dw_dmac: remove unnecessary tx_list field in dw_dma_chan

The soft LLP mode is working for active descriptor only. So, we do not need to
have a copy of its pointer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index ddd3ad2a96a3..721beafe8f7a 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -282,9 +282,9 @@ static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
 
                 dwc_initialize(dwc);
 
-                dwc->tx_list = &first->tx_list;
                 dwc->tx_node_active = &first->tx_list;
 
+                /* Submit first block */
                 dwc_do_single_block(dwc, first);
 
                 return;
@@ -402,15 +402,25 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
                 dma_writel(dw, CLEAR.XFER, dwc->mask);
 
                 if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags)) {
-                        if (dwc->tx_node_active != dwc->tx_list) {
-                                desc = to_dw_desc(dwc->tx_node_active);
+                        struct list_head *head, *active = dwc->tx_node_active;
+
+                        /*
+                         * We are inside first active descriptor.
+                         * Otherwise something is really wrong.
+                         */
+                        desc = dwc_first_active(dwc);
+
+                        head = &desc->tx_list;
+                        if (active != head) {
+                                child = to_dw_desc(active);
 
                                 /* Submit next block */
-                                dwc_do_single_block(dwc, desc);
-                                spin_unlock_irqrestore(&dwc->lock, flags);
+                                dwc_do_single_block(dwc, child);
 
+                                spin_unlock_irqrestore(&dwc->lock, flags);
                                 return;
                         }
+
                         /* We are done here */
                         clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
                 }