int n)
 461 {
 462         int i, irq, chip;
 463         struct scc_info *info;
 464         struct net_device *dev;
 465         struct scc_priv *priv;
 466         unsigned long time;
 467         unsigned int irqs;
 468         int tmr_base = card_base + hw[type].tmr_offset;
 469         int scc_base = card_base + hw[type].scc_offset;
 470         char *chipnames[] = CHIPNAMES;
 471
 472         /* Allocate memory */
 473         info = kmalloc(sizeof(struct scc_info), GFP_KERNEL | GFP_DMA);
 474         if (!info) {
 475                 printk(KERN_ERR "dmascc: "
 476                        "could not allocate memory for %s at %#3x\n",
 477                        hw[type].name, card_base);
 478                 goto out;
 479         }
 480
 481         /* Initialize what is necessary for write_scc and write_scc_data */
 482         memset(info, 0, sizeof(struct scc_info));
 483
 484         info->dev[0] = alloc_netdev(0, "", dev_setup);
 485         if (!info->dev[0]) {
 486                 printk(KERN_ERR "dmascc: "
 487                        "could not allocate memory for %s at %#3x\n",
 488                        hw[type].name, card_base);
 489                 goto out1;
 490         }
 491
 492         info->dev[1] = alloc_netdev(0, "", dev_setup);
 493         if (!info->dev[1]) {
 494                 printk(KERN_ERR "dmascc: "
 495                        "could not allocate memory for %s at %#3x\n",
 496                        hw[type].name, card_base);
 497                 goto out2;
 498         }
 499         spin_lock_init(&info->register_lock);
 500
 501         priv = &info->priv[0];
 502         priv->type = type;
 503         priv->card_base = card_base;
 504         priv->scc_cmd = scc_base + SCCA_CMD;
 505         priv->scc_data = scc_base + SCCA_DATA;
 506         priv->register_lock = &info->register_lock;
 507
 508         /* Reset SCC */
 509         write_scc(priv, R9, FHWRES | MIE | NV);
 510
 511         /* Determine type of chip by enabling SDLC/HDLC enhancements */
 512         write_scc(priv, R15, SHDLCE);
 513         if (!read_scc(priv, R15)) {
 514                 /* WR7' not present. This is an ordinary Z8530 SCC. */
 515                 chip = Z8530;
 516         } else {
 517                 /* Put one character in TX FIFO */
 518                 write_scc_data(priv, 0, 0);
 519                 if (read_scc(priv, R0) & Tx_BUF_EMP) {
 520                         /* TX FIFO not full. This is a Z85230 ESCC with a 4-byte FIFO. */
 521                         chip = Z85230;
 522                 } else {
 523                         /* TX FIFO full. This is a Z85C30 SCC with a 1-byte FIFO. */
 524                         chip = Z85C30;
 525                 }
 526         }
 527         write_scc(priv, R15, 0);
 528
 529         /* Start IRQ auto-detection */
 530         irqs = probe_irq_on();
 531
 532         /* Enable interrupts */
 533         if (type == TYPE_TWIN) {
 534                 outb(0, card_base + TWIN_DMA_CFG);
 535                 inb(card_base + TWIN_CLR_TMR1);
 536                 inb(card_base + TWIN_CLR_TMR2);
 537                 info->twin_serial_cfg = TWIN_EI;
 538                 outb(info->twin_serial_cfg, card_base + TWIN_SERIAL_CFG);
 539         } else {
 540                 write_scc(priv, R15, CTSIE);
 541                 write_scc(priv, R0, RES_EXT_INT);
 542                 write_scc(priv, R1, EXT_INT_ENAB);
 543         }
 544
 545         /* Start timer */
 546         outb(1, tmr_base + TMR_CNT1);
 547         outb(0, tmr_base + TMR_CNT1);
 548
 549         /* Wait and detect IRQ */
 550         time = jiffies;
 551         while (jiffies - time < 2 + HZ / TMR_0_HZ);
 552         irq = probe_irq_off(irqs);
 553
 554         /* Clear pending interrupt, disable interrupts */
 555         if (type == TYPE_TWIN) {
 556                 inb(card_base + TWIN_CLR_TMR1);
 557         } else {
 558                 write_scc(priv, R1, 0);
 559                 write_scc(priv, R15, 0);
 560                 write_scc(priv, R0, RES_EXT_INT);
 561         }
 562
 563         if (irq <= 0) {
 564                 printk(KERN_ERR
 565                        "dmascc: could not find irq of %s at %#3x (irq=%d)\n",
 566                        hw[type].name, card_base, irq);
 567                 goto out3;
 568         }
 569
 570         /* Set up data structures */
 571         for (i = 0; i < 2; i++) {
 572                 dev = info->dev[i];
 573                 priv = &info->priv[i];
 574                 priv->type = type;
 575                 priv->chip = chip;
 576                 priv->dev = dev;
 577                 priv->info = info;
 578                 priv->channel = i;
 579                 spin_lock_init(&priv->ring_lock);
 580                 priv->register_lock = &info->register_lock;
 581                 priv->card_base = card_base;
