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   1 /*
   2     Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
   3
   4     National Semiconductor SCx200 ACCESS.bus support
   5
   6     Based on i2c-keywest.c which is:
   7         Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   8         Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
   9
  10     This program is free software; you can redistribute it and/or
  11     modify it under the terms of the GNU General Public License as
  12     published by the Free Software Foundation; either version 2 of the
  13     License, or (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18     General Public License for more details.
  19
  20     You should have received a copy of the GNU General Public License
  21     along with this program; if not, write to the Free Software
  22     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include <linux/module.h>
  26 #include <linux/errno.h>
  27 #include <linux/kernel.h>
  28 #include <linux/init.h>
  29 #include <linux/i2c.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/pci.h>
  32 #include <linux/delay.h>
  33 #include <asm/io.h>
  34
  35 #include <linux/scx200.h>
  36
  37 #define NAME "scx200_acb"
  38
  39 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  40 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  41 MODULE_LICENSE("GPL");
  42
  43 #define MAX_DEVICES 4
  44 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  45 module_param_array(base, int, NULL, 0);
  46 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  47
  48 #ifdef DEBUG
  49 #define DBG(x...) printk(KERN_DEBUG NAME ": " x)
  50 #else
  51 #define DBG(x...)
  52 #endif
  53
  54 /* The hardware supports interrupt driven mode too, but I haven't
  55    implemented that. */
  56 #define POLLED_MODE 1
  57 #define POLL_TIMEOUT (HZ)
  58
  59 enum scx200_acb_state {
  60         state_idle,
  61         state_address,
  62         state_command,
  63         state_repeat_start,
  64         state_quick,
  65         state_read,
  66         state_write,
  67 };
  68
  69 static const char *scx200_acb_state_name[] = {
  70         "idle",
  71         "address",
  72         "command",
  73         "repeat_start",
  74         "quick",
  75         "read",
  76         "write",
  77 };
  78
  79 /* Physical interface */
  80 struct scx200_acb_iface {
  81         struct scx200_acb_iface *next;
  82         struct i2c_adapter adapter;
  83         unsigned base;
  84         struct semaphore sem;
  85
  86         /* State machine data */
  87         enum scx200_acb_state state;
  88         int result;
  89         u8 address_byte;
  90         u8 command;
  91         u8 *ptr;
  92         char needs_reset;
  93         unsigned len;
  94 };
  95
  96 /* Register Definitions */
  97 #define ACBSDA          (iface->base + 0)
  98 #define ACBST           (iface->base + 1)
  99 #define    ACBST_SDAST          0x40 /* SDA Status */
 100 #define    ACBST_BER            0x20
 101 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
 102 #define    ACBST_STASTR         0x08 /* Stall After Start */
 103 #define    ACBST_MASTER         0x02
 104 #define ACBCST          (iface->base + 2)
 105 #define    ACBCST_BB            0x02
 106 #define ACBCTL1         (iface->base + 3)
 107 #define    ACBCTL1_STASTRE      0x80
 108 #define    ACBCTL1_NMINTE       0x40
 109 #define    ACBCTL1_ACK          0x10
 110 #define    ACBCTL1_STOP         0x02
 111 #define    ACBCTL1_START        0x01
 112 #define ACBADDR         (iface->base + 4)
 113 #define ACBCTL2         (iface->base + 5)
 114 #define    ACBCTL2_ENABLE       0x01
 115
 116 /************************************************************************/
 117
 118 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 119 {
 120         const char *errmsg;
 121
 122         DBG("state %s, status = 0x%02x\n",
 123             scx200_acb_state_name[iface->state], status);
 124
 125         if (status & ACBST_BER) {
 126                 errmsg = "bus error";
 127                 goto error;
 128         }
 129         if (!(status & ACBST_MASTER)) {
 130                 errmsg = "not master";
 131                 goto error;
 132         }
 133         if (status & ACBST_NEGACK)
 134                 goto negack;
 135
 136         switch (iface->state) {
 137         case state_idle:
 138                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 139                 break;
 140
 141         case state_address:
 142                 /* Do a pointer write first */
 143                 outb(iface->address_byte & ~1, ACBSDA);
 144
 145                 iface->state = state_command;
 146                 break;
 147
 148         case state_command:
 149                 outb(iface->command, ACBSDA);
 150
 151                 if (iface->address_byte & 1)
 152                         iface->state = state_repeat_start;
 153                 else
 154                         iface->state = state_write;
 155                 break;
 156
 157         case state_repeat_start:
 158                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 159                 /* fallthrough */
 160
 161         case state_quick:
 162                 if (iface->address_byte & 1) {
 163                         if (iface->len == 1)
 164                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 165                         else
 166                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 167                         outb(iface->address_byte, ACBSDA);
 168
 169                         iface->state = state_read;
 170                 } else {
 171                         outb(iface->address_byte, ACBSDA);
 172
 173                         iface->state = state_write;
 174                 }
 175                 break;
 176
 177         case state_read:
 178                 /* Set ACK if receiving the last byte */
 179                 if (iface->len == 1)
 180                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 181                 else
