drivers/net/hamradio/dmascc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for high-speed SCC boards (those with DMA support)
   4  * Copyright (C) 1997-2000 Klaus Kudielka
   5  *
   6  * S5SCC/DMA support by Janko Koleznik S52HI
   7  */
   8
   9
  10 #include <linux/module.h>
  11 #include <linux/bitops.h>
  12 #include <linux/delay.h>
  13 #include <linux/errno.h>
  14 #include <linux/if_arp.h>
  15 #include <linux/in.h>
  16 #include <linux/init.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/ioport.h>
  19 #include <linux/kernel.h>
  20 #include <linux/mm.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/slab.h>
  23 #include <linux/rtnetlink.h>
  24 #include <linux/sockios.h>
  25 #include <linux/workqueue.h>
  26 #include <linux/atomic.h>
  27 #include <asm/dma.h>
  28 #include <asm/io.h>
  29 #include <asm/irq.h>
  30 #include <linux/uaccess.h>
  31 #include <net/ax25.h>
  32 #include "z8530.h"
  33
  34
  35 /* Number of buffers per channel */
  36
  37 #define NUM_TX_BUF      2       /* NUM_TX_BUF >= 1 (min. 2 recommended) */
  38 #define NUM_RX_BUF      6       /* NUM_RX_BUF >= 1 (min. 2 recommended) */
  39 #define BUF_SIZE        1576    /* BUF_SIZE >= mtu + hard_header_len */
  40
  41
  42 /* Cards supported */
  43
  44 #define HW_PI           { "Ottawa PI", 0x300, 0x20, 0x10, 8, \
  45                             0, 8, 1843200, 3686400 }
  46 #define HW_PI2          { "Ottawa PI2", 0x300, 0x20, 0x10, 8, \
  47                             0, 8, 3686400, 7372800 }
  48 #define HW_TWIN         { "Gracilis PackeTwin", 0x200, 0x10, 0x10, 32, \
  49                             0, 4, 6144000, 6144000 }
  50 #define HW_S5           { "S5SCC/DMA", 0x200, 0x10, 0x10, 32, \
  51                           0, 8, 4915200, 9830400 }
  52
  53 #define HARDWARE        { HW_PI, HW_PI2, HW_TWIN, HW_S5 }
  54
  55 #define TMR_0_HZ        25600   /* Frequency of timer 0 */
  56
  57 #define TYPE_PI         0
  58 #define TYPE_PI2        1
  59 #define TYPE_TWIN       2
  60 #define TYPE_S5         3
  61 #define NUM_TYPES       4
  62
  63 #define MAX_NUM_DEVS    32
  64
  65
  66 /* SCC chips supported */
  67
  68 #define Z8530           0
  69 #define Z85C30          1
  70 #define Z85230          2
  71
  72 #define CHIPNAMES       { "Z8530", "Z85C30", "Z85230" }
  73
  74
  75 /* I/O registers */
  76
  77 /* 8530 registers relative to card base */
  78 #define SCCB_CMD        0x00
  79 #define SCCB_DATA       0x01
  80 #define SCCA_CMD        0x02
  81 #define SCCA_DATA       0x03
  82
  83 /* 8253/8254 registers relative to card base */
  84 #define TMR_CNT0        0x00
  85 #define TMR_CNT1        0x01
  86 #define TMR_CNT2        0x02
  87 #define TMR_CTRL        0x03
  88
  89 /* Additional PI/PI2 registers relative to card base */
  90 #define PI_DREQ_MASK    0x04
  91
  92 /* Additional PackeTwin registers relative to card base */
  93 #define TWIN_INT_REG    0x08
  94 #define TWIN_CLR_TMR1   0x09
  95 #define TWIN_CLR_TMR2   0x0a
  96 #define TWIN_SPARE_1    0x0b
  97 #define TWIN_DMA_CFG    0x08
  98 #define TWIN_SERIAL_CFG 0x09
  99 #define TWIN_DMA_CLR_FF 0x0a
 100 #define TWIN_SPARE_2    0x0b
 101
 102
 103 /* PackeTwin I/O register values */
 104
 105 /* INT_REG */
 106 #define TWIN_SCC_MSK       0x01
 107 #define TWIN_TMR1_MSK      0x02
 108 #define TWIN_TMR2_MSK      0x04
 109 #define TWIN_INT_MSK       0x07
 110
 111 /* SERIAL_CFG */
 112 #define TWIN_DTRA_ON       0x01
 113 #define TWIN_DTRB_ON       0x02
 114 #define TWIN_EXTCLKA       0x04
 115 #define TWIN_EXTCLKB       0x08
 116 #define TWIN_LOOPA_ON      0x10
 117 #define TWIN_LOOPB_ON      0x20
 118 #define TWIN_EI            0x80
 119
 120 /* DMA_CFG */
 121 #define TWIN_DMA_HDX_T1    0x08
 122 #define TWIN_DMA_HDX_R1    0x0a
 123 #define TWIN_DMA_HDX_T3    0x14
 124 #define TWIN_DMA_HDX_R3    0x16
 125 #define TWIN_DMA_FDX_T3R1  0x1b
 126 #define TWIN_DMA_FDX_T1R3  0x1d
 127
 128
 129 /* Status values */
 130
 131 #define IDLE      0
 132 #define TX_HEAD   1
 133 #define TX_DATA   2
 134 #define TX_PAUSE  3
 135 #define TX_TAIL   4
 136 #define RTS_OFF   5
 137 #define WAIT      6
 138 #define DCD_ON    7
 139 #define RX_ON     8
 140 #define DCD_OFF   9
 141
 142
 143 /* Ioctls */
 144
 145 #define SIOCGSCCPARAM SIOCDEVPRIVATE
 146 #define SIOCSSCCPARAM (SIOCDEVPRIVATE+1)
 147
 148
 149 /* Data types */
 150
 151 struct scc_param {
 152         int pclk_hz;            /* frequency of BRG input (don't change) */
 153         int brg_tc;             /* BRG terminal count; BRG disabled if < 0 */
 154         int nrzi;               /* 0 (nrz), 1 (nrzi) */
 155         int clocks;             /* see dmascc_cfg documentation */
 156         int txdelay;            /* [1/TMR_0_HZ] */
 157         int txtimeout;          /* [1/HZ] */
 158         int txtail;             /* [1/TMR_0_HZ] */
 159         int waittime;           /* [1/TMR_0_HZ] */
 160         int slottime;           /* [1/TMR_0_HZ] */
 161         int persist;            /* 1 ... 256 */
 162         int dma;                /* -1 (disable), 0, 1, 3 */
 163         int txpause;            /* [1/TMR_0_HZ] */
 164         int rtsoff;             /* [1/TMR_0_HZ] */
 165         int dcdon;              /* [1/TMR_0_HZ] */
 166         int dcdoff;             /* [1/TMR_0_HZ] */
 167 };
 168
 169 struct scc_hardware {
 170         char *name;
 171         int io_region;
 172         int io_delta;
 173         int io_size;
 174         int num_devs;
 175         int scc_offset;
 176         int tmr_offset;
 177         int tmr_hz;
 178         int pclk_hz;
 179 };
 180
 181 struct scc_priv {
 182         int type;
 183         int chip;
 184         struct net_device *dev;
 185         struct scc_info *info;
 186
 187         int channel;
 188         int card_base, scc_cmd, scc_data;
 189         int tmr_cnt, tmr_ctrl, tmr_mode;
 190         struct scc_param param;
 191         char rx_buf[NUM_RX_BUF][BUF_SIZE];
 192         int rx_len[NUM_RX_BUF];
 193         int rx_ptr;
 194         struct work_struct rx_work;
 195         int rx_head, rx_tail, rx_count;
 196         int rx_over;
 197         char tx_buf[NUM_TX_BUF][BUF_SIZE];
 198         int tx_len[NUM_TX_BUF];
 199         int tx_ptr;
 200         int tx_head, tx_tail, tx_count;
 201         int state;
 202         unsigned long tx_start;
 203         int rr0;
 204         spinlock_t *register_lock;      /* Per scc_info */
 205         spinlock_t ring_lock;
 206 };
 207
 208 struct scc_info {
 209         int irq_used;
 210         int twin_serial_cfg;
 211         struct net_device *dev[2];
 212         struct scc_priv priv[2];
 213         struct scc_info *next;
 214         spinlock_t register_lock;       /* Per device register lock */
 215 };
 216
 217
 218 /* Function declarations */
 219 static int setup_adapter(int card_base, int type, int n) __init;
 220
 221 static void write_scc(struct scc_priv *priv, int reg, int val);
 222 static void write_scc_data(struct scc_priv *priv, int val, int fast);
 223 static int read_scc(struct scc_priv *priv, int reg);
 224 static int read_scc_data(struct scc_priv *priv);
 225
 226 static int scc_open(struct net_device *dev);
 227 static int scc_close(struct net_device *dev);
 228 static int scc_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
 229                               void __user *data, int cmd);
 230 static int scc_send_packet(struct sk_buff *skb, struct net_device *dev);
 231 static int scc_set_mac_address(struct net_device *dev, void *sa);
 232
