| Message ID | 1487261306-2494-4-git-send-email-peter.huewe@infineon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
That's is correct, this is a mistake on my side and never saw it :-(. I guess it was possibly leading to "waste" at least 1 wait state on some TPMs. Wouldn't it be better to merge that with #1 and update the comment consequently? On 16/02/2017 08:08, Peter Huewe wrote: > 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: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") > Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> > Signed-off-by: Peter Huewe <peter.huewe@infineon.com> > --- > drivers/char/tpm/tpm_tis_spi.c | 40 +++++++++++++++++++++------------------- > 1 file changed, 21 insertions(+), 19 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c > index d782b9974c14..16938e2253d2 100644 > --- a/drivers/char/tpm/tpm_tis_spi.c > +++ b/drivers/char/tpm/tpm_tis_spi.c > @@ -60,7 +60,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 len, > u8 *buffer, u8 direction) > { > struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); > - int ret, i; > + int ret; > struct spi_message m; > struct spi_transfer spi_xfer = { > .tx_buf = phy->tx_buf, > @@ -85,25 +85,27 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 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 > + int i; > + > + 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; ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot
Am 17. Februar 2017 06:09:30 MEZ schrieb Christophe Ricard <christophe.ricard@gmail.com>: >That's is correct, this is a mistake on my side and never saw it :-(. > >I guess it was possibly leading to "waste" at least 1 wait state on >some >TPMs. Unfortunately the 1 for indicating end of waitstates does only appear once so it actually rendered the driver non-functional - atleast with our tpms. > >Wouldn't it be better to merge that with #1 and update the comment >consequently? Yes, that's what I wanted to express in the cover letter, logically it makes sense to squash #1 and #3 - but reviewing it merged with #1 is quite hard since it "obfuscates" the problem - since too much stuff moves around. That's why I decided to split it - for easier review. Peter > > >On 16/02/2017 08:08, Peter Huewe wrote: >> 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: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") >> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> >> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> >> --- >> drivers/char/tpm/tpm_tis_spi.c | 40 >+++++++++++++++++++++------------------- >> 1 file changed, 21 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/char/tpm/tpm_tis_spi.c >b/drivers/char/tpm/tpm_tis_spi.c >> index d782b9974c14..16938e2253d2 100644 >> --- a/drivers/char/tpm/tpm_tis_spi.c >> +++ b/drivers/char/tpm/tpm_tis_spi.c >> @@ -60,7 +60,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data >*data, u32 addr, u8 len, >> u8 *buffer, u8 direction) >> { >> struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); >> - int ret, i; >> + int ret; >> struct spi_message m; >> struct spi_transfer spi_xfer = { >> .tx_buf = phy->tx_buf, >> @@ -85,25 +85,27 @@ static int tpm_tis_spi_transfer(struct >tpm_tis_data *data, u32 addr, u8 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 >> + int i; >> + >> + 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;
On Thu, Feb 16, 2017 at 04:08:24PM +0000, Peter Huewe wrote: > 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: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") > Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> > Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkien <jarkko.sakkinen@linux.intel.com> /Jarkko > --- > drivers/char/tpm/tpm_tis_spi.c | 40 +++++++++++++++++++++------------------- > 1 file changed, 21 insertions(+), 19 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c > index d782b9974c14..16938e2253d2 100644 > --- a/drivers/char/tpm/tpm_tis_spi.c > +++ b/drivers/char/tpm/tpm_tis_spi.c > @@ -60,7 +60,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 len, > u8 *buffer, u8 direction) > { > struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); > - int ret, i; > + int ret; > struct spi_message m; > struct spi_transfer spi_xfer = { > .tx_buf = phy->tx_buf, > @@ -85,25 +85,27 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 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 > + int i; > + > + 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 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index d782b9974c14..16938e2253d2 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -60,7 +60,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 len, u8 *buffer, u8 direction) { struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); - int ret, i; + int ret; struct spi_message m; struct spi_transfer spi_xfer = { .tx_buf = phy->tx_buf, @@ -85,25 +85,27 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 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 + int i; + + 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;
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: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> --- drivers/char/tpm/tpm_tis_spi.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-)