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tpm_tis_spi: Check correct byte for wait state indicator

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Wait states are signaled in the last byte received from the TPM in
response to the header, not the first byte. Check rx_buf[3] instead of
rx_buf[0].

Cc: <stable@vger.kernel.org>
Fixes: 0edbfea537 ("tpm/tpm_tis_spi: Add support for spi phy")
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Benoit Houyere <benoit.houyere@st.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Peter Huewe 2017-03-02 13:03:13 +00:00 committed by Jarkko Sakkinen
parent 975094ddc3
commit e110cc69dc
1 changed files with 17 additions and 17 deletions
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34
drivers/char/tpm/tpm_tis_spi.c
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@ -85,25 +85,25 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
if (ret < 0)
goto exit;
phy->tx_buf[0] = 0;
if ((phy->rx_buf[3] & 0x01) == 0) {
// handle SPI wait states
phy->tx_buf[0] = 0;
/* According to TCG PTP specification, if there is no TPM present at
* all, then the design has a weak pull-up on MISO. If a TPM is not
* present, a pull-up on MISO means that the SB controller sees a 1,
* and will latch in 0xFF on the read.
*/
for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
spi_xfer.len = 1;
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
ret = spi_sync_locked(phy->spi_device, &m);
if (ret < 0)
for (i = 0; i < TPM_RETRY; i++) {
spi_xfer.len = 1;
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
ret = spi_sync_locked(phy->spi_device, &m);
if (ret < 0)
goto exit;
if (phy->rx_buf[0] & 0x01)
break;
}
if (i == TPM_RETRY) {
ret = -ETIMEDOUT;
goto exit;
}
if (i == TPM_RETRY) {
ret = -ETIMEDOUT;
goto exit;
}
}
spi_xfer.cs_change = 0;