 233 static inline void tx_on(struct scc_priv *priv);
 234 static inline void rx_on(struct scc_priv *priv);
 235 static inline void rx_off(struct scc_priv *priv);
 236 static void start_timer(struct scc_priv *priv, int t, int r15);
 237 static inline unsigned char random(void);
 238
 239 static inline void z8530_isr(struct scc_info *info);
 240 static irqreturn_t scc_isr(int irq, void *dev_id);
 241 static void rx_isr(struct scc_priv *priv);
 242 static void special_condition(struct scc_priv *priv, int rc);
 243 static void rx_bh(struct work_struct *);
 244 static void tx_isr(struct scc_priv *priv);
 245 static void es_isr(struct scc_priv *priv);
 246 static void tm_isr(struct scc_priv *priv);
 247
 248
 249 /* Initialization variables */
 250
 251 static int io[MAX_NUM_DEVS] __initdata = { 0, };
 252
 253 /* Beware! hw[] is also used in dmascc_exit(). */
 254 static struct scc_hardware hw[NUM_TYPES] = HARDWARE;
 255
 256
 257 /* Global variables */
 258
 259 static struct scc_info *first;
 260 static unsigned long rand;
 261
 262
 263 MODULE_AUTHOR("Klaus Kudielka");
 264 MODULE_DESCRIPTION("Driver for high-speed SCC boards");
 265 module_param_hw_array(io, int, ioport, NULL, 0);
 266 MODULE_LICENSE("GPL");
 267
 268 static void __exit dmascc_exit(void)
 269 {
 270         int i;
 271         struct scc_info *info;
 272
 273         while (first) {
 274                 info = first;
 275
 276                 /* Unregister devices */
 277                 for (i = 0; i < 2; i++)
 278                         unregister_netdev(info->dev[i]);
 279
 280                 /* Reset board */
 281                 if (info->priv[0].type == TYPE_TWIN)
 282                         outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 283                 write_scc(&info->priv[0], R9, FHWRES);
 284                 release_region(info->dev[0]->base_addr,
 285                                hw[info->priv[0].type].io_size);
 286
 287                 for (i = 0; i < 2; i++)
 288                         free_netdev(info->dev[i]);
 289
 290                 /* Free memory */
 291                 first = info->next;
 292                 kfree(info);
 293         }
 294 }
 295
 296 static int __init dmascc_init(void)
 297 {
 298         int h, i, j, n;
 299         int base[MAX_NUM_DEVS], tcmd[MAX_NUM_DEVS], t0[MAX_NUM_DEVS],
 300             t1[MAX_NUM_DEVS];
 301         unsigned t_val;
 302         unsigned long time, start[MAX_NUM_DEVS], delay[MAX_NUM_DEVS],
 303             counting[MAX_NUM_DEVS];
 304
 305         /* Initialize random number generator */
 306         rand = jiffies;
 307         /* Cards found = 0 */
 308         n = 0;
 309         /* Warning message */
 310         if (!io[0])
 311                 printk(KERN_INFO "dmascc: autoprobing (dangerous)\n");
 312
 313         /* Run autodetection for each card type */
 314         for (h = 0; h < NUM_TYPES; h++) {
 315
 316                 if (io[0]) {
 317                         /* User-specified I/O address regions */
 318                         for (i = 0; i < hw[h].num_devs; i++)
 319                                 base[i] = 0;
 320                         for (i = 0; i < MAX_NUM_DEVS && io[i]; i++) {
 321                                 j = (io[i] -
 322                                      hw[h].io_region) / hw[h].io_delta;
 323                                 if (j >= 0 && j < hw[h].num_devs &&
 324                                     hw[h].io_region +
 325                                     j * hw[h].io_delta == io[i]) {
 326                                         base[j] = io[i];
 327                                 }
 328                         }
 329                 } else {
 330                         /* Default I/O address regions */
 331                         for (i = 0; i < hw[h].num_devs; i++) {
 332                                 base[i] =
 333                                     hw[h].io_region + i * hw[h].io_delta;
 334                         }
 335                 }
 336
 337                 /* Check valid I/O address regions */
 338                 for (i = 0; i < hw[h].num_devs; i++)
 339                         if (base[i]) {
 340                                 if (!request_region
 341                                     (base[i], hw[h].io_size, "dmascc"))
 342                                         base[i] = 0;
 343                                 else {
 344                                         tcmd[i] =
 345                                             base[i] + hw[h].tmr_offset +
 346                                             TMR_CTRL;
 347                                         t0[i] =
 348                                             base[i] + hw[h].tmr_offset +
 349                                             TMR_CNT0;
 350                                         t1[i] =
 351                                             base[i] + hw[h].tmr_offset +
 352                                             TMR_CNT1;
 353                                 }
 354                         }
 355
 356                 /* Start timers */
 357                 for (i = 0; i < hw[h].num_devs; i++)
 358                         if (base[i]) {
 359                                 /* Timer 0: LSB+MSB, Mode 3, TMR_0_HZ */
 360                                 outb(0x36, tcmd[i]);
 361                                 outb((hw[h].tmr_hz / TMR_0_HZ) & 0xFF,
 362                                      t0[i]);
 363                                 outb((hw[h].tmr_hz / TMR_0_HZ) >> 8,
 364                                      t0[i]);
 365                                 /* Timer 1: LSB+MSB, Mode 0, HZ/10 */
 366                                 outb(0x70, tcmd[i]);
 367                                 outb((TMR_0_HZ / HZ * 10) & 0xFF, t1[i]);
 368                                 outb((TMR_0_HZ / HZ * 10) >> 8, t1[i]);
 369                                 start[i] = jiffies;
 370                                 delay[i] = 0;
 371                                 counting[i] = 1;
 372                                 /* Timer 2: LSB+MSB, Mode 0 */
 373                                 outb(0xb0, tcmd[i]);
 374                         }
 375                 time = jiffies;
 376                 /* Wait until counter registers are loaded */
 377                 udelay(2000000 / TMR_0_HZ);
 378
 379                 /* Timing loop */
 380                 while (jiffies - time < 13) {
 381                         for (i = 0; i < hw[h].num_devs; i++)
 382                                 if (base[i] && counting[i]) {
 383                                         /* Read back Timer 1: latch; read LSB; read MSB */
 384                                         outb(0x40, tcmd[i]);
 385                                         t_val =
 386                                             inb(t1[i]) + (inb(t1[i]) << 8);
 387                                         /* Also check whether counter did wrap */
 388                                         if (t_val == 0 ||
 389                                             t_val > TMR_0_HZ / HZ * 10)
 390                                                 counting[i] = 0;
 391                                         delay[i] = jiffies - start[i];
 392                                 }
 393                 }
 394
 395                 /* Evaluate measurements */
 396                 for (i = 0; i < hw[h].num_devs; i++)
 397                         if (base[i]) {
 398                                 if ((delay[i] >= 9 && delay[i] <= 11) &&
