On Wed, Nov 15, 2023 at 08:03:47PM +0100, Stefan Wahren wrote: > Hi Umang, > > Am 09.11.23 um 22:02 schrieb Umang Jain: > > From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> > > > > With the vc-sm-cma driver we can support zero copy of buffers between > > the kernel and VPU. Add this support to mmal-vchiq. > > > > Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> > > Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx> > > --- > > .../staging/vc04_services/vchiq-mmal/Kconfig | 1 + > > .../vc04_services/vchiq-mmal/mmal-common.h | 4 + > > .../vc04_services/vchiq-mmal/mmal-vchiq.c | 84 +++++++++++++++++-- > > .../vc04_services/vchiq-mmal/mmal-vchiq.h | 1 + > > 4 files changed, 83 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/staging/vc04_services/vchiq-mmal/Kconfig b/drivers/staging/vc04_services/vchiq-mmal/Kconfig > > index c99525a0bb45..a7c1a7bf516e 100644 > > --- a/drivers/staging/vc04_services/vchiq-mmal/Kconfig > > +++ b/drivers/staging/vc04_services/vchiq-mmal/Kconfig > > @@ -1,6 +1,7 @@ > > config BCM2835_VCHIQ_MMAL > > tristate "BCM2835 MMAL VCHIQ service" > > depends on BCM2835_VCHIQ > > + select BCM_VC_SM_CMA > > i think we need more explanation in the commit message of the relation > between these both modules. > > On the one side BCM_VC_SM_CMA should be a driver, but it's not a driver > for a specific hardware. It looks like more an extension of VCHIQ MMAL > or does other (maybe not yet imported) vc04 driver make also use of this. > > My question is: is BCM_VC_SM_CMA a real member on the VCHIQ bus and why? The vchiq_device pointer passed to the vc_sm_cma probe function is used in the driver for the sole purpose of accessing the underlying struct device, which, beside being used for dev_*() log calls, is just passed to dma_buf_attach(). It does indeed appear to be more of a service than a device. -- Regards, Laurent Pinchart
