Hi Eddie, On Sat, 23 Sep 2017, at 06:35, Eddie James wrote: > From: "Edward A. James" <[email protected]> > > IBM POWER9 processors contain some embedded hardware and software bits > collectively referred to as the self boot engine (SBE). One role of > the SBE is to act as a proxy that provides access to the registers of > the POWER chip from other (embedded) systems. > > The POWER9 chip contains a hardware frontend for communicating with > the SBE from remote systems called the SBEFIFO. The SBEFIFO logic > is contained within an FSI CFAM and as such the driver implements an > FSI bus device. > > The SBE expects to communicate using a defined wire protocol; however, > the driver knows nothing of the protocol and only provides raw access > to the fifo device to userspace applications wishing to communicate with > the SBE using the wire protocol. > > The SBEFIFO consists of two hardware fifos. The upstream fifo is used > by the driver to transfer data to the SBE on the POWER chip, from the > system hosting the driver. The downstream fifo is used by the driver to > transfer data from the SBE on the power chip to the system hosting the > driver. > > Signed-off-by: Brad Bishop <[email protected]> > Signed-off-by: Edward A. James <[email protected]> > --- > drivers/fsi/Kconfig | 7 + > drivers/fsi/Makefile | 1 + > drivers/fsi/fsi-sbefifo.c | 861 > ++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 869 insertions(+) > create mode 100644 drivers/fsi/fsi-sbefifo.c
My general feeling is the implementation is too complex by half for what is required. I may be wrong and the solution genuinely needs the complexity, but to test that I'll cook up a counter-proposal patch and we can debate that. I'm away for the next few days, but I hope to send something by the end of next week. Cheers, Andrew
