1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Silicon Labs C2 port core Linux support
   4 *
   5 *  Copyright (c) 2007 Rodolfo Giometti <giometti@linux.it>
   6 *  Copyright (c) 2007 Eurotech S.p.A. <info@eurotech.it>
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/init.h>
  11#include <linux/device.h>
  12#include <linux/errno.h>
  13#include <linux/err.h>
  14#include <linux/kernel.h>
  15#include <linux/ctype.h>
  16#include <linux/delay.h>
  17#include <linux/idr.h>
  18#include <linux/sched.h>
  19#include <linux/slab.h>
  20
  21#include <linux/c2port.h>
  22
  23#define DRIVER_NAME             "c2port"
  24#define DRIVER_VERSION          "0.51.0"
  25
  26static DEFINE_SPINLOCK(c2port_idr_lock);
  27static DEFINE_IDR(c2port_idr);
  28
  29/*
  30 * Local variables
  31 */
  32
  33static struct class *c2port_class;
  34
  35/*
  36 * C2 registers & commands defines
  37 */
  38
  39/* C2 registers */
  40#define C2PORT_DEVICEID		0x00
  41#define C2PORT_REVID		0x01
  42#define C2PORT_FPCTL		0x02
  43#define C2PORT_FPDAT		0xB4
  44
  45/* C2 interface commands */
  46#define C2PORT_GET_VERSION	0x01
  47#define C2PORT_DEVICE_ERASE	0x03
  48#define C2PORT_BLOCK_READ	0x06
  49#define C2PORT_BLOCK_WRITE	0x07
  50#define C2PORT_PAGE_ERASE	0x08
  51
  52/* C2 status return codes */
  53#define C2PORT_INVALID_COMMAND	0x00
  54#define C2PORT_COMMAND_FAILED	0x02
  55#define C2PORT_COMMAND_OK	0x0d
  56
  57/*
  58 * C2 port low level signal managements
  59 */
  60
  61static void c2port_reset(struct c2port_device *dev)
  62{
  63	struct c2port_ops *ops = dev->ops;
  64
  65	/* To reset the device we have to keep clock line low for at least
  66	 * 20us.
  67	 */
  68	local_irq_disable();
  69	ops->c2ck_set(dev, 0);
  70	udelay(25);
  71	ops->c2ck_set(dev, 1);
  72	local_irq_enable();
  73
  74	udelay(1);
  75}
  76
  77static void c2port_strobe_ck(struct c2port_device *dev)
  78{
  79	struct c2port_ops *ops = dev->ops;
  80
  81	/* During hi-low-hi transition we disable local IRQs to avoid
  82	 * interructions since C2 port specification says that it must be
  83	 * shorter than 5us, otherwise the microcontroller may consider
  84	 * it as a reset signal!
  85	 */
  86	local_irq_disable();
  87	ops->c2ck_set(dev, 0);
  88	udelay(1);
  89	ops->c2ck_set(dev, 1);
  90	local_irq_enable();
  91
  92	udelay(1);
  93}
  94
  95/*
  96 * C2 port basic functions
  97 */
  98
  99static void c2port_write_ar(struct c2port_device *dev, u8 addr)
 100{
 101	struct c2port_ops *ops = dev->ops;
 102	int i;
 103
 104	/* START field */
 105	c2port_strobe_ck(dev);
 106
 107	/* INS field (11b, LSB first) */
 108	ops->c2d_dir(dev, 0);
 109	ops->c2d_set(dev, 1);
 110	c2port_strobe_ck(dev);
 111	ops->c2d_set(dev, 1);
 112	c2port_strobe_ck(dev);
 113
 114	/* ADDRESS field */
 115	for (i = 0; i < 8; i++) {
 116		ops->c2d_set(dev, addr & 0x01);
 117		c2port_strobe_ck(dev);
 118
 119		addr >>= 1;
 120	}
 121
 122	/* STOP field */
 123	ops->c2d_dir(dev, 1);
 124	c2port_strobe_ck(dev);
 125}
 126
 127static int c2port_read_ar(struct c2port_device *dev, u8 *addr)
 128{
 129	struct c2port_ops *ops = dev->ops;
 130	int i;
 131
 132	/* START field */
 133	c2port_strobe_ck(dev);
 134