 399                                     /* Ok, we have found an adapter */
 400                                     (setup_adapter(base[i], h, n) == 0))
 401                                         n++;
 402                                 else
 403                                         release_region(base[i],
 404                                                        hw[h].io_size);
 405                         }
 406
 407         }                       /* NUM_TYPES */
 408
 409         /* If any adapter was successfully initialized, return ok */
 410         if (n)
 411                 return 0;
 412
 413         /* If no adapter found, return error */
 414         printk(KERN_INFO "dmascc: no adapters found\n");
 415         return -EIO;
 416 }
 417
 418 module_init(dmascc_init);
 419 module_exit(dmascc_exit);
 420
 421 static void __init dev_setup(struct net_device *dev)
 422 {
 423         dev->type = ARPHRD_AX25;
 424         dev->hard_header_len = AX25_MAX_HEADER_LEN;
 425         dev->mtu = 1500;
 426         dev->addr_len = AX25_ADDR_LEN;
 427         dev->tx_queue_len = 64;
 428         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 429         memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
 430 }
 431
 432 static const struct net_device_ops scc_netdev_ops = {
 433         .ndo_open = scc_open,
 434         .ndo_stop = scc_close,
 435         .ndo_start_xmit = scc_send_packet,
 436         .ndo_siocdevprivate = scc_siocdevprivate,
 437         .ndo_set_mac_address = scc_set_mac_address,
 438 };
 439
 440 static int __init setup_adapter(int card_base, int type, int n)
 441 {
 442         int i, irq, chip, err;
 443         struct scc_info *info;
 444         struct net_device *dev;
 445         struct scc_priv *priv;
 446         unsigned long time;
 447         unsigned int irqs;
 448         int tmr_base = card_base + hw[type].tmr_offset;
 449         int scc_base = card_base + hw[type].scc_offset;
 450         char *chipnames[] = CHIPNAMES;
 451
 452         /* Initialize what is necessary for write_scc and write_scc_data */
 453         info = kzalloc(sizeof(struct scc_info), GFP_KERNEL | GFP_DMA);
 454         if (!info) {
 455                 err = -ENOMEM;
 456                 goto out;
 457         }
 458
 459         info->dev[0] = alloc_netdev(0, "", NET_NAME_UNKNOWN, dev_setup);
 460         if (!info->dev[0]) {
 461                 printk(KERN_ERR "dmascc: "
 462                        "could not allocate memory for %s at %#3x\n",
 463                        hw[type].name, card_base);
 464                 err = -ENOMEM;
 465                 goto out1;
 466         }
 467
 468         info->dev[1] = alloc_netdev(0, "", NET_NAME_UNKNOWN, dev_setup);
 469         if (!info->dev[1]) {
 470                 printk(KERN_ERR "dmascc: "
 471                        "could not allocate memory for %s at %#3x\n",
 472                        hw[type].name, card_base);
 473                 err = -ENOMEM;
 474                 goto out2;
 475         }
 476         spin_lock_init(&info->register_lock);
 477
 478         priv = &info->priv[0];
 479         priv->type = type;
 480         priv->card_base = card_base;
 481         priv->scc_cmd = scc_base + SCCA_CMD;
 482         priv->scc_data = scc_base + SCCA_DATA;
 483         priv->register_lock = &info->register_lock;
 484
 485         /* Reset SCC */
 486         write_scc(priv, R9, FHWRES | MIE | NV);
 487
 488         /* Determine type of chip by enabling SDLC/HDLC enhancements */
 489         write_scc(priv, R15, SHDLCE);
 490         if (!read_scc(priv, R15)) {
 491                 /* WR7' not present. This is an ordinary Z8530 SCC. */
 492                 chip = Z8530;
 493         } else {
 494                 /* Put one character in TX FIFO */
 495                 write_scc_data(priv, 0, 0);
 496                 if (read_scc(priv, R0) & Tx_BUF_EMP) {
 497                         /* TX FIFO not full. This is a Z85230 ESCC with a 4-byte FIFO. */
 498                         chip = Z85230;
 499                 } else {
 500                         /* TX FIFO full. This is a Z85C30 SCC with a 1-byte FIFO. */
 501                         chip = Z85C30;
 502                 }
 503         }
 504         write_scc(priv, R15, 0);
 505
 506         /* Start IRQ auto-detection */
 507         irqs = probe_irq_on();
 508
 509         /* Enable interrupts */
 510         if (type == TYPE_TWIN) {
 511                 outb(0, card_base + TWIN_DMA_CFG);
 512                 inb(card_base + TWIN_CLR_TMR1);
 513                 inb(card_base + TWIN_CLR_TMR2);
 514                 info->twin_serial_cfg = TWIN_EI;
 515                 outb(info->twin_serial_cfg, card_base + TWIN_SERIAL_CFG);
 516         } else {
 517                 write_scc(priv, R15, CTSIE);
 518                 write_scc(priv, R0, RES_EXT_INT);
 519                 write_scc(priv, R1, EXT_INT_ENAB);
 520         }
 521
 522         /* Start timer */
 523         outb(1, tmr_base + TMR_CNT1);
 524         outb(0, tmr_base + TMR_CNT1);
 525
 526         /* Wait and detect IRQ */
 527         time = jiffies;
 528         while (jiffies - time < 2 + HZ / TMR_0_HZ);
 529         irq = probe_irq_off(irqs);
 530
 531         /* Clear pending interrupt, disable interrupts */
 532         if (type == TYPE_TWIN) {
 533                 inb(card_base + TWIN_CLR_TMR1);
 534         } else {
 535                 write_scc(priv, R1, 0);
 536                 write_scc(priv, R15, 0);
 537                 write_scc(priv, R0, RES_EXT_INT);
 538         }
 539
 540         if (irq <= 0) {
 541                 printk(KERN_ERR
 542                        "dmascc: could not find irq of %s at %#3x (irq=%d)\n",
 543                        hw[type].name, card_base, irq);
 544                 err = -ENODEV;
 545                 goto out3;
 546         }
 547
 548         /* Set up data structures */
 549         for (i = 0; i < 2; i++) {
 550                 dev = info->dev[i];
 551                 priv = &info->priv[i];
 552                 priv->type = type;
 553                 priv->chip = chip;
 554                 priv->dev = dev;
 555                 priv->info = info;
 556                 priv->channel = i;
 557                 spin_lock_init(&priv->ring_lock);
 558                 priv->register_lock = &info->register_lock;
 559                 priv->card_base = card_base;
 560                 priv->scc_cmd = scc_base + (i ? SCCB_CMD : SCCA_CMD);
 561                 priv->scc_data = scc_base + (i ? SCCB_DATA : SCCA_DATA);
 562                 priv->tmr_cnt = tmr_base + (i ? TMR_CNT2 : TMR_CNT1);
 563                 priv->tmr_ctrl = tmr_base + TMR_CTRL;
 564                 priv->tmr_mode = i ? 0xb0 : 0x70;
 565                 priv->param.pclk_hz = hw[type].pclk_hz;
 566                 priv->param.brg_tc = -1;
 567                 priv->param.clocks = TCTRxCP | RCRTxCP;
 568                 priv->param.persist = 256;
 569                 priv->param.dma = -1;
 570                 INIT_WORK(&priv->rx_work, rx_bh);
 571                 dev->ml_priv = priv;
 572                 snprintf(dev->name, sizeof(dev->name), "dmascc%i", 2 * n + i);
 573                 dev->base_addr = card_base;
 574                 dev->irq = irq;
 575                 dev->netdev_ops = &scc_netdev_ops;
 576                 dev->header_ops = &ax25_header_ops;
 577         }
 578         if (register_netdev(info->dev[0])) {
 579                 printk(KERN_ERR "dmascc: could not register %s\n",
 580                        info->dev[0]->name);
