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/bitops.h>
  25 #include <linux/delay.h>
  26 #include <linux/errno.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/in.h>
  29 #include <linux/init.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/ioport.h>
  32 #include <linux/kernel.h>
  33 #include <linux/mm.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/sockios.h>
  37 #include <linux/workqueue.h>
  38 #include <asm/atomic.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);
 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(struct work_struct *);
 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 dmascc_exit(). */
 266 static struct scc_hardware hw[NUM_TYPES] = HARDWARE;
 267
 268
 269 /* Global variables */
 270
 271 static struct scc_info *first;
 272 static unsigned long rand;
 273
 274
 275 MODULE_AUTHOR("Klaus Kudielka");
 276 MODULE_DESCRIPTION("Driver for high-speed SCC boards");
 277 module_param_array(io, int, NULL, 0);
 278 MODULE_LICENSE("GPL");
 279
 280 static void __exit dmascc_exit(void)
 281 {
 282         int i;
 283         struct scc_info *info;
 284
 285         while (first) {
 286                 info = first;
 287
 288                 /* Unregister devices */
 289                 for (i = 0; i < 2; i++)
 290                         unregister_netdev(info->dev[i]);
 291
 292                 /* Reset board */
 293                 if (info->priv[0].type == TYPE_TWIN)
 294                         outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 295                 write_scc(&info->priv[0], R9, FHWRES);
 296                 release_region(info->dev[0]->base_addr,
 297                                hw[info->priv[0].type].io_size);
 298
 299                 for (i = 0; i < 2; i++)
 300                         free_netdev(info->dev[i]);
 301
 302                 /* Free memory */
 303                 first = info->next;
 304                 kfree(info);
 305         }
 306 }
 307
 308 static int __init dmascc_init(void)
 309 {
 310         int h, i, j, n;
 311         int base[MAX_NUM_DEVS], tcmd[MAX_NUM_DEVS], t0[MAX_NUM_DEVS],
 312             t1[MAX_NUM_DEVS];
 313         unsigned t_val;
 314         unsigned long time, start[MAX_NUM_DEVS], delay[MAX_NUM_DEVS],
 315             counting[MAX_NUM_DEVS];
 316
 317         /* Initialize random number generator */
 318         rand = jiffies;
 319         /* Cards found = 0 */
 320         n = 0;
 321         /* Warning message */
 322         if (!io[0])
 323                 printk(KERN_INFO "dmascc: autoprobing (dangerous)\n");
 324
 325         /* Run autodetection for each card type */
 326         for (h = 0; h < NUM_TYPES; h++) {
 327
 328                 if (io[0]) {
 329                         /* User-specified I/O address regions */
 330                         for (i = 0; i < hw[h].num_devs; i++)
 331                                 base[i] = 0;
 332                         for (i = 0; i < MAX_NUM_DEVS && io[i]; i++) {
 333                                 j = (io[i] -
 334                                      hw[h].io_region) / hw[h].io_delta;
 335                                 if (j >= 0 && j < hw[h].num_devs
 336                                     && hw[h].io_region +
 337                                     j * hw[h].io_delta == io[i]) {
 338                                         base[j] = io[i];
 339                                 }
 340                         }
 341                 } else {
 342                         /* Default I/O address regions */
 343                         for (i = 0; i < hw[h].num_devs; i++) {
 344                                 base[i] =
 345                                     hw[h].io_region + i * hw[h].io_delta;
 346                         }
 347                 }
 348
 349                 /* Check valid I/O address regions */
 350                 for (i = 0; i < hw[h].num_devs; i++)
 351                         if (base[i]) {
 352                                 if (!request_region
 353                                     (base[i], hw[h].io_size, "dmascc"))
 354                                         base[i] = 0;
 355                                 else {
 356                                         tcmd[i] =
 357                                             base[i] + hw[h].tmr_offset +
 358                                             TMR_CTRL;
 359                                         t0[i] =
 360                                             base[i] + hw[h].tmr_offset +
 361                                             TMR_CNT0;
 362                                         t1[i] =
 363                                             base[i] + hw[h].tmr_offset +
 364                                             TMR_CNT1;
 365                                 }
 366                         }
 367
 368                 /* Start timers */
 369                 for (i = 0; i < hw[h].num_devs; i++)
 370                         if (base[i]) {
 371                                 /* Timer 0: LSB+MSB, Mode 3, TMR_0_HZ */
 372                                 outb(0x36, tcmd[i]);
 373                                 outb((hw[h].tmr_hz / TMR_0_HZ) & 0xFF,
 374                                      t0[i]);
 375                                 outb((hw[h].tmr_hz / TMR_0_HZ) >> 8,
 376                                      t0[i]);
 377                                 /* Timer 1: LSB+MSB, Mode 0, HZ/10 */
 378                                 outb(0x70, tcmd[i]);
 379                                 outb((TMR_0_HZ / HZ * 10) & 0xFF, t1[i]);
 380                                 outb((TMR_0_HZ / HZ * 10) >> 8, t1[i]);
 381                                 start[i] = jiffies;
 382                                 delay[i] = 0;
 383                                 counting[i] = 1;
 384                                 /* Timer 2: LSB+MSB, Mode 0 */
 385                                 outb(0xb0, tcmd[i]);
 386                         }
 387                 time = jiffies;
 388                 /* Wait until counter registers are loaded */
 389                 udelay(2000000 / TMR_0_HZ);
 390
