The XDMAC supports memset transfers, both over contiguous areas, and over
discontiguous areas through a LLI.
The current memset operation only supports contiguous memset for now, add some
support for it. Scatter-gathered memset will come eventually.
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
drivers/dma/at_xdmac.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index cbeadeeed9c0..18d0484c092b 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -881,6 +881,93 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
return &first->tx_dma_desc;
}
+static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan,
+ struct at_xdmac_chan *atchan,
+ dma_addr_t dst_addr,
+ size_t len,
+ int value)
+{
+ struct at_xdmac_desc *desc;
+ unsigned long flags;
+ size_t ublen;
+ u32 dwidth;
+ /*
+ * WARNING: The channel configuration is set here since there is no
+ * dmaengine_slave_config call in this case. Moreover we don't know the
+ * direction, it involves we can't dynamically set the source and dest
+ * interface so we have to use the same one. Only interface 0 allows EBI
+ * access. Hopefully we can access DDR through both ports (at least on
+ * SAMA5D4x), so we can use the same interface for source and dest,
+ * that solves the fact we don't know the direction.
+ */
+ u32 chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM
+ | AT_XDMAC_CC_SAM_INCREMENTED_AM
+ | AT_XDMAC_CC_DIF(0)
+ | AT_XDMAC_CC_SIF(0)
+ | AT_XDMAC_CC_MBSIZE_SIXTEEN
+ | AT_XDMAC_CC_MEMSET_HW_MODE
+ | AT_XDMAC_CC_TYPE_MEM_TRAN;
+
+ dwidth = at_xdmac_align_width(chan, dst_addr);
+
+ if (len >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
+ dev_err(chan2dev(chan),
+ "%s: Transfer too large, aborting...\n",
+ __func__);
+ return NULL;
+ }
+
+ spin_lock_irqsave(&atchan->lock, flags);
+ desc = at_xdmac_get_desc(atchan);
+ spin_unlock_irqrestore(&atchan->lock, flags);
+ if (!desc) {
+ dev_err(chan2dev(chan), "can't get descriptor\n");
+ return NULL;
+ }
+
+ chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
+
+ ublen = len >> dwidth;
+
+ desc->lld.mbr_da = dst_addr;
+ desc->lld.mbr_ds = value;
+ desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
+ | AT_XDMAC_MBR_UBC_NDEN
+ | AT_XDMAC_MBR_UBC_NSEN
+ | ublen;
+ desc->lld.mbr_cfg = chan_cc;
+
+ dev_dbg(chan2dev(chan),
+ "%s: lld: mbr_da=0x%08x, mbr_ds=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
+ __func__, desc->lld.mbr_da, desc->lld.mbr_ds, desc->lld.mbr_ubc,
+ desc->lld.mbr_cfg);
+
+ return desc;
+}
+
+struct dma_async_tx_descriptor *
+at_xdmac_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
+ size_t len, unsigned long flags)
+{
+ struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
+ struct at_xdmac_desc *desc;
+
+ dev_dbg(chan2dev(chan), "%s: dest=0x%08x, len=%d, pattern=0x%x, flags=0x%lx\n",
+ __func__, dest, len, value, flags);
+
+ if (unlikely(!len))
+ return NULL;
+
+ desc = at_xdmac_memset_create_desc(chan, atchan, dest, len, value);
+ list_add_tail(&desc->desc_node, &desc->descs_list);
+
+ desc->tx_dma_desc.cookie = -EBUSY;
+ desc->tx_dma_desc.flags = flags;
+ desc->xfer_size = len;
+
+ return &desc->tx_dma_desc;
+}
+
static enum dma_status
at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
struct dma_tx_state *txstate)
@@ -1406,6 +1493,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
+ dma_cap_set(DMA_MEMSET, atxdmac->dma.cap_mask);
dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
/*
* Without DMA_PRIVATE the driver is not able to allocate more than
@@ -1419,6 +1507,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
atxdmac->dma.device_issue_pending = at_xdmac_issue_pending;
atxdmac->dma.device_prep_dma_cyclic = at_xdmac_prep_dma_cyclic;
atxdmac->dma.device_prep_dma_memcpy = at_xdmac_prep_dma_memcpy;
+ atxdmac->dma.device_prep_dma_memset = at_xdmac_prep_dma_memset;
atxdmac->dma.device_prep_slave_sg = at_xdmac_prep_slave_sg;
atxdmac->dma.device_config = at_xdmac_device_config;
atxdmac->dma.device_pause = at_xdmac_device_pause;
--
2.4.1
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