dmaengine: dw: enable and disable controller when needed

Enable controller automatically whenever first user requires for a channel and
disable it when the last user gone.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 35 insertions, 25 deletions

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 48126380e036..244722170410 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1094,6 +1094,31 @@ static void dwc_issue_pending(struct dma_chan *chan)
         spin_unlock_irqrestore(&dwc->lock, flags);
 }
 
+/*----------------------------------------------------------------------*/
+
+static void dw_dma_off(struct dw_dma *dw)
+{
+        int i;
+
+        dma_writel(dw, CFG, 0);
+
+        channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
+        channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
+        channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
+        channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
+
+        while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
+                cpu_relax();
+
+        for (i = 0; i < dw->dma.chancnt; i++)
+                dw->chan[i].initialized = false;
+}
+
+static void dw_dma_on(struct dw_dma *dw)
+{
+        dma_writel(dw, CFG, DW_CFG_DMA_EN);
+}
+
 static int dwc_alloc_chan_resources(struct dma_chan *chan)
 {
         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
@@ -1118,6 +1143,11 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
          * doesn't mean what you think it means), and status writeback.
          */
 
+        /* Enable controller here if needed */
+        if (!dw->in_use)
+                dw_dma_on(dw);
+        dw->in_use |= dwc->mask;
+
         spin_lock_irqsave(&dwc->lock, flags);
         i = dwc->descs_allocated;
         while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -1182,6 +1212,11 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
 
         spin_unlock_irqrestore(&dwc->lock, flags);
 
+        /* Disable controller in case it was a last user */
+        dw->in_use &= ~dwc->mask;
+        if (!dw->in_use)
+                dw_dma_off(dw);
+
         list_for_each_entry_safe(desc, _desc, &list, desc_node) {
                 dev_vdbg(chan2dev(chan), "  freeing descriptor %p\n", desc);
                 dma_pool_free(dw->desc_pool, desc, desc->txd.phys);
@@ -1452,29 +1487,6 @@ EXPORT_SYMBOL(dw_dma_cyclic_free);
 
 /*----------------------------------------------------------------------*/
 
-static void dw_dma_off(struct dw_dma *dw)
-{
-        int i;
-
-        dma_writel(dw, CFG, 0);
-
-        channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
-        channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
-        channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
-        channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
-
-        while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
-                cpu_relax();
-
-        for (i = 0; i < dw->dma.chancnt; i++)
-                dw->chan[i].initialized = false;
-}
-
-static void dw_dma_on(struct dw_dma *dw)
-{
-        dma_writel(dw, CFG, DW_CFG_DMA_EN);
-}
-
 int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 {
         struct dw_dma           *dw;
@@ -1648,8 +1660,6 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
         dw->dma.device_tx_status = dwc_tx_status;
         dw->dma.device_issue_pending = dwc_issue_pending;
 
-        dw_dma_on(dw);
-
         err = dma_async_device_register(&dw->dma);
         if (err)
                 goto err_dma_register;