 391                 /* Timing loop */
 392                 while (jiffies - time < 13) {
 393                         for (i = 0; i < hw[h].num_devs; i++)
 394                                 if (base[i] && counting[i]) {
 395                                         /* Read back Timer 1: latch; read LSB; read MSB */
 396                                         outb(0x40, tcmd[i]);
 397                                         t_val =
 398                                             inb(t1[i]) + (inb(t1[i]) << 8);
 399                                         /* Also check whether counter did wrap */
 400                                         if (t_val == 0
 401                                             || t_val > TMR_0_HZ / HZ * 10)
 402                                                 counting[i] = 0;
 403                                         delay[i] = jiffies - start[i];
 404                                 }
 405                 }
 406
 407                 /* Evaluate measurements */
 408                 for (i = 0; i < hw[h].num_devs; i++)
 409                         if (base[i]) {
 410                                 if ((delay[i] >= 9 && delay[i] <= 11) &&
 411                                     /* Ok, we have found an adapter */
 412                                     (setup_adapter(base[i], h, n) == 0))
 413                                         n++;
 414                                 else
 415                                         release_region(base[i],
 416                                                        hw[h].io_size);
 417                         }
 418
 419         }                       /* NUM_TYPES */
 420
 421         /* If any adapter was successfully initialized, return ok */
 422         if (n)
 423                 return 0;
 424
 425         /* If no adapter found, return error */
 426         printk(KERN_INFO "dmascc: no adapters found\n");
 427         return -EIO;
 428 }
 429
 430 module_init(dmascc_init);
 431 module_exit(dmascc_exit);
 432
 433 static void __init dev_setup(struct net_device *dev)
 434 {
 435         dev->type = ARPHRD_AX25;
 436         dev->hard_header_len = AX25_MAX_HEADER_LEN;
 437         dev->mtu = 1500;
 438         dev->addr_len = AX25_ADDR_LEN;
 439         dev->tx_queue_len = 64;
 440         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 441         memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
 442 }
 443
 444 static int __init setup_adapter(int card_base, int type, int n)
 445 {
 446         int i, irq, chip;
 447         struct scc_info *info;
 448         struct net_device *dev;
 449         struct scc_priv *priv;
 450         unsigned long time;
 451         unsigned int irqs;
 452         int tmr_base = card_base + hw[type].tmr_offset;
 453         int scc_base = card_base + hw[type].scc_offset;
 454         char *chipnames[] = CHIPNAMES;
 455
 456         /* Initialize what is necessary for write_scc and write_scc_data */
 457         info = kzalloc(sizeof(struct scc_info), GFP_KERNEL | GFP_DMA);
 458         if (!info) {
 459                 printk(KERN_ERR "dmascc: "
 460                        "could not allocate memory for %s at %#3x\n",
 461                        hw[type].name, card_base);
 462                 goto out;
 463         }
 464
 465
 466         info->dev[0] = alloc_netdev(0, "", dev_setup);
 467         if (!info->dev[0]) {
 468                 printk(KERN_ERR "dmascc: "
 469                        "could not allocate memory for %s at %#3x\n",
 470                        hw[type].name, card_base);
 471                 goto out1;
 472         }
 473
 474         info->dev[1] = alloc_netdev(0, "", dev_setup);
 475         if (!info->dev[1]) {
 476                 printk(KERN_ERR "dmascc: "
 477                        "could not allocate memory for %s at %#3x\n",
 478                        hw[type].name, card_base);
 479                 goto out2;
 480         }
 481         spin_lock_init(&info->register_lock);
 482
 483         priv = &info->priv[0];
 484         priv->type = type;
 485         priv->card_base = card_base;
 486         priv->scc_cmd = scc_base + SCCA_CMD;
 487         priv->scc_data = scc_base + SCCA_DATA;
 488         priv->register_lock = &info->register_lock;
 489
 490         /* Reset SCC */
 491         write_scc(priv, R9, FHWRES | MIE | NV);
 492
 493         /* Determine type of chip by enabling SDLC/HDLC enhancements */
 494         write_scc(priv, R15, SHDLCE);
 495         if (!read_scc(priv, R15)) {
 496                 /* WR7' not present. This is an ordinary Z8530 SCC. */
 497                 chip = Z8530;
 498         } else {
 499                 /* Put one character in TX FIFO */
 500                 write_scc_data(priv, 0, 0);
 501                 if (read_scc(priv, R0) & Tx_BUF_EMP) {
 502                         /* TX FIFO not full. This is a Z85230 ESCC with a 4-byte FIFO. */
 503                         chip = Z85230;
 504                 } else {
 505                         /* TX FIFO full. This is a Z85C30 SCC with a 1-byte FIFO. */
 506                         chip = Z85C30;
 507                 }
 508         }
 509         write_scc(priv, R15, 0);
 510
 511         /* Start IRQ auto-detection */
 512         irqs = probe_irq_on();
 513
 514         /* Enable interrupts */
 515         if (type == TYPE_TWIN) {
 516                 outb(0, card_base + TWIN_DMA_CFG);
 517                 inb(card_base + TWIN_CLR_TMR1);
 518                 inb(card_base + TWIN_CLR_TMR2);
 519                 info->twin_serial_cfg = TWIN_EI;
 520                 outb(info->twin_serial_cfg, card_base + TWIN_SERIAL_CFG);
 521         } else {
 522                 write_scc(priv, R15, CTSIE);
 523                 write_scc(priv, R0, RES_EXT_INT);
 524                 write_scc(priv, R1, EXT_INT_ENAB);
 525         }
 526
 527         /* Start timer */
 528         outb(1, tmr_base + TMR_CNT1);
 529         outb(0, tmr_base + TMR_CNT1);
 530
 531         /* Wait and detect IRQ */
 532         time = jiffies;
 533         while (jiffies - time < 2 + HZ / TMR_0_HZ);
 534         irq = probe_irq_off(irqs);
