On 28/02/2024 06:21, Vishal Sagar wrote:
From: Rohit Visavalia <rohit.visavalia@xxxxxxxxxx>
This patch adds support for DPDMA cyclic dma mode,
DMA cyclic transfers are required by audio streaming.
Signed-off-by: Rohit Visavalia <rohit.visavalia@xxxxxxx>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
Signed-off-by: Vishal Sagar <vishal.sagar@xxxxxxx>
---
drivers/dma/xilinx/xilinx_dpdma.c | 97 +++++++++++++++++++++++++++++++
1 file changed, 97 insertions(+)
diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index 28d9af8f00f0..88ad2f35538a 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -669,6 +669,84 @@ static void xilinx_dpdma_chan_free_tx_desc(struct virt_dma_desc *vdesc)
kfree(desc);
}
+/**
+ * xilinx_dpdma_chan_prep_cyclic - Prepare a cyclic dma descriptor
+ * @chan: DPDMA channel
+ * @buf_addr: buffer address
+ * @buf_len: buffer length
+ * @period_len: number of periods
+ * @flags: tx flags argument passed in to prepare function
+ *
+ * Prepare a tx descriptor incudling internal software/hardware descriptors
+ * for the given cyclic transaction.
+ *
+ * Return: A dma async tx descriptor on success, or NULL.
+ */
+static struct dma_async_tx_descriptor *
+xilinx_dpdma_chan_prep_cyclic(struct xilinx_dpdma_chan *chan,
+ dma_addr_t buf_addr, size_t buf_len,
+ size_t period_len, unsigned long flags)
+{
+ struct xilinx_dpdma_tx_desc *tx_desc;
+ struct xilinx_dpdma_sw_desc *sw_desc, *last = NULL;
+ unsigned int periods = buf_len / period_len;
+ unsigned int i;
+
+ tx_desc = xilinx_dpdma_chan_alloc_tx_desc(chan);
+ if (!tx_desc)
+ return (void *)tx_desc;
Just return NULL here?
+
+ for (i = 0; i < periods; i++) {
+ struct xilinx_dpdma_hw_desc *hw_desc;
+
+ if (!IS_ALIGNED(buf_addr, XILINX_DPDMA_ALIGN_BYTES)) {
+ dev_err(chan->xdev->dev,
+ "buffer should be aligned at %d B\n",
+ XILINX_DPDMA_ALIGN_BYTES);
+ goto error;
+ }
+
+ sw_desc = xilinx_dpdma_chan_alloc_sw_desc(chan);
+ if (!sw_desc)
+ goto error;
+
+ xilinx_dpdma_sw_desc_set_dma_addrs(chan->xdev, sw_desc, last,
+ &buf_addr, 1);
+ hw_desc = &sw_desc->hw;
+ hw_desc->xfer_size = period_len;
+ hw_desc->hsize_stride =
+ FIELD_PREP(XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_MASK,
+ period_len) |
+ FIELD_PREP(XILINX_DPDMA_DESC_HSIZE_STRIDE_STRIDE_MASK,
+ period_len);
+ hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_PREEMBLE;
+ hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE;
+ hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR;
You could:
hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_PREEMBLE |
XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE |
XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR;
Although... Shouldn't control always be 0 here, so you can just
hw_desc->control = ...;
+
+ list_add_tail(&sw_desc->node, &tx_desc->descriptors);
+
+ buf_addr += period_len;
+ last = sw_desc;
+ }
+
+ sw_desc = list_first_entry(&tx_desc->descriptors,
+ struct xilinx_dpdma_sw_desc, node);
+ last->hw.next_desc = lower_32_bits(sw_desc->dma_addr);
+ if (chan->xdev->ext_addr)
+ last->hw.addr_ext |=
+ FIELD_PREP(XILINX_DPDMA_DESC_ADDR_EXT_NEXT_ADDR_MASK,
+ upper_32_bits(sw_desc->dma_addr));
+
+ last->hw.control |= XILINX_DPDMA_DESC_CONTROL_LAST_OF_FRAME;
+
+ return vchan_tx_prep(&chan->vchan, &tx_desc->vdesc, flags);
+
+error:
+ xilinx_dpdma_chan_free_tx_desc(&tx_desc->vdesc);
+
+ return NULL;
+}
+
/**
* xilinx_dpdma_chan_prep_interleaved_dma - Prepare an interleaved dma
* descriptor
@@ -1190,6 +1268,23 @@ static void xilinx_dpdma_chan_handle_err(struct xilinx_dpdma_chan *chan)
/* -----------------------------------------------------------------------------
* DMA Engine Operations
*/
+static struct dma_async_tx_descriptor *
+xilinx_dpdma_prep_dma_cyclic(struct dma_chan *dchan, dma_addr_t buf_addr,
+ size_t buf_len, size_t period_len,
+ enum dma_transfer_direction direction,
+ unsigned long flags)
+{
+ struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
+
+ if (direction != DMA_MEM_TO_DEV)
+ return NULL;
+
+ if (buf_len % period_len)
+ return NULL;
+
+ return xilinx_dpdma_chan_prep_cyclic(chan, buf_addr, buf_len,
+ period_len, flags);
The parameters should be aligned above.
+}
static struct dma_async_tx_descriptor *
xilinx_dpdma_prep_interleaved_dma(struct dma_chan *dchan,
@@ -1673,6 +1768,7 @@ static int xilinx_dpdma_probe(struct platform_device *pdev)
dma_cap_set(DMA_SLAVE, ddev->cap_mask);
dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
+ dma_cap_set(DMA_CYCLIC, ddev->cap_mask);
dma_cap_set(DMA_INTERLEAVE, ddev->cap_mask);
dma_cap_set(DMA_REPEAT, ddev->cap_mask);
dma_cap_set(DMA_LOAD_EOT, ddev->cap_mask);
@@ -1680,6 +1776,7 @@ static int xilinx_dpdma_probe(struct platform_device *pdev)
ddev->device_alloc_chan_resources = xilinx_dpdma_alloc_chan_resources;
ddev->device_free_chan_resources = xilinx_dpdma_free_chan_resources;
+ ddev->device_prep_dma_cyclic = xilinx_dpdma_prep_dma_cyclic;
ddev->device_prep_interleaved_dma = xilinx_dpdma_prep_interleaved_dma;
/* TODO: Can we achieve better granularity ? */
ddev->device_tx_status = dma_cookie_status;
While I'm not too familiar with dma engines, this looks fine to me. So,
other than the few cosmetics comments:
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Tomi
