dmaengine: nbpfaxi: Provide some missing attribute docs and split out slave info

Fixes the following W=1 kernel build warning(s):

 drivers/dma/nbpfaxi.c:157: warning: Function parameter or member 'chan' not described in 'nbpf_desc'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'tasklet' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_src_addr' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_src_width' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_src_burst' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_dst_addr' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_dst_width' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'slave_dst_burst' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'running' not described in 'nbpf_channel'
 drivers/dma/nbpfaxi.c:220: warning: Function parameter or member 'paused' not described in 'nbpf_channel'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20200714111546.1755231-14-lee.jones@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/nbpfaxi.c

@@ -144,6 +144,7 @@ struct nbpf_link_desc {
  * @async_tx:	dmaengine object
  * @user_wait:	waiting for a user ack
  * @length:	total transfer length
+ * @chan:	associated DMAC channel
  * @sg:		list of hardware descriptors, represented by struct nbpf_link_desc
  * @node:	member in channel descriptor lists
  */
@@ -174,13 +175,17 @@ struct nbpf_desc_page {
 /**
  * struct nbpf_channel - one DMAC channel
  * @dma_chan:	standard dmaengine channel object
+ * @tasklet:	channel specific tasklet used for callbacks
  * @base:	register address base
  * @nbpf:	DMAC
  * @name:	IRQ name
  * @irq:	IRQ number
- * @slave_addr:	address for slave DMA
- * @slave_width:slave data size in bytes
- * @slave_burst:maximum slave burst size in bytes
+ * @slave_src_addr:	source address for slave DMA
+ * @slave_src_width:	source slave data size in bytes
+ * @slave_src_burst:	maximum source slave burst size in bytes
+ * @slave_dst_addr:	destination address for slave DMA
+ * @slave_dst_width:	destination slave data size in bytes
+ * @slave_dst_burst:	maximum destination slave burst size in bytes
  * @terminal:	DMA terminal, assigned to this channel
  * @dmarq_cfg:	DMA request line configuration - high / low, edge / level for NBPF_CHAN_CFG
  * @flags:	configuration flags from DT
@@ -191,6 +196,8 @@ struct nbpf_desc_page {
  * @active:	list of descriptors, scheduled for processing
  * @done:	list of completed descriptors, waiting post-processing
  * @desc_page:	list of additionally allocated descriptor pages - if any
+ * @running:	linked descriptor of running transaction
+ * @paused:	are translations on this channel paused?
  */
 struct nbpf_channel {
 	struct dma_chan dma_chan;