 535
 536         /* Clear pending interrupt, disable interrupts */
 537         if (type == TYPE_TWIN) {
 538                 inb(card_base + TWIN_CLR_TMR1);
 539         } else {
 540                 write_scc(priv, R1, 0);
 541                 write_scc(priv, R15, 0);
 542                 write_scc(priv, R0, RES_EXT_INT);
 543         }
 544
 545         if (irq <= 0) {
 546                 printk(KERN_ERR
 547                        "dmascc: could not find irq of %s at %#3x (irq=%d)\n",
 548                        hw[type].name, card_base, irq);
 549                 goto out3;
 550         }
 551
 552         /* Set up data structures */
 553         for (i = 0; i < 2; i++) {
 554                 dev = info->dev[i];
 555                 priv = &info->priv[i];
 556                 priv->type = type;
 557                 priv->chip = chip;
 558                 priv->dev = dev;
 559                 priv->info = info;
 560                 priv->channel = i;
 561                 spin_lock_init(&priv->ring_lock);
 562                 priv->register_lock = &info->register_lock;
 563                 priv->card_base = card_base;
 564                 priv->scc_cmd = scc_base + (i ? SCCB_CMD : SCCA_CMD);
 565                 priv->scc_data = scc_base + (i ? SCCB_DATA : SCCA_DATA);
 566                 priv->tmr_cnt = tmr_base + (i ? TMR_CNT2 : TMR_CNT1);
 567                 priv->tmr_ctrl = tmr_base + TMR_CTRL;
 568                 priv->tmr_mode = i ? 0xb0 : 0x70;
 569                 priv->param.pclk_hz = hw[type].pclk_hz;
 570                 priv->param.brg_tc = -1;
 571                 priv->param.clocks = TCTRxCP | RCRTxCP;
 572                 priv->param.persist = 256;
 573                 priv->param.dma = -1;
 574                 INIT_WORK(&priv->rx_work, rx_bh);
 575                 dev->priv = priv;
 576                 sprintf(dev->name, "dmascc%i", 2 * n + i);
 577                 dev->base_addr = card_base;
 578                 dev->irq = irq;
 579                 dev->open = scc_open;
 580                 dev->stop = scc_close;
 581                 dev->do_ioctl = scc_ioctl;
 582                 dev->hard_start_xmit = scc_send_packet;
 583                 dev->get_stats = scc_get_stats;
 584                 dev->header_ops = &ax25_header_ops;
 585                 dev->set_mac_address = scc_set_mac_address;
 586         }
 587         if (register_netdev(info->dev[0])) {
 588                 printk(KERN_ERR "dmascc: could not register %s\n",
 589                        info->dev[0]->name);
 590                 goto out3;
 591         }
 592         if (register_netdev(info->dev[1])) {
 593                 printk(KERN_ERR "dmascc: could not register %s\n",
 594                        info->dev[1]->name);
 595                 goto out4;
 596         }
 597
 598
 599         info->next = first;
 600         first = info;
 601         printk(KERN_INFO "dmascc: found %s (%s) at %#3x, irq %d\n",
 602                hw[type].name, chipnames[chip], card_base, irq);
 603         return 0;
 604
 605       out4:
 606         unregister_netdev(info->dev[0]);
 607       out3:
 608         if (info->priv[0].type == TYPE_TWIN)
 609                 outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 610         write_scc(&info->priv[0], R9, FHWRES);
 611         free_netdev(info->dev[1]);
 612       out2:
 613         free_netdev(info->dev[0]);
 614       out1:
 615         kfree(info);
 616       out:
 617         return -1;
 618 }
 619
 620
 621 /* Driver functions */
 622
 623 static void write_scc(struct scc_priv *priv, int reg, int val)
 624 {
 625         unsigned long flags;
 626         switch (priv->type) {
 627         case TYPE_S5:
 628                 if (reg)
 629                         outb(reg, priv->scc_cmd);
 630                 outb(val, priv->scc_cmd);
 631                 return;
 632         case TYPE_TWIN:
 633                 if (reg)
 634                         outb_p(reg, priv->scc_cmd);
 635                 outb_p(val, priv->scc_cmd);
 636                 return;
 637         default:
 638                 spin_lock_irqsave(priv->register_lock, flags);
 639                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 640                 if (reg)
 641                         outb_p(reg, priv->scc_cmd);
 642                 outb_p(val, priv->scc_cmd);
 643                 outb(1, priv->card_base + PI_DREQ_MASK);
 644                 spin_unlock_irqrestore(priv->register_lock, flags);
 645                 return;
 646         }
 647 }
 648
 649
 650 static void write_scc_data(struct scc_priv *priv, int val, int fast)
 651 {
 652         unsigned long flags;
 653         switch (priv->type) {
 654         case TYPE_S5:
 655                 outb(val, priv->scc_data);
 656                 return;
 657         case TYPE_TWIN:
 658                 outb_p(val, priv->scc_data);
 659                 return;
 660         default:
 661                 if (fast)
 662                         outb_p(val, priv->scc_data);
 663                 else {
 664                         spin_lock_irqsave(priv->register_lock, flags);
 665                         outb_p(0, priv->card_base + PI_DREQ_MASK);
 666                         outb_p(val, priv->scc_data);
 667                         outb(1, priv->card_base + PI_DREQ_MASK);
 668                         spin_unlock_irqrestore(priv->register_lock, flags);
 669                 }
 670                 return;
 671         }
 672 }
 673
 674
 675 static int read_scc(struct scc_priv *priv, int reg)
 676 {
 677         int rc;
 678         unsigned long flags;
 679         switch (priv->type) {
 680         case TYPE_S5:
 681                 if (reg)
 682                         outb(reg, priv->scc_cmd);
 683                 return inb(priv->scc_cmd);
 684         case TYPE_TWIN:
 685                 if (reg)
 686                         outb_p(reg, priv->scc_cmd);
 687                 return inb_p(priv->scc_cmd);
 688         default:
 689                 spin_lock_irqsave(priv->register_lock, flags);
 690                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 691                 if (reg)
