1 // SPDX-License-Identifier: GPL-2.0-only
13  * Infineon I2C Protocol Stack Specification v0.20.
18 #include <linux/i2c.h>
25 /* max. number of iterations after I2C NAK */
31 /* max. number of iterations after I2C NAK for 'long' commands
62 	/* In addition to the data itself, the buffer must fit the 7-bit I2C
74  * iic_tpm_read() - read from TPM register
80  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
82  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
86  * provided by the i2c core as the TPM currently does not support the
90  * Return -EIO on error, 0 on success.
96 		.addr = tpm_dev.client->addr,  in iic_tpm_read()
101 		.addr = tpm_dev.client->addr,  in iic_tpm_read()
109 	int count;  in iic_tpm_read()  local
113 	if (!tpm_dev.client->adapter->algo->master_xfer)  in iic_tpm_read()
114 		return -EOPNOTSUPP;  in iic_tpm_read()
115 	i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);  in iic_tpm_read()
124 		for (count = 0; count < MAX_COUNT; count++) {  in iic_tpm_read()
125 			rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);  in iic_tpm_read()
136 			for (count = 0; count < MAX_COUNT; count++) {  in iic_tpm_read()
137 				rc = __i2c_transfer(tpm_dev.client->adapter,  in iic_tpm_read()
153 			for (count = 0; count < MAX_COUNT; count++) {  in iic_tpm_read()
162 				rc = __i2c_transfer(tpm_dev.client->adapter,  in iic_tpm_read()
171 						len -= msglen;  in iic_tpm_read()
175 				/* If the I2C adapter rejected the request (e.g  in iic_tpm_read()
179 				if (rc == -EOPNOTSUPP)  in iic_tpm_read()
190 	i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);  in iic_tpm_read()
199 		return -EIO;  in iic_tpm_read()
208 	int rc = -EIO;  in iic_tpm_write_generic()
209 	int count;  in iic_tpm_write_generic()  local
212 		.addr = tpm_dev.client->addr,  in iic_tpm_write_generic()
218 		return -EINVAL;  in iic_tpm_write_generic()
220 	if (!tpm_dev.client->adapter->algo->master_xfer)  in iic_tpm_write_generic()
221 		return -EOPNOTSUPP;  in iic_tpm_write_generic()
222 	i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);  in iic_tpm_write_generic()
234 	for (count = 0; count < max_count; count++) {  in iic_tpm_write_generic()
235 		rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);  in iic_tpm_write_generic()
241 	i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);  in iic_tpm_write_generic()
250 		return -EIO;  in iic_tpm_write_generic()
256  * iic_tpm_write() - write to TPM register
264  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
269  * Return -EIO on error, 0 on success
355 	stop = jiffies + chip->timeout_a;  in request_locality()
362 	return -ETIME;  in request_locality()
367 	/* NOTE: since I2C read may fail, return 0 in this case --> time-out */  in tpm_tis_i2c_status()
397 	stop = jiffies + chip->timeout_d;  in get_burstcount()
410 	return -EBUSY;  in get_burstcount()
433 	return -ETIME;  in wait_for_stat()
436 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)  in recv_data()  argument
443 	while (size < count) {  in recv_data()
451 		if (burstcnt > (count - size))  in recv_data()
452 			burstcnt = count - size;  in recv_data()
463 			return -EIO;  in recv_data()
468 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)  in tpm_tis_i2c_recv()  argument
474 	if (count < TPM_HEADER_SIZE) {  in tpm_tis_i2c_recv()
475 		size = -EIO;  in tpm_tis_i2c_recv()
482 		dev_err(&chip->dev, "Unable to read header\n");  in tpm_tis_i2c_recv()
487 	if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {  in tpm_tis_i2c_recv()
488 		size = -EIO;  in tpm_tis_i2c_recv()
493 			  expected - TPM_HEADER_SIZE);  in tpm_tis_i2c_recv()
495 		dev_err(&chip->dev, "Unable to read remainder of result\n");  in tpm_tis_i2c_recv()
496 		size = -ETIME;  in tpm_tis_i2c_recv()
500 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);  in tpm_tis_i2c_recv()
501 	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */  in tpm_tis_i2c_recv()
502 		dev_err(&chip->dev, "Error left over data\n");  in tpm_tis_i2c_recv()
503 		size = -EIO;  in tpm_tis_i2c_recv()
521 	size_t count = 0;  in tpm_tis_i2c_send()  local
526 		return -E2BIG;  in tpm_tis_i2c_send()
529 		return -EBUSY;  in tpm_tis_i2c_send()
536 		     chip->timeout_b, &status) < 0) {  in tpm_tis_i2c_send()
537 			rc = -ETIME;  in tpm_tis_i2c_send()
542 	while (count < len - 1) {  in tpm_tis_i2c_send()
549 		if (burstcnt > (len - 1 - count))  in tpm_tis_i2c_send()
550 			burstcnt = len - 1 - count;  in tpm_tis_i2c_send()
553 				   &(buf[count]), burstcnt);  in tpm_tis_i2c_send()
555 			count += burstcnt;  in tpm_tis_i2c_send()
561 			rc = -EIO;  in tpm_tis_i2c_send()
566 			      chip->timeout_c, &status);  in tpm_tis_i2c_send()
569 			rc = -EIO;  in tpm_tis_i2c_send()
575 	iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);  in tpm_tis_i2c_send()
576 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);  in tpm_tis_i2c_send()
578 		rc = -EIO;  in tpm_tis_i2c_send()
623 	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);  in tpm_tis_i2c_init()
624 	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);  in tpm_tis_i2c_init()
625 	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);  in tpm_tis_i2c_init()
626 	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);  in tpm_tis_i2c_init()
630 		rc = -ENODEV;  in tpm_tis_i2c_init()
637 		rc = -EIO;  in tpm_tis_i2c_init()
647 		rc = -ENODEV;  in tpm_tis_i2c_init()
651 	dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);  in tpm_tis_i2c_init()
670 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
688 	struct device *dev = &(client->dev);  in tpm_tis_i2c_probe()
692 		return -EBUSY;	/* We only support one client */  in tpm_tis_i2c_probe()
695 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {  in tpm_tis_i2c_probe()
696 		dev_err(dev, "no algorithms associated to the i2c bus\n");  in tpm_tis_i2c_probe()
697 		return -ENODEV;  in tpm_tis_i2c_probe()
701 	rc = tpm_tis_i2c_init(&client->dev);  in tpm_tis_i2c_probe()
704 		rc = -ENODEV;  in tpm_tis_i2c_probe()
733 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");