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>

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 4812638..2447221 100644 (file)
--- 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;

diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index e8f92b2..848e232 100644 (file)
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -281,6 +281,7 @@ struct dw_dma {
        /* channels */
        struct dw_dma_chan      *chan;
        u8                      all_chan_mask;
+       u8                      in_use;
 
        /* hardware configuration */
        unsigned char           nr_masters;