1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * ATMEL I2C TPM AT97SC3204T
9  * Device driver for ATMEL I2C TPMs.
11  * Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
12  * devices the raw TCG formatted TPM command data is written via I2C and then
13  * raw TCG formatted TPM command data is returned via I2C.
22 #include <linux/i2c.h>
35 	 * fair number of read responses in the buffer so a 2nd retry can be
42 	struct priv_data *priv = dev_get_drvdata(&chip->dev);  in i2c_atmel_send()
43 	struct i2c_client *client = to_i2c_client(chip->dev.parent);  in i2c_atmel_send()
46 	priv->len = 0;  in i2c_atmel_send()
49 		return -EIO;  in i2c_atmel_send()
53 	dev_dbg(&chip->dev,  in i2c_atmel_send()
54 		"%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,  in i2c_atmel_send()
62 		return -E2BIG;  in i2c_atmel_send()
67 static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)  in i2c_atmel_recv()  argument
69 	struct priv_data *priv = dev_get_drvdata(&chip->dev);  in i2c_atmel_recv()
70 	struct i2c_client *client = to_i2c_client(chip->dev.parent);  in i2c_atmel_recv()
71 	struct tpm_header *hdr = (struct tpm_header *)priv->buffer;  in i2c_atmel_recv()
75 	if (priv->len == 0)  in i2c_atmel_recv()
76 		return -EIO;  in i2c_atmel_recv()
79 	 * whole message in read_status then we need to re-read the  in i2c_atmel_recv()
81 	expected_len = be32_to_cpu(hdr->length);  in i2c_atmel_recv()
82 	if (expected_len > count)  in i2c_atmel_recv()
83 		return -ENOMEM;  in i2c_atmel_recv()
85 	if (priv->len >= expected_len) {  in i2c_atmel_recv()
86 		dev_dbg(&chip->dev,  in i2c_atmel_recv()
87 			"%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,  in i2c_atmel_recv()
88 			(int)min_t(size_t, 64, expected_len), buf, count,  in i2c_atmel_recv()
90 		memcpy(buf, priv->buffer, expected_len);  in i2c_atmel_recv()
95 	dev_dbg(&chip->dev,  in i2c_atmel_recv()
96 		"%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,  in i2c_atmel_recv()
97 		(int)min_t(size_t, 64, expected_len), buf, count,  in i2c_atmel_recv()
104 	dev_err(&chip->dev, "TPM operation cancellation was requested, but is not supported");  in i2c_atmel_cancel()
109 	struct priv_data *priv = dev_get_drvdata(&chip->dev);  in i2c_atmel_read_status()
110 	struct i2c_client *client = to_i2c_client(chip->dev.parent);  in i2c_atmel_read_status()
113 	/* The TPM fails the I2C read until it is ready, so we do the entire  in i2c_atmel_read_status()
116 	priv->len = 0;  in i2c_atmel_read_status()
117 	memset(priv->buffer, 0, sizeof(priv->buffer));  in i2c_atmel_read_status()
122 	rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));  in i2c_atmel_read_status()
123 	dev_dbg(&chip->dev,  in i2c_atmel_read_status()
128 	priv->len = rc;  in i2c_atmel_read_status()
153 	struct device *dev = &client->dev;  in i2c_atmel_probe()
156 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))  in i2c_atmel_probe()
157 		return -ENODEV;  in i2c_atmel_probe()
165 		return -ENOMEM;  in i2c_atmel_probe()
168 	chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);  in i2c_atmel_probe()
169 	chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);  in i2c_atmel_probe()
170 	chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);  in i2c_atmel_probe()
171 	chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);  in i2c_atmel_probe()
173 	dev_set_drvdata(&chip->dev, priv);  in i2c_atmel_probe()
184 	struct device *dev = &(client->dev);  in i2c_atmel_remove()
194 MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
220 MODULE_DESCRIPTION("Atmel TPM I2C Driver");