 692                         outb_p(reg, priv->scc_cmd);
 693                 rc = inb_p(priv->scc_cmd);
 694                 outb(1, priv->card_base + PI_DREQ_MASK);
 695                 spin_unlock_irqrestore(priv->register_lock, flags);
 696                 return rc;
 697         }
 698 }
 699
 700
 701 static int read_scc_data(struct scc_priv *priv)
 702 {
 703         int rc;
 704         unsigned long flags;
 705         switch (priv->type) {
 706         case TYPE_S5:
 707                 return inb(priv->scc_data);
 708         case TYPE_TWIN:
 709                 return inb_p(priv->scc_data);
 710         default:
 711                 spin_lock_irqsave(priv->register_lock, flags);
 712                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 713                 rc = inb_p(priv->scc_data);
 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 scc_open(struct net_device *dev)
 722 {
 723         struct scc_priv *priv = dev->priv;
 724         struct scc_info *info = priv->info;
 725         int card_base = priv->card_base;
 726
 727         /* Request IRQ if not already used by other channel */
 728         if (!info->irq_used) {
 729                 if (request_irq(dev->irq, scc_isr, 0, "dmascc", info)) {
 730                         return -EAGAIN;
 731                 }
 732         }
 733         info->irq_used++;
 734
 735         /* Request DMA if required */
 736         if (priv->param.dma >= 0) {
 737                 if (request_dma(priv->param.dma, "dmascc")) {
 738                         if (--info->irq_used == 0)
 739                                 free_irq(dev->irq, info);
 740                         return -EAGAIN;
 741                 } else {
 742                         unsigned long flags = claim_dma_lock();
 743                         clear_dma_ff(priv->param.dma);
 744                         release_dma_lock(flags);
 745                 }
 746         }
 747
 748         /* Initialize local variables */
 749         priv->rx_ptr = 0;
 750         priv->rx_over = 0;
 751         priv->rx_head = priv->rx_tail = priv->rx_count = 0;
 752         priv->state = IDLE;
 753         priv->tx_head = priv->tx_tail = priv->tx_count = 0;
 754         priv->tx_ptr = 0;
 755
 756         /* Reset channel */
 757         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 758         /* X1 clock, SDLC mode */
 759         write_scc(priv, R4, SDLC | X1CLK);
 760         /* DMA */
 761         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
 762         /* 8 bit RX char, RX disable */
 763         write_scc(priv, R3, Rx8);
 764         /* 8 bit TX char, TX disable */
 765         write_scc(priv, R5, Tx8);
 766         /* SDLC address field */
 767         write_scc(priv, R6, 0);
 768         /* SDLC flag */
 769         write_scc(priv, R7, FLAG);
 770         switch (priv->chip) {
 771         case Z85C30:
 772                 /* Select WR7' */
 773                 write_scc(priv, R15, SHDLCE);
 774                 /* Auto EOM reset */
 775                 write_scc(priv, R7, AUTOEOM);
 776                 write_scc(priv, R15, 0);
 777                 break;
 778         case Z85230:
 779                 /* Select WR7' */
 780                 write_scc(priv, R15, SHDLCE);
 781                 /* The following bits are set (see 2.5.2.1):
 782                    - Automatic EOM reset
 783                    - Interrupt request if RX FIFO is half full
 784                    This bit should be ignored in DMA mode (according to the
 785                    documentation), but actually isn't. The receiver doesn't work if
 786                    it is set. Thus, we have to clear it in DMA mode.
 787                    - Interrupt/DMA request if TX FIFO is completely empty
 788                    a) If set, the ESCC behaves as if it had no TX FIFO (Z85C30
 789                    compatibility).
 790                    b) If cleared, DMA requests may follow each other very quickly,
 791                    filling up the TX FIFO.
 792                    Advantage: TX works even in case of high bus latency.
 793                    Disadvantage: Edge-triggered DMA request circuitry may miss
 794                    a request. No more data is delivered, resulting
 795                    in a TX FIFO underrun.
 796                    Both PI2 and S5SCC/DMA seem to work fine with TXFIFOE cleared.
 797                    The PackeTwin doesn't. I don't know about the PI, but let's
 798                    assume it behaves like the PI2.
 799                  */
 800                 if (priv->param.dma >= 0) {
 801                         if (priv->type == TYPE_TWIN)
 802                                 write_scc(priv, R7, AUTOEOM | TXFIFOE);
 803                         else
 804                                 write_scc(priv, R7, AUTOEOM);
 805                 } else {
 806                         write_scc(priv, R7, AUTOEOM | RXFIFOH);
 807                 }
 808                 write_scc(priv, R15, 0);
 809                 break;
 810         }
 811         /* Preset CRC, NRZ(I) encoding */
 812         write_scc(priv, R10, CRCPS | (priv->param.nrzi ? NRZI : NRZ));
 813
 814         /* Configure baud rate generator */
 815         if (priv->param.brg_tc >= 0) {
 816                 /* Program BR generator */
 817                 write_scc(priv, R12, priv->param.brg_tc & 0xFF);
 818                 write_scc(priv, R13, (priv->param.brg_tc >> 8) & 0xFF);
 819                 /* BRG source = SYS CLK; enable BRG; DTR REQ function (required by
 820                    PackeTwin, not connected on the PI2); set DPLL source to BRG */
 821                 write_scc(priv, R14, SSBR | DTRREQ | BRSRC | BRENABL);
 822                 /* Enable DPLL */
 823                 write_scc(priv, R14, SEARCH | DTRREQ | BRSRC | BRENABL);
 824         } else {
 825                 /* Disable BR generator */
 826                 write_scc(priv, R14, DTRREQ | BRSRC);
 827         }
 828
 829         /* Configure clocks */
 830         if (priv->type == TYPE_TWIN) {