 582                 priv->scc_cmd = scc_base + (i ? SCCB_CMD : SCCA_CMD);
 583                 priv->scc_data = scc_base + (i ? SCCB_DATA : SCCA_DATA);
 584                 priv->tmr_cnt = tmr_base + (i ? TMR_CNT2 : TMR_CNT1);
 585                 priv->tmr_ctrl = tmr_base + TMR_CTRL;
 586                 priv->tmr_mode = i ? 0xb0 : 0x70;
 587                 priv->param.pclk_hz = hw[type].pclk_hz;
 588                 priv->param.brg_tc = -1;
 589                 priv->param.clocks = TCTRxCP | RCRTxCP;
 590                 priv->param.persist = 256;
 591                 priv->param.dma = -1;
 592                 INIT_WORK(&priv->rx_work, rx_bh, priv);
 593                 dev->priv = priv;
 594                 sprintf(dev->name, "dmascc%i", 2 * n + i);
 595                 SET_MODULE_OWNER(dev);
 596                 dev->base_addr = card_base;
 597                 dev->irq = irq;
 598                 dev->open = scc_open;
 599                 dev->stop = scc_close;
 600                 dev->do_ioctl = scc_ioctl;
 601                 dev->hard_start_xmit = scc_send_packet;
 602                 dev->get_stats = scc_get_stats;
 603                 dev->hard_header = ax25_encapsulate;
 604                 dev->rebuild_header = ax25_rebuild_header;
 605                 dev->set_mac_address = scc_set_mac_address;
 606         }
 607         if (register_netdev(info->dev[0])) {
 608                 printk(KERN_ERR "dmascc: could not register %s\n",
 609                        info->dev[0]->name);
 610                 goto out3;
 611         }
 612         if (register_netdev(info->dev[1])) {
 613                 printk(KERN_ERR "dmascc: could not register %s\n",
 614                        info->dev[1]->name);
 615                 goto out4;
 616         }
 617
 618
 619         info->next = first;
 620         first = info;
 621         printk(KERN_INFO "dmascc: found %s (%s) at %#3x, irq %d\n",
 622                hw[type].name, chipnames[chip], card_base, irq);
 623         return 0;
 624
 625       out4:
 626         unregister_netdev(info->dev[0]);
 627       out3:
 628         if (info->priv[0].type == TYPE_TWIN)
 629                 outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 630         write_scc(&info->priv[0], R9, FHWRES);
 631         free_netdev(info->dev[1]);
 632       out2:
 633         free_netdev(info->dev[0]);
 634       out1:
 635         kfree(info);
 636       out:
 637         return -1;
 638 }
 639
 640
 641 /* Driver functions */
 642
 643 static void write_scc(struct scc_priv *priv, int reg, int val)
 644 {
 645         unsigned long flags;
 646         switch (priv->type) {
 647         case TYPE_S5:
 648                 if (reg)
 649                         outb(reg, priv->scc_cmd);
 650                 outb(val, priv->scc_cmd);
 651                 return;
 652         case TYPE_TWIN:
 653                 if (reg)
 654                         outb_p(reg, priv->scc_cmd);
 655                 outb_p(val, priv->scc_cmd);
 656                 return;
 657         default:
 658                 spin_lock_irqsave(priv->register_lock, flags);
 659                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 660                 if (reg)
 661                         outb_p(reg, priv->scc_cmd);
 662                 outb_p(val, priv->scc_cmd);
 663                 outb(1, priv->card_base + PI_DREQ_MASK);
 664                 spin_unlock_irqrestore(priv->register_lock, flags);
 665                 return;
 666         }
 667 }
 668
 669
 670 static void write_scc_data(struct scc_priv *priv, int val, int fast)
 671 {
 672         unsigned long flags;
 673         switch (priv->type) {
 674         case TYPE_S5:
 675                 outb(val, priv->scc_data);
 676                 return;
 677         case TYPE_TWIN:
 678                 outb_p(val, priv->scc_data);
 679                 return;
 680         default:
 681                 if (fast)
 682                         outb_p(val, priv->scc_data);
 683                 else {
 684                         spin_lock_irqsave(priv->register_lock, flags);
 685                         outb_p(0, priv->card_base + PI_DREQ_MASK);
 686                         outb_p(val, priv->scc_data);
 687                         outb(1, priv->card_base + PI_DREQ_MASK);
 688                         spin_unlock_irqrestore(priv->register_lock, flags);
 689                 }
 690                 return;
 691         }
 692 }
 693
 694
 695 static int read_scc(struct scc_priv *priv, int reg)
 696 {
 697         int rc;
 698         unsigned long flags;
 699         switch (priv->type) {
 700         case TYPE_S5:
 701                 if (reg)
 702                         outb(reg, priv->scc_cmd);
 703                 return inb(priv->scc_cmd);
 704         case TYPE_TWIN:
 705                 if (reg)
 706                         outb_p(reg, priv->scc_cmd);
 707                 return inb_p(priv->scc_cmd);
