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

Underlying I2C bus drivers not always support longer transfers and
imx-lpi2c for instance doesn't. The fix is symmetric to previous patch
which fixed the read direction.

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 17:40:40 +02:00 committed by Jarkko Sakkinen
parent f3b70b6e33
commit 83e7e5d89f
1 changed files with 15 additions and 7 deletions
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22
drivers/char/tpm/tpm_tis_i2c.c
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@ -230,19 +230,27 @@ static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
struct i2c_msg msg = { .addr = phy->i2c_client->addr };
u8 reg = tpm_tis_i2c_address_to_register(addr);
int ret;
u16 wrote = 0;
if (len > TPM_BUFSIZE - 1)
return -EIO;
/* write register and data in one go */
phy->io_buf[0] = reg;
memcpy(phy->io_buf + sizeof(reg), value, len);
msg.len = sizeof(reg) + len;
msg.buf = phy->io_buf;
ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
if (ret < 0)
return ret;
while (wrote < len) {
/* write register and data in one go */
msg.len = sizeof(reg) + len - wrote;
if (msg.len > I2C_SMBUS_BLOCK_MAX)
msg.len = I2C_SMBUS_BLOCK_MAX;
memcpy(phy->io_buf + sizeof(reg), value + wrote,
msg.len - sizeof(reg));
ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
if (ret < 0)
return ret;
wrote += msg.len - sizeof(reg);
}
return 0;
}