 135	/* INS field (10b, LSB first) */
 136	ops->c2d_dir(dev, 0);
 137	ops->c2d_set(dev, 0);
 138	c2port_strobe_ck(dev);
 139	ops->c2d_set(dev, 1);
 140	c2port_strobe_ck(dev);
 141
 142	/* ADDRESS field */
 143	ops->c2d_dir(dev, 1);
 144	*addr = 0;
 145	for (i = 0; i < 8; i++) {
 146		*addr >>= 1;	/* shift in 8-bit ADDRESS field LSB first */
 147
 148		c2port_strobe_ck(dev);
 149		if (ops->c2d_get(dev))
 150			*addr |= 0x80;
 151	}
 152
 153	/* STOP field */
 154	c2port_strobe_ck(dev);
 155
 156	return 0;
 157}
 158
 159static int c2port_write_dr(struct c2port_device *dev, u8 data)
 160{
 161	struct c2port_ops *ops = dev->ops;
 162	int timeout, i;
 163
 164	/* START field */
 165	c2port_strobe_ck(dev);
 166
 167	/* INS field (01b, LSB first) */
 168	ops->c2d_dir(dev, 0);
 169	ops->c2d_set(dev, 1);
 170	c2port_strobe_ck(dev);
 171	ops->c2d_set(dev, 0);
 172	c2port_strobe_ck(dev);
 173
 174	/* LENGTH field (00b, LSB first -> 1 byte) */
 175	ops->c2d_set(dev, 0);
 176	c2port_strobe_ck(dev);
 177	ops->c2d_set(dev, 0);
 178	c2port_strobe_ck(dev);
 179
 180	/* DATA field */
 181	for (i = 0; i < 8; i++) {
 182		ops->c2d_set(dev, data & 0x01);
 183		c2port_strobe_ck(dev);
 184
 185		data >>= 1;
 186	}
 187
 188	/* WAIT field */
 189	ops->c2d_dir(dev, 1);
 190	timeout = 20;
 191	do {
 192		c2port_strobe_ck(dev);
 193		if (ops->c2d_get(dev))
 194			break;
 195
 196		udelay(1);
 197	} while (--timeout > 0);
 198	if (timeout == 0)
 199		return -EIO;
 200
 201	/* STOP field */
 202	c2port_strobe_ck(dev);
 203
 204	return 0;
 205}
 206
 207static int c2port_read_dr(struct c2port_device *dev, u8 *data)
 208{
 209	struct c2port_ops *ops = dev->ops;
 210	int timeout, i;
 211
 212	/* START field */
 213	c2port_strobe_ck(dev);
 214
 215	/* INS field (00b, LSB first) */
 216	ops->c2d_dir(dev, 0);
 217	ops->c2d_set(dev, 0);
 218	c2port_strobe_ck(dev);
 219	ops->c2d_set(dev, 0);
 220	c2port_strobe_ck(dev);
 221
 222	/* LENGTH field (00b, LSB first -> 1 byte) */
 223	ops->c2d_set(dev, 0);
 224	c2port_strobe_ck(dev);
 225	ops->c2d_set(dev, 0);
 226	c2port_strobe_ck(dev);
 227
 228	/* WAIT field */
 229	ops->c2d_dir(dev, 1);
 230	timeout = 20;
 231	do {
 232		c2port_strobe_ck(dev);
 233		if (ops->c2d_get(dev))
 234			break;
 235
 236		udelay(1);
 237	} while (--timeout > 0);
 238	if (timeout == 0)
 239		return -EIO;
 240
 241	/* DATA field */
 242	*data = 0;
 243	for (i = 0; i < 8; i++) {
 244		*data >>= 1;	/* shift in 8-bit DATA field LSB first */
 245
 246		c2port_strobe_ck(dev);
 247		if (ops->c2d_get(dev))
 248			*data |= 0x80;
 249	}
 250
 251	/* STOP field */
 252	c2port_strobe_ck(dev);
 253
 254	return 0;
 255}
 256
 257static int c2port_poll_in_busy(struct c2port_device *dev)
 258{
 259	u8 addr;
 260	int ret, timeout = 20;
 261
 262	do {
 263		ret = (c2port_read_ar(dev, &addr));
 264		if (ret < 0)
 265			return -EIO;
 266
 267		if (!(addr & 0x02))
 268			break;
 269
 270		udelay(1);
 271	} while (--timeout > 0);
 272	if (timeout == 0)
 273		return -EIO;
 274
 275	return 0;
 276}
 277
 278static int c2port_poll_out_ready(struct c2port_device *dev)
 279{
 280	u8 addr;
 281	int ret, timeout = 10000; /* erase flash needs long time... */
 282
 283	do {
 284		ret = (c2port_read_ar(dev, &addr));
 285		if (ret < 0)
