2 files changed, 46 insertions, 2 deletions

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 5816da34129d..35c8dd5f1013 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -282,6 +282,7 @@ static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
 
                 dwc_initialize(dwc);
 
+                dwc->residue = first->total_len;
                 dwc->tx_node_active = &first->tx_list;
 
                 /* Submit first block */
@@ -385,6 +386,15 @@ static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
                 dwc_descriptor_complete(dwc, desc, true);
 }
 
+/* Returns how many bytes were already received from source */
+static inline u32 dwc_get_sent(struct dw_dma_chan *dwc)
+{
+        u32 ctlhi = channel_readl(dwc, CTL_HI);
+        u32 ctllo = channel_readl(dwc, CTL_LO);
+
+        return (ctlhi & DWC_CTLH_BLOCK_TS_MASK) * (1 << (ctllo >> 4 & 7));
+}
+
 static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
 {
         dma_addr_t llp;
@@ -412,6 +422,12 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
 
                         head = &desc->tx_list;
                         if (active != head) {
+                                /* Update desc to reflect last sent one */
+                                if (active != head->next)
+                                        desc = to_dw_desc(active->prev);
+
+                                dwc->residue -= desc->len;
+
                                 child = to_dw_desc(active);
 
                                 /* Submit next block */
@@ -424,6 +440,9 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
                         /* We are done here */
                         clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
                 }
+
+                dwc->residue = 0;
+
                 spin_unlock_irqrestore(&dwc->lock, flags);
 
                 dwc_complete_all(dw, dwc);
@@ -431,6 +450,7 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
         }
 
         if (list_empty(&dwc->active_list)) {
+                dwc->residue = 0;
                 spin_unlock_irqrestore(&dwc->lock, flags);
                 return;
         }
@@ -445,6 +465,9 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
                         (unsigned long long)llp);
 
         list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
+                /* initial residue value */
+                dwc->residue = desc->total_len;
+
                 /* check first descriptors addr */
                 if (desc->txd.phys == llp) {
                         spin_unlock_irqrestore(&dwc->lock, flags);
@@ -454,16 +477,21 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
                 /* check first descriptors llp */
                 if (desc->lli.llp == llp) {
                         /* This one is currently in progress */
+                        dwc->residue -= dwc_get_sent(dwc);
                         spin_unlock_irqrestore(&dwc->lock, flags);
                         return;
                 }
 
-                list_for_each_entry(child, &desc->tx_list, desc_node)
+                dwc->residue -= desc->len;
+                list_for_each_entry(child, &desc->tx_list, desc_node) {
                         if (child->lli.llp == llp) {
                                 /* Currently in progress */
+                                dwc->residue -= dwc_get_sent(dwc);
                                 spin_unlock_irqrestore(&dwc->lock, flags);
                                 return;
                         }
+                        dwc->residue -= child->len;
+                }
 
                 /*
                  * No descriptors so far seem to be in progress, i.e.
@@ -1054,6 +1082,21 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
         return 0;
 }
 
+static inline u32 dwc_get_residue(struct dw_dma_chan *dwc)
+{
+        unsigned long flags;
+        u32 residue;
+
+        spin_lock_irqsave(&dwc->lock, flags);
+
+        residue = dwc->residue;
+        if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags) && residue)
+                residue -= dwc_get_sent(dwc);
+
+        spin_unlock_irqrestore(&dwc->lock, flags);
+        return residue;
+}
+
 static enum dma_status
 dwc_tx_status(struct dma_chan *chan,
               dma_cookie_t cookie,
@@ -1070,7 +1113,7 @@ dwc_tx_status(struct dma_chan *chan,
         }
 
         if (ret != DMA_SUCCESS)
-                dma_set_residue(txstate, dwc_first_active(dwc)->len);
+                dma_set_residue(txstate, dwc_get_residue(dwc));
 
         if (dwc->paused)
                 return DMA_PAUSED;
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 833b4cf9843d..88dd8eb31957 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -203,6 +203,7 @@ struct dw_dma_chan {
         struct list_head        active_list;
         struct list_head        queue;
         struct list_head        free_list;
+        u32                     residue;
         struct dw_cyclic_desc   *cdesc;
 
         unsigned int            descs_allocated;