[media] st-hva: multi-format video encoder V4L2 driver

This patch adds V4L2 HVA (Hardware Video Accelerator) video encoder
driver for STMicroelectronics SoC. It uses the V4L2 mem2mem framework.

This patch only contains the core parts of the driver:
- the V4L2 interface with the userland (hva-v4l2.c)
- the hardware services (hva-hw.c)
- the memory management utilities (hva-mem.c)

This patch doesn't include the support of specific codec (e.g. H.264)
video encoding: this support is part of subsequent patches.

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Signed-off-by: Jean-Christophe Trotin <jean-christophe.trotin@st.com>
Acked-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/Kconfig

@@ -257,6 +257,21 @@ config VIDEO_STI_BDISP
 	help
 	  This v4l2 mem2mem driver is a 2D blitter for STMicroelectronics SoC.
 
+config VIDEO_STI_HVA
+	tristate "STMicroelectronics HVA multi-format video encoder V4L2 driver"
+	depends on VIDEO_DEV && VIDEO_V4L2
+	depends on HAS_DMA
+	depends on ARCH_STI || COMPILE_TEST
+	select VIDEOBUF2_DMA_CONTIG
+	select V4L2_MEM2MEM_DEV
+	help
+	  This V4L2 driver enables HVA (Hardware Video Accelerator) multi-format
+	  video encoder of STMicroelectronics SoC, allowing hardware encoding of
+	  raw uncompressed formats in various compressed video bitstreams format.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called st-hva.
+
 config VIDEO_SH_VEU
 	tristate "SuperH VEU mem2mem video processing driver"
 	depends on VIDEO_DEV && VIDEO_V4L2 && HAS_DMA