Thread (23 messages) 23 messages, 9 authors, 2018-07-12
STALE2876d
Revisions (2)
  1. v1 [diff vs current]
  2. v2 current

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

From: Peter Rosin <hidden>
Date: 2018-06-20 05:21:40
Also in: linux-arm-kernel, linux-i2c, linux-iio, linux-integrity, linux-media, linux-samsung-soc, lkml
Subsystem: the rest, tpm device driver · Maintainers: Linus Torvalds, Peter Huewe, Jarkko Sakkinen

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 <redacted>
---
 drivers/char/tpm/tpm_i2c_infineon.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
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);
 
-- 
2.11.0
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