 708         default:
 709                 spin_lock_irqsave(priv->register_lock, flags);
 710                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 711                 if (reg)
 712                         outb_p(reg, priv->scc_cmd);
 713                 rc = inb_p(priv->scc_cmd);
 714                 outb(1, priv->card_base + PI_DREQ_MASK);
 715                 spin_unlock_irqrestore(priv->register_lock, flags);
 716                 return rc;
 717         }
 718 }
 719
 720
 721 static int read_scc_data(struct scc_priv *priv)
 722 {
 723         int rc;
 724         unsigned long flags;
 725         switch (priv->type) {
 726         case TYPE_S5:
 727                 return inb(priv->scc_data);
 728         case TYPE_TWIN:
 729                 return inb_p(priv->scc_data);
 730         default:
 731                 spin_lock_irqsave(priv->register_lock, flags);
 732                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 733                 rc = inb_p(priv->scc_data);
 734                 outb(1, priv->card_base + PI_DREQ_MASK);
 735                 spin_unlock_irqrestore(priv->register_lock, flags);
 736                 return rc;
 737         }
 738 }
 739
 740
 741 static int scc_open(struct net_device *dev)
 742 {
 743         struct scc_priv *priv = dev->priv;
 744         struct scc_info *info = priv->info;
 745         int card_base = priv->card_base;
 746
 747         /* Request IRQ if not already used by other channel */
 748         if (!info->irq_used) {
 749                 if (request_irq(dev->irq, scc_isr, 0, "dmascc", info)) {
 750                         return -EAGAIN;
 751                 }
 752         }
 753         info->irq_used++;
 754
 755         /* Request DMA if required */
 756         if (priv->param.dma >= 0) {
 757                 if (request_dma(priv->param.dma, "dmascc")) {
 758                         if (--info->irq_used == 0)
 759                                 free_irq(dev->irq, info);
 760                         return -EAGAIN;
 761                 } else {
 762                         unsigned long flags = claim_dma_lock();
 763                         clear_dma_ff(priv->param.dma);
 764                         release_dma_lock(flags);
 765                 }
 766         }
 767
 768         /* Initialize local variables */
 769         priv->rx_ptr = 0;
 770         priv->rx_over = 0;
 771         priv->rx_head = priv->rx_tail = priv->rx_count = 0;
 772         priv->state = IDLE;
 773         priv->tx_head = priv->tx_tail = priv->tx_count = 0;
 774         priv->tx_ptr = 0;
 775
 776         /* Reset channel */
 777         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 778         /* X1 clock, SDLC mode */
 779         write_scc(priv, R4, SDLC | X1CLK);
 780         /* DMA */
 781         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
 782         /* 8 bit RX char, RX disable */
 783         write_scc(priv, R3, Rx8);
 784         /* 8 bit TX char, TX disable */
 785         write_scc(priv, R5, Tx8);
 786         /* SDLC address field */
 787         write_scc(priv, R6, 0);
 788         /* SDLC flag */
 789         write_scc(priv, R7, FLAG);
 790         switch (priv->chip) {
 791         case Z85C30:
 792                 /* Select WR7' */
 793                 write_scc(priv, R15, SHDLCE);
 794                 /* Auto EOM reset */
 795                 write_scc(priv, R7, AUTOEOM);
 796                 write_scc(priv, R15, 0);
 797                 break;
 798         case Z85230:
 799                 /* Select WR7' */
 800                 write_scc(priv, R15, SHDLCE);
 801                 /* The following bits are set (see 2.5.2.1):
 802                    - Automatic EOM reset
 803                    - Interrupt request if RX FIFO is half full
 804                    This bit should be ignored in DMA mode (according to the
 805                    documentation), but actually isn't. The receiver doesn't work if
 806                    it is set. Thus, we have to clear it in DMA mode.
 807                    - Interrupt/DMA request if TX FIFO is completely empty
 808                    a) If set, the ESCC behaves as if it had no TX FIFO (Z85C30
 809                    compatibility).
 810                    b) If cleared, DMA requests may follow each other very quickly,
 811                    filling up the TX FIFO.
 812                    Advantage: TX works even in case of high bus latency.
 813                    Disadvantage: Edge-triggered DMA request circuitry may miss
 814                    a request. No more data is delivered, resulting
 815                    in a TX FIFO underrun.
 816                    Both PI2 and S5SCC/DMA seem to work fine with TXFIFOE cleared.
 817                    The PackeTwin doesn't. I don't know about the PI, but let's
 818                    assume it behaves like the PI2.
