habanalabs: add command buffer module

This patch adds the command buffer (CB) module, which allows the user to
create and destroy CBs and to map them to the user's process
address-space.

A command buffer is a memory blocks that reside in DMA-able address-space
and is physically contiguous so it can be accessed by the device without
MMU translation. The command buffer memory is allocated using the
coherent DMA API.

When creating a new CB, the IOCTL returns a handle of it, and the
user-space process needs to use that handle to mmap the buffer to get a VA
in the user's address-space.

Before destroying (freeing) a CB, the user must unmap the CB's VA using the
CB handle.

Each CB has a reference counter, which tracks its usage in command
submissions and also its mmaps (only a single mmap is allowed).

The driver maintains a pool of pre-allocated CBs in order to reduce
latency during command submissions. In case the pool is empty, the driver
will go to the slow-path of allocating a new CB, i.e. calling
dma_alloc_coherent.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/misc/habanalabs/Makefile b/drivers/misc/habanalabs/Makefile
index 3ffbadc2ca01..2530c9b78ca4 100644
--- a/drivers/misc/habanalabs/Makefile
+++ b/drivers/misc/habanalabs/Makefile
@@ -4,7 +4,8 @@
 
 obj-m	:= habanalabs.o
 
-habanalabs-y := habanalabs_drv.o device.o context.o asid.o
+habanalabs-y := habanalabs_drv.o device.o context.o asid.o habanalabs_ioctl.o \
+		command_buffer.o
 
 include $(src)/goya/Makefile
 habanalabs-y += $(HL_GOYA_FILES)