 286			return -EIO;
 287
 288		if (addr & 0x01)
 289			break;
 290
 291		udelay(1);
 292	} while (--timeout > 0);
 293	if (timeout == 0)
 294		return -EIO;
 295
 296	return 0;
 297}
 298
 299/*
 300 * sysfs methods
 301 */
 302
 303static ssize_t c2port_show_name(struct device *dev,
 304				struct device_attribute *attr, char *buf)
 305{
 306	struct c2port_device *c2dev = dev_get_drvdata(dev);
 307
 308	return sprintf(buf, "%s\n", c2dev->name);
 309}
 310static DEVICE_ATTR(name, 0444, c2port_show_name, NULL);
 311
 312static ssize_t c2port_show_flash_blocks_num(struct device *dev,
 313				struct device_attribute *attr, char *buf)
 314{
 315	struct c2port_device *c2dev = dev_get_drvdata(dev);
 316	struct c2port_ops *ops = c2dev->ops;
 317
 318	return sprintf(buf, "%d\n", ops->blocks_num);
 319}
 320static DEVICE_ATTR(flash_blocks_num, 0444, c2port_show_flash_blocks_num, NULL);
 321
 322static ssize_t c2port_show_flash_block_size(struct device *dev,
 323				struct device_attribute *attr, char *buf)
 324{
 325	struct c2port_device *c2dev = dev_get_drvdata(dev);
 326	struct c2port_ops *ops = c2dev->ops;
 327
 328	return sprintf(buf, "%d\n", ops->block_size);
 329}
 330static DEVICE_ATTR(flash_block_size, 0444, c2port_show_flash_block_size, NULL);
 331
 332static ssize_t c2port_show_flash_size(struct device *dev,
 333				struct device_attribute *attr, char *buf)
 334{
 335	struct c2port_device *c2dev = dev_get_drvdata(dev);
 336	struct c2port_ops *ops = c2dev->ops;
 337
 338	return sprintf(buf, "%d\n", ops->blocks_num * ops->block_size);
 339}
 340static DEVICE_ATTR(flash_size, 0444, c2port_show_flash_size, NULL);
 341
 342static ssize_t access_show(struct device *dev, struct device_attribute *attr,
 343			   char *buf)
 344{
 345	struct c2port_device *c2dev = dev_get_drvdata(dev);
 346
 347	return sprintf(buf, "%d\n", c2dev->access);
 348}
 349
 350static ssize_t access_store(struct device *dev, struct device_attribute *attr,
 351			    const char *buf, size_t count)
 352{
 353	struct c2port_device *c2dev = dev_get_drvdata(dev);
 354	struct c2port_ops *ops = c2dev->ops;
 355	int status, ret;
 356
 357	ret = sscanf(buf, "%d", &status);
 358	if (ret != 1)
 359		return -EINVAL;
 360
 361	mutex_lock(&c2dev->mutex);
 362
 363	c2dev->access = !!status;
 364
 365	/* If access is "on" clock should be HIGH _before_ setting the line
 366	 * as output and data line should be set as INPUT anyway */
 367	if (c2dev->access)
 368		ops->c2ck_set(c2dev, 1);
 369	ops->access(c2dev, c2dev->access);
 370	if (c2dev->access)
 371		ops->c2d_dir(c2dev, 1);
 372
 373	mutex_unlock(&c2dev->mutex);
 374
 375	return count;
 376}
 377static DEVICE_ATTR_RW(access);
 378
 379static ssize_t c2port_store_reset(struct device *dev,
 380				struct device_attribute *attr,
 381				const char *buf, size_t count)
 382{
 383	struct c2port_device *c2dev = dev_get_drvdata(dev);
 384
 385	/* Check the device access status */
 386	if (!c2dev->access)
 387		return -EBUSY;
 388
 389	mutex_lock(&c2dev->mutex);
 390
 391	c2port_reset(c2dev);
 392	c2dev->flash_access = 0;
 393
 394	mutex_unlock(&c2dev->mutex);
 395
 396	return count;
 397}
 398static DEVICE_ATTR(reset, 0200, NULL, c2port_store_reset);
 399
