summaryrefslogtreecommitdiffstats
path: root/drivers/dma/edma.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/dma/edma.c')
-rw-r--r--drivers/dma/edma.c198
1 files changed, 126 insertions, 72 deletions
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 098a8da450f0..e47e3c9e37b2 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -250,6 +250,117 @@ static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
return ret;
}
+/*
+ * A PaRAM set configuration abstraction used by other modes
+ * @chan: Channel who's PaRAM set we're configuring
+ * @pset: PaRAM set to initialize and setup.
+ * @src_addr: Source address of the DMA
+ * @dst_addr: Destination address of the DMA
+ * @burst: In units of dev_width, how much to send
+ * @dev_width: How much is the dev_width
+ * @dma_length: Total length of the DMA transfer
+ * @direction: Direction of the transfer
+ */
+static int edma_config_pset(struct dma_chan *chan, struct edmacc_param *pset,
+ dma_addr_t src_addr, dma_addr_t dst_addr, u32 burst,
+ enum dma_slave_buswidth dev_width, unsigned int dma_length,
+ enum dma_transfer_direction direction)
+{
+ struct edma_chan *echan = to_edma_chan(chan);
+ struct device *dev = chan->device->dev;
+ int acnt, bcnt, ccnt, cidx;
+ int src_bidx, dst_bidx, src_cidx, dst_cidx;
+ int absync;
+
+ acnt = dev_width;
+ /*
+ * If the maxburst is equal to the fifo width, use
+ * A-synced transfers. This allows for large contiguous
+ * buffer transfers using only one PaRAM set.
+ */
+ if (burst == 1) {
+ /*
+ * For the A-sync case, bcnt and ccnt are the remainder
+ * and quotient respectively of the division of:
+ * (dma_length / acnt) by (SZ_64K -1). This is so
+ * that in case bcnt over flows, we have ccnt to use.
+ * Note: In A-sync tranfer only, bcntrld is used, but it
+ * only applies for sg_dma_len(sg) >= SZ_64K.
+ * In this case, the best way adopted is- bccnt for the
+ * first frame will be the remainder below. Then for
+ * every successive frame, bcnt will be SZ_64K-1. This
+ * is assured as bcntrld = 0xffff in end of function.
+ */
+ absync = false;
+ ccnt = dma_length / acnt / (SZ_64K - 1);
+ bcnt = dma_length / acnt - ccnt * (SZ_64K - 1);
+ /*
+ * If bcnt is non-zero, we have a remainder and hence an
+ * extra frame to transfer, so increment ccnt.
+ */
+ if (bcnt)
+ ccnt++;
+ else
+ bcnt = SZ_64K - 1;
+ cidx = acnt;
+ } else {
+ /*
+ * If maxburst is greater than the fifo address_width,
+ * use AB-synced transfers where A count is the fifo
+ * address_width and B count is the maxburst. In this
+ * case, we are limited to transfers of C count frames
+ * of (address_width * maxburst) where C count is limited
+ * to SZ_64K-1. This places an upper bound on the length
+ * of an SG segment that can be handled.
+ */
+ absync = true;
+ bcnt = burst;
+ ccnt = dma_length / (acnt * bcnt);
+ if (ccnt > (SZ_64K - 1)) {
+ dev_err(dev, "Exceeded max SG segment size\n");
+ return -EINVAL;
+ }
+ cidx = acnt * bcnt;
+ }
+
+ if (direction == DMA_MEM_TO_DEV) {
+ src_bidx = acnt;
+ src_cidx = cidx;
+ dst_bidx = 0;
+ dst_cidx = 0;
+ } else if (direction == DMA_DEV_TO_MEM) {
+ src_bidx = 0;
+ src_cidx = 0;
+ dst_bidx = acnt;
+ dst_cidx = cidx;
+ } else {
+ dev_err(dev, "%s: direction not implemented yet\n", __func__);
+ return -EINVAL;
+ }
+
+ pset->opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
+ /* Configure A or AB synchronized transfers */
+ if (absync)
+ pset->opt |= SYNCDIM;
+
+ pset->src = src_addr;
+ pset->dst = dst_addr;
+
+ pset->src_dst_bidx = (dst_bidx << 16) | src_bidx;
+ pset->src_dst_cidx = (dst_cidx << 16) | src_cidx;
+
+ pset->a_b_cnt = bcnt << 16 | acnt;
+ pset->ccnt = ccnt;
+ /*
+ * Only time when (bcntrld) auto reload is required is for
+ * A-sync case, and in this case, a requirement of reload value
+ * of SZ_64K-1 only is assured. 'link' is initially set to NULL
+ * and then later will be populated by edma_execute.
