On Wed Oct 9, 2024 at 12:42 PM EEST, Grzegorz Bernacki wrote: > From: Jan Dabros <[email protected]> > > 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: Jan Dabros <[email protected]> > --- > drivers/char/tpm/tpm_tis_i2c_cr50.c | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c > b/drivers/char/tpm/tpm_tis_i2c_cr50.c > index 1b1e403383fc..104ef6c7f11c 100644 > --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c > +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c > @@ -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; > } > > /**
Nothing apparently wrong in this. Will re-check after 1/2 is good. BR, Jarkko