 831                 /* Disable external TX clock receiver */
 832                 outb((info->twin_serial_cfg &=
 833                       ~(priv->channel ? TWIN_EXTCLKB : TWIN_EXTCLKA)),
 834                      card_base + TWIN_SERIAL_CFG);
 835         }
 836         write_scc(priv, R11, priv->param.clocks);
 837         if ((priv->type == TYPE_TWIN) && !(priv->param.clocks & TRxCOI)) {
 838                 /* Enable external TX clock receiver */
 839                 outb((info->twin_serial_cfg |=
 840                       (priv->channel ? TWIN_EXTCLKB : TWIN_EXTCLKA)),
 841                      card_base + TWIN_SERIAL_CFG);
 842         }
 843
 844         /* Configure PackeTwin */
 845         if (priv->type == TYPE_TWIN) {
 846                 /* Assert DTR, enable interrupts */
 847                 outb((info->twin_serial_cfg |= TWIN_EI |
 848                       (priv->channel ? TWIN_DTRB_ON : TWIN_DTRA_ON)),
 849                      card_base + TWIN_SERIAL_CFG);
 850         }
 851
 852         /* Read current status */
 853         priv->rr0 = read_scc(priv, R0);
 854         /* Enable DCD interrupt */
 855         write_scc(priv, R15, DCDIE);
 856
 857         netif_start_queue(dev);
 858
 859         return 0;
 860 }
 861
 862
 863 static int scc_close(struct net_device *dev)
 864 {
 865         struct scc_priv *priv = dev->priv;
 866         struct scc_info *info = priv->info;
 867         int card_base = priv->card_base;
 868
 869         netif_stop_queue(dev);
 870
 871         if (priv->type == TYPE_TWIN) {
 872                 /* Drop DTR */
 873                 outb((info->twin_serial_cfg &=
 874                       (priv->channel ? ~TWIN_DTRB_ON : ~TWIN_DTRA_ON)),
 875                      card_base + TWIN_SERIAL_CFG);
 876         }
 877
 878         /* Reset channel, free DMA and IRQ */
 879         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 880         if (priv->param.dma >= 0) {
 881                 if (priv->type == TYPE_TWIN)
 882                         outb(0, card_base + TWIN_DMA_CFG);
 883                 free_dma(priv->param.dma);
 884         }
 885         if (--info->irq_used == 0)
 886                 free_irq(dev->irq, info);
 887
 888         return 0;
 889 }
 890
 891
 892 static int scc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 893 {
 894         struct scc_priv *priv = dev->priv;
 895
 896         switch (cmd) {
 897         case SIOCGSCCPARAM:
 898                 if (copy_to_user
 899                     (ifr->ifr_data, &priv->param,
 900                      sizeof(struct scc_param)))
 901                         return -EFAULT;
 902                 return 0;
 903         case SIOCSSCCPARAM:
 904                 if (!capable(CAP_NET_ADMIN))
 905                         return -EPERM;
 906                 if (netif_running(dev))
 907                         return -EAGAIN;
 908                 if (copy_from_user
 909                     (&priv->param, ifr->ifr_data,
 910                      sizeof(struct scc_param)))
 911                         return -EFAULT;
 912                 return 0;
 913         default:
 914                 return -EINVAL;
 915         }
 916 }
 917
 918
 919 static int scc_send_packet(struct sk_buff *skb, struct net_device *dev)
 920 {
 921         struct scc_priv *priv = dev->priv;
 922         unsigned long flags;
 923         int i;
 924
 925         /* Temporarily stop the scheduler feeding us packets */
 926         netif_stop_queue(dev);
 927
 928         /* Transfer data to DMA buffer */
 929         i = priv->tx_head;
 930         skb_copy_from_linear_data_offset(skb, 1, priv->tx_buf[i], skb->len - 1);
 931         priv->tx_len[i] = skb->len - 1;
 932
 933         /* Clear interrupts while we touch our circular buffers */
 934
 935         spin_lock_irqsave(&priv->ring_lock, flags);
 936         /* Move the ring buffer's head */
 937         priv->tx_head = (i + 1) % NUM_TX_BUF;
 938         priv->tx_count++;
 939
 940         /* If we just filled up the last buffer, leave queue stopped.
 941            The higher layers must wait until we have a DMA buffer
 942            to accept the data. */
 943         if (priv->tx_count < NUM_TX_BUF)
 944                 netif_wake_queue(dev);
 945
 946         /* Set new TX state */
 947         if (priv->state == IDLE) {
 948                 /* Assert RTS, start timer */
 949                 priv->state = TX_HEAD;
 950                 priv->tx_start = jiffies;
 951                 write_scc(priv, R5, TxCRC_ENAB | RTS | TxENAB | Tx8);
 952                 write_scc(priv, R15, 0);
 953                 start_timer(priv, priv->param.txdelay, 0);
 954         }
 955
 956         /* Turn interrupts back on and free buffer */
 957         spin_unlock_irqrestore(&priv->ring_lock, flags);
 958         dev_kfree_skb(skb);
 959
 960         return 0;
 961 }
 962
 963
 964 static struct net_device_stats *scc_get_stats(struct net_device *dev)
 965 {
 966         struct scc_priv *priv = dev->priv;
 967
 968         return &priv->stats;
 969 }
 970
 971
 972 static int scc_set_mac_address(struct net_device *dev, void *sa)
 973 {
 974         memcpy(dev->dev_addr, ((struct sockaddr *) sa)->sa_data,
 975                dev->addr_len);
 976         return 0;
 977 }
 978
 979
 980 static inline void tx_on(struct scc_priv *priv)
 981 {
 982         int i, n;
 983         unsigned long flags;
 984
 985         if (priv->param.dma >= 0) {
 986                 n = (priv->chip == Z85230) ? 3 : 1;
 987                 /* Program DMA controller */
 988                 flags = claim_dma_lock();
 989                 set_dma_mode(priv->param.dma, DMA_MODE_WRITE);
 990                 set_dma_addr(priv->param.dma,
 991                              (int) priv->tx_buf[priv->tx_tail] + n);
 992                 set_dma_count(priv->param.dma,
 993                               priv->tx_len[priv->tx_tail] - n);
 994                 release_dma_lock(flags);
 995                 /* Enable TX underrun interrupt */
 996                 write_scc(priv, R15, TxUIE);
 997                 /* Configure DREQ */
 998                 if (priv->type == TYPE_TWIN)
