1 // SPDX-License-Identifier: GPL-2.0
3  * Copyright (c) 2014-2021 Nuvoton Technology corporation
4  * Copyright (C) 2019-2022 Infineon Technologies AG
13 #include <linux/i2c.h>
14 #include <linux/crc-ccitt.h>
27 /* TIS-compatible register address to avoid clash with TPM_ACCESS (0x00) */
30 /* Mask to extract the I2C register from TIS register addresses */
37 /* Guard Time of 250µs after I2C slave NACK */
77  * those addresses need to mapped to the registers defined for I2C TPMs in
78  * Table 51 "I2C-TPM Register Overview".
82  * since the corresponding I2C registers have been moved around. TPM_LOC_SEL is
83  * only defined for I2C TPMs and is also mapped explicitly here to distinguish
110 	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);  in tpm_tis_i2c_retry_transfer_until_ack()  local
115 	if (msg->flags & I2C_M_RD)  in tpm_tis_i2c_retry_transfer_until_ack()
116 		guard_time = phy->guard_time_read;  in tpm_tis_i2c_retry_transfer_until_ack()
118 		guard_time = phy->guard_time_write;  in tpm_tis_i2c_retry_transfer_until_ack()
121 		ret = i2c_transfer(phy->i2c_client->adapter, msg, 1);  in tpm_tis_i2c_retry_transfer_until_ack()
125 			usleep_range(phy->guard_time_min, phy->guard_time_max);  in tpm_tis_i2c_retry_transfer_until_ack()
175 		pr_debug("TPM I2C read of register 0x%02x failed sanity check: 0x%x\n", reg, value);  in tpm_tis_i2c_sanity_check_read()
176 		return -EIO;  in tpm_tis_i2c_sanity_check_read()
185 	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);  in tpm_tis_i2c_read_bytes()  local
186 	struct i2c_msg msg = { .addr = phy->i2c_client->addr };  in tpm_tis_i2c_read_bytes()
205 			msg.len = len - read;  in tpm_tis_i2c_read_bytes()
229 	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);  in tpm_tis_i2c_write_bytes()  local
230 	struct i2c_msg msg = { .addr = phy->i2c_client->addr };  in tpm_tis_i2c_write_bytes()
235 	if (len > TPM_BUFSIZE - 1)  in tpm_tis_i2c_write_bytes()
236 		return -EIO;  in tpm_tis_i2c_write_bytes()
238 	phy->io_buf[0] = reg;  in tpm_tis_i2c_write_bytes()
239 	msg.buf = phy->io_buf;  in tpm_tis_i2c_write_bytes()
242 		msg.len = sizeof(reg) + len - wrote;  in tpm_tis_i2c_write_bytes()
246 		memcpy(phy->io_buf + sizeof(reg), value + wrote,  in tpm_tis_i2c_write_bytes()
247 		       msg.len - sizeof(reg));  in tpm_tis_i2c_write_bytes()
252 		wrote += msg.len - sizeof(reg);  in tpm_tis_i2c_write_bytes()
271 		return -EIO;  in tpm_tis_i2c_verify_crc()
278  * After each I2C operation, the TPM might require the master to wait.
279  * The time period is vendor-specific and must be read from the
282  * Before the Guard Time is read (or after the TPM failed to send an I2C NACK),
286  *  - SR: <I2C read with repeated start> <guard time> <I2C read>
287  *  - RR: <I2C read> <guard time> <I2C read>
288  *  - RW: <I2C read> <guard time> <I2C write>
289  *  - WR: <I2C write> <guard time> <I2C read>
290  *  - WW: <I2C write> <guard time> <I2C write>
294 static int tpm_tis_i2c_init_guard_time(struct tpm_tis_i2c_phy *phy)  in tpm_tis_i2c_init_guard_time()  argument
299 	phy->guard_time_read = true;  in tpm_tis_i2c_init_guard_time()
300 	phy->guard_time_write = true;  in tpm_tis_i2c_init_guard_time()
301 	phy->guard_time_min = GUARD_TIME_DEFAULT_MIN;  in tpm_tis_i2c_init_guard_time()
302 	phy->guard_time_max = GUARD_TIME_DEFAULT_MAX;  in tpm_tis_i2c_init_guard_time()
304 	ret = tpm_tis_i2c_read_bytes(&phy->priv, TPM_I2C_INTERFACE_CAPABILITY,  in tpm_tis_i2c_init_guard_time()
310 	phy->guard_time_read = (i2c_caps & TPM_GUARD_TIME_RR_MASK) ||  in tpm_tis_i2c_init_guard_time()
312 	phy->guard_time_write = (i2c_caps & TPM_GUARD_TIME_WR_MASK) ||  in tpm_tis_i2c_init_guard_time()
314 	phy->guard_time_min = (i2c_caps & TPM_GUARD_TIME_MIN_MASK) >>  in tpm_tis_i2c_init_guard_time()
317 	phy->guard_time_max = phy->guard_time_min + phy->guard_time_min / 5;  in tpm_tis_i2c_init_guard_time()
332 	struct tpm_tis_i2c_phy *phy;  in tpm_tis_i2c_probe()  local
337 	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_i2c_phy),  in tpm_tis_i2c_probe()
339 	if (!phy)  in tpm_tis_i2c_probe()
340 		return -ENOMEM;  in tpm_tis_i2c_probe()
342 	phy->io_buf = devm_kzalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL);  in tpm_tis_i2c_probe()
343 	if (!phy->io_buf)  in tpm_tis_i2c_probe()
344 		return -ENOMEM;  in tpm_tis_i2c_probe()
346 	set_bit(TPM_TIS_DEFAULT_CANCELLATION, &phy->priv.flags);  in tpm_tis_i2c_probe()
347 	phy->i2c_client = dev;  in tpm_tis_i2c_probe()
350 	ret = tpm_tis_i2c_init_guard_time(phy);  in tpm_tis_i2c_probe()
354 	ret = tpm_tis_i2c_write_bytes(&phy->priv, TPM_LOC_SEL, sizeof(locality),  in tpm_tis_i2c_probe()
359 	ret = tpm_tis_i2c_write_bytes(&phy->priv, TPM_I2C_DATA_CSUM_ENABLE,  in tpm_tis_i2c_probe()
365 	return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops,  in tpm_tis_i2c_probe()
381 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id);
387 	{ .compatible = "tcg,tpm-tis-i2c", },
405 MODULE_DESCRIPTION("TPM Driver for native I2C access");