[PATCH 4.9 49/70] tpm/tpm_i2c_infineon: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

Greg Kroah-Hartman
2018-09-17T22:59:37Z

From: Peter Rosin <peda@axentia.se>

[ Upstream commit bb853aac2c478ce78116128263801189408ad2a8 ]

Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.

Signed-off-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/tpm/tpm_i2c_infineon.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -115,7 +115,7 @@ static int iic_tpm_read(u8 addr, u8 *buf
/* Lock the adapter for the duration of the whole sequence. */
if (!tpm_dev.client->adapter->algo->master_xfer)
return -EOPNOTSUPP;
- i2c_lock_adapter(tpm_dev.client->adapter);
+ i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);

if (tpm_dev.chip_type == SLB9645) {
/* use a combined read for newer chips
@@ -156,7 +156,7 @@ static int iic_tpm_read(u8 addr, u8 *buf
}

out:
- i2c_unlock_adapter(tpm_dev.client->adapter);
+ i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
/* take care of 'guard time' */
usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);

@@ -188,7 +188,7 @@ static int iic_tpm_write_generic(u8 addr

if (!tpm_dev.client->adapter->algo->master_xfer)
return -EOPNOTSUPP;
- i2c_lock_adapter(tpm_dev.client->adapter);
+ i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);

/* prepend the 'register address' to the buffer */
tpm_dev.buf[0] = addr;
@@ -207,7 +207,7 @@ static int iic_tpm_write_generic(u8 addr
usleep_range(sleep_low, sleep_hi);
}

- i2c_unlock_adapter(tpm_dev.client->adapter);
+ i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
/* take care of 'guard time' */
usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);