tpm_i2c_nuvoton: fix potential buffer overruns caused by bit glitches on the bus
[sfrench/cifs-2.6.git] / drivers / char / tpm / tpm_i2c_nuvoton.c
1  /******************************************************************************
2  * Nuvoton TPM I2C Device Driver Interface for WPCT301/NPCT501/NPCT6XX,
3  * based on the TCG TPM Interface Spec version 1.2.
4  * Specifications at www.trustedcomputinggroup.org
5  *
6  * Copyright (C) 2011, Nuvoton Technology Corporation.
7  *  Dan Morav <dan.morav@nuvoton.com>
8  * Copyright (C) 2013, Obsidian Research Corp.
9  *  Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
10  *
11  * This program is free software: you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation, either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program.  If not, see http://www.gnu.org/licenses/>.
23  *
24  * Nuvoton contact information: APC.Support@nuvoton.com
25  *****************************************************************************/
26
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/slab.h>
31 #include <linux/interrupt.h>
32 #include <linux/wait.h>
33 #include <linux/i2c.h>
34 #include <linux/of_device.h>
35 #include "tpm.h"
36
37 /* I2C interface offsets */
38 #define TPM_STS                0x00
39 #define TPM_BURST_COUNT        0x01
40 #define TPM_DATA_FIFO_W        0x20
41 #define TPM_DATA_FIFO_R        0x40
42 #define TPM_VID_DID_RID        0x60
43 /* TPM command header size */
44 #define TPM_HEADER_SIZE        10
45 #define TPM_RETRY      5
46 /*
47  * I2C bus device maximum buffer size w/o counting I2C address or command
48  * i.e. max size required for I2C write is 34 = addr, command, 32 bytes data
49  */
50 #define TPM_I2C_MAX_BUF_SIZE           32
51 #define TPM_I2C_RETRY_COUNT            32
52 #define TPM_I2C_BUS_DELAY              1000             /* usec */
53 #define TPM_I2C_RETRY_DELAY_SHORT      (2 * 1000)       /* usec */
54 #define TPM_I2C_RETRY_DELAY_LONG       (10 * 1000)      /* usec */
55 #define TPM_I2C_DELAY_RANGE            300              /* usec */
56
57 #define OF_IS_TPM2 ((void *)1)
58 #define I2C_IS_TPM2 1
59
60 struct priv_data {
61         int irq;
62         unsigned int intrs;
63         wait_queue_head_t read_queue;
64 };
65
66 static s32 i2c_nuvoton_read_buf(struct i2c_client *client, u8 offset, u8 size,
67                                 u8 *data)
68 {
69         s32 status;
70
71         status = i2c_smbus_read_i2c_block_data(client, offset, size, data);
72         dev_dbg(&client->dev,
73                 "%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
74                 offset, size, (int)size, data, status);
75         return status;
76 }
77
78 static s32 i2c_nuvoton_write_buf(struct i2c_client *client, u8 offset, u8 size,
79                                  u8 *data)
80 {
81         s32 status;
82
83         status = i2c_smbus_write_i2c_block_data(client, offset, size, data);
84         dev_dbg(&client->dev,
85                 "%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
86                 offset, size, (int)size, data, status);
87         return status;
88 }
89
90 #define TPM_STS_VALID          0x80
91 #define TPM_STS_COMMAND_READY  0x40
92 #define TPM_STS_GO             0x20
93 #define TPM_STS_DATA_AVAIL     0x10
94 #define TPM_STS_EXPECT         0x08
95 #define TPM_STS_RESPONSE_RETRY 0x02
96 #define TPM_STS_ERR_VAL        0x07    /* bit2...bit0 reads always 0 */
97
98 #define TPM_I2C_SHORT_TIMEOUT  750     /* ms */
99 #define TPM_I2C_LONG_TIMEOUT   2000    /* 2 sec */
100
101 /* read TPM_STS register */
102 static u8 i2c_nuvoton_read_status(struct tpm_chip *chip)
103 {
104         struct i2c_client *client = to_i2c_client(chip->dev.parent);
105         s32 status;
106         u8 data;
107
108         status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data);
109         if (status <= 0) {
110                 dev_err(&chip->dev, "%s() error return %d\n", __func__,
111                         status);
112                 data = TPM_STS_ERR_VAL;
113         }
114
115         return data;
116 }
117
118 /* write byte to TPM_STS register */
119 static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
120 {
121         s32 status;
122         int i;
123
124         /* this causes the current command to be aborted */
125         for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
126                 status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
127                 if (status < 0)
128                         usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
129                                      + TPM_I2C_DELAY_RANGE);
130         }
131         return status;
132 }
133
134 /* write commandReady to TPM_STS register */
135 static void i2c_nuvoton_ready(struct tpm_chip *chip)
136 {
137         struct i2c_client *client = to_i2c_client(chip->dev.parent);
138         s32 status;
139
140         /* this causes the current command to be aborted */
141         status = i2c_nuvoton_write_status(client, TPM_STS_COMMAND_READY);