 819                  */
 820                 if (priv->param.dma >= 0) {
 821                         if (priv->type == TYPE_TWIN)
 822                                 write_scc(priv, R7, AUTOEOM | TXFIFOE);
 823                         else
 824                                 write_scc(priv, R7, AUTOEOM);
 825                 } else {
 826                         write_scc(priv, R7, AUTOEOM | RXFIFOH);
 827                 }
 828                 write_scc(priv, R15, 0);
 829                 break;
 830         }
 831         /* Preset CRC, NRZ(I) encoding */
 832         write_scc(priv, R10, CRCPS | (priv->param.nrzi ? NRZI : NRZ));
 833
 834         /* Configure baud rate generator */
 835         if (priv->param.brg_tc >= 0) {
 836                 /* Program BR generator */
 837                 write_scc(priv, R12, priv->param.brg_tc & 0xFF);
 838                 write_scc(priv, R13, (priv->param.brg_tc >> 8) & 0xFF);
 839                 /* BRG source = SYS CLK; enable BRG; DTR REQ function (required by
 840                    PackeTwin, not connected on the PI2); set DPLL source to BRG */
 841                 write_scc(priv, R14, SSBR | DTRREQ | BRSRC | BRENABL);
 842                 /* Enable DPLL */
 843                 write_scc(priv, R14, SEARCH | DTRREQ | BRSRC | BRENABL);
 844         } else {
 845                 /* Disable BR generator */
 846                 write_scc(priv, R14, DTRREQ | BRSRC);
 847         }
 848
 849         /* Configure clocks */
 850         if (priv->type == TYPE_TWIN) {
 851                 /* Disable external TX clock receiver */
 852                 outb((info->twin_serial_cfg &=
 853                       ~(priv->channel ? TWIN_EXTCLKB : TWIN_EXTCLKA)),
 854                      card_base + TWIN_SERIAL_CFG);
 855         }
 856         write_scc(priv, R11, priv->param.clocks);
 857         if ((priv->type == TYPE_TWIN) && !(priv->param.clocks & TRxCOI)) {
 858                 /* Enable external TX clock receiver */
 859                 outb((info->twin_serial_cfg |=
 860                       (priv->channel ? TWIN_EXTCLKB : TWIN_EXTCLKA)),
 861                      card_base + TWIN_SERIAL_CFG);
 862         }
 863
 864         /* Configure PackeTwin */
 865         if (priv->type == TYPE_TWIN) {
 866                 /* Assert DTR, enable interrupts */
 867                 outb((info->twin_serial_cfg |= TWIN_EI |
 868                       (priv->channel ? TWIN_DTRB_ON : TWIN_DTRA_ON)),
 869                      card_base + TWIN_SERIAL_CFG);
 870         }
 871
 872         /* Read current status */
 873         priv->rr0 = read_scc(priv, R0);
 874         /* Enable DCD interrupt */
 875         write_scc(priv, R15, DCDIE);
 876
 877         netif_start_queue(dev);
 878
 879         return 0;
 880 }
 881
 882
 883 static int scc_close(struct net_device *dev)
 884 {
 885         struct scc_priv *priv = dev->priv;
 886         struct scc_info *info = priv->info;
 887         int card_base = priv->card_base;
 888
 889         netif_stop_queue(dev);
 890
 891         if (priv->type == TYPE_TWIN) {
 892                 /* Drop DTR */
 893                 outb((info->twin_serial_cfg &=
 894                       (priv->channel ? ~TWIN_DTRB_ON : ~TWIN_DTRA_ON)),
 895                      card_base + TWIN_SERIAL_CFG);
 896         }
 897
 898         /* Reset channel, free DMA and IRQ */
 899         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 900         if (priv->param.dma >= 0) {
 901                 if (priv->type == TYPE_TWIN)
 902                         outb(0, card_base + TWIN_DMA_CFG);
 903                 free_dma(priv->param.dma);
 904         }
 905         if (--info->irq_used == 0)
 906                 free_irq(dev->irq, info);
 907
 908         return 0;
 909 }
 910
 911
 912 static int scc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 913 {
 914         struct scc_priv *priv = dev->priv;
 915
 916         switch (cmd) {
 917         case SIOCGSCCPARAM:
 918                 if (copy_to_user
 919                     (ifr->ifr_data, &priv->param,
 920                      sizeof(struct scc_param)))
 921                         return -EFAULT;
 922                 return 0;
 923         case SIOCSSCCPARAM:
 924                 if (!capable(CAP_NET_ADMIN))
 925                         return -EPERM;
 926                 if (netif_running(dev))
 927                         return -EAGAIN;
 928                 if (copy_from_user
 929                     (&priv->param, ifr->ifr_data,
 930                      sizeof(struct scc_param)))
 931                         return -EFAULT;
 932                 return 0;
 933         default:
 934                 return -EINVAL;
 935         }
 936 }
 937
 938
 939 static int scc_send_packet(struct sk_buff *skb, struct net_device *dev)
 940 {
 941         struct scc_priv *priv = dev->priv;
 942         unsigned long flags;
 943         int i;
 944
 945         /* Temporarily stop the scheduler feeding us packets */
 946         netif_stop_queue(dev);
 947
 948         /* Transfer data to DMA buffer */
 949         i = priv->tx_head;
 950         memcpy(priv->tx_buf[i], skb->data + 1, skb->len - 1);
 951         priv->tx_len[i] = skb->len - 1;
 952
 953         /* Clear interrupts while we touch our circular buffers */
 954
 955         spin_lock_irqsave(&priv->ring_lock, flags);
 956         /* Move the ring buffer's head */
 957         priv->tx_head = (i + 1) % NUM_TX_BUF;
 958         priv->tx_count++;
 959
 960         /* If we just filled up the last buffer, leave queue stopped.
