From: Peter Huewe <peter.huewe-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
To: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Peter Huewe <peter.huewe-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
Subject: [PATCH v2 3/5] tpm_tis_spi: Check correct byte for wait state indicator
Date: Thu, 2 Mar 2017 13:03:13 +0000 [thread overview]
Message-ID: <1488459879-24349-4-git-send-email-peter.huewe@infineon.com> (raw)
In-Reply-To: <1488459879-24349-1-git-send-email-peter.huewe-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy")
Signed-off-by: Alexander Steffen <Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
Signed-off-by: Peter Huewe <peter.huewe-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Tested-by: Benoit Houyere <benoit.houyere-qxv4g6HH51o@public.gmane.org>
---
drivers/char/tpm/tpm_tis_spi.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index 639614f2d415..62f50b6c9ef6 100644
--- 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 tpm_tis_data *data, u32 addr, u16 len,
if (ret < 0)
goto exit;
- 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)
+ if ((phy->rx_buf[3] & 0x01) == 0) {
+ // handle SPI wait states
+ phy->tx_buf[0] = 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;
--
2.7.4
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next prev parent reply other threads:[~2017-03-02 13:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 13:03 [PATCH v2 0/5] Fix whole native SPI TPM driver Peter Huewe
[not found] ` <1488459879-24349-1-git-send-email-peter.huewe-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
2017-03-02 13:03 ` [PATCH v2 1/5] tpm_tis_spi: Use single function to transfer data Peter Huewe
2017-03-02 13:03 ` [PATCH v2 2/5] tpm_tis_spi: Abort transfer when too many wait states are signaled Peter Huewe
2017-03-02 13:03 ` Peter Huewe [this message]
2017-03-02 13:03 ` [PATCH v2 4/5] tpm_tis_spi: Remove limitation of transfers to MAX_SPI_FRAMESIZE bytes Peter Huewe
2017-03-02 13:03 ` [PATCH v2 5/5] tpm_tis_spi: Add small delay after last transfer Peter Huewe
2017-03-06 21:10 ` [PATCH v2 0/5] Fix whole native SPI TPM driver Jarkko Sakkinen
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