142         if (status < 0)
143                 dev_err(&chip->dev,
144                         "%s() fail to write TPM_STS.commandReady\n", __func__);
145 }
146
147 /* read burstCount field from TPM_STS register
148  * return -1 on fail to read */
149 static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
150                                       struct tpm_chip *chip)
151 {
152         unsigned long stop = jiffies + chip->timeout_d;
153         s32 status;
154         int burst_count = -1;
155         u8 data;
156
157         /* wait for burstcount to be non-zero */
158         do {
159                 /* in I2C burstCount is 1 byte */
160                 status = i2c_nuvoton_read_buf(client, TPM_BURST_COUNT, 1,
161                                               &data);
162                 if (status > 0 && data > 0) {
163                         burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
164                         break;
165                 }
166                 usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
167                              + TPM_I2C_DELAY_RANGE);
168         } while (time_before(jiffies, stop));
169
170         return burst_count;
171 }
172
173 /*
174  * WPCT301/NPCT501/NPCT6XX SINT# supports only dataAvail
175  * any call to this function which is not waiting for dataAvail will
176  * set queue to NULL to avoid waiting for interrupt
177  */
178 static bool i2c_nuvoton_check_status(struct tpm_chip *chip, u8 mask, u8 value)
179 {
180         u8 status = i2c_nuvoton_read_status(chip);
181         return (status != TPM_STS_ERR_VAL) && ((status & mask) == value);
182 }
183
184 static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
185                                      u32 timeout, wait_queue_head_t *queue)
186 {
187         if ((chip->flags & TPM_CHIP_FLAG_IRQ) && queue) {
188                 s32 rc;
189                 struct priv_data *priv = dev_get_drvdata(&chip->dev);
190                 unsigned int cur_intrs = priv->intrs;
191
192                 enable_irq(priv->irq);
193                 rc = wait_event_interruptible_timeout(*queue,
194                                                       cur_intrs != priv->intrs,
195                                                       timeout);
196                 if (rc > 0)
197                         return 0;
198                 /* At this point we know that the SINT pin is asserted, so we
199                  * do not need to do i2c_nuvoton_check_status */
200         } else {
201                 unsigned long ten_msec, stop;
202                 bool status_valid;
203
204                 /* check current status */
205                 status_valid = i2c_nuvoton_check_status(chip, mask, value);
206                 if (status_valid)
207                         return 0;
208
209                 /* use polling to wait for the event */
210                 ten_msec = jiffies + usecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
211                 stop = jiffies + timeout;
212                 do {
213                         if (time_before(jiffies, ten_msec))
214                                 usleep_range(TPM_I2C_RETRY_DELAY_SHORT,
215                                              TPM_I2C_RETRY_DELAY_SHORT
216                                              + TPM_I2C_DELAY_RANGE);
217                         else
218                                 usleep_range(TPM_I2C_RETRY_DELAY_LONG,
219                                              TPM_I2C_RETRY_DELAY_LONG
220                                              + TPM_I2C_DELAY_RANGE);
221                         status_valid = i2c_nuvoton_check_status(chip, mask,
222                                                                 value);
223                         if (status_valid)
224                                 return 0;
225                 } while (time_before(jiffies, stop));
226         }
227         dev_err(&chip->dev, "%s(%02x, %02x) -> timeout\n", __func__, mask,
228                 value);
229         return -ETIMEDOUT;
230 }
231
232 /* wait for dataAvail field to be set in the TPM_STS register */
233 static int i2c_nuvoton_wait_for_data_avail(struct tpm_chip *chip, u32 timeout,
234                                            wait_queue_head_t *queue)
235 {
236         return i2c_nuvoton_wait_for_stat(chip,
237                                          TPM_STS_DATA_AVAIL | TPM_STS_VALID,
238                                          TPM_STS_DATA_AVAIL | TPM_STS_VALID,
239                                          timeout, queue);
240 }
241
242 /* Read @count bytes into @buf from TPM_RD_FIFO register */
243 static int i2c_nuvoton_recv_data(struct i2c_client *client,
244                                  struct tpm_chip *chip, u8 *buf, size_t count)
245 {
246         struct priv_data *priv = dev_get_drvdata(&chip->dev);
247         s32 rc;
248         int burst_count, bytes2read, size = 0;
249
250         while (size < count &&