 182                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 183
 184                 *iface->ptr++ = inb(ACBSDA);
 185                 --iface->len;
 186
 187                 if (iface->len == 0) {
 188                         iface->result = 0;
 189                         iface->state = state_idle;
 190                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 191                 }
 192
 193                 break;
 194
 195         case state_write:
 196                 if (iface->len == 0) {
 197                         iface->result = 0;
 198                         iface->state = state_idle;
 199                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 200                         break;
 201                 }
 202
 203                 outb(*iface->ptr++, ACBSDA);
 204                 --iface->len;
 205
 206                 break;
 207         }
 208
 209         return;
 210
 211  negack:
 212         DBG("negative acknowledge in state %s\n",
 213             scx200_acb_state_name[iface->state]);
 214
 215         iface->state = state_idle;
 216         iface->result = -ENXIO;
 217
 218         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 219         outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 220         return;
 221
 222  error:
 223         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 224                 scx200_acb_state_name[iface->state]);
 225
 226         iface->state = state_idle;
 227         iface->result = -EIO;
 228         iface->needs_reset = 1;
 229 }
 230
 231 static void scx200_acb_timeout(struct scx200_acb_iface *iface)
 232 {
 233         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 234                 scx200_acb_state_name[iface->state]);
 235
 236         iface->state = state_idle;
 237         iface->result = -EIO;
 238         iface->needs_reset = 1;
 239 }
 240
 241 #ifdef POLLED_MODE
 242 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 243 {
 244         u8 status = 0;
 245         unsigned long timeout;
 246
 247         timeout = jiffies + POLL_TIMEOUT;
 248         while (time_before(jiffies, timeout)) {
 249                 status = inb(ACBST);
 250                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 251                         scx200_acb_machine(iface, status);
 252                         return;
 253                 }
 254                 msleep(10);
 255         }
 256
 257         scx200_acb_timeout(iface);
 258 }
 259 #endif /* POLLED_MODE */
 260
 261 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 262 {
 263         /* Disable the ACCESS.bus device and Configure the SCL
 264            frequency: 16 clock cycles */
 265         outb(0x70, ACBCTL2);
 266         /* Polling mode */
 267         outb(0, ACBCTL1);
 268         /* Disable slave address */
 269         outb(0, ACBADDR);
 270         /* Enable the ACCESS.bus device */
 271         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 272         /* Free STALL after START */
 273         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 274         /* Send a STOP */
 275         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 276         /* Clear BER, NEGACK and STASTR bits */
 277         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 278         /* Clear BB bit */
 279         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 280 }
 281
 282 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 283                                  u16 address, unsigned short flags,
 284                                  char rw, u8 command, int size,
 285                                  union i2c_smbus_data *data)
 286 {
 287         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 288         int len;
 289         u8 *buffer;
 290         u16 cur_word;
 291         int rc;
 292
 293         switch (size) {
 294         case I2C_SMBUS_QUICK:
 295                 len = 0;
 296                 buffer = NULL;
 297                 break;
 298
 299         case I2C_SMBUS_BYTE:
 300                 if (rw == I2C_SMBUS_READ) {
 301                         len = 1;
 302                         buffer = &data->byte;
 303                 } else {
 304                         len = 1;
 305                         buffer = &command;
 306                 }
 307                 break;
 308
 309         case I2C_SMBUS_BYTE_DATA:
 310                 len = 1;
 311                 buffer = &data->byte;
 312                 break;
 313
 314         case I2C_SMBUS_WORD_DATA:
 315                 len = 2;
 316                 cur_word = cpu_to_le16(data->word);
 317                 buffer = (u8 *)&cur_word;
 318                 break;
 319
 320         case I2C_SMBUS_BLOCK_DATA:
 321                 len = data->block[0];
 322                 buffer = &data->block[1];
 323                 break;
 324
 325         default:
 326                 return -EINVAL;
 327         }
 328
 329         DBG("size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 330             size, address, command, len, rw == I2C_SMBUS_READ);
 331
 332         if (!len && rw == I2C_SMBUS_READ) {
 333                 dev_warn(&adapter->dev, "zero length read\n");
 334                 return -EINVAL;
 335         }
 336
 337         if (len && !buffer) {
 338                 dev_warn(&adapter->dev, "nonzero length but no buffer\n");
 339                 return -EFAULT;
 340         }
 341
 342         down(&iface->sem);
 343
 344         iface->address_byte = address<<1;
 345         if (rw == I2C_SMBUS_READ)
 346                 iface->address_byte |= 1;
 347         iface->command = command;
 348         iface->ptr = buffer;
 349         iface->len = len;
 350         iface->result = -EINVAL;
 351         iface->needs_reset = 0;
 352
 353         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 354
 355         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 356                 iface->state = state_quick;
 357         else
 358                 iface->state = state_address;