 400static ssize_t __c2port_show_dev_id(struct c2port_device *dev, char *buf)
 401{
 402	u8 data;
 403	int ret;
 404
 405	/* Select DEVICEID register for C2 data register accesses */
 406	c2port_write_ar(dev, C2PORT_DEVICEID);
 407
 408	/* Read and return the device ID register */
 409	ret = c2port_read_dr(dev, &data);
 410	if (ret < 0)
 411		return ret;
 412
 413	return sprintf(buf, "%d\n", data);
 414}
 415
 416static ssize_t c2port_show_dev_id(struct device *dev,
 417				struct device_attribute *attr, char *buf)
 418{
 419	struct c2port_device *c2dev = dev_get_drvdata(dev);
 420	ssize_t ret;
 421
 422	/* Check the device access status */
 423	if (!c2dev->access)
 424		return -EBUSY;
 425
 426	mutex_lock(&c2dev->mutex);
 427	ret = __c2port_show_dev_id(c2dev, buf);
 428	mutex_unlock(&c2dev->mutex);
 429
 430	if (ret < 0)
 431		dev_err(dev, "cannot read from %s\n", c2dev->name);
 432
 433	return ret;
 434}
 435static DEVICE_ATTR(dev_id, 0444, c2port_show_dev_id, NULL);
 436
 437static ssize_t __c2port_show_rev_id(struct c2port_device *dev, char *buf)
 438{
 439	u8 data;
 440	int ret;
 441
 442	/* Select REVID register for C2 data register accesses */
 443	c2port_write_ar(dev, C2PORT_REVID);
 444
 445	/* Read and return the revision ID register */
 446	ret = c2port_read_dr(dev, &data);
 447	if (ret < 0)
 448		return ret;
 449
 450	return sprintf(buf, "%d\n", data);
 451}
 452
 453static ssize_t c2port_show_rev_id(struct device *dev,
 454				struct device_attribute *attr, char *buf)
 455{
 456	struct c2port_device *c2dev = dev_get_drvdata(dev);
 457	ssize_t ret;
 458
 459	/* Check the device access status */
 460	if (!c2dev->access)
 461		return -EBUSY;
 462
 463	mutex_lock(&c2dev->mutex);
 464	ret = __c2port_show_rev_id(c2dev, buf);
 465	mutex_unlock(&c2dev->mutex);
 466
 467	if (ret < 0)
 468		dev_err(c2dev->dev, "cannot read from %s\n", c2dev->name);
 469
 470	return ret;
 471}
 472static DEVICE_ATTR(rev_id, 0444, c2port_show_rev_id, NULL);
 473
 474static ssize_t c2port_show_flash_access(struct device *dev,
 475				struct device_attribute *attr, char *buf)
 476{
 477	struct c2port_device *c2dev = dev_get_drvdata(dev);
 478
 479	return sprintf(buf, "%d\n", c2dev->flash_access);
 480}
 481
 482static ssize_t __c2port_store_flash_access(struct c2port_device *dev,
 483						int status)
 484{
 485	int ret;
 486
 487	/* Check the device access status */
 488	if (!dev->access)
 489		return -EBUSY;
 490
 491	dev->flash_access = !!status;
 492
 493	/* If flash_access is off we have nothing to do... */
 494	if (dev->flash_access == 0)
 495		return 0;
 496
 497	/* Target the C2 flash programming control register for C2 data
 498	 * register access */
 499	c2port_write_ar(dev, C2PORT_FPCTL);
 500
 501	/* Write the first keycode to enable C2 Flash programming */
 502	ret = c2port_write_dr(dev, 0x02);
 503	if (ret < 0)
 504		return ret;
 505
 506	/* Write the second keycode to enable C2 Flash programming */
 507	ret = c2port_write_dr(dev, 0x01);
 508	if (ret < 0)
 509		return ret;
 510
 511	/* Delay for at least 20ms to ensure the target is ready for
 512	 * C2 flash programming */
 513	mdelay(25);
 514
 515	return 0;
 516}
 517
 518static ssize_t c2port_store_flash_access(struct device *dev,
 519				struct device_attribute *attr,