 999                         outb((priv->param.dma ==
1000                               1) ? TWIN_DMA_HDX_T1 : TWIN_DMA_HDX_T3,
1001                              priv->card_base + TWIN_DMA_CFG);
1002                 else
1003                         write_scc(priv, R1,
1004                                   EXT_INT_ENAB | WT_FN_RDYFN |
1005                                   WT_RDY_ENAB);
1006                 /* Write first byte(s) */
1007                 spin_lock_irqsave(priv->register_lock, flags);
1008                 for (i = 0; i < n; i++)
1009                         write_scc_data(priv,
1010                                        priv->tx_buf[priv->tx_tail][i], 1);
1011                 enable_dma(priv->param.dma);
1012                 spin_unlock_irqrestore(priv->register_lock, flags);
1013         } else {
1014                 write_scc(priv, R15, TxUIE);
1015                 write_scc(priv, R1,
1016                           EXT_INT_ENAB | WT_FN_RDYFN | TxINT_ENAB);
1017                 tx_isr(priv);
1018         }
1019         /* Reset EOM latch if we do not have the AUTOEOM feature */
1020         if (priv->chip == Z8530)
1021                 write_scc(priv, R0, RES_EOM_L);
1022 }
1023
1024
1025 static inline void rx_on(struct scc_priv *priv)
1026 {
1027         unsigned long flags;
1028
1029         /* Clear RX FIFO */
1030         while (read_scc(priv, R0) & Rx_CH_AV)
1031                 read_scc_data(priv);
1032         priv->rx_over = 0;
1033         if (priv->param.dma >= 0) {
1034                 /* Program DMA controller */
1035                 flags = claim_dma_lock();
1036                 set_dma_mode(priv->param.dma, DMA_MODE_READ);
1037                 set_dma_addr(priv->param.dma,
1038                              (int) priv->rx_buf[priv->rx_head]);
1039                 set_dma_count(priv->param.dma, BUF_SIZE);
1040                 release_dma_lock(flags);
1041                 enable_dma(priv->param.dma);
1042                 /* Configure PackeTwin DMA */
1043                 if (priv->type == TYPE_TWIN) {
1044                         outb((priv->param.dma ==
1045                               1) ? TWIN_DMA_HDX_R1 : TWIN_DMA_HDX_R3,
1046                              priv->card_base + TWIN_DMA_CFG);
1047                 }
1048                 /* Sp. cond. intr. only, ext int enable, RX DMA enable */
1049                 write_scc(priv, R1, EXT_INT_ENAB | INT_ERR_Rx |
1050                           WT_RDY_RT | WT_FN_RDYFN | WT_RDY_ENAB);
1051         } else {
1052                 /* Reset current frame */
1053                 priv->rx_ptr = 0;
1054                 /* Intr. on all Rx characters and Sp. cond., ext int enable */
1055                 write_scc(priv, R1, EXT_INT_ENAB | INT_ALL_Rx | WT_RDY_RT |
1056                           WT_FN_RDYFN);
1057         }
1058         write_scc(priv, R0, ERR_RES);
1059         write_scc(priv, R3, RxENABLE | Rx8 | RxCRC_ENAB);
1060 }
1061
1062
1063 static inline void rx_off(struct scc_priv *priv)
1064 {
1065         /* Disable receiver */
1066         write_scc(priv, R3, Rx8);
1067         /* Disable DREQ / RX interrupt */
1068         if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1069                 outb(0, priv->card_base + TWIN_DMA_CFG);
1070         else
1071                 write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1072         /* Disable DMA */
1073         if (priv->param.dma >= 0)
1074                 disable_dma(priv->param.dma);
1075 }
1076
1077
1078 static void start_timer(struct scc_priv *priv, int t, int r15)
1079 {
1080         unsigned long flags;
1081
1082         outb(priv->tmr_mode, priv->tmr_ctrl);
1083         if (t == 0) {
1084                 tm_isr(priv);
1085         } else if (t > 0) {
1086                 outb(t & 0xFF, priv->tmr_cnt);
1087                 outb((t >> 8) & 0xFF, priv->tmr_cnt);
1088                 if (priv->type != TYPE_TWIN) {
1089                         write_scc(priv, R15, r15 | CTSIE);
1090                         priv->rr0 |= CTS;
1091                 }
1092         }
1093 }
1094
1095
1096 static inline unsigned char random(void)
1097 {
1098         /* See "Numerical Recipes in C", second edition, p. 284 */
1099         rand = rand * 1664525L + 1013904223L;
1100         return (unsigned char) (rand >> 24);
1101 }
1102
1103 static inline void z8530_isr(struct scc_info *info)
1104 {
1105         int is, i = 100;
1106
1107         while ((is = read_scc(&info->priv[0], R3)) && i--) {
1108                 if (is & CHARxIP) {
1109                         rx_isr(&info->priv[0]);
1110                 } else if (is & CHATxIP) {
1111                         tx_isr(&info->priv[0]);
1112                 } else if (is & CHAEXT) {
1113                         es_isr(&info->priv[0]);
1114                 } else if (is & CHBRxIP) {
1115                         rx_isr(&info->priv[1]);
1116                 } else if (is & CHBTxIP) {
1117                         tx_isr(&info->priv[1]);
1118                 } else {
1119                         es_isr(&info->priv[1]);
1120                 }
1121                 write_scc(&info->priv[0], R0, RES_H_IUS);
1122                 i++;
1123         }
1124         if (i < 0) {
1125                 printk(KERN_ERR "dmascc: stuck in ISR with RR3=0x%02x.\n",
1126                        is);
1127         }
1128         /* Ok, no interrupts pending from this 8530. The INT line should
1129            be inactive now. */
1130 }
1131
1132
1133 static irqreturn_t scc_isr(int irq, void *dev_id)
1134 {
1135         struct scc_info *info = dev_id;
1136
1137         spin_lock(info->priv[0].register_lock);
1138         /* At this point interrupts are enabled, and the interrupt under service
1139            is already acknowledged, but masked off.
1140
1141            Interrupt processing: We loop until we know that the IRQ line is
1142            low. If another positive edge occurs afterwards during the ISR,
1143            another interrupt will be triggered by the interrupt controller
1144            as soon as the IRQ level is enabled again (see asm/irq.h).
