diff mbox

[v2,01/10] tpm/tpm_i2c_infineon: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

Message ID 20180620051803.12206-2-peda@axentia.se (mailing list archive)
State New, archived
Headers show

Commit Message

Peter Rosin June 20, 2018, 5:17 a.m. UTC
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>
---
 drivers/char/tpm/tpm_i2c_infineon.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Jarkko Sakkinen June 25, 2018, 10:24 a.m. UTC | #1
On Wed, Jun 20, 2018 at 07:17:54AM +0200, Peter Rosin wrote:
> 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>

Studied enough so that I can give

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Do not have hardware to test this, however.

/Jarkko
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Alexander Steffen June 26, 2018, 10:07 a.m. UTC | #2
On 25.06.2018 12:24, Jarkko Sakkinen wrote:
> On Wed, Jun 20, 2018 at 07:17:54AM +0200, Peter Rosin wrote:
>> 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>
> 
> Studied enough so that I can give
> 
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> 
> Do not have hardware to test this, however.

I don't have a mux-locked I2C mux either, but at least I can confirm 
that this change did not break my existing test setup (SLB9635/SLB9645 
on Raspberry Pi 2B).

Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>

Alexander
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jarkko Sakkinen June 26, 2018, 12:05 p.m. UTC | #3
On Tue, 2018-06-26 at 12:07 +0200, Alexander Steffen wrote:
> On 25.06.2018 12:24, Jarkko Sakkinen wrote:
> > On Wed, Jun 20, 2018 at 07:17:54AM +0200, Peter Rosin wrote:
> > > 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>
> > 
> > Studied enough so that I can give
> > 
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > 
> > Do not have hardware to test this, however.
> 
> I don't have a mux-locked I2C mux either, but at least I can confirm 
> that this change did not break my existing test setup (SLB9635/SLB9645 
> on Raspberry Pi 2B).
> 
> Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> 
> Alexander

Given the scope of the change and since analogous change works for
every other subsystem, this should be enough! Thank you.

/Jarkko
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jarkko Sakkinen June 26, 2018, 12:07 p.m. UTC | #4
On Tue, 2018-06-26 at 15:05 +0300, Jarkko Sakkinen wrote:
> On Tue, 2018-06-26 at 12:07 +0200, Alexander Steffen wrote:
> > On 25.06.2018 12:24, Jarkko Sakkinen wrote:
> > > On Wed, Jun 20, 2018 at 07:17:54AM +0200, Peter Rosin wrote:
> > > > 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>
> > > 
> > > Studied enough so that I can give
> > > 
> > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > > 
> > > Do not have hardware to test this, however.
> > 
> > I don't have a mux-locked I2C mux either, but at least I can confirm 
> > that this change did not break my existing test setup (SLB9635/SLB9645 
> > on Raspberry Pi 2B).
> > 
> > Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> > 
> > Alexander
> 
> Given the scope of the change and since analogous change works for
> every other subsystem, this should be enough! Thank you.

It is now applied to my tree (master). I will move it to the
next branch once James has updated security/next-general.

/Jarkko
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
index 6116cd05e228..9086edc9066b 100644
--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -117,7 +117,7 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 	/* 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
@@ -192,7 +192,7 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 	}
 
 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);
 
@@ -224,7 +224,7 @@  static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 
 	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;
@@ -243,7 +243,7 @@  static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 		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);