 581                 err = -ENODEV;
 582                 goto out3;
 583         }
 584         if (register_netdev(info->dev[1])) {
 585                 printk(KERN_ERR "dmascc: could not register %s\n",
 586                        info->dev[1]->name);
 587                 err = -ENODEV;
 588                 goto out4;
 589         }
 590
 591
 592         info->next = first;
 593         first = info;
 594         printk(KERN_INFO "dmascc: found %s (%s) at %#3x, irq %d\n",
 595                hw[type].name, chipnames[chip], card_base, irq);
 596         return 0;
 597
 598       out4:
 599         unregister_netdev(info->dev[0]);
 600       out3:
 601         if (info->priv[0].type == TYPE_TWIN)
 602                 outb(0, info->dev[0]->base_addr + TWIN_SERIAL_CFG);
 603         write_scc(&info->priv[0], R9, FHWRES);
 604         free_netdev(info->dev[1]);
 605       out2:
 606         free_netdev(info->dev[0]);
 607       out1:
 608         kfree(info);
 609       out:
 610         return err;
 611 }
 612
 613
 614 /* Driver functions */
 615
 616 static void write_scc(struct scc_priv *priv, int reg, int val)
 617 {
 618         unsigned long flags;
 619         switch (priv->type) {
 620         case TYPE_S5:
 621                 if (reg)
 622                         outb(reg, priv->scc_cmd);
 623                 outb(val, priv->scc_cmd);
 624                 return;
 625         case TYPE_TWIN:
 626                 if (reg)
 627                         outb_p(reg, priv->scc_cmd);
 628                 outb_p(val, priv->scc_cmd);
 629                 return;
 630         default:
 631                 spin_lock_irqsave(priv->register_lock, flags);
 632                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 633                 if (reg)
 634                         outb_p(reg, priv->scc_cmd);
 635                 outb_p(val, priv->scc_cmd);
 636                 outb(1, priv->card_base + PI_DREQ_MASK);
 637                 spin_unlock_irqrestore(priv->register_lock, flags);
 638                 return;
 639         }
 640 }
 641
 642
 643 static void write_scc_data(struct scc_priv *priv, int val, int fast)
 644 {
 645         unsigned long flags;
 646         switch (priv->type) {
 647         case TYPE_S5:
 648                 outb(val, priv->scc_data);
 649                 return;
 650         case TYPE_TWIN:
 651                 outb_p(val, priv->scc_data);
 652                 return;
 653         default:
 654                 if (fast)
 655                         outb_p(val, priv->scc_data);
 656                 else {
 657                         spin_lock_irqsave(priv->register_lock, flags);
 658                         outb_p(0, priv->card_base + PI_DREQ_MASK);
 659                         outb_p(val, priv->scc_data);
 660                         outb(1, priv->card_base + PI_DREQ_MASK);
 661                         spin_unlock_irqrestore(priv->register_lock, flags);
 662                 }
 663                 return;
 664         }
 665 }
 666
 667
 668 static int read_scc(struct scc_priv *priv, int reg)
 669 {
 670         int rc;
 671         unsigned long flags;
 672         switch (priv->type) {
 673         case TYPE_S5:
 674                 if (reg)
 675                         outb(reg, priv->scc_cmd);
 676                 return inb(priv->scc_cmd);
 677         case TYPE_TWIN:
 678                 if (reg)
 679                         outb_p(reg, priv->scc_cmd);
 680                 return inb_p(priv->scc_cmd);
 681         default:
 682                 spin_lock_irqsave(priv->register_lock, flags);
 683                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 684                 if (reg)
 685                         outb_p(reg, priv->scc_cmd);
 686                 rc = inb_p(priv->scc_cmd);
 687                 outb(1, priv->card_base + PI_DREQ_MASK);
 688                 spin_unlock_irqrestore(priv->register_lock, flags);
 689                 return rc;
 690         }
 691 }
 692
 693
 694 static int read_scc_data(struct scc_priv *priv)
 695 {
 696         int rc;
 697         unsigned long flags;
 698         switch (priv->type) {
 699         case TYPE_S5:
 700                 return inb(priv->scc_data);
 701         case TYPE_TWIN:
 702                 return inb_p(priv->scc_data);
 703         default:
 704                 spin_lock_irqsave(priv->register_lock, flags);
 705                 outb_p(0, priv->card_base + PI_DREQ_MASK);
 706                 rc = inb_p(priv->scc_data);
 707                 outb(1, priv->card_base + PI_DREQ_MASK);
 708                 spin_unlock_irqrestore(priv->register_lock, flags);
 709                 return rc;
 710         }
 711 }
 712
 713
 714 static int scc_open(struct net_device *dev)
 715 {
 716         struct scc_priv *priv = dev->ml_priv;
 717         struct scc_info *info = priv->info;
 718         int card_base = priv->card_base;
 719
 720         /* Request IRQ if not already used by other channel */
 721         if (!info->irq_used) {
 722                 if (request_irq(dev->irq, scc_isr, 0, "dmascc", info)) {
 723                         return -EAGAIN;
 724                 }
 725         }
 726         info->irq_used++;
 727
 728         /* Request DMA if required */
 729         if (priv->param.dma >= 0) {
 730                 if (request_dma(priv->param.dma, "dmascc")) {
 731                         if (--info->irq_used == 0)
 732                                 free_irq(dev->irq, info);
 733                         return -EAGAIN;
 734                 } else {
 735                         unsigned long flags = claim_dma_lock();
 736                         clear_dma_ff(priv->param.dma);
 737                         release_dma_lock(flags);
 738                 }
 739         }
 740
 741         /* Initialize local variables */
 742         priv->rx_ptr = 0;
 743         priv->rx_over = 0;
 744         priv->rx_head = priv->rx_tail = priv->rx_count = 0;
 745         priv->state = IDLE;
 746         priv->tx_head = priv->tx_tail = priv->tx_count = 0;
 747         priv->tx_ptr = 0;
 748
 749         /* Reset channel */
 750         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 751         /* X1 clock, SDLC mode */
 752         write_scc(priv, R4, SDLC | X1CLK);
 753         /* DMA */
 754         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
 755         /* 8 bit RX char, RX disable */
 756         write_scc(priv, R3, Rx8);
 757         /* 8 bit TX char, TX disable */
 758         write_scc(priv, R5, Tx8);
 759         /* SDLC address field */
 760         write_scc(priv, R6, 0);
 761         /* SDLC flag */
 762         write_scc(priv, R7, FLAG);
 763         switch (priv->chip) {
 764         case Z85C30:
 765                 /* Select WR7' */
 766                 write_scc(priv, R15, SHDLCE);
 767                 /* Auto EOM reset */
 768                 write_scc(priv, R7, AUTOEOM);
 769                 write_scc(priv, R15, 0);
 770                 break;
 771         case Z85230:
 772                 /* Select WR7' */
 773                 write_scc(priv, R15, SHDLCE);
 774                 /* The following bits are set (see 2.5.2.1):
 775                    - Automatic EOM reset
 776                    - Interrupt request if RX FIFO is half full
 777                    This bit should be ignored in DMA mode (according to the
 778                    documentation), but actually isn't. The receiver doesn't work if
 779                    it is set. Thus, we have to clear it in DMA mode.