251                i2c_nuvoton_wait_for_data_avail(chip,
252                                                chip->timeout_c,
253                                                &priv->read_queue) == 0) {
254                 burst_count = i2c_nuvoton_get_burstcount(client, chip);
255                 if (burst_count < 0) {
256                         dev_err(&chip->dev,
257                                 "%s() fail to read burstCount=%d\n", __func__,
258                                 burst_count);
259                         return -EIO;
260                 }
261                 bytes2read = min_t(size_t, burst_count, count - size);
262                 rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_R,
263                                           bytes2read, &buf[size]);
264                 if (rc < 0) {
265                         dev_err(&chip->dev,
266                                 "%s() fail on i2c_nuvoton_read_buf()=%d\n",
267                                 __func__, rc);
268                         return -EIO;
269                 }
270                 dev_dbg(&chip->dev, "%s(%d):", __func__, bytes2read);
271                 size += bytes2read;
272         }
273
274         return size;
275 }
276
277 /* Read TPM command results */
278 static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
279 {
280         struct priv_data *priv = dev_get_drvdata(&chip->dev);
281         struct device *dev = chip->dev.parent;
282         struct i2c_client *client = to_i2c_client(dev);
283         s32 rc;
284         int status;
285         int burst_count;
286         int retries;
287         int size = 0;
288         u32 expected;
289
290         if (count < TPM_HEADER_SIZE) {
291                 i2c_nuvoton_ready(chip);    /* return to idle */
292                 dev_err(dev, "%s() count < header size\n", __func__);
293                 return -EIO;
294         }
295         for (retries = 0; retries < TPM_RETRY; retries++) {
296                 if (retries > 0) {
297                         /* if this is not the first trial, set responseRetry */
298                         i2c_nuvoton_write_status(client,
299                                                  TPM_STS_RESPONSE_RETRY);
300                 }
301                 /*
302                  * read first available (> 10 bytes), including:
303                  * tag, paramsize, and result
304                  */
305                 status = i2c_nuvoton_wait_for_data_avail(
306                         chip, chip->timeout_c, &priv->read_queue);
307                 if (status != 0) {
308                         dev_err(dev, "%s() timeout on dataAvail\n", __func__);
309                         size = -ETIMEDOUT;
310                         continue;
311                 }
312                 burst_count = i2c_nuvoton_get_burstcount(client, chip);
313                 if (burst_count < 0) {
314                         dev_err(dev, "%s() fail to get burstCount\n", __func__);
315                         size = -EIO;
316                         continue;
317                 }
318                 size = i2c_nuvoton_recv_data(client, chip, buf,
319                                              burst_count);
320                 if (size < TPM_HEADER_SIZE) {
321                         dev_err(dev, "%s() fail to read header\n", __func__);
322                         size = -EIO;
323                         continue;
324                 }
325                 /*
326                  * convert number of expected bytes field from big endian 32 bit
327                  * to machine native
328                  */
329                 expected = be32_to_cpu(*(__be32 *) (buf + 2));
330                 if (expected > count || expected < size) {
331                         dev_err(dev, "%s() expected > count\n", __func__);
332                         size = -EIO;
333                         continue;
334                 }
335                 rc = i2c_nuvoton_recv_data(client, chip, &buf[size],
336                                            expected - size);
337                 size += rc;
338                 if (rc < 0 || size < expected) {
339                         dev_err(dev, "%s() fail to read remainder of result\n",
340                                 __func__);
341                         size = -EIO;
342                         continue;
343                 }
344                 if (i2c_nuvoton_wait_for_stat(
345                             chip, TPM_STS_VALID | TPM_STS_DATA_AVAIL,
346                             TPM_STS_VALID, chip->timeout_c,
347                             NULL)) {
348                         dev_err(dev, "%s() error left over data\n", __func__);
349                         size = -ETIMEDOUT;
350                         continue;
351                 }
352                 break;
353         }
354         i2c_nuvoton_ready(chip);
355         dev_dbg(&chip->dev, "%s() -> %d\n", __func__, size);
356         return size;
357 }
358
359 /*
360  * Send TPM command.
