dmaengine: omap-dma: Support for slave devices with data port window

Based on the src/dst_port_window_size - if it is set - configure the DMA
channel to use double indexing in order to be able to loop within the
address window.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 61 insertions, 2 deletions

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index 15eb8024666b..ac68666cd3f4 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -166,6 +166,9 @@ enum {
         CSDP_DST_BURST_16       = 1 << 14,
         CSDP_DST_BURST_32       = 2 << 14,
         CSDP_DST_BURST_64       = 3 << 14,
+        CSDP_WRITE_NON_POSTED   = 0 << 16,
+        CSDP_WRITE_POSTED       = 1 << 16,
+        CSDP_WRITE_LAST_NON_POSTED = 2 << 16,
 
         CICR_TOUT_IE            = BIT(0),       /* OMAP1 only */
         CICR_DROP_IE            = BIT(1),
@@ -881,15 +884,18 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
         unsigned i, es, en, frame_bytes;
         bool ll_failed = false;
         u32 burst;
+        u32 port_window, port_window_bytes;
 
         if (dir == DMA_DEV_TO_MEM) {
                 dev_addr = c->cfg.src_addr;
                 dev_width = c->cfg.src_addr_width;
                 burst = c->cfg.src_maxburst;
+                port_window = c->cfg.src_port_window_size;
         } else if (dir == DMA_MEM_TO_DEV) {
                 dev_addr = c->cfg.dst_addr;
                 dev_width = c->cfg.dst_addr_width;
                 burst = c->cfg.dst_maxburst;
+                port_window = c->cfg.dst_port_window_size;
         } else {
                 dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
                 return NULL;
@@ -910,6 +916,12 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
                 return NULL;
         }
 
+        /* When the port_window is used, one frame must cover the window */
+        if (port_window) {
+                burst = port_window;
+                port_window_bytes = port_window * es_bytes[es];
+        }
+
         /* Now allocate and setup the descriptor. */
         d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
         if (!d)
@@ -921,11 +933,45 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 
         d->ccr = c->ccr | CCR_SYNC_FRAME;
         if (dir == DMA_DEV_TO_MEM) {
-                d->ccr |= CCR_DST_AMODE_POSTINC | CCR_SRC_AMODE_CONSTANT;
                 d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED;
+
+                d->ccr |= CCR_DST_AMODE_POSTINC;
+                if (port_window) {
+                        d->ccr |= CCR_SRC_AMODE_DBLIDX;
+                        d->ei = 1;
+                        /*
+                         * One frame covers the port_window and by  configure
+                         * the source frame index to be -1 * (port_window - 1)
+                         * we instruct the sDMA that after a frame is processed
+                         * it should move back to the start of the window.
+                         */
+                        d->fi = -(port_window_bytes - 1);
+
+                        if (port_window_bytes >= 64)
+                                d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED;
+                        else if (port_window_bytes >= 32)
+                                d->csdp = CSDP_SRC_BURST_32 | CSDP_SRC_PACKED;
+                        else if (port_window_bytes >= 16)
+                                d->csdp = CSDP_SRC_BURST_16 | CSDP_SRC_PACKED;
+                } else {
+                        d->ccr |= CCR_SRC_AMODE_CONSTANT;
+                }
         } else {
-                d->ccr |= CCR_DST_AMODE_CONSTANT | CCR_SRC_AMODE_POSTINC;
                 d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED;
+
+                d->ccr |= CCR_SRC_AMODE_POSTINC;
+                if (port_window) {
+                        d->ccr |= CCR_DST_AMODE_DBLIDX;
+
+                        if (port_window_bytes >= 64)
+                                d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED;
+                        else if (port_window_bytes >= 32)
+                                d->csdp = CSDP_DST_BURST_32 | CSDP_DST_PACKED;
+                        else if (port_window_bytes >= 16)
+                                d->csdp = CSDP_DST_BURST_16 | CSDP_DST_PACKED;
+                } else {
+                        d->ccr |= CCR_DST_AMODE_CONSTANT;
+                }
         }
 
         d->cicr = CICR_DROP_IE | CICR_BLOCK_IE;
@@ -943,6 +989,9 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
                         d->ccr |= CCR_TRIGGER_SRC;
 
                 d->cicr |= CICR_MISALIGNED_ERR_IE | CICR_TRANS_ERR_IE;
+
+                if (port_window)
+                        d->csdp |= CSDP_WRITE_LAST_NON_POSTED;
         }
         if (od->plat->errata & DMA_ERRATA_PARALLEL_CHANNELS)
                 d->clnk_ctrl = c->dma_ch;
@@ -968,6 +1017,16 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
                 osg->addr = sg_dma_address(sgent);
                 osg->en = en;
                 osg->fn = sg_dma_len(sgent) / frame_bytes;
+                if (port_window && dir == DMA_MEM_TO_DEV) {
+                        osg->ei = 1;
+                        /*
+                         * One frame covers the port_window and by  configure
+                         * the source frame index to be -1 * (port_window - 1)
+                         * we instruct the sDMA that after a frame is processed
+                         * it should move back to the start of the window.
+                         */
+                        osg->fi = -(port_window_bytes - 1);
+                }
 
                 if (d->using_ll) {
                         osg->t2_desc = dma_pool_alloc(od->desc_pool, GFP_ATOMIC,