 520				const char *buf, size_t count)
 521{
 522	struct c2port_device *c2dev = dev_get_drvdata(dev);
 523	int status;
 524	ssize_t ret;
 525
 526	ret = sscanf(buf, "%d", &status);
 527	if (ret != 1)
 528		return -EINVAL;
 529
 530	mutex_lock(&c2dev->mutex);
 531	ret = __c2port_store_flash_access(c2dev, status);
 532	mutex_unlock(&c2dev->mutex);
 533
 534	if (ret < 0) {
 535		dev_err(c2dev->dev, "cannot enable %s flash programming\n",
 536			c2dev->name);
 537		return ret;
 538	}
 539
 540	return count;
 541}
 542static DEVICE_ATTR(flash_access, 0644, c2port_show_flash_access,
 543		   c2port_store_flash_access);
 544
 545static ssize_t __c2port_write_flash_erase(struct c2port_device *dev)
 546{
 547	u8 status;
 548	int ret;
 549
 550	/* Target the C2 flash programming data register for C2 data register
 551	 * access.
 552	 */
 553	c2port_write_ar(dev, C2PORT_FPDAT);
 554
 555	/* Send device erase command */
 556	c2port_write_dr(dev, C2PORT_DEVICE_ERASE);
 557
 558	/* Wait for input acknowledge */
 559	ret = c2port_poll_in_busy(dev);
 560	if (ret < 0)
 561		return ret;
 562
 563	/* Should check status before starting FLASH access sequence */
 564
 565	/* Wait for status information */
 566	ret = c2port_poll_out_ready(dev);
 567	if (ret < 0)
 568		return ret;
 569
 570	/* Read flash programming interface status */
 571	ret = c2port_read_dr(dev, &status);
 572	if (ret < 0)
 573		return ret;
 574	if (status != C2PORT_COMMAND_OK)
 575		return -EBUSY;
 576
 577	/* Send a three-byte arming sequence to enable the device erase.
 578	 * If the sequence is not received correctly, the command will be
 579	 * ignored.
 580	 * Sequence is: 0xde, 0xad, 0xa5.
 581	 */
 582	c2port_write_dr(dev, 0xde);
 583	ret = c2port_poll_in_busy(dev);
 584	if (ret < 0)
 585		return ret;
 586	c2port_write_dr(dev, 0xad);
 587	ret = c2port_poll_in_busy(dev);
 588	if (ret < 0)
 589		return ret;
 590	c2port_write_dr(dev, 0xa5);
 591	ret = c2port_poll_in_busy(dev);
 592	if (ret < 0)
 593		return ret;
 594
 595	ret = c2port_poll_out_ready(dev);
 596	if (ret < 0)
 597		return ret;
 598
 599	return 0;
 600}
 601
 602static ssize_t c2port_store_flash_erase(struct device *dev,
 603				struct device_attribute *attr,
 604				const char *buf, size_t count)
 605{
 606	struct c2port_device *c2dev = dev_get_drvdata(dev);
 607	int ret;
 608
 609	/* Check the device and flash access status */
 610	if (!c2dev->access || !c2dev->flash_access)
 611		return -EBUSY;
 612
 613	mutex_lock(&c2dev->mutex);
 614	ret = __c2port_write_flash_erase(c2dev);
 615	mutex_unlock(&c2dev->mutex);
 616
 617	if (ret < 0) {
 618		dev_err(c2dev->dev, "cannot erase %s flash\n", c2dev->name);
 619		return ret;
 620	}
 621
 622	return count;
 623}
 624static DEVICE_ATTR(flash_erase, 0200, NULL, c2port_store_flash_erase);
 625
 626static ssize_t __c2port_read_flash_data(struct c2port_device *dev,
 627				char *buffer, loff_t offset, size_t count)
 628{
 629	struct c2port_ops *ops = dev->ops;
 630	u8 status, nread = 128;
 631	int i, ret;
 632
 633	/* Check for flash end */
 634	if (offset >= ops->block_size * ops->blocks_num)
 635		return 0;
 636
 637	if (ops->block_size * ops->blocks_num - offset < nread)
 638		nread = ops->block_size * ops->blocks_num - offset;