361  *
362  * If interrupts are used (signaled by an irq set in the vendor structure)
363  * tpm.c can skip polling for the data to be available as the interrupt is
364  * waited for here
365  */
366 static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
367 {
368         struct priv_data *priv = dev_get_drvdata(&chip->dev);
369         struct device *dev = chip->dev.parent;
370         struct i2c_client *client = to_i2c_client(dev);
371         u32 ordinal;
372         size_t count = 0;
373         int burst_count, bytes2write, retries, rc = -EIO;
374
375         for (retries = 0; retries < TPM_RETRY; retries++) {
376                 i2c_nuvoton_ready(chip);
377                 if (i2c_nuvoton_wait_for_stat(chip, TPM_STS_COMMAND_READY,
378                                               TPM_STS_COMMAND_READY,
379                                               chip->timeout_b, NULL)) {
380                         dev_err(dev, "%s() timeout on commandReady\n",
381                                 __func__);
382                         rc = -EIO;
383                         continue;
384                 }
385                 rc = 0;
386                 while (count < len - 1) {
387                         burst_count = i2c_nuvoton_get_burstcount(client,
388                                                                  chip);
389                         if (burst_count < 0) {
390                                 dev_err(dev, "%s() fail get burstCount\n",
391                                         __func__);
392                                 rc = -EIO;
393                                 break;
394                         }
395                         bytes2write = min_t(size_t, burst_count,
396                                             len - 1 - count);
397                         rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W,
398                                                    bytes2write, &buf[count]);
399                         if (rc < 0) {
400                                 dev_err(dev, "%s() fail i2cWriteBuf\n",
401                                         __func__);
402                                 break;
403                         }
404                         dev_dbg(dev, "%s(%d):", __func__, bytes2write);
405                         count += bytes2write;
406                         rc = i2c_nuvoton_wait_for_stat(chip,
407                                                        TPM_STS_VALID |
408                                                        TPM_STS_EXPECT,
409                                                        TPM_STS_VALID |
410                                                        TPM_STS_EXPECT,
411                                                        chip->timeout_c,
412                                                        NULL);
413                         if (rc < 0) {
414                                 dev_err(dev, "%s() timeout on Expect\n",
415                                         __func__);
416                                 rc = -ETIMEDOUT;
417                                 break;
418                         }
419                 }
420                 if (rc < 0)
421                         continue;
422
423                 /* write last byte */
424                 rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W, 1,
425                                            &buf[count]);
426                 if (rc < 0) {
427                         dev_err(dev, "%s() fail to write last byte\n",
428                                 __func__);
429                         rc = -EIO;
430                         continue;
431                 }
432                 dev_dbg(dev, "%s(last): %02x", __func__, buf[count]);
433                 rc = i2c_nuvoton_wait_for_stat(chip,
434                                                TPM_STS_VALID | TPM_STS_EXPECT,
435                                                TPM_STS_VALID,
436                                                chip->timeout_c, NULL);
437                 if (rc) {
438                         dev_err(dev, "%s() timeout on Expect to clear\n",
439                                 __func__);
440                         rc = -ETIMEDOUT;
441                         continue;
442                 }
443                 break;
444         }
445         if (rc < 0) {
446                 /* retries == TPM_RETRY */
447                 i2c_nuvoton_ready(chip);
448                 return rc;
449         }
450         /* execute the TPM command */
451         rc = i2c_nuvoton_write_status(client, TPM_STS_GO);
452         if (rc < 0) {
453                 dev_err(dev, "%s() fail to write Go\n", __func__);
454                 i2c_nuvoton_ready(chip);