 780                    - Interrupt/DMA request if TX FIFO is completely empty
 781                    a) If set, the ESCC behaves as if it had no TX FIFO (Z85C30
 782                    compatibility).
 783                    b) If cleared, DMA requests may follow each other very quickly,
 784                    filling up the TX FIFO.
 785                    Advantage: TX works even in case of high bus latency.
 786                    Disadvantage: Edge-triggered DMA request circuitry may miss
 787                    a request. No more data is delivered, resulting
 788                    in a TX FIFO underrun.
 789                    Both PI2 and S5SCC/DMA seem to work fine with TXFIFOE cleared.
 790                    The PackeTwin doesn't. I don't know about the PI, but let's
 791                    assume it behaves like the PI2.
 792                  */
 793                 if (priv->param.dma >= 0) {
 794                         if (priv->type == TYPE_TWIN)
 795                                 write_scc(priv, R7, AUTOEOM | TXFIFOE);
 796                         else
 797                                 write_scc(priv, R7, AUTOEOM);
 798                 } else {
 799                         write_scc(priv, R7, AUTOEOM | RXFIFOH);
 800                 }
 801                 write_scc(priv, R15, 0);
 802                 break;
 803         }
 804         /* Preset CRC, NRZ(I) encoding */
 805         write_scc(priv, R10, CRCPS | (priv->param.nrzi ? NRZI : NRZ));
 806
 807         /* Configure baud rate generator */
 808         if (priv->param.brg_tc >= 0) {
 809                 /* Program BR generator */
 810                 write_scc(priv, R12, priv->param.brg_tc & 0xFF);
 811                 write_scc(priv, R13, (priv->param.brg_tc >> 8) & 0xFF);
 812                 /* BRG source = SYS CLK; enable BRG; DTR REQ function (required by
 813                    PackeTwin, not connected on the PI2); set DPLL source to BRG */
 814                 write_scc(priv, R14, SSBR | DTRREQ | BRSRC | BRENABL);
 815                 /* Enable DPLL */
 816                 write_scc(priv, R14, SEARCH | DTRREQ | BRSRC | BRENABL);
 817         } else {
 818                 /* Disable BR generator */
 819                 write_scc(priv, R14, DTRREQ | BRSRC);
 820         }
 821
 822         /* Configure clocks */
 823         if (priv->type == TYPE_TWIN) {
 824                 /* Disable external TX clock receiver */
 825                 outb((info->twin_serial_cfg &=
 826                       ~(priv->channel ? TWIN_EXTCLKB : TWIN_EXTCLKA)),
 827                      card_base + TWIN_SERIAL_CFG);
 828         }
 829         write_scc(priv, R11, priv->param.clocks);
 830         if ((priv->type == TYPE_TWIN) && !(priv->param.clocks & TRxCOI)) {
 831                 /* Enable 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
 837         /* Configure PackeTwin */
 838         if (priv->type == TYPE_TWIN) {
 839                 /* Assert DTR, enable interrupts */
 840                 outb((info->twin_serial_cfg |= TWIN_EI |
 841                       (priv->channel ? TWIN_DTRB_ON : TWIN_DTRA_ON)),
 842                      card_base + TWIN_SERIAL_CFG);
 843         }
 844
 845         /* Read current status */
 846         priv->rr0 = read_scc(priv, R0);
 847         /* Enable DCD interrupt */
 848         write_scc(priv, R15, DCDIE);
 849
 850         netif_start_queue(dev);
 851
 852         return 0;
 853 }
 854
 855
 856 static int scc_close(struct net_device *dev)
 857 {
 858         struct scc_priv *priv = dev->ml_priv;
 859         struct scc_info *info = priv->info;
 860         int card_base = priv->card_base;
 861
 862         netif_stop_queue(dev);
 863
 864         if (priv->type == TYPE_TWIN) {
 865                 /* Drop DTR */
 866                 outb((info->twin_serial_cfg &=
 867                       (priv->channel ? ~TWIN_DTRB_ON : ~TWIN_DTRA_ON)),
 868                      card_base + TWIN_SERIAL_CFG);
 869         }
 870
 871         /* Reset channel, free DMA and IRQ */
 872         write_scc(priv, R9, (priv->channel ? CHRB : CHRA) | MIE | NV);
 873         if (priv->param.dma >= 0) {
 874                 if (priv->type == TYPE_TWIN)
 875                         outb(0, card_base + TWIN_DMA_CFG);
 876                 free_dma(priv->param.dma);
 877         }
 878         if (--info->irq_used == 0)
 879                 free_irq(dev->irq, info);
 880
 881         return 0;
 882 }
 883
 884
 885 static int scc_siocdevprivate(struct net_device *dev, struct ifreq *ifr, void __user *data, int cmd)
 886 {
 887         struct scc_priv *priv = dev->ml_priv;
 888
 889         switch (cmd) {
 890         case SIOCGSCCPARAM:
 891                 if (copy_to_user(data, &priv->param, sizeof(struct scc_param)))
 892                         return -EFAULT;
 893                 return 0;
 894         case SIOCSSCCPARAM:
 895                 if (!capable(CAP_NET_ADMIN))
 896                         return -EPERM;
 897                 if (netif_running(dev))
 898                         return -EAGAIN;
 899                 if (copy_from_user(&priv->param, data,
 900                                    sizeof(struct scc_param)))
 901                         return -EFAULT;
 902                 return 0;
 903         default:
 904                 return -EOPNOTSUPP;
 905         }
 906 }
 907
 908
 909 static int scc_send_packet(struct sk_buff *skb, struct net_device *dev)
 910 {
 911         struct scc_priv *priv = dev->ml_priv;
 912         unsigned long flags;
 913         int i;
 914
 915         if (skb->protocol == htons(ETH_P_IP))
 916                 return ax25_ip_xmit(skb);
 917
 918         /* Temporarily stop the scheduler feeding us packets */
 919         netif_stop_queue(dev);
 920
 921         /* Transfer data to DMA buffer */
 922         i = priv->tx_head;
 923         skb_copy_from_linear_data_offset(skb, 1, priv->tx_buf[i], skb->len - 1);
 924         priv->tx_len[i] = skb->len - 1;
 925
 926         /* Clear interrupts while we touch our circular buffers */
 927
 928         spin_lock_irqsave(&priv->ring_lock, flags);
 929         /* Move the ring buffer's head */
 930         priv->tx_head = (i + 1) % NUM_TX_BUF;
 931         priv->tx_count++;
 932
 933         /* If we just filled up the last buffer, leave queue stopped.