 961            The higher layers must wait until we have a DMA buffer
 962            to accept the data. */
 963         if (priv->tx_count < NUM_TX_BUF)
 964                 netif_wake_queue(dev);
 965
 966         /* Set new TX state */
 967         if (priv->state == IDLE) {
 968                 /* Assert RTS, start timer */
 969                 priv->state = TX_HEAD;
 970                 priv->tx_start = jiffies;
 971                 write_scc(priv, R5, TxCRC_ENAB | RTS | TxENAB | Tx8);
 972                 write_scc(priv, R15, 0);
 973                 start_timer(priv, priv->param.txdelay, 0);
 974         }
 975
 976         /* Turn interrupts back on and free buffer */
 977         spin_unlock_irqrestore(&priv->ring_lock, flags);
 978         dev_kfree_skb(skb);
 979
 980         return 0;
 981 }
 982
 983
 984 static struct net_device_stats *scc_get_stats(struct net_device *dev)
 985 {
 986         struct scc_priv *priv = dev->priv;
 987
 988         return &priv->stats;
 989 }
 990
 991
 992 static int scc_set_mac_address(struct net_device *dev, void *sa)
 993 {
 994         memcpy(dev->dev_addr, ((struct sockaddr *) sa)->sa_data,
 995                dev->addr_len);
 996         return 0;
 997 }
 998
 999
1000 static inline void tx_on(struct scc_priv *priv)
1001 {
1002         int i, n;
1003         unsigned long flags;
1004
1005         if (priv->param.dma >= 0) {
1006                 n = (priv->chip == Z85230) ? 3 : 1;
1007                 /* Program DMA controller */
1008                 flags = claim_dma_lock();
1009                 set_dma_mode(priv->param.dma, DMA_MODE_WRITE);
1010                 set_dma_addr(priv->param.dma,
1011                              (int) priv->tx_buf[priv->tx_tail] + n);
1012                 set_dma_count(priv->param.dma,
1013                               priv->tx_len[priv->tx_tail] - n);
1014                 release_dma_lock(flags);
1015                 /* Enable TX underrun interrupt */
1016                 write_scc(priv, R15, TxUIE);
1017                 /* Configure DREQ */
1018                 if (priv->type == TYPE_TWIN)
1019                         outb((priv->param.dma ==
1020                               1) ? TWIN_DMA_HDX_T1 : TWIN_DMA_HDX_T3,
1021                              priv->card_base + TWIN_DMA_CFG);
1022                 else
1023                         write_scc(priv, R1,
1024                                   EXT_INT_ENAB | WT_FN_RDYFN |
1025                                   WT_RDY_ENAB);
1026                 /* Write first byte(s) */
1027                 spin_lock_irqsave(priv->register_lock, flags);
1028                 for (i = 0; i < n; i++)
1029                         write_scc_data(priv,
1030                                        priv->tx_buf[priv->tx_tail][i], 1);
1031                 enable_dma(priv->param.dma);
1032                 spin_unlock_irqrestore(priv->register_lock, flags);
1033         } else {
1034                 write_scc(priv, R15, TxUIE);
1035                 write_scc(priv, R1,
1036                           EXT_INT_ENAB | WT_FN_RDYFN | TxINT_ENAB);
1037                 tx_isr(priv);
1038         }
1039         /* Reset EOM latch if we do not have the AUTOEOM feature */
1040         if (priv->chip == Z8530)
1041                 write_scc(priv, R0, RES_EOM_L);
1042 }
1043
1044
1045 static inline void rx_on(struct scc_priv *priv)
1046 {
1047         unsigned long flags;
1048
1049         /* Clear RX FIFO */
1050         while (read_scc(priv, R0) & Rx_CH_AV)
1051                 read_scc_data(priv);
1052         priv->rx_over = 0;
1053         if (priv->param.dma >= 0) {
1054                 /* Program DMA controller */
1055                 flags = claim_dma_lock();
1056                 set_dma_mode(priv->param.dma, DMA_MODE_READ);
1057                 set_dma_addr(priv->param.dma,
1058                              (int) priv->rx_buf[priv->rx_head]);
1059                 set_dma_count(priv->param.dma, BUF_SIZE);
1060                 release_dma_lock(flags);
1061                 enable_dma(priv->param.dma);
1062                 /* Configure PackeTwin DMA */
1063                 if (priv->type == TYPE_TWIN) {
1064                         outb((priv->param.dma ==
1065                               1) ? TWIN_DMA_HDX_R1 : TWIN_DMA_HDX_R3,
1066                              priv->card_base + TWIN_DMA_CFG);
1067                 }
1068                 /* Sp. cond. intr. only, ext int enable, RX DMA enable */
1069                 write_scc(priv, R1, EXT_INT_ENAB | INT_ERR_Rx |
1070                           WT_RDY_RT | WT_FN_RDYFN | WT_RDY_ENAB);
1071         } else {
1072                 /* Reset current frame */
1073                 priv->rx_ptr = 0;
1074                 /* Intr. on all Rx characters and Sp. cond., ext int enable */
1075                 write_scc(priv, R1, EXT_INT_ENAB | INT_ALL_Rx | WT_RDY_RT |
1076                           WT_FN_RDYFN);
1077         }