455                 return rc;
456         }
457         ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
458         rc = i2c_nuvoton_wait_for_data_avail(chip,
459                                              tpm_calc_ordinal_duration(chip,
460                                                                        ordinal),
461                                              &priv->read_queue);
462         if (rc) {
463                 dev_err(dev, "%s() timeout command duration\n", __func__);
464                 i2c_nuvoton_ready(chip);
465                 return rc;
466         }
467
468         dev_dbg(dev, "%s() -> %zd\n", __func__, len);
469         return len;
470 }
471
472 static bool i2c_nuvoton_req_canceled(struct tpm_chip *chip, u8 status)
473 {
474         return (status == TPM_STS_COMMAND_READY);
475 }
476
477 static const struct tpm_class_ops tpm_i2c = {
478         .flags = TPM_OPS_AUTO_STARTUP,
479         .status = i2c_nuvoton_read_status,
480         .recv = i2c_nuvoton_recv,
481         .send = i2c_nuvoton_send,
482         .cancel = i2c_nuvoton_ready,
483         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
484         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
485         .req_canceled = i2c_nuvoton_req_canceled,
486 };
487
488 /* The only purpose for the handler is to signal to any waiting threads that
489  * the interrupt is currently being asserted. The driver does not do any
490  * processing triggered by interrupts, and the chip provides no way to mask at
491  * the source (plus that would be slow over I2C). Run the IRQ as a one-shot,
492  * this means it cannot be shared. */
493 static irqreturn_t i2c_nuvoton_int_handler(int dummy, void *dev_id)
494 {
495         struct tpm_chip *chip = dev_id;
496         struct priv_data *priv = dev_get_drvdata(&chip->dev);
497
498         priv->intrs++;
499         wake_up(&priv->read_queue);
500         disable_irq_nosync(priv->irq);
501         return IRQ_HANDLED;
502 }
503
504 static int get_vid(struct i2c_client *client, u32 *res)
505 {
506         static const u8 vid_did_rid_value[] = { 0x50, 0x10, 0xfe };
507         u32 temp;
508         s32 rc;
509
510         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
511                 return -ENODEV;
512         rc = i2c_nuvoton_read_buf(client, TPM_VID_DID_RID, 4, (u8 *)&temp);
513         if (rc < 0)
514                 return rc;
515
516         /* check WPCT301 values - ignore RID */
517         if (memcmp(&temp, vid_did_rid_value, sizeof(vid_did_rid_value))) {
518                 /*
519                  * f/w rev 2.81 has an issue where the VID_DID_RID is not
520                  * reporting the right value. so give it another chance at
521                  * offset 0x20 (FIFO_W).
522                  */
523                 rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_W, 4,
524                                           (u8 *) (&temp));
525                 if (rc < 0)
526                         return rc;
527
528                 /* check WPCT301 values - ignore RID */
529                 if (memcmp(&temp, vid_did_rid_value,
530                            sizeof(vid_did_rid_value)))
531                         return -ENODEV;
532         }
533
534         *res = temp;
535         return 0;
536 }
537
538 static int i2c_nuvoton_probe(struct i2c_client *client,
539                              const struct i2c_device_id *id)
540 {
541         int rc;
542         struct tpm_chip *chip;
543         struct device *dev = &client->dev;
544         struct priv_data *priv;
545         u32 vid = 0;
546
547         rc = get_vid(client, &vid);
548         if (rc)
549                 return rc;
550
551         dev_info(dev, "VID: %04X DID: %02X RID: %02X\n", (u16) vid,
552                  (u8) (vid >> 16), (u8) (vid >> 24));
553
554         chip = tpmm_chip_alloc(dev, &tpm_i2c);
555         if (IS_ERR(chip))
556                 return PTR_ERR(chip);
557
558         priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
559         if (!priv)
560                 return -ENOMEM;
561
562         if (dev->of_node) {
563                 const struct of_device_id *of_id;
564
565                 of_id = of_match_device(dev->driver->of_match_table, dev);
566                 if (of_id && of_id->data == OF_IS_TPM2)
567                         chip->flags |= TPM_CHIP_FLAG_TPM2;
568         } else
569                 if (id->driver_data == I2C_IS_TPM2)
570                         chip->flags |= TPM_CHIP_FLAG_TPM2;
571
572         init_waitqueue_head(&priv->read_queue);
573
574         /* Default timeouts */
575         chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
576         chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
