On Fri, Sep 20, 2019 at 11:32:38AM -0700, Stephen Boyd wrote: > From: Andrey Pronin <apronin@xxxxxxxxxxxx> > > Add TPM2.0 PTP FIFO compatible SPI interface for chips with Cr50 > firmware. The firmware running on the currently supported H1 Secure > Microcontroller requires a special driver to handle its specifics: > > - need to ensure a certain delay between SPI transactions, or else > the chip may miss some part of the next transaction > - if there is no SPI activity for some time, it may go to sleep, > and needs to be waken up before sending further commands > - access to vendor-specific registers > > Cr50 firmware has a requirement to wait for the TPM to wakeup before > sending commands over the SPI bus. Otherwise, the firmware could be in > deep sleep and not respond. The method to wait for the device to wakeup > is slightly different than the usual flow control mechanism described in > the TCG SPI spec. Add a completion to tpm_tis_spi_transfer() before we > start a SPI transfer so we can keep track of the last time the TPM > driver accessed the SPI bus to support the flow control mechanism. > > Split the cr50 logic off into a different file to keep it out of the > normal code flow of the existing SPI driver while making it all part of > the same module when the code is optionally compiled into the same > module. Export a new function, tpm_tis_spi_init(), and the associated > read/write/transfer APIs so that we can do this. Make the cr50 code wrap > the tpm_tis_spi_phy struct with its own struct to override the behavior > of tpm_tis_spi_transfer() by supplying a custom flow control hook. This > shares the most code between the core driver and the cr50 support > without combining everything into the core driver or exporting module > symbols. > > Signed-off-by: Andrey Pronin <apronin@xxxxxxxxxxxx> > Cc: Andrey Pronin <apronin@xxxxxxxxxxxx> > Cc: Duncan Laurie <dlaurie@xxxxxxxxxxxx> > Cc: Jason Gunthorpe <jgg@xxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Guenter Roeck <groeck@xxxxxxxxxxxx> > Cc: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx> > Cc: Heiko Stuebner <heiko@xxxxxxxxx> First, I apologize for such a long latency (two weeks). I think this looks legit now. Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> /Jarkko
