iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tpm_tis_spi: Check correct byte for wait state indicator

Browse Source 
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: 0edbfea537d1 ("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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/char/tpm/tpm_tis_spi.c
View File

@ -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;