577         chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
578         chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
579
580         dev_set_drvdata(&chip->dev, priv);
581
582         /*
583          * I2C intfcaps (interrupt capabilitieis) in the chip are hard coded to:
584          *   TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
585          * The IRQ should be set in the i2c_board_info (which is done
586          * automatically in of_i2c_register_devices, for device tree users */
587         priv->irq = client->irq;
588         if (client->irq) {
589                 dev_dbg(dev, "%s() priv->irq\n", __func__);
590                 rc = devm_request_irq(dev, client->irq,
591                                       i2c_nuvoton_int_handler,
592                                       IRQF_TRIGGER_LOW,
593                                       dev_name(&chip->dev),
594                                       chip);
595                 if (rc) {
596                         dev_err(dev, "%s() Unable to request irq: %d for use\n",
597                                 __func__, priv->irq);
598                         priv->irq = 0;
599                 } else {
600                         chip->flags |= TPM_CHIP_FLAG_IRQ;
601                         /* Clear any pending interrupt */
602                         i2c_nuvoton_ready(chip);
603                         /* - wait for TPM_STS==0xA0 (stsValid, commandReady) */
604                         rc = i2c_nuvoton_wait_for_stat(chip,
605                                                        TPM_STS_COMMAND_READY,
606                                                        TPM_STS_COMMAND_READY,
607                                                        chip->timeout_b,
608                                                        NULL);
609                         if (rc == 0) {
610                                 /*
611                                  * TIS is in ready state
612                                  * write dummy byte to enter reception state
613                                  * TPM_DATA_FIFO_W <- rc (0)
614                                  */
615                                 rc = i2c_nuvoton_write_buf(client,
616                                                            TPM_DATA_FIFO_W,
617                                                            1, (u8 *) (&rc));
618                                 if (rc < 0)
619                                         return rc;
620                                 /* TPM_STS <- 0x40 (commandReady) */
621                                 i2c_nuvoton_ready(chip);
622                         } else {
623                                 /*
624                                  * timeout_b reached - command was
625                                  * aborted. TIS should now be in idle state -
626                                  * only TPM_STS_VALID should be set
627                                  */
628                                 if (i2c_nuvoton_read_status(chip) !=
629                                     TPM_STS_VALID)
630                                         return -EIO;
631                         }
632                 }
633         }
634
635         return tpm_chip_register(chip);
636 }
637
638 static int i2c_nuvoton_remove(struct i2c_client *client)
639 {
640         struct tpm_chip *chip = i2c_get_clientdata(client);
641
642         tpm_chip_unregister(chip);
643         return 0;
644 }
645
646 static const struct i2c_device_id i2c_nuvoton_id[] = {
647         {"tpm_i2c_nuvoton"},
648         {"tpm2_i2c_nuvoton", .driver_data = I2C_IS_TPM2},
649         {}
650 };
651 MODULE_DEVICE_TABLE(i2c, i2c_nuvoton_id);
652
653 #ifdef CONFIG_OF
654 static const struct of_device_id i2c_nuvoton_of_match[] = {
655         {.compatible = "nuvoton,npct501"},
656         {.compatible = "winbond,wpct301"},
657         {.compatible = "nuvoton,npct601", .data = OF_IS_TPM2},
658         {},
659 };
660 MODULE_DEVICE_TABLE(of, i2c_nuvoton_of_match);
661 #endif
662
663 static SIMPLE_DEV_PM_OPS(i2c_nuvoton_pm_ops, tpm_pm_suspend, tpm_pm_resume);
664
665 static struct i2c_driver i2c_nuvoton_driver = {
666         .id_table = i2c_nuvoton_id,
667         .probe = i2c_nuvoton_probe,
668         .remove = i2c_nuvoton_remove,
669         .driver = {
670                 .name = "tpm_i2c_nuvoton",
671                 .pm = &i2c_nuvoton_pm_ops,
672                 .of_match_table = of_match_ptr(i2c_nuvoton_of_match),
673         },
674 };
675
676 module_i2c_driver(i2c_nuvoton_driver);
677
678 MODULE_AUTHOR("Dan Morav (dan.morav@nuvoton.com)");
679 MODULE_DESCRIPTION("Nuvoton TPM I2C Driver");
680 MODULE_LICENSE("GPL");