1078         write_scc(priv, R0, ERR_RES);
1079         write_scc(priv, R3, RxENABLE | Rx8 | RxCRC_ENAB);
1080 }
1081
1082
1083 static inline void rx_off(struct scc_priv *priv)
1084 {
1085         /* Disable receiver */
1086         write_scc(priv, R3, Rx8);
1087         /* Disable DREQ / RX interrupt */
1088         if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1089                 outb(0, priv->card_base + TWIN_DMA_CFG);
1090         else
1091                 write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1092         /* Disable DMA */
1093         if (priv->param.dma >= 0)
1094                 disable_dma(priv->param.dma);
1095 }
1096
1097
1098 static void start_timer(struct scc_priv *priv, int t, int r15)
1099 {
1100         unsigned long flags;
1101
1102         outb(priv->tmr_mode, priv->tmr_ctrl);
1103         if (t == 0) {
1104                 tm_isr(priv);
1105         } else if (t > 0) {
1106                 save_flags(flags);
1107                 cli();
1108                 outb(t & 0xFF, priv->tmr_cnt);
1109                 outb((t >> 8) & 0xFF, priv->tmr_cnt);
1110                 if (priv->type != TYPE_TWIN) {
1111                         write_scc(priv, R15, r15 | CTSIE);
1112                         priv->rr0 |= CTS;
1113                 }
1114                 restore_flags(flags);
1115         }
1116 }
1117
1118
1119 static inline unsigned char random(void)
1120 {
1121         /* See "Numerical Recipes in C", second edition, p. 284 */
1122         rand = rand * 1664525L + 1013904223L;
1123         return (unsigned char) (rand >> 24);
1124 }
1125
1126 static inline void z8530_isr(struct scc_info *info)
1127 {
1128         int is, i = 100;
1129
1130         while ((is = read_scc(&info->priv[0], R3)) && i--) {
1131                 if (is & CHARxIP) {
1132                         rx_isr(&info->priv[0]);
1133                 } else if (is & CHATxIP) {
1134                         tx_isr(&info->priv[0]);
1135                 } else if (is & CHAEXT) {
1136                         es_isr(&info->priv[0]);
1137                 } else if (is & CHBRxIP) {
1138                         rx_isr(&info->priv[1]);
1139                 } else if (is & CHBTxIP) {
1140                         tx_isr(&info->priv[1]);
1141                 } else {
1142                         es_isr(&info->priv[1]);
1143                 }
1144                 write_scc(&info->priv[0], R0, RES_H_IUS);
1145                 i++;
1146         }
1147         if (i < 0) {
1148                 printk(KERN_ERR "dmascc: stuck in ISR with RR3=0x%02x.\n",
1149                        is);
1150         }
1151         /* Ok, no interrupts pending from this 8530. The INT line should
1152            be inactive now. */
1153 }
1154
1155
1156 static irqreturn_t scc_isr(int irq, void *dev_id, struct pt_regs *regs)
1157 {
1158         struct scc_info *info = dev_id;
1159
1160         spin_lock(info->priv[0].register_lock);
1161         /* At this point interrupts are enabled, and the interrupt under service
1162            is already acknowledged, but masked off.
1163
1164            Interrupt processing: We loop until we know that the IRQ line is
1165            low. If another positive edge occurs afterwards during the ISR,
1166            another interrupt will be triggered by the interrupt controller
1167            as soon as the IRQ level is enabled again (see asm/irq.h).
1168
1169            Bottom-half handlers will be processed after scc_isr(). This is
1170            important, since we only have small ringbuffers and want new data
1171            to be fetched/delivered immediately. */
1172
1173         if (info->priv[0].type == TYPE_TWIN) {
1174                 int is, card_base = info->priv[0].card_base;
1175                 while ((is = ~inb(card_base + TWIN_INT_REG)) &
1176                        TWIN_INT_MSK) {
1177                         if (is & TWIN_SCC_MSK) {
1178                                 z8530_isr(info);
1179                         } else if (is & TWIN_TMR1_MSK) {
1180                                 inb(card_base + TWIN_CLR_TMR1);
1181                                 tm_isr(&info->priv[0]);
1182                         } else {
1183                                 inb(card_base + TWIN_CLR_TMR2);
1184                                 tm_isr(&info->priv[1]);
1185                         }
1186                 }
1187         } else
1188                 z8530_isr(info);
1189         spin_unlock(info->priv[0].register_lock);
1190         return IRQ_HANDLED;
1191 }
1192
1193
1194 static void rx_isr(struct scc_priv *priv)
1195 {
1196         if (priv->param.dma >= 0) {
1197                 /* Check special condition and perform error reset. See 2.4.7.5. */
1198                 special_condition(priv, read_scc(priv, R1));
1199                 write_scc(priv, R0, ERR_RES);
1200         } else {
1201                 /* Check special condition for each character. Error reset not necessary.