 639	if (count < nread)
 640		nread = count;
 641	if (nread == 0)
 642		return nread;
 643
 644	/* Target the C2 flash programming data register for C2 data register
 645	 * access */
 646	c2port_write_ar(dev, C2PORT_FPDAT);
 647
 648	/* Send flash block read command */
 649	c2port_write_dr(dev, C2PORT_BLOCK_READ);
 650
 651	/* Wait for input acknowledge */
 652	ret = c2port_poll_in_busy(dev);
 653	if (ret < 0)
 654		return ret;
 655
 656	/* Should check status before starting FLASH access sequence */
 657
 658	/* Wait for status information */
 659	ret = c2port_poll_out_ready(dev);
 660	if (ret < 0)
 661		return ret;
 662
 663	/* Read flash programming interface status */
 664	ret = c2port_read_dr(dev, &status);
 665	if (ret < 0)
 666		return ret;
 667	if (status != C2PORT_COMMAND_OK)
 668		return -EBUSY;
 669
 670	/* Send address high byte */
 671	c2port_write_dr(dev, offset >> 8);
 672	ret = c2port_poll_in_busy(dev);
 673	if (ret < 0)
 674		return ret;
 675
 676	/* Send address low byte */
 677	c2port_write_dr(dev, offset & 0x00ff);
 678	ret = c2port_poll_in_busy(dev);
 679	if (ret < 0)
 680		return ret;
 681
 682	/* Send address block size */
 683	c2port_write_dr(dev, nread);
 684	ret = c2port_poll_in_busy(dev);
 685	if (ret < 0)
 686		return ret;
 687
 688	/* Should check status before reading FLASH block */
 689
 690	/* Wait for status information */
 691	ret = c2port_poll_out_ready(dev);
 692	if (ret < 0)
 693		return ret;
 694
 695	/* Read flash programming interface status */
 696	ret = c2port_read_dr(dev, &status);
 697	if (ret < 0)
 698		return ret;
 699	if (status != C2PORT_COMMAND_OK)
 700		return -EBUSY;
 701
 702	/* Read flash block */
 703	for (i = 0; i < nread; i++) {
 704		ret = c2port_poll_out_ready(dev);
 705		if (ret < 0)
 706			return ret;
 707
 708		ret = c2port_read_dr(dev, buffer+i);
 709		if (ret < 0)
 710			return ret;
 711	}
 712
 713	return nread;
 714}
 715
 716static ssize_t c2port_read_flash_data(struct file *filp, struct kobject *kobj,
 717				struct bin_attribute *attr,
 718				char *buffer, loff_t offset, size_t count)
 719{
 720	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
 721	ssize_t ret;
 722
 723	/* Check the device and flash access status */
 724	if (!c2dev->access || !c2dev->flash_access)
 725		return -EBUSY;
 726
 727	mutex_lock(&c2dev->mutex);
 728	ret = __c2port_read_flash_data(c2dev, buffer, offset, count);
 729	mutex_unlock(&c2dev->mutex);
 730
 731	if (ret < 0)
 732		dev_err(c2dev->dev, "cannot read %s flash\n", c2dev->name);
 733
 734	return ret;
 735}
 736
 737static ssize_t __c2port_write_flash_data(struct c2port_device *dev,
 738				char *buffer, loff_t offset, size_t count)
 739{
 740	struct c2port_ops *ops = dev->ops;
 741	u8 status, nwrite = 128;
 742	int i, ret;
 743
 744	if (nwrite > count)
 745		nwrite = count;
 746	if (ops->block_size * ops->blocks_num - offset < nwrite)
 747		nwrite = ops->block_size * ops->blocks_num - offset;
 748
 749	/* Check for flash end */
 750	if (offset >= ops->block_size * ops->blocks_num)
 751		return -EINVAL;
 752
 753	/* Target the C2 flash programming data register for C2 data register
 754	 * access */
 755	c2port_write_ar(dev, C2PORT_FPDAT);
 756