 934            The higher layers must wait until we have a DMA buffer
 935            to accept the data. */
 936         if (priv->tx_count < NUM_TX_BUF)
 937                 netif_wake_queue(dev);
 938
 939         /* Set new TX state */
 940         if (priv->state == IDLE) {
 941                 /* Assert RTS, start timer */
 942                 priv->state = TX_HEAD;
 943                 priv->tx_start = jiffies;
 944                 write_scc(priv, R5, TxCRC_ENAB | RTS | TxENAB | Tx8);
 945                 write_scc(priv, R15, 0);
 946                 start_timer(priv, priv->param.txdelay, 0);
 947         }
 948
 949         /* Turn interrupts back on and free buffer */
 950         spin_unlock_irqrestore(&priv->ring_lock, flags);
 951         dev_kfree_skb(skb);
 952
 953         return NETDEV_TX_OK;
 954 }
 955
 956
 957 static int scc_set_mac_address(struct net_device *dev, void *sa)
 958 {
 959         memcpy(dev->dev_addr, ((struct sockaddr *) sa)->sa_data,
 960                dev->addr_len);
 961         return 0;
 962 }
 963
 964
 965 static inline void tx_on(struct scc_priv *priv)
 966 {
 967         int i, n;
 968         unsigned long flags;
 969
 970         if (priv->param.dma >= 0) {
 971                 n = (priv->chip == Z85230) ? 3 : 1;
 972                 /* Program DMA controller */
 973                 flags = claim_dma_lock();
 974                 set_dma_mode(priv->param.dma, DMA_MODE_WRITE);
 975                 set_dma_addr(priv->param.dma,
 976                              virt_to_bus(priv->tx_buf[priv->tx_tail]) + n);
 977                 set_dma_count(priv->param.dma,
 978                               priv->tx_len[priv->tx_tail] - n);
 979                 release_dma_lock(flags);
 980                 /* Enable TX underrun interrupt */
 981                 write_scc(priv, R15, TxUIE);
 982                 /* Configure DREQ */
 983                 if (priv->type == TYPE_TWIN)
 984                         outb((priv->param.dma ==
 985                               1) ? TWIN_DMA_HDX_T1 : TWIN_DMA_HDX_T3,
 986                              priv->card_base + TWIN_DMA_CFG);
 987                 else
 988                         write_scc(priv, R1,
 989                                   EXT_INT_ENAB | WT_FN_RDYFN |
 990                                   WT_RDY_ENAB);
 991                 /* Write first byte(s) */
 992                 spin_lock_irqsave(priv->register_lock, flags);
 993                 for (i = 0; i < n; i++)
 994                         write_scc_data(priv,
 995                                        priv->tx_buf[priv->tx_tail][i], 1);
 996                 enable_dma(priv->param.dma);
 997                 spin_unlock_irqrestore(priv->register_lock, flags);
 998         } else {
 999                 write_scc(priv, R15, TxUIE);
1000                 write_scc(priv, R1,
1001                           EXT_INT_ENAB | WT_FN_RDYFN | TxINT_ENAB);
1002                 tx_isr(priv);
1003         }
1004         /* Reset EOM latch if we do not have the AUTOEOM feature */
1005         if (priv->chip == Z8530)
1006                 write_scc(priv, R0, RES_EOM_L);
1007 }
1008
1009
1010 static inline void rx_on(struct scc_priv *priv)
1011 {
1012         unsigned long flags;
1013
1014         /* Clear RX FIFO */
1015         while (read_scc(priv, R0) & Rx_CH_AV)
1016                 read_scc_data(priv);
1017         priv->rx_over = 0;
1018         if (priv->param.dma >= 0) {
1019                 /* Program DMA controller */
1020                 flags = claim_dma_lock();
1021                 set_dma_mode(priv->param.dma, DMA_MODE_READ);
1022                 set_dma_addr(priv->param.dma,
1023                              virt_to_bus(priv->rx_buf[priv->rx_head]));
1024                 set_dma_count(priv->param.dma, BUF_SIZE);
1025                 release_dma_lock(flags);
1026                 enable_dma(priv->param.dma);
1027                 /* Configure PackeTwin DMA */
1028                 if (priv->type == TYPE_TWIN) {
1029                         outb((priv->param.dma ==
1030                               1) ? TWIN_DMA_HDX_R1 : TWIN_DMA_HDX_R3,
1031                              priv->card_base + TWIN_DMA_CFG);
1032                 }
1033                 /* Sp. cond. intr. only, ext int enable, RX DMA enable */
1034                 write_scc(priv, R1, EXT_INT_ENAB | INT_ERR_Rx |
1035                           WT_RDY_RT | WT_FN_RDYFN | WT_RDY_ENAB);
1036         } else {
1037                 /* Reset current frame */
1038                 priv->rx_ptr = 0;
1039                 /* Intr. on all Rx characters and Sp. cond., ext int enable */
1040                 write_scc(priv, R1, EXT_INT_ENAB | INT_ALL_Rx | WT_RDY_RT |
1041                           WT_FN_RDYFN);
1042         }
1043         write_scc(priv, R0, ERR_RES);
1044         write_scc(priv, R3, RxENABLE | Rx8 | RxCRC_ENAB);
1045 }
1046
1047
1048 static inline void rx_off(struct scc_priv *priv)
1049 {
1050         /* Disable receiver */
1051         write_scc(priv, R3, Rx8);
1052         /* Disable DREQ / RX interrupt */
1053         if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1054                 outb(0, priv->card_base + TWIN_DMA_CFG);
1055         else
1056                 write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1057         /* Disable DMA */
1058         if (priv->param.dma >= 0)
1059                 disable_dma(priv->param.dma);
1060 }
1061
1062
1063 static void start_timer(struct scc_priv *priv, int t, int r15)
1064 {
1065         outb(priv->tmr_mode, priv->tmr_ctrl);
1066         if (t == 0) {
1067                 tm_isr(priv);
1068         } else if (t > 0) {
1069                 outb(t & 0xFF, priv->tmr_cnt);
1070                 outb((t >> 8) & 0xFF, priv->tmr_cnt);
1071                 if (priv->type != TYPE_TWIN) {
1072                         write_scc(priv, R15, r15 | CTSIE);
1073                         priv->rr0 |= CTS;
1074                 }
1075         }
1076 }
1077
1078
1079 static inline unsigned char random(void)
1080 {
1081         /* See "Numerical Recipes in C", second edition, p. 284 */
1082         rand = rand * 1664525L + 1013904223L;
1083         return (unsigned char) (rand >> 24);
1084 }
1085
1086 static inline void z8530_isr(struct scc_info *info)
1087 {
1088         int is, i = 100;
1089
1090         while ((is = read_scc(&info->priv[0], R3)) && i--) {
1091                 if (is & CHARxIP) {
1092                         rx_isr(&info->priv[0]);
1093                 } else if (is & CHATxIP) {
1094                         tx_isr(&info->priv[0]);
1095                 } else if (is & CHAEXT) {
1096                         es_isr(&info->priv[0]);
1097                 } else if (is & CHBRxIP) {
1098                         rx_isr(&info->priv[1]);
1099                 } else if (is & CHBTxIP) {
1100                         tx_isr(&info->priv[1]);
1101                 } else {
1102                         es_isr(&info->priv[1]);
1103                 }
1104                 write_scc(&info->priv[0], R0, RES_H_IUS);
1105                 i++;
1106         }
1107         if (i < 0) {
1108                 printk(KERN_ERR "dmascc: stuck in ISR with RR3=0x%02x.\n",
1109                        is);
1110         }
1111         /* Ok, no interrupts pending from this 8530. The INT line should
1112            be inactive now. */
1113 }
1114
1115
1116 static irqreturn_t scc_isr(int irq, void *dev_id)
1117 {
1118         struct scc_info *info = dev_id;
1119
1120         spin_lock(info->priv[0].register_lock);
1121         /* At this point interrupts are enabled, and the interrupt under service
1122            is already acknowledged, but masked off.
