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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Alexander Steffen <Alexander.Steffen@infineon.com>
Cc: tpmdd-devel@lists.sourceforge.net, benoit.houyere@st.com,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory
Date: Fri, 8 Sep 2017 15:11:22 +0300	[thread overview]
Message-ID: <20170908121122.2frkkcoidoc3u7g2@linux.intel.com> (raw)
In-Reply-To: <20170906125458.ueqpmokh7bg64olc@linux.intel.com>

On Wed, Sep 06, 2017 at 03:54:58PM +0300, Jarkko Sakkinen wrote:
> On Thu, Aug 31, 2017 at 06:58:17PM +0200, Alexander Steffen wrote:
> > The documentation says that DMA-safe memory is required for SPI transfers.
> > The I/O buffers passed in by the caller can be allocated anywhere,
> > including on the stack, which is not DMA-safe. So the data needs to be
> > copied to separate, DMA-safe buffers.
> > 
> > We did not see any DMA-related issues on our test systems, even without
> > DMA-safe buffers. But this might simply be due to the fact that the SPI
> > transfer size is rather small, so our systems do not bother to set up DMA
> > transfers. Other systems might do so.
> > 
> > v2:
> > - Updated commit message with more explanations.
> > 
> > v3:
> > - Split into two patches, one for making the buffers DMA-safe and another
> >   for using only a single buffer.
> > 
> > Alexander Steffen (2):
> >   tpm_tis_spi: Use DMA-safe memory for SPI transfers
> >   tpm_tis_spi: Use a single buffer for SPI transfers
> > 
> >  drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++--------------
> >  1 file changed, 18 insertions(+), 14 deletions(-)
> > 
> > -- 
> > 2.7.4
> > 
> 
> Applied to my bleeding edge master brach for more convenient testing.
> Have not yet applied to my next branch.
> 
> /Jarkko

Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

My XP13 happened to have suitable TPM.

/Jarkko

      reply	other threads:[~2017-09-08 12:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31 16:58 Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 2/2] tpm_tis_spi: Use a single buffer " Alexander Steffen
2017-09-02 10:54 ` [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Jarkko Sakkinen
2017-09-06 12:54 ` Jarkko Sakkinen
2017-09-08 12:11   ` Jarkko Sakkinen [this message]

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