[PATCH v6 2/2] dmaengine: Add Xilinx AXI Central Direct Memory Access Engine driver support

On Mon, Sep 07, 2015 at 06:03:18PM +0530, Kedareswara rao Appana wrote:

+static struct xilinx_cdma_tx_segment *
+xilinx_cdma_alloc_tx_segment(struct xilinx_cdma_chan *chan)
+{
+	struct xilinx_cdma_tx_segment *segment;
+	dma_addr_t phys;
+
+	segment = dma_pool_alloc(chan->desc_pool, GFP_ATOMIC, &phys);
+	if (!segment)
+		return NULL;
+
+	memset(segment, 0, sizeof(*segment));

dma_pool_zalloc() pls

+static void xilinx_cdma_start_transfer(struct xilinx_cdma_chan *chan)
+{
+	struct xilinx_cdma_tx_descriptor *head_desc, *tail_desc;
+	struct xilinx_cdma_tx_segment *tail_segment;
+	u32 ctrl_reg = cdma_read(chan, XILINX_CDMA_CONTROL_OFFSET);
+
+	if (chan->err)
+		return;
+
+	if (list_empty(&chan->pending_list))
+		return;
+
+	if (!chan->idle)
+		return;

this and err case can be combined !

+static struct dma_async_tx_descriptor *
+xilinx_cdma_prep_memcpy(struct dma_chan *dchan, dma_addr_t dma_dst,
+			dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+	struct xilinx_cdma_chan *chan = to_xilinx_chan(dchan);
+	struct xilinx_cdma_desc_hw *hw;
+	struct xilinx_cdma_tx_descriptor *desc;
+	struct xilinx_cdma_tx_segment *segment, *prev;
+
+	if (!len || len > XILINX_CDMA_MAX_TRANS_LEN)
+		return NULL;
+
+	desc = xilinx_cdma_alloc_tx_descriptor(chan);
+	if (!desc)
+		return NULL;
+
+	dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
+	desc->async_tx.tx_submit = xilinx_cdma_tx_submit;
+	async_tx_ack(&desc->async_tx);

Why do you need this ?

+static int xilinx_cdma_terminate_all(struct dma_chan *dchan)
+{
+	struct xilinx_cdma_chan *chan = to_xilinx_chan(dchan);
+
+	/* Reset the channel */
+	xilinx_cdma_chan_reset(chan);

what about the irqs that are already fired/tasklets scheduled?

+
+	/* Remove and free all of the descriptors in the lists */
+	xilinx_cdma_free_descriptors(chan);
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Probe and remove
+ */
+
+/**
+ * xilinx_cdma_free_channel - Channel remove function
+ * @chan: Driver specific cdma channel
+ */
+static void xilinx_cdma_free_channel(struct xilinx_cdma_chan *chan)

Free channel is a bad name, as we alloc and free channels from dmaengine API

-- 
~Vinod