1123
1124            Interrupt processing: We loop until we know that the IRQ line is
1125            low. If another positive edge occurs afterwards during the ISR,
1126            another interrupt will be triggered by the interrupt controller
1127            as soon as the IRQ level is enabled again (see asm/irq.h).
1128
1129            Bottom-half handlers will be processed after scc_isr(). This is
1130            important, since we only have small ringbuffers and want new data
1131            to be fetched/delivered immediately. */
1132
1133         if (info->priv[0].type == TYPE_TWIN) {
1134                 int is, card_base = info->priv[0].card_base;
1135                 while ((is = ~inb(card_base + TWIN_INT_REG)) &
1136                        TWIN_INT_MSK) {
1137                         if (is & TWIN_SCC_MSK) {
1138                                 z8530_isr(info);
1139                         } else if (is & TWIN_TMR1_MSK) {
1140                                 inb(card_base + TWIN_CLR_TMR1);
1141                                 tm_isr(&info->priv[0]);
1142                         } else {
1143                                 inb(card_base + TWIN_CLR_TMR2);
1144                                 tm_isr(&info->priv[1]);
1145                         }
1146                 }
1147         } else
1148                 z8530_isr(info);
1149         spin_unlock(info->priv[0].register_lock);
1150         return IRQ_HANDLED;
1151 }
1152
1153
1154 static void rx_isr(struct scc_priv *priv)
1155 {
1156         if (priv->param.dma >= 0) {
1157                 /* Check special condition and perform error reset. See 2.4.7.5. */
1158                 special_condition(priv, read_scc(priv, R1));
1159                 write_scc(priv, R0, ERR_RES);
1160         } else {
1161                 /* Check special condition for each character. Error reset not necessary.
1162                    Same algorithm for SCC and ESCC. See 2.4.7.1 and 2.4.7.4. */
1163                 int rc;
1164                 while (read_scc(priv, R0) & Rx_CH_AV) {
1165                         rc = read_scc(priv, R1);
1166                         if (priv->rx_ptr < BUF_SIZE)
1167                                 priv->rx_buf[priv->rx_head][priv->
1168                                                             rx_ptr++] =
1169                                     read_scc_data(priv);
1170                         else {
1171                                 priv->rx_over = 2;
1172                                 read_scc_data(priv);
1173                         }
1174                         special_condition(priv, rc);
1175                 }
1176         }
1177 }
1178
1179
1180 static void special_condition(struct scc_priv *priv, int rc)
1181 {
1182         int cb;
1183         unsigned long flags;
1184
1185         /* See Figure 2-15. Only overrun and EOF need to be checked. */
1186
1187         if (rc & Rx_OVR) {
1188                 /* Receiver overrun */
1189                 priv->rx_over = 1;
1190                 if (priv->param.dma < 0)
1191                         write_scc(priv, R0, ERR_RES);
1192         } else if (rc & END_FR) {
1193                 /* End of frame. Get byte count */
1194                 if (priv->param.dma >= 0) {
1195                         flags = claim_dma_lock();
1196                         cb = BUF_SIZE - get_dma_residue(priv->param.dma) -
1197                             2;
1198                         release_dma_lock(flags);
1199                 } else {
1200                         cb = priv->rx_ptr - 2;
1201                 }
1202                 if (priv->rx_over) {
1203                         /* We had an overrun */
1204                         priv->dev->stats.rx_errors++;
1205                         if (priv->rx_over == 2)
1206                                 priv->dev->stats.rx_length_errors++;
1207                         else
1208                                 priv->dev->stats.rx_fifo_errors++;
1209                         priv->rx_over = 0;
1210                 } else if (rc & CRC_ERR) {
1211                         /* Count invalid CRC only if packet length >= minimum */
1212                         if (cb >= 15) {
1213                                 priv->dev->stats.rx_errors++;
1214                                 priv->dev->stats.rx_crc_errors++;
1215                         }
1216                 } else {
1217                         if (cb >= 15) {
1218                                 if (priv->rx_count < NUM_RX_BUF - 1) {
1219                                         /* Put good frame in FIFO */
1220                                         priv->rx_len[priv->rx_head] = cb;
1221                                         priv->rx_head =
1222                                             (priv->rx_head +
1223                                              1) % NUM_RX_BUF;
1224                                         priv->rx_count++;
1225                                         schedule_work(&priv->rx_work);
1226                                 } else {
1227                                         priv->dev->stats.rx_errors++;
1228                                         priv->dev->stats.rx_over_errors++;
1229                                 }
1230                         }
1231                 }
1232                 /* Get ready for new frame */
1233                 if (priv->param.dma >= 0) {
1234                         flags = claim_dma_lock();
1235                         set_dma_addr(priv->param.dma,
1236                                      virt_to_bus(priv->rx_buf[priv->rx_head]));
1237                         set_dma_count(priv->param.dma, BUF_SIZE);
1238                         release_dma_lock(flags);
1239                 } else {
1240                         priv->rx_ptr = 0;
1241                 }
1242         }
1243 }
1244
1245
1246 static void rx_bh(struct work_struct *ugli_api)
1247 {
1248         struct scc_priv *priv = container_of(ugli_api, struct scc_priv, rx_work);
1249         int i = priv->rx_tail;
1250         int cb;
1251         unsigned long flags;
1252         struct sk_buff *skb;
1253         unsigned char *data;
1254
1255         spin_lock_irqsave(&priv->ring_lock, flags);
1256         while (priv->rx_count) {
1257                 spin_unlock_irqrestore(&priv->ring_lock, flags);
1258                 cb = priv->rx_len[i];
1259                 /* Allocate buffer */
1260                 skb = dev_alloc_skb(cb + 1);
1261                 if (skb == NULL) {
1262                         /* Drop packet */
1263                         priv->dev->stats.rx_dropped++;
1264                 } else {
1265                         /* Fill buffer */
1266                         data = skb_put(skb, cb + 1);
1267                         data[0] = 0;
1268                         memcpy(&data[1], priv->rx_buf[i], cb);
1269                         skb->protocol = ax25_type_trans(skb, priv->dev);
1270                         netif_rx(skb);
1271                         priv->dev->stats.rx_packets++;
1272                         priv->dev->stats.rx_bytes += cb;
1273                 }
1274                 spin_lock_irqsave(&priv->ring_lock, flags);
1275                 /* Move tail */
1276                 priv->rx_tail = i = (i + 1) % NUM_RX_BUF;
1277                 priv->rx_count--;
1278         }
1279         spin_unlock_irqrestore(&priv->ring_lock, flags);
1280 }
1281
1282
1283 static void tx_isr(struct scc_priv *priv)
1284 {
1285         int i = priv->tx_tail, p = priv->tx_ptr;
1286
1287         /* Suspend TX interrupts if we don't want to send anything.
