4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Huewe <peter.huewe@xxxxxxxxxxxx>
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 <Alexander.Steffen@xxxxxxxxxxxx>
Signed-off-by: Peter Huewe <peter.huewe@xxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Tested-by: Benoit Houyere <benoit.houyere@xxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;