4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Peter Huewe <[email protected]> commit e110cc69dc2ad679d6d478df636b99b14e6fbbc9 upstream. 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]. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <[email protected]> Signed-off-by: Peter Huewe <[email protected]> Reviewed-by: Jarkko Sakkinen <[email protected]> Tested-by: Benoit Houyere <[email protected]> Signed-off-by: Jarkko Sakkinen <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/char/tpm/tpm_tis_spi.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -86,25 +86,25 @@ static int tpm_tis_spi_transfer(struct t 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) - goto exit; - } + 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;
