From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44636 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765021AbdEWULH (ORCPT ); Tue, 23 May 2017 16:11:07 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Steffen , Peter Huewe , Jarkko Sakkinen , Benoit Houyere Subject: [PATCH 4.11 012/197] tpm_tis_spi: Check correct byte for wait state indicator Date: Tue, 23 May 2017 22:06:13 +0200 Message-Id: <20170523200823.021795669@linuxfoundation.org> In-Reply-To: <20170523200821.666872592@linuxfoundation.org> References: <20170523200821.666872592@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Huewe 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 Signed-off-by: Peter Huewe Reviewed-by: Jarkko Sakkinen Tested-by: Benoit Houyere Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman --- 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 @@ -85,25 +85,25 @@ 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;