1288            See Figure 2-22. */
1289         if (p == priv->tx_len[i]) {
1290                 write_scc(priv, R0, RES_Tx_P);
1291                 return;
1292         }
1293
1294         /* Write characters */
1295         while ((read_scc(priv, R0) & Tx_BUF_EMP) && p < priv->tx_len[i]) {
1296                 write_scc_data(priv, priv->tx_buf[i][p++], 0);
1297         }
1298
1299         /* Reset EOM latch of Z8530 */
1300         if (!priv->tx_ptr && p && priv->chip == Z8530)
1301                 write_scc(priv, R0, RES_EOM_L);
1302
1303         priv->tx_ptr = p;
1304 }
1305
1306
1307 static void es_isr(struct scc_priv *priv)
1308 {
1309         int i, rr0, drr0, res;
1310         unsigned long flags;
1311
1312         /* Read status, reset interrupt bit (open latches) */
1313         rr0 = read_scc(priv, R0);
1314         write_scc(priv, R0, RES_EXT_INT);
1315         drr0 = priv->rr0 ^ rr0;
1316         priv->rr0 = rr0;
1317
1318         /* Transmit underrun (2.4.9.6). We can't check the TxEOM flag, since
1319            it might have already been cleared again by AUTOEOM. */
1320         if (priv->state == TX_DATA) {
1321                 /* Get remaining bytes */
1322                 i = priv->tx_tail;
1323                 if (priv->param.dma >= 0) {
1324                         disable_dma(priv->param.dma);
1325                         flags = claim_dma_lock();
1326                         res = get_dma_residue(priv->param.dma);
1327                         release_dma_lock(flags);
1328                 } else {
1329                         res = priv->tx_len[i] - priv->tx_ptr;
1330                         priv->tx_ptr = 0;
1331                 }
1332                 /* Disable DREQ / TX interrupt */
1333                 if (priv->param.dma >= 0 && priv->type == TYPE_TWIN)
1334                         outb(0, priv->card_base + TWIN_DMA_CFG);
1335                 else
1336                         write_scc(priv, R1, EXT_INT_ENAB | WT_FN_RDYFN);
1337                 if (res) {
1338                         /* Update packet statistics */
1339                         priv->dev->stats.tx_errors++;
1340                         priv->dev->stats.tx_fifo_errors++;
1341                         /* Other underrun interrupts may already be waiting */
1342                         write_scc(priv, R0, RES_EXT_INT);
1343                         write_scc(priv, R0, RES_EXT_INT);
1344                 } else {
1345                         /* Update packet statistics */
1346                         priv->dev->stats.tx_packets++;
1347                         priv->dev->stats.tx_bytes += priv->tx_len[i];
1348                         /* Remove frame from FIFO */
1349                         priv->tx_tail = (i + 1) % NUM_TX_BUF;
1350                         priv->tx_count--;
1351                         /* Inform upper layers */
1352                         netif_wake_queue(priv->dev);
1353                 }
1354                 /* Switch state */
1355                 write_scc(priv, R15, 0);
1356                 if (priv->tx_count &&
1357                     (jiffies - priv->tx_start) < priv->param.txtimeout) {
1358                         priv->state = TX_PAUSE;
1359                         start_timer(priv, priv->param.txpause, 0);
1360                 } else {
1361                         priv->state = TX_TAIL;
1362                         start_timer(priv, priv->param.txtail, 0);
1363                 }
1364         }
1365
1366         /* DCD transition */
1367         if (drr0 & DCD) {
1368                 if (rr0 & DCD) {
1369                         switch (priv->state) {
1370                         case IDLE:
1371                         case WAIT:
1372                                 priv->state = DCD_ON;
1373                                 write_scc(priv, R15, 0);
1374                                 start_timer(priv, priv->param.dcdon, 0);
1375                         }
1376                 } else {
1377                         switch (priv->state) {
1378                         case RX_ON:
1379                                 rx_off(priv);
1380                                 priv->state = DCD_OFF;
1381                                 write_scc(priv, R15, 0);
1382                                 start_timer(priv, priv->param.dcdoff, 0);
1383                         }
1384                 }
1385         }
1386
1387         /* CTS transition */
1388         if ((drr0 & CTS) && (~rr0 & CTS) && priv->type != TYPE_TWIN)
1389                 tm_isr(priv);
1390
1391 }
1392
1393
1394 static void tm_isr(struct scc_priv *priv)
1395 {
1396         switch (priv->state) {
1397         case TX_HEAD:
1398         case TX_PAUSE:
1399                 tx_on(priv);
1400                 priv->state = TX_DATA;
1401                 break;
1402         case TX_TAIL:
1403                 write_scc(priv, R5, TxCRC_ENAB | Tx8);
1404                 priv->state = RTS_OFF;
1405                 if (priv->type != TYPE_TWIN)
1406                         write_scc(priv, R15, 0);
1407                 start_timer(priv, priv->param.rtsoff, 0);
1408                 break;
1409         case RTS_OFF:
1410                 write_scc(priv, R15, DCDIE);
1411                 priv->rr0 = read_scc(priv, R0);
1412                 if (priv->rr0 & DCD) {
1413                         priv->dev->stats.collisions++;
1414                         rx_on(priv);
1415                         priv->state = RX_ON;
1416                 } else {
1417                         priv->state = WAIT;
1418                         start_timer(priv, priv->param.waittime, DCDIE);
1419                 }
1420                 break;
1421         case WAIT:
1422                 if (priv->tx_count) {
1423                         priv->state = TX_HEAD;
1424                         priv->tx_start = jiffies;
1425                         write_scc(priv, R5,
1426                                   TxCRC_ENAB | RTS | TxENAB | Tx8);
1427                         write_scc(priv, R15, 0);
1428                         start_timer(priv, priv->param.txdelay, 0);
1429                 } else {
1430                         priv->state = IDLE;
1431                         if (priv->type != TYPE_TWIN)
1432                                 write_scc(priv, R15, DCDIE);
1433                 }
1434                 break;
1435         case DCD_ON:
1436         case DCD_OFF:
1437                 write_scc(priv, R15, DCDIE);
1438                 priv->rr0 = read_scc(priv, R0);
1439                 if (priv->rr0 & DCD) {
1440                         rx_on(priv);
1441                         priv->state = RX_ON;
1442                 } else {
1443                         priv->state = WAIT;
1444                         start_timer(priv,
1445                                     random() / priv->param.persist *
1446                                     priv->param.slottime, DCDIE);
1447                 }
1448                 break;
1449         }
1450 }