1145
1146            Bottom-half handlers will be processed after scc_isr(). This is
1147            important, since we only have small ringbuffers and want new data
1148            to be fetched/delivered immediately. */
1149
1150         if (info->priv[0].type == TYPE_TWIN) {
1151                 int is, card_base = info->priv[0].card_base;
1152                 while ((is = ~inb(card_base + TWIN_INT_REG)) &
1153                        TWIN_INT_MSK) {
1154                         if (is & TWIN_SCC_MSK) {
1155                                 z8530_isr(info);
1156                         } else if (is & TWIN_TMR1_MSK) {
1157                                 inb(card_base + TWIN_CLR_TMR1);
1158                                 tm_isr(&info->priv[0]);
1159                         } else {
1160                                 inb(card_base + TWIN_CLR_TMR2);
1161                                 tm_isr(&info->priv[1]);
1162                         }
1163                 }
1164         } else
1165                 z8530_isr(info);
1166         spin_unlock(info->priv[0].register_lock);
1167         return IRQ_HANDLED;
1168 }
1169
1170
1171 static void rx_isr(struct scc_priv *priv)
1172 {
1173         if (priv->param.dma >= 0) {
1174                 /* Check special condition and perform error reset. See 2.4.7.5. */
1175                 special_condition(priv, read_scc(priv, R1));
1176                 write_scc(priv, R0, ERR_RES);
1177         } else {
1178                 /* Check special condition for each character. Error reset not necessary.
1179                    Same algorithm for SCC and ESCC. See 2.4.7.1 and 2.4.7.4. */
1180                 int rc;
1181                 while (read_scc(priv, R0) & Rx_CH_AV) {
1182                         rc = read_scc(priv, R1);
1183                         if (priv->rx_ptr < BUF_SIZE)
1184                                 priv->rx_buf[priv->rx_head][priv->
1185                                                             rx_ptr++] =
1186                                     read_scc_data(priv);
1187                         else {
1188                                 priv->rx_over = 2;
1189                                 read_scc_data(priv);
1190                         }
1191                         special_condition(priv, rc);
1192                 }
1193         }
1194 }
1195
1196
1197 static void special_condition(struct scc_priv *priv, int rc)
1198 {
1199         int cb;
1200         unsigned long flags;
1201
1202         /* See Figure 2-15. Only overrun and EOF need to be checked. */
1203
1204         if (rc & Rx_OVR) {
1205                 /* Receiver overrun */
1206                 priv->rx_over = 1;
1207                 if (priv->param.dma < 0)
1208                         write_scc(priv, R0, ERR_RES);
1209         } else if (rc & END_FR) {
1210                 /* End of frame. Get byte count */
1211                 if (priv->param.dma >= 0) {
1212                         flags = claim_dma_lock();
1213                         cb = BUF_SIZE - get_dma_residue(priv->param.dma) -
1214                             2;
1215                         release_dma_lock(flags);
1216                 } else {
1217                         cb = priv->rx_ptr - 2;
1218                 }
1219                 if (priv->rx_over) {
1220                         /* We had an overrun */
1221                         priv->stats.rx_errors++;
1222                         if (priv->rx_over == 2)
1223                                 priv->stats.rx_length_errors++;
1224                         else
1225                                 priv->stats.rx_fifo_errors++;
1226                         priv->rx_over = 0;
1227                 } else if (rc & CRC_ERR) {
1228                         /* Count invalid CRC only if packet length >= minimum */
1229                         if (cb >= 15) {
1230                                 priv->stats.rx_errors++;
1231                                 priv->stats.rx_crc_errors++;
1232                         }
1233                 } else {
1234                         if (cb >= 15) {
1235                                 if (priv->rx_count < NUM_RX_BUF - 1) {
1236                                         /* Put good frame in FIFO */
1237                                         priv->rx_len[priv->rx_head] = cb;
1238                                         priv->rx_head =
1239                                             (priv->rx_head +
1240                                              1) % NUM_RX_BUF;
1241                                         priv->rx_count++;
1242                                         schedule_work(&priv->rx_work);
1243                                 } else {
1244                                         priv->stats.rx_errors++;
1245                                         priv->stats.rx_over_errors++;
1246                                 }
1247                         }
1248                 }
1249                 /* Get ready for new frame */
1250                 if (priv->param.dma >= 0) {
1251                         flags = claim_dma_lock();
1252                         set_dma_addr(priv->param.dma,
1253                                      (int) priv->rx_buf[priv->rx_head]);
1254                         set_dma_count(priv->param.dma, BUF_SIZE);
1255                         release_dma_lock(flags);
1256                 } else {
1257                         priv->rx_ptr = 0;
1258                 }
1259         }
1260 }
1261
1262
1263 static void rx_bh(struct work_struct *ugli_api)
1264 {
1265         struct scc_priv *priv = container_of(ugli_api, struct scc_priv, rx_work);
1266         int i = priv->rx_tail;
1267         int cb;
1268         unsigned long flags;
1269         struct sk_buff *skb;
1270         unsigned char *data;
1271
1272         spin_lock_irqsave(&priv->ring_lock, flags);
1273         while (priv->rx_count) {
1274                 spin_unlock_irqrestore(&priv->ring_lock, flags);
1275                 cb = priv->rx_len[i];
1276                 /* Allocate buffer */
1277                 skb = dev_alloc_skb(cb + 1);
1278                 if (skb == NULL) {
1279                         /* Drop packet */
1280                         priv->stats.rx_dropped++;
1281                 } else {
1282                         /* Fill buffer */
1283                         data = skb_put(skb, cb + 1);
1284                         data[0] = 0;
1285                         memcpy(&data[1], priv->rx_buf[i], cb);
1286                         skb->protocol = ax25_type_trans(skb, priv->dev);
1287                         netif_rx(skb);
1288                         priv->dev->last_rx = jiffies;
1289                         priv->stats.rx_packets++;
1290                         priv->stats.rx_bytes += cb;
1291                 }
1292                 spin_lock_irqsave(&priv->ring_lock, flags);
1293                 /* Move tail */
1294                 priv->rx_tail = i = (i + 1) % NUM_RX_BUF;
1295                 priv->rx_count--;
1296         }
1297         spin_unlock_irqrestore(&priv->ring_lock, flags);
1298 }
1299
1300
1301 static void tx_isr(struct scc_priv *priv)
1302 {
1303         int i = priv->tx_tail, p = priv->tx_ptr;
1304
1305         /* Suspend TX interrupts if we don't want to send anything.