 757	/* Send flash block write command */
 758	c2port_write_dr(dev, C2PORT_BLOCK_WRITE);
 759
 760	/* Wait for input acknowledge */
 761	ret = c2port_poll_in_busy(dev);
 762	if (ret < 0)
 763		return ret;
 764
 765	/* Should check status before starting FLASH access sequence */
 766
 767	/* Wait for status information */
 768	ret = c2port_poll_out_ready(dev);
 769	if (ret < 0)
 770		return ret;
 771
 772	/* Read flash programming interface status */
 773	ret = c2port_read_dr(dev, &status);
 774	if (ret < 0)
 775		return ret;
 776	if (status != C2PORT_COMMAND_OK)
 777		return -EBUSY;
 778
 779	/* Send address high byte */
 780	c2port_write_dr(dev, offset >> 8);
 781	ret = c2port_poll_in_busy(dev);
 782	if (ret < 0)
 783		return ret;
 784
 785	/* Send address low byte */
 786	c2port_write_dr(dev, offset & 0x00ff);
 787	ret = c2port_poll_in_busy(dev);
 788	if (ret < 0)
 789		return ret;
 790
 791	/* Send address block size */
 792	c2port_write_dr(dev, nwrite);
 793	ret = c2port_poll_in_busy(dev);
 794	if (ret < 0)
 795		return ret;
 796
 797	/* Should check status before writing FLASH block */
 798
 799	/* Wait for status information */
 800	ret = c2port_poll_out_ready(dev);
 801	if (ret < 0)
 802		return ret;
 803
 804	/* Read flash programming interface status */
 805	ret = c2port_read_dr(dev, &status);
 806	if (ret < 0)
 807		return ret;
 808	if (status != C2PORT_COMMAND_OK)
 809		return -EBUSY;
 810
 811	/* Write flash block */
 812	for (i = 0; i < nwrite; i++) {
 813		ret = c2port_write_dr(dev, *(buffer+i));
 814		if (ret < 0)
 815			return ret;
 816
 817		ret = c2port_poll_in_busy(dev);
 818		if (ret < 0)
 819			return ret;
 820
 821	}
 822
 823	/* Wait for last flash write to complete */
 824	ret = c2port_poll_out_ready(dev);
 825	if (ret < 0)
 826		return ret;
 827
 828	return nwrite;
 829}
 830
 831static ssize_t c2port_write_flash_data(struct file *filp, struct kobject *kobj,
 832				struct bin_attribute *attr,
 833				char *buffer, loff_t offset, size_t count)
 834{
 835	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
 836	int ret;
 837
 838	/* Check the device access status */
 839	if (!c2dev->access || !c2dev->flash_access)
 840		return -EBUSY;
 841
 842	mutex_lock(&c2dev->mutex);
 843	ret = __c2port_write_flash_data(c2dev, buffer, offset, count);
 844	mutex_unlock(&c2dev->mutex);
 845
 846	if (ret < 0)
 847		dev_err(c2dev->dev, "cannot write %s flash\n", c2dev->name);
 848
 849	return ret;
 850}
 851/* size is computed at run-time */
 852static BIN_ATTR(flash_data, 0644, c2port_read_flash_data,
 853		c2port_write_flash_data, 0);
 854
 855/*
 856 * Class attributes
 857 */
 858static struct attribute *c2port_attrs[] = {
 859	&dev_attr_name.attr,
 860	&dev_attr_flash_blocks_num.attr,
 861	&dev_attr_flash_block_size.attr,
 862	&dev_attr_flash_size.attr,
 863	&dev_attr_access.attr,
 864	&dev_attr_reset.attr,
 865	&dev_attr_dev_id.attr,
 866	&dev_attr_rev_id.attr,
 867	&dev_attr_flash_access.attr,
 868	&dev_attr_flash_erase.attr,
 869	NULL,
 870};
 871
 872static struct bin_attribute *c2port_bin_attrs[] = {
 873	&bin_attr_flash_data,
 874	NULL,
 875};
 876
 877static const struct attribute_group c2port_group = {
 878	.attrs = c2port_attrs,
 879	.bin_attrs = c2port_bin_attrs,
