Commit 44637b0b authored by Jan Dabros's avatar Jan Dabros Committed by Jarkko Sakkinen
Browse files

char: tpm: cr50: Move i2c locking to request/relinquish locality ops 



Move i2c locking primitives to request_locality and relinquish_locality
callbacks, what effectively blocks TPM bus for the whole duration of
logical TPM operation.

With this in place, cr50-equipped TPM may be shared with external CPUs -
assuming that underneath i2c controller driver is aware of this setup
(see i2c-designware-amdpsp as an example).

Signed-off-by: default avatarJan Dabros <jsd@semihalf.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 932e3a5e

drivers/char/tpm/tpm_tis_i2c_cr50.c

+13 −9
Original line number Diff line number Diff line
@@ -201,8 +201,6 @@ static int tpm_cr50_i2c_read(struct tpm_chip *chip, u8 addr, u8 *buffer, size_t 
	};

	int rc;



	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);



	/* Prepare for completion interrupt */

	tpm_cr50_i2c_enable_tpm_irq(chip);
@@ -221,7 +219,6 @@ static int tpm_cr50_i2c_read(struct tpm_chip *chip, u8 addr, u8 *buffer, size_t 


out:

	tpm_cr50_i2c_disable_tpm_irq(chip);

	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);



	if (rc < 0)

		return rc;
@@ -263,8 +260,6 @@ static int tpm_cr50_i2c_write(struct tpm_chip *chip, u8 addr, u8 *buffer, 
	priv->buf[0] = addr;

	memcpy(priv->buf + 1, buffer, len);



	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);



	/* Prepare for completion interrupt */

	tpm_cr50_i2c_enable_tpm_irq(chip);
@@ -278,7 +273,6 @@ static int tpm_cr50_i2c_write(struct tpm_chip *chip, u8 addr, u8 *buffer, 


out:

	tpm_cr50_i2c_disable_tpm_irq(chip);

	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);



	if (rc < 0)

		return rc;
@@ -322,6 +316,7 @@ static int tpm_cr50_check_locality(struct tpm_chip *chip, int loc) 
 */

static int tpm_cr50_release_locality(struct tpm_chip *chip, int loc)

{

	struct i2c_client *client = to_i2c_client(chip->dev.parent);

	u8 mask = TPM_ACCESS_VALID | TPM_ACCESS_REQUEST_PENDING;

	u8 addr = TPM_I2C_ACCESS(loc);

	u8 buf;
@@ -329,13 +324,15 @@ static int tpm_cr50_release_locality(struct tpm_chip *chip, int loc) 


	rc = tpm_cr50_i2c_read(chip, addr, &buf, sizeof(buf));

	if (rc < 0)

		return rc;

		goto unlock_out;



	if ((buf & mask) == mask) {

		buf = TPM_ACCESS_ACTIVE_LOCALITY;

		rc = tpm_cr50_i2c_write(chip, addr, &buf, sizeof(buf));

	}



unlock_out:

	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);

	return rc;

}
@@ -350,16 +347,19 @@ static int tpm_cr50_release_locality(struct tpm_chip *chip, int loc) 
 */

static int tpm_cr50_request_locality(struct tpm_chip *chip, int loc)

{

	struct i2c_client *client = to_i2c_client(chip->dev.parent);

	u8 buf = TPM_ACCESS_REQUEST_USE;

	unsigned long stop;

	int rc;



	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);



	if (tpm_cr50_check_locality(chip, loc) == loc)

		return loc;



	rc = tpm_cr50_i2c_write(chip, TPM_I2C_ACCESS(loc), &buf, sizeof(buf));

	if (rc < 0)

		return rc;

		goto unlock_out;



	stop = jiffies + chip->timeout_a;

	do {
@@ -369,7 +369,11 @@ static int tpm_cr50_request_locality(struct tpm_chip *chip, int loc) 
		msleep(TPM_CR50_TIMEOUT_SHORT_MS);

	} while (time_before(jiffies, stop));



	return -ETIMEDOUT;

	rc = -ETIMEDOUT;



unlock_out:

	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);

	return rc;

}



/**