1202                    Same algorithm for SCC and ESCC. See 2.4.7.1 and 2.4.7.4. */
1203                 int rc;
1204                 while (read_scc(priv, R0) & Rx_CH_AV) {
1205                         rc = read_scc(priv, R1);
1206                         if (priv->rx_ptr < BUF_SIZE)
1207                                 priv->rx_buf[priv->rx_head][priv->
1208                                                             rx_ptr++] =
1209                                     read_scc_data(priv);
1210                         else {
1211                                 priv->rx_over = 2;
1212                                 read_scc_data(priv);
1213                         }
1214                         special_condition(priv, rc);
1215                 }
1216         }
1217 }
1218
1219
1220 static void special_condition(struct scc_priv *priv, int rc)
1221 {
1222         int cb;
1223         unsigned long flags;
1224
1225         /* See Figure 2-15. Only overrun and EOF need to be checked. */
1226
1227         if (rc & Rx_OVR) {
1228                 /* Receiver overrun */
1229                 priv->rx_over = 1;
1230                 if (priv->param.dma < 0)
1231                         write_scc(priv, R0, ERR_RES);
1232         } else if (rc & END_FR) {
1233                 /* End of frame. Get byte count */
1234                 if (priv->param.dma >= 0) {
1235                         flags = claim_dma_lock();
1236                         cb = BUF_SIZE - get_dma_residue(priv->param.dma) -
1237                             2;
1238                         release_dma_lock(flags);
1239                 } else {
1240                         cb = priv->rx_ptr - 2;
1241                 }
1242                 if (priv->rx_over) {
1243                         /* We had an overrun */
1244                         priv->stats.rx_errors++;
1245                         if (priv->rx_over == 2)
1246                                 priv->stats.rx_length_errors++;
1247                         else
1248                                 priv->stats.rx_fifo_errors++;
1249                         priv->rx_over = 0;
1250                 } else if (rc & CRC_ERR) {
1251                         /* Count invalid CRC only if packet length >= minimum */
1252                         if (cb >= 15) {
1253                                 priv->stats.rx_errors++;
1254                                 priv->stats.rx_crc_errors++;
1255                         }
1256                 } else {
1257                         if (cb >= 15) {
1258                                 if (priv->rx_count < NUM_RX_BUF - 1) {
1259                                         /* Put good frame in FIFO */
1260                                         priv->rx_len[priv->rx_head] = cb;
1261                                         priv->rx_head =
1262                                             (priv->rx_head +
1263                                              1) % NUM_RX_BUF;
1264                                         priv->rx_count++;
1265                                         schedule_work(&priv->rx_work);
1266                                 } else {
1267                                         priv->stats.rx_errors++;
1268                                         priv->stats.rx_over_errors++;
1269                                 }
1270                         }
1271                 }
1272                 /* Get ready for new frame */
1273                 if (priv->param.dma >= 0) {
1274                         flags = claim_dma_lock();
1275                         set_dma_addr(priv->param.dma,
1276                                      (int) priv->rx_buf[priv->rx_head]);
1277                         set_dma_count(priv->param.dma, BUF_SIZE);
1278                         release_dma_lock(flags);
1279                 } else {
1280                         priv->rx_ptr = 0;
1281                 }
1282         }
1283 }
1284
1285
1286 static void rx_bh(void *arg)
1287 {
1288         struct scc_priv *priv = arg;
1289         int i = priv->rx_tail;
1290         int cb;
1291         unsigned long flags;
1292         struct sk_buff *skb;
1293         unsigned char *data;
1294
1295         spin_lock_irqsave(&priv->ring_lock, flags);
1296         while (priv->rx_count) {
1297                 spin_unlock_irqrestore(&priv->ring_lock, flags);
1298                 cb = priv->rx_len[i];
1299                 /* Allocate buffer */
1300                 skb = dev_alloc_skb(cb + 1);
1301                 if (skb == NULL) {
1302                         /* Drop packet */
1303                         priv->stats.rx_dropped++;
1304                 } else {
1305                         /* Fill buffer */
1306                         data = skb_put(skb, cb + 1);
1307                         data[0] = 0;
1308                         memcpy(&data[1], priv->rx_buf[i], cb);
1309                         skb->protocol = ax25_type_trans(skb, priv->dev);
1310                         netif_rx(skb);
1311                         priv->dev->last_rx = jiffies;
1312                         priv->stats.rx_packets++;
1313                         priv->stats.rx_bytes += cb;
1314                 }
1315                 spin_lock_irqsave(&priv->ring_lock, flags);
1316                 /* Move tail */
1317                 priv->rx_tail = i = (i + 1) % NUM_RX_BUF;
1318                 priv->rx_count--;
1319         }
1320         spin_unlock_irqrestore(&priv->ring_lock, flags);
1321 }
1322
1323
1324 static void tx_isr(struct scc_priv *priv)
1325 {
1326         int i = priv->tx_tail, p = priv->tx_ptr;
1327
1328         /* Suspend TX interrupts if we don't want to send anything.
