Messages in this thread | | | Date | Fri, 8 Sep 2017 15:11:22 +0300 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory |
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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
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