 359
 360 #ifdef POLLED_MODE
 361         while (iface->state != state_idle)
 362                 scx200_acb_poll(iface);
 363 #else /* POLLED_MODE */
 364 #error Interrupt driven mode not implemented
 365 #endif /* POLLED_MODE */
 366
 367         if (iface->needs_reset)
 368                 scx200_acb_reset(iface);
 369
 370         rc = iface->result;
 371
 372         up(&iface->sem);
 373
 374         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 375                 data->word = le16_to_cpu(cur_word);
 376
 377 #ifdef DEBUG
 378         DBG(": transfer done, result: %d", rc);
 379         if (buffer) {
 380                 int i;
 381                 printk(" data:");
 382                 for (i = 0; i < len; ++i)
 383                         printk(" %02x", buffer[i]);
 384         }
 385         printk("\n");
 386 #endif
 387
 388         return rc;
 389 }
 390
 391 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 392 {
 393         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 394                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 395                I2C_FUNC_SMBUS_BLOCK_DATA;
 396 }
 397
 398 /* For now, we only handle combined mode (smbus) */
 399 static struct i2c_algorithm scx200_acb_algorithm = {
 400         .smbus_xfer     = scx200_acb_smbus_xfer,
 401         .functionality  = scx200_acb_func,
 402 };
 403
 404 static struct scx200_acb_iface *scx200_acb_list;
 405
 406 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 407 {
 408         u8 val;
 409
 410         /* Disable the ACCESS.bus device and Configure the SCL
 411            frequency: 16 clock cycles */
 412         outb(0x70, ACBCTL2);
 413
 414         if (inb(ACBCTL2) != 0x70) {
 415                 DBG("ACBCTL2 readback failed\n");
 416                 return -ENXIO;
 417         }
 418
 419         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 420
 421         val = inb(ACBCTL1);
 422         if (val) {
 423                 DBG("disabled, but ACBCTL1=0x%02x\n", val);
 424                 return -ENXIO;
 425         }
 426
 427         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 428
 429         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 430
 431         val = inb(ACBCTL1);
 432         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 433                 DBG("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", val);
 434                 return -ENXIO;
 435         }
 436
 437         return 0;
 438 }
 439
 440 static int  __init scx200_acb_create(int base, int index)
 441 {
 442         struct scx200_acb_iface *iface;
 443         struct i2c_adapter *adapter;
 444         int rc = 0;
 445         char description[64];
 446
 447         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 448         if (!iface) {
 449                 printk(KERN_ERR NAME ": can't allocate memory\n");
 450                 rc = -ENOMEM;
 451                 goto errout;
 452         }
 453
 454         adapter = &iface->adapter;
 455         i2c_set_adapdata(adapter, iface);
 456         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 457         adapter->owner = THIS_MODULE;
 458         adapter->id = I2C_HW_SMBUS_SCX200;
 459         adapter->algo = &scx200_acb_algorithm;
 460         adapter->class = I2C_CLASS_HWMON;
 461
 462         init_MUTEX(&iface->sem);
 463
 464         snprintf(description, sizeof(description),
 465                  "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 466         if (request_region(base, 8, description) == 0) {
 467                 dev_err(&adapter->dev, "can't allocate io 0x%x-0x%x\n",
 468                         base, base + 8-1);
 469                 rc = -EBUSY;
 470                 goto errout;
 471         }
 472         iface->base = base;
 473
 474         rc = scx200_acb_probe(iface);
 475         if (rc) {
 476                 dev_warn(&adapter->dev, "probe failed\n");
 477                 goto errout;
 478         }
 479
 480         scx200_acb_reset(iface);
 481
 482         if (i2c_add_adapter(adapter) < 0) {
 483                 dev_err(&adapter->dev, "failed to register\n");
 484                 rc = -ENODEV;
 485                 goto errout;
 486         }
 487
 488         lock_kernel();
 489         iface->next = scx200_acb_list;
 490         scx200_acb_list = iface;
 491         unlock_kernel();
 492
 493         return 0;
 494
 495  errout:
 496         if (iface) {
 497                 if (iface->base)
 498                         release_region(iface->base, 8);
 499                 kfree(iface);
 500         }
 501         return rc;
 502 }
 503
 504 static struct pci_device_id scx200[] = {
 505         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 506         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 507         { },
 508 };
 509
 510 static int __init scx200_acb_init(void)
 511 {
 512         int i;
 513         int rc;
 514
 515         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 516
 517         /* Verify that this really is a SCx200 processor */
 518         if (pci_dev_present(scx200) == 0)
 519                 return -ENODEV;
 520
 521         rc = -ENXIO;
 522         for (i = 0; i < MAX_DEVICES; ++i) {
 523                 if (base[i] > 0)
 524                         rc = scx200_acb_create(base[i], i);
 525         }
 526         if (scx200_acb_list)
 527                 return 0;
 528         return rc;
 529 }
 530
 531 static void __exit scx200_acb_cleanup(void)
 532 {
 533         struct scx200_acb_iface *iface;
 534
 535         lock_kernel();
 536         while ((iface = scx200_acb_list) != NULL) {
 537                 scx200_acb_list = iface->next;
 538                 unlock_kernel();
 539
 540                 i2c_del_adapter(&iface->adapter);
 541                 release_region(iface->base, 8);
 542                 kfree(iface);
 543                 lock_kernel();
 544         }
 545         unlock_kernel();
 546 }
 547
 548 module_init(scx200_acb_init);
 549 module_exit(scx200_acb_cleanup);