1306            See Figure 2-22. */
1307         if (p == priv->tx_len[i]) {
1308                 write_scc(priv, R0, RES_Tx_P);
1309                 return;
1310         }
1311
1312         /* Write characters */
1313         while ((read_scc(priv, R0) & Tx_BUF_EMP) && p < priv->tx_len[i]) {
1314                 write_scc_data(priv, priv->tx_buf[i][p++], 0);
1315         }
1316
1317         /* Reset EOM latch of Z8530 */
1318         if (!priv->tx_ptr && p && priv->chip == Z8530)
1319                 write_scc(priv, R0, RES_EOM_L);
1320
1321         priv->tx_ptr = p;
1322 }
1323
1324
1325 static void es_isr(struct scc_priv *priv)
1326 {
1327         int i, rr0, drr0, res;
1328         unsigned long flags;
1329
1330         /* Read status, reset interrupt bit (open latches) */
1331         rr0 = read_scc(priv, R0);
1332         write_scc(priv, R0, RES_EXT_INT);
1333         drr0 = priv->rr0 ^ rr0;
1334         priv->rr0 = rr0;
1335
1336         /* Transmit underrun (2.4.9.6). We can't check the TxEOM flag, since
1337            it might have already been cleared again by AUTOEOM. */
1338         if (priv->state == TX_DATA) {
1339                 /* Get remaining bytes */
1340                 i = priv->tx_tail;
1341                 if (priv->param.dma >= 0) {
1342                         disable_dma(priv->param.dma);
1343                         flags = claim_dma_lock();
1344                         res = get_dma_residue(priv->param.dma);
1345                         release_dma_lock(flags);
1346                 } else {
1347                         res = priv->tx_len[i] - priv->tx_ptr;
1348                         priv->tx_ptr = 0;
1349                 }
1350                 /* Disable DREQ / TX interrupt */
1351                 if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1352                         outb(0, priv->card_base + TWIN_DMA_CFG);
1353                 else
1354                         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1355                 if (res) {
1356                         /* Update packet statistics */
1357                         priv->stats.tx_errors++;
1358                         priv->stats.tx_fifo_errors++;
1359                         /* Other underrun interrupts may already be waiting */
1360                         write_scc(priv, R0, RES_EXT_INT);
1361                         write_scc(priv, R0, RES_EXT_INT);
1362                 } else {
1363                         /* Update packet statistics */
1364                         priv->stats.tx_packets++;
1365                         priv->stats.tx_bytes += priv->tx_len[i];
1366                         /* Remove frame from FIFO */
1367                         priv->tx_tail = (i + 1) % NUM_TX_BUF;
1368                         priv->tx_count--;
1369                         /* Inform upper layers */
1370                         netif_wake_queue(priv->dev);
1371                 }
1372                 /* Switch state */
1373                 write_scc(priv, R15, 0);
1374                 if (priv->tx_count &&
1375                     (jiffies - priv->tx_start) < priv->param.txtimeout) {
1376                         priv->state = TX_PAUSE;
1377                         start_timer(priv, priv->param.txpause, 0);
1378                 } else {
1379                         priv->state = TX_TAIL;
1380                         start_timer(priv, priv->param.txtail, 0);
1381                 }
1382         }
1383
1384         /* DCD transition */
1385         if (drr0 & DCD) {
1386                 if (rr0 & DCD) {
1387                         switch (priv->state) {
1388                         case IDLE:
1389                         case WAIT:
1390                                 priv->state = DCD_ON;
1391                                 write_scc(priv, R15, 0);
1392                                 start_timer(priv, priv->param.dcdon, 0);
1393                         }
1394                 } else {
1395                         switch (priv->state) {
1396                         case RX_ON:
1397                                 rx_off(priv);
1398                                 priv->state = DCD_OFF;
1399                                 write_scc(priv, R15, 0);
1400                                 start_timer(priv, priv->param.dcdoff, 0);
1401                         }
1402                 }
1403         }
1404
1405         /* CTS transition */
1406         if ((drr0 & CTS) && (~rr0 & CTS) && priv->type != TYPE_TWIN)
1407                 tm_isr(priv);
1408
1409 }
1410
1411
1412 static void tm_isr(struct scc_priv *priv)
1413 {
1414         switch (priv->state) {
1415         case TX_HEAD:
1416         case TX_PAUSE:
1417                 tx_on(priv);
1418                 priv->state = TX_DATA;
1419                 break;
1420         case TX_TAIL:
1421                 write_scc(priv, R5, TxCRC_ENAB | Tx8);
1422                 priv->state = RTS_OFF;
1423                 if (priv->type != TYPE_TWIN)
1424                         write_scc(priv, R15, 0);
1425                 start_timer(priv, priv->param.rtsoff, 0);
1426                 break;
1427         case RTS_OFF:
1428                 write_scc(priv, R15, DCDIE);
1429                 priv->rr0 = read_scc(priv, R0);
1430                 if (priv->rr0 & DCD) {
1431                         priv->stats.collisions++;
1432                         rx_on(priv);
1433                         priv->state = RX_ON;
1434                 } else {
1435                         priv->state = WAIT;
1436                         start_timer(priv, priv->param.waittime, DCDIE);
1437                 }
1438                 break;
1439         case WAIT:
1440                 if (priv->tx_count) {
1441                         priv->state = TX_HEAD;
1442                         priv->tx_start = jiffies;
1443                         write_scc(priv, R5,
1444                                   TxCRC_ENAB | RTS | TxENAB | Tx8);
1445                         write_scc(priv, R15, 0);
1446                         start_timer(priv, priv->param.txdelay, 0);
1447                 } else {
1448                         priv->state = IDLE;
1449                         if (priv->type != TYPE_TWIN)
1450                                 write_scc(priv, R15, DCDIE);
1451                 }
1452                 break;
1453         case DCD_ON:
1454         case DCD_OFF:
1455                 write_scc(priv, R15, DCDIE);
1456                 priv->rr0 = read_scc(priv, R0);
1457                 if (priv->rr0 & DCD) {
1458                         rx_on(priv);
1459                         priv->state = RX_ON;
1460                 } else {
1461                         priv->state = WAIT;
1462                         start_timer(priv,
1463                                     random() / priv->param.persist *
1464                                     priv->param.slottime, DCDIE);
1465                 }
1466                 break;
1467         }
1468 }