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Commit e110cc69 authored by Peter Huewe's avatar Peter Huewe Committed by Jarkko Sakkinen
Browse files

tpm_tis_spi: Check correct byte for wait state indicator 



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: 0edbfea5 ("tpm/tpm_tis_spi: Add support for spi phy")
Signed-off-by: default avatarAlexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: default avatarPeter Huewe <peter.huewe@infineon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarBenoit Houyere <benoit.houyere@st.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 975094dd

drivers/char/tpm/tpm_tis_spi.c

+18 −18
Original line number Diff line number Diff line
@@ -85,26 +85,26 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, 
	if (ret < 0)

		goto exit;



	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++) {

		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;

		}

	}



	spi_xfer.cs_change = 0;

	spi_xfer.len = len;