1329            See Figure 2-22. */
1330         if (p == priv->tx_len[i]) {
1331                 write_scc(priv, R0, RES_Tx_P);
1332                 return;
1333         }
1334
1335         /* Write characters */
1336         while ((read_scc(priv, R0) & Tx_BUF_EMP) && p < priv->tx_len[i]) {
1337                 write_scc_data(priv, priv->tx_buf[i][p++], 0);
1338         }
1339
1340         /* Reset EOM latch of Z8530 */
1341         if (!priv->tx_ptr && p && priv->chip == Z8530)
1342                 write_scc(priv, R0, RES_EOM_L);
1343
1344         priv->tx_ptr = p;
1345 }
1346
1347
1348 static void es_isr(struct scc_priv *priv)
1349 {
1350         int i, rr0, drr0, res;
1351         unsigned long flags;
1352
1353         /* Read status, reset interrupt bit (open latches) */
1354         rr0 = read_scc(priv, R0);
1355         write_scc(priv, R0, RES_EXT_INT);
1356         drr0 = priv->rr0 ^ rr0;
1357         priv->rr0 = rr0;
1358
1359         /* Transmit underrun (2.4.9.6). We can't check the TxEOM flag, since
1360            it might have already been cleared again by AUTOEOM. */
1361         if (priv->state == TX_DATA) {
1362                 /* Get remaining bytes */
1363                 i = priv->tx_tail;
1364                 if (priv->param.dma >= 0) {
1365                         disable_dma(priv->param.dma);
1366                         flags = claim_dma_lock();
1367                         res = get_dma_residue(priv->param.dma);
1368                         release_dma_lock(flags);
1369                 } else {
1370                         res = priv->tx_len[i] - priv->tx_ptr;
1371                         priv->tx_ptr = 0;
1372                 }
1373                 /* Disable DREQ / TX interrupt */
1374                 if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1375                         outb(0, priv->card_base + TWIN_DMA_CFG);
1376                 else
1377                         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1378                 if (res) {
1379                         /* Update packet statistics */
1380                         priv->stats.tx_errors++;
1381                         priv->stats.tx_fifo_errors++;
1382                         /* Other underrun interrupts may already be waiting */
1383                         write_scc(priv, R0, RES_EXT_INT);
1384                         write_scc(priv, R0, RES_EXT_INT);
1385                 } else {
1386                         /* Update packet statistics */
1387                         priv->stats.tx_packets++;
1388                         priv->stats.tx_bytes += priv->tx_len[i];
1389                         /* Remove frame from FIFO */
1390                         priv->tx_tail = (i + 1) % NUM_TX_BUF;
1391                         priv->tx_count--;
1392                         /* Inform upper layers */
1393                         netif_wake_queue(priv->dev);
1394                 }
1395                 /* Switch state */
1396                 write_scc(priv, R15, 0);
1397                 if (priv->tx_count &&
1398                     (jiffies - priv->tx_start) < priv->param.txtimeout) {
1399                         priv->state = TX_PAUSE;
1400                         start_timer(priv, priv->param.txpause, 0);
1401                 } else {
1402                         priv->state = TX_TAIL;
1403                         start_timer(priv, priv->param.txtail, 0);
1404                 }
1405         }
1406
1407         /* DCD transition */
1408         if (drr0 & DCD) {
1409                 if (rr0 & DCD) {
1410                         switch (priv->state) {
1411                         case IDLE:
1412                         case WAIT:
1413                                 priv->state = DCD_ON;
1414                                 write_scc(priv, R15, 0);
1415                                 start_timer(priv, priv->param.dcdon, 0);
1416                         }
1417                 } else {
1418                         switch (priv->state) {
1419                         case RX_ON:
1420                                 rx_off(priv);
1421                                 priv->state = DCD_OFF;
1422                                 write_scc(priv, R15, 0);
1423                                 start_timer(priv, priv->param.dcdoff, 0);
1424                         }
1425                 }
1426         }
1427
1428         /* CTS transition */
1429         if ((drr0 & CTS) && (~rr0 & CTS) && priv->type != TYPE_TWIN)
1430                 tm_isr(priv);
1431
1432 }
1433
1434
1435 static void tm_isr(struct scc_priv *priv)
1436 {
1437         switch (priv->state) {
1438         case TX_HEAD:
1439         case TX_PAUSE:
1440                 tx_on(priv);
1441                 priv->state = TX_DATA;
1442                 break;
1443         case TX_TAIL:
1444                 write_scc(priv, R5, TxCRC_ENAB | Tx8);
1445                 priv->state = RTS_OFF;
1446                 if (priv->type != TYPE_TWIN)
1447                         write_scc(priv, R15, 0);
1448                 start_timer(priv, priv->param.rtsoff, 0);
1449                 break;
1450         case RTS_OFF:
1451                 write_scc(priv, R15, DCDIE);
1452                 priv->rr0 = read_scc(priv, R0);
1453                 if (priv->rr0 & DCD) {
1454                         priv->stats.collisions++;
1455                         rx_on(priv);
1456                         priv->state = RX_ON;
1457                 } else {
1458                         priv->state = WAIT;
1459                         start_timer(priv, priv->param.waittime, DCDIE);
1460                 }
1461                 break;
1462         case WAIT:
1463                 if (priv->tx_count) {
1464                         priv->state = TX_HEAD;
1465                         priv->tx_start = jiffies;
1466                         write_scc(priv, R5,
1467                                   TxCRC_ENAB | RTS | TxENAB | Tx8);
1468                         write_scc(priv, R15, 0);
1469                         start_timer(priv, priv->param.txdelay, 0);
1470                 } else {
1471                         priv->state = IDLE;
1472                         if (priv->type != TYPE_TWIN)
1473                                 write_scc(priv, R15, DCDIE);
1474                 }
1475                 break;
1476         case DCD_ON:
1477         case DCD_OFF:
1478                 write_scc(priv, R15, DCDIE);
1479                 priv->rr0 = read_scc(priv, R0);
1480                 if (priv->rr0 & DCD) {
1481                         rx_on(priv);
1482                         priv->state = RX_ON;
1483                 } else {
1484                         priv->state = WAIT;
1485                         start_timer(priv,
1486                                     random() / priv->param.persist *
1487                                     priv->param.slottime, DCDIE);
1488                 }
1489                 break;
1490         }
1491 }