 880};
 881
 882static const struct attribute_group *c2port_groups[] = {
 883	&c2port_group,
 884	NULL,
 885};
 886
 887/*
 888 * Exported functions
 889 */
 890
 891struct c2port_device *c2port_device_register(char *name,
 892					struct c2port_ops *ops, void *devdata)
 893{
 894	struct c2port_device *c2dev;
 895	int ret;
 896
 897	if (unlikely(!ops) || unlikely(!ops->access) || \
 898		unlikely(!ops->c2d_dir) || unlikely(!ops->c2ck_set) || \
 899		unlikely(!ops->c2d_get) || unlikely(!ops->c2d_set))
 900		return ERR_PTR(-EINVAL);
 901
 902	c2dev = kzalloc(sizeof(struct c2port_device), GFP_KERNEL);
 903	if (unlikely(!c2dev))
 904		return ERR_PTR(-ENOMEM);
 905
 906	idr_preload(GFP_KERNEL);
 907	spin_lock_irq(&c2port_idr_lock);
 908	ret = idr_alloc(&c2port_idr, c2dev, 0, 0, GFP_NOWAIT);
 909	spin_unlock_irq(&c2port_idr_lock);
 910	idr_preload_end();
 911
 912	if (ret < 0)
 913		goto error_idr_alloc;
 914	c2dev->id = ret;
 915
 916	bin_attr_flash_data.size = ops->blocks_num * ops->block_size;
 917
 918	c2dev->dev = device_create(c2port_class, NULL, 0, c2dev,
 919				   "c2port%d", c2dev->id);
 920	if (IS_ERR(c2dev->dev)) {
 921		ret = PTR_ERR(c2dev->dev);
 922		goto error_device_create;
 923	}
 924	dev_set_drvdata(c2dev->dev, c2dev);
 925
 926	strscpy(c2dev->name, name, sizeof(c2dev->name));
 927	c2dev->ops = ops;
 928	mutex_init(&c2dev->mutex);
 929
 930	/* By default C2 port access is off */
 931	c2dev->access = c2dev->flash_access = 0;
 932	ops->access(c2dev, 0);
 933
 934	dev_info(c2dev->dev, "C2 port %s added\n", name);
 935	dev_info(c2dev->dev, "%s flash has %d blocks x %d bytes "
 936				"(%d bytes total)\n",
 937				name, ops->blocks_num, ops->block_size,
 938				ops->blocks_num * ops->block_size);
 939
 940	return c2dev;
 941
 942error_device_create:
 943	spin_lock_irq(&c2port_idr_lock);
 944	idr_remove(&c2port_idr, c2dev->id);
 945	spin_unlock_irq(&c2port_idr_lock);
 946
 947error_idr_alloc:
 948	kfree(c2dev);
 949
 950	return ERR_PTR(ret);
 951}
 952EXPORT_SYMBOL(c2port_device_register);
 953
 954void c2port_device_unregister(struct c2port_device *c2dev)
 955{
 956	if (!c2dev)
 957		return;
 958
 959	dev_info(c2dev->dev, "C2 port %s removed\n", c2dev->name);
 960
 961	spin_lock_irq(&c2port_idr_lock);
 962	idr_remove(&c2port_idr, c2dev->id);
 963	spin_unlock_irq(&c2port_idr_lock);
 964
 965	device_destroy(c2port_class, c2dev->id);
 966
 967	kfree(c2dev);
 968}
 969EXPORT_SYMBOL(c2port_device_unregister);
 970
 971/*
 972 * Module stuff
 973 */
 974
 975static int __init c2port_init(void)
 976{
 977	printk(KERN_INFO "Silicon Labs C2 port support v. " DRIVER_VERSION
 978		" - (C) 2007 Rodolfo Giometti\n");
 979
 980	c2port_class = class_create("c2port");
 981	if (IS_ERR(c2port_class)) {
 982		printk(KERN_ERR "c2port: failed to allocate class\n");
 983		return PTR_ERR(c2port_class);
 984	}
 985	c2port_class->dev_groups = c2port_groups;
 986
 987	return 0;
 988}
 989
 990static void __exit c2port_exit(void)
 991{
 992	class_destroy(c2port_class);
 993}
 994
 995module_init(c2port_init);
 996module_exit(c2port_exit);
 997
 998MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 999MODULE_DESCRIPTION("Silicon Labs C2 port support v. " DRIVER_VERSION);
1000MODULE_LICENSE("GPL");