+ */
+ pset->link_bcntrld = 0xffffffff;
+ return absync;
+}
+
static struct dma_async_tx_descriptor *edma_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
@@ -258,23 +369,21 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
struct edma_chan *echan = to_edma_chan(chan);
struct device *dev = chan->device->dev;
struct edma_desc *edesc;
- dma_addr_t dev_addr;
+ dma_addr_t src_addr = 0, dst_addr = 0;
enum dma_slave_buswidth dev_width;
u32 burst;
struct scatterlist *sg;
- int acnt, bcnt, ccnt, src, dst, cidx;
- int src_bidx, dst_bidx, src_cidx, dst_cidx;
- int i, nslots;
+ int i, nslots, ret;
if (unlikely(!echan || !sgl || !sg_len))
return NULL;
if (direction == DMA_DEV_TO_MEM) {
- dev_addr = echan->cfg.src_addr;
+ src_addr = echan->cfg.src_addr;
dev_width = echan->cfg.src_addr_width;
burst = echan->cfg.src_maxburst;
} else if (direction == DMA_MEM_TO_DEV) {
- dev_addr = echan->cfg.dst_addr;
+ dst_addr = echan->cfg.dst_addr;
dev_width = echan->cfg.dst_addr_width;
burst = echan->cfg.dst_maxburst;
} else {
@@ -313,63 +422,19 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
/* Configure PaRAM sets for each SG */
for_each_sg(sgl, sg, sg_len, i) {
+ /* Get address for each SG */
+ if (direction == DMA_DEV_TO_MEM)
+ dst_addr = sg_dma_address(sg);
+ else
+ src_addr = sg_dma_address(sg);
- acnt = dev_width;
-
- /*
- * If the maxburst is equal to the fifo width, use
- * A-synced transfers. This allows for large contiguous
- * buffer transfers using only one PaRAM set.
- */
- if (burst == 1) {
- edesc->absync = false;
- ccnt = sg_dma_len(sg) / acnt / (SZ_64K - 1);
- bcnt = sg_dma_len(sg) / acnt - ccnt * (SZ_64K - 1);
- if (bcnt)
- ccnt++;
- else
- bcnt = SZ_64K - 1;
- cidx = acnt;
- /*
- * If maxburst is greater than the fifo address_width,
- * use AB-synced transfers where A count is the fifo
- * address_width and B count is the maxburst. In this
- * case, we are limited to transfers of C count frames
- * of (address_width * maxburst) where C count is limited
- * to SZ_64K-1. This places an upper bound on the length
- * of an SG segment that can be handled.
- */
- } else {
- edesc->absync = true;
- bcnt = burst;
- ccnt = sg_dma_len(sg) / (acnt * bcnt);
- if (ccnt > (SZ_64K - 1)) {
- dev_err(dev, "Exceeded max SG segment size\n");
- return NULL;
- }
- cidx = acnt * bcnt;
- }
-
- if (direction == DMA_MEM_TO_DEV) {
- src = sg_dma_address(sg);
- dst = dev_addr;
- src_bidx = acnt;
- src_cidx = cidx;
- dst_bidx = 0;
- dst_cidx = 0;
- } else {
- src = dev_addr;
- dst = sg_dma_address(sg);
- src_bidx = 0;
- src_cidx = 0;
- dst_bidx = acnt;
- dst_cidx = cidx;
- }
+ ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
+ dst_addr, burst, dev_width,
+ sg_dma_len(sg), direction);
+ if (ret < 0)
+ return NULL;
- edesc->pset[i].opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
- /* Configure A or AB synchronized transfers */
- if (edesc->absync)
- edesc->pset[i].opt |= SYNCDIM;
+ edesc->absync = ret;
/* If this is the last in a current SG set of transactions,
enable interrupts so that next set is processed */
@@ -379,17 +444,6 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
/* If this is the last set, enable completion interrupt flag */
if (i == sg_len - 1)
edesc->pset[i].opt |= TCINTEN;
-
- edesc->pset[i].src = src;
- edesc->pset[i].dst = dst;
-
- edesc->pset[i].src_dst_bidx = (dst_bidx << 16) | src_bidx;
- edesc->pset[i].src_dst_cidx = (dst_cidx << 16) | src_cidx;
-
- edesc->pset[i].a_b_cnt = bcnt << 16 | acnt;
- edesc->pset[i].ccnt = ccnt;
- edesc->pset[i].link_bcntrld = 0xffffffff;
-
}
return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-15 03:04:56 +0000