1 files changed, 151 insertions, 8 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 183ec85cb6ca..592f3be8b435 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -60,6 +60,7 @@
 struct edma_desc {
         struct virt_dma_desc            vdesc;
         struct list_head                node;
+        int                             cyclic;
         int                             absync;
         int                             pset_nr;
         int                             processed;
@@ -173,8 +174,13 @@ static void edma_execute(struct edma_chan *echan)
          * then setup a link to the dummy slot, this results in all future
          * events being absorbed and that's OK because we're done
          */
-        if (edesc->processed == edesc->pset_nr)
-                edma_link(echan->slot[nslots-1], echan->ecc->dummy_slot);
+        if (edesc->processed == edesc->pset_nr) {
+                if (edesc->cyclic)
+                        edma_link(echan->slot[nslots-1], echan->slot[1]);
+                else
+                        edma_link(echan->slot[nslots-1],
+                                  echan->ecc->dummy_slot);
+        }
 
         edma_resume(echan->ch_num);
 
@@ -459,6 +465,138 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
         return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
 }
 
+static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
+        struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+        size_t period_len, enum dma_transfer_direction direction,
+        unsigned long tx_flags, void *context)
+{
+        struct edma_chan *echan = to_edma_chan(chan);
+        struct device *dev = chan->device->dev;
+        struct edma_desc *edesc;
+        dma_addr_t src_addr, dst_addr;
+        enum dma_slave_buswidth dev_width;
+        u32 burst;
+        int i, ret, nslots;
+
+        if (unlikely(!echan || !buf_len || !period_len))
+                return NULL;
+
+        if (direction == DMA_DEV_TO_MEM) {
+                src_addr = echan->cfg.src_addr;
+                dst_addr = buf_addr;
+                dev_width = echan->cfg.src_addr_width;
+                burst = echan->cfg.src_maxburst;
+        } else if (direction == DMA_MEM_TO_DEV) {
+                src_addr = buf_addr;
+                dst_addr = echan->cfg.dst_addr;
+                dev_width = echan->cfg.dst_addr_width;
+                burst = echan->cfg.dst_maxburst;
+        } else {
+                dev_err(dev, "%s: bad direction?\n", __func__);
+                return NULL;
+        }
+
+        if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+                dev_err(dev, "Undefined slave buswidth\n");
+                return NULL;
+        }
+
+        if (unlikely(buf_len % period_len)) {
+                dev_err(dev, "Period should be multiple of Buffer length\n");
+                return NULL;
+        }
+
+        nslots = (buf_len / period_len) + 1;
+
+        /*
+         * Cyclic DMA users such as audio cannot tolerate delays introduced
+         * by cases where the number of periods is more than the maximum
+         * number of SGs the EDMA driver can handle at a time. For DMA types
+         * such as Slave SGs, such delays are tolerable and synchronized,
+         * but the synchronization is difficult to achieve with Cyclic and
+         * cannot be guaranteed, so we error out early.
+         */
+        if (nslots > MAX_NR_SG)
+                return NULL;
+
+        edesc = kzalloc(sizeof(*edesc) + nslots *
+                sizeof(edesc->pset[0]), GFP_ATOMIC);
+        if (!edesc) {
+                dev_dbg(dev, "Failed to allocate a descriptor\n");
+                return NULL;
+        }
+
+        edesc->cyclic = 1;
+        edesc->pset_nr = nslots;
+
+        dev_dbg(dev, "%s: nslots=%d\n", __func__, nslots);
+        dev_dbg(dev, "%s: period_len=%d\n", __func__, period_len);
+        dev_dbg(dev, "%s: buf_len=%d\n", __func__, buf_len);
+
+        for (i = 0; i < nslots; i++) {
+                /* Allocate a PaRAM slot, if needed */
+                if (echan->slot[i] < 0) {
+                        echan->slot[i] =
+                                edma_alloc_slot(EDMA_CTLR(echan->ch_num),
+                                                EDMA_SLOT_ANY);
+                        if (echan->slot[i] < 0) {
+                                dev_err(dev, "Failed to allocate slot\n");
+                                return NULL;
+                        }
+                }
+
+                if (i == nslots - 1) {
+                        memcpy(&edesc->pset[i], &edesc->pset[0],
+                               sizeof(edesc->pset[0]));
+                        break;
+                }
+
+                ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
+                                       dst_addr, burst, dev_width, period_len,
+                                       direction);
+                if (ret < 0)
+                        return NULL;
+
+                if (direction == DMA_DEV_TO_MEM)
+                        dst_addr += period_len;
+                else
+                        src_addr += period_len;
+
+                dev_dbg(dev, "%s: Configure period %d of buf:\n", __func__, i);
+                dev_dbg(dev,
+                        "\n pset[%d]:\n"
+                        "  chnum\t%d\n"
+                        "  slot\t%d\n"
+                        "  opt\t%08x\n"
+                        "  src\t%08x\n"
+                        "  dst\t%08x\n"
+                        "  abcnt\t%08x\n"
+                        "  ccnt\t%08x\n"
+                        "  bidx\t%08x\n"
+                        "  cidx\t%08x\n"
+                        "  lkrld\t%08x\n",
+                        i, echan->ch_num, echan->slot[i],
+                        edesc->pset[i].opt,
+                        edesc->pset[i].src,
+                        edesc->pset[i].dst,
+                        edesc->pset[i].a_b_cnt,
+                        edesc->pset[i].ccnt,
+                        edesc->pset[i].src_dst_bidx,
+                        edesc->pset[i].src_dst_cidx,
+                        edesc->pset[i].link_bcntrld);
+
+                edesc->absync = ret;
+
+                /*
+                 * Enable interrupts for every period because callback
+                 * has to be called for every period.
+                 */
+                edesc->pset[i].opt |= TCINTEN;
+        }
+
+        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
 static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 {
         struct edma_chan *echan = data;
@@ -467,24 +605,28 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
         unsigned long flags;
         struct edmacc_param p;
 
-        /* Pause the channel */
-        edma_pause(echan->ch_num);
+        edesc = echan->edesc;
+
+        /* Pause the channel for non-cyclic */
+        if (!edesc || (edesc && !edesc->cyclic))
+                edma_pause(echan->ch_num);
 
         switch (ch_status) {
         case EDMA_DMA_COMPLETE:
                 spin_lock_irqsave(&echan->vchan.lock, flags);
 
-                edesc = echan->edesc;
                 if (edesc) {
-                        if (edesc->processed == edesc->pset_nr) {
+                        if (edesc->cyclic) {
+                                vchan_cyclic_callback(&edesc->vdesc);
+                        } else if (edesc->processed == edesc->pset_nr) {
                                 dev_dbg(dev, "Transfer complete, stopping channel %d\n", ch_num);
                                 edma_stop(echan->ch_num);
                                 vchan_cookie_complete(&edesc->vdesc);
+                                edma_execute(echan);
                         } else {
                                 dev_dbg(dev, "Intermediate transfer complete on channel %d\n", ch_num);
+                                edma_execute(echan);
                         }
-
-                        edma_execute(echan);
                 }
 
                 spin_unlock_irqrestore(&echan->vchan.lock, flags);
@@ -680,6 +822,7 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
                           struct device *dev)
 {
         dma->device_prep_slave_sg = edma_prep_slave_sg;
+        dma->device_prep_dma_cyclic = edma_prep_dma_cyclic;
         dma->device_alloc_chan_resources = edma_alloc_chan_resources;
         dma->device_free_chan_resources = edma_free_chan_resources;
         dma->device_issue_pending = edma_issue_pending;