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tpm: tis_i2c: Limit read bursts to I2C_SMBUS_BLOCK_MAX (32) bytes

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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: bbc23a07b0 ("tpm: Add tpm_tis_i2c backend for tpm_tis_core")
Tested-by: Michael Haener <michael.haener@siemens.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This commit is contained in:
Alexander Sverdlin 2023-05-24 17:40:39 +02:00 committed by Jarkko Sakkinen
parent f0afba4042
commit f3b70b6e33
1 changed files with 21 additions and 14 deletions
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35
drivers/char/tpm/tpm_tis_i2c.c
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@ -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 = &reg;
msg.flags = 0;
ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
if (ret < 0)
return ret;
u16 read = 0;
/* 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;
while (read < len) {
/* write register */
msg.len = sizeof(reg);
msg.buf = &reg;
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)