From f3b70b6e3390bfdf18fdd7d278a72a12784fdcce Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin Date: Wed, 24 May 2023 17:40:39 +0200 Subject: tpm: tis_i2c: Limit read bursts to I2C_SMBUS_BLOCK_MAX (32) bytes Underlying I2C bus drivers not always support longer transfers and imx-lpi2c for instance doesn't. SLB 9673 offers 427-bytes packets. Visible symptoms are: tpm tpm0: Error left over data tpm tpm0: tpm_transmit: tpm_recv: error -5 tpm_tis_i2c: probe of 1-002e failed with error -5 Cc: stable@vger.kernel.org # v5.20+ Fixes: bbc23a07b072 ("tpm: Add tpm_tis_i2c backend for tpm_tis_core") Tested-by: Michael Haener Signed-off-by: Alexander Sverdlin Reviewed-by: Jarkko Sakkinen Reviewed-by: Jerry Snitselaar Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_i2c.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c index c8c34adc14c0..106fd20d94e4 100644 --- a/drivers/char/tpm/tpm_tis_i2c.c +++ b/drivers/char/tpm/tpm_tis_i2c.c @@ -189,21 +189,28 @@ static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len, int ret; for (i = 0; i < TPM_RETRY; i++) { - /* write register */ - msg.len = sizeof(reg); - msg.buf = ® - msg.flags = 0; - ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg); - if (ret < 0) - return ret; - - /* read data */ - msg.buf = result; - msg.len = len; - msg.flags = I2C_M_RD; - ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg); - if (ret < 0) - return ret; + u16 read = 0; + + while (read < len) { + /* write register */ + msg.len = sizeof(reg); + msg.buf = ® + msg.flags = 0; + ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg); + if (ret < 0) + return ret; + + /* read data */ + msg.buf = result + read; + msg.len = len - read; + msg.flags = I2C_M_RD; + if (msg.len > I2C_SMBUS_BLOCK_MAX) + msg.len = I2C_SMBUS_BLOCK_MAX; + ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg); + if (ret < 0) + return ret; + read += msg.len; + } ret = tpm_tis_i2c_sanity_check_read(reg, len, result); if (ret == 0) -- cgit v1.2.3