dmaengine: PL08x: fix tx_status function to return correct residue

Now that we're converted to use the generic vchan support, we can fix
the residue return from tx_status to be compliant with dmaengine.  This
returns the number of bytes remaining for the _specified_ cookie, not
the number of bytes in all pending transfers on the channel.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 34 insertions, 27 deletions

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 6a35e37d14bc..c42c7ef6b93a 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -473,10 +473,8 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
 {
         struct pl08x_phy_chan *ch;
         struct pl08x_txd *txd;
-        unsigned long flags;
         size_t bytes = 0;
 
-        spin_lock_irqsave(&plchan->vc.lock, flags);
         ch = plchan->phychan;
         txd = plchan->at;
 
@@ -516,27 +514,6 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
                 }
         }
 
-        /* Sum up all queued transactions */
-        if (!list_empty(&plchan->vc.desc_issued)) {
-                struct pl08x_txd *txdi;
-                list_for_each_entry(txdi, &plchan->vc.desc_issued, vd.node) {
-                        struct pl08x_sg *dsg;
-                        list_for_each_entry(dsg, &txd->dsg_list, node)
-                                bytes += dsg->len;
-                }
-        }
-
-        if (!list_empty(&plchan->vc.desc_submitted)) {
-                struct pl08x_txd *txdi;
-                list_for_each_entry(txdi, &plchan->vc.desc_submitted, vd.node) {
-                        struct pl08x_sg *dsg;
-                        list_for_each_entry(dsg, &txd->dsg_list, node)
-                                bytes += dsg->len;
-                }
-        }
-
-        spin_unlock_irqrestore(&plchan->vc.lock, flags);
-
         return bytes;
 }
 
@@ -1171,23 +1148,53 @@ static enum dma_status pl08x_dma_tx_status(struct dma_chan *chan,
                 dma_cookie_t cookie, struct dma_tx_state *txstate)
 {
         struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+        struct virt_dma_desc *vd;
+        unsigned long flags;
         enum dma_status ret;
+        size_t bytes = 0;
 
         ret = dma_cookie_status(chan, cookie, txstate);
         if (ret == DMA_SUCCESS)
                 return ret;
 
         /*
+         * There's no point calculating the residue if there's
+         * no txstate to store the value.
+         */
+        if (!txstate) {
+                if (plchan->state == PL08X_CHAN_PAUSED)
+                        ret = DMA_PAUSED;
+                return ret;
+        }
+
+        spin_lock_irqsave(&plchan->vc.lock, flags);
+        ret = dma_cookie_status(chan, cookie, txstate);
+        if (ret != DMA_SUCCESS) {
+                vd = vchan_find_desc(&plchan->vc, cookie);
+                if (vd) {
+                        /* On the issued list, so hasn't been processed yet */
+                        struct pl08x_txd *txd = to_pl08x_txd(&vd->tx);
+                        struct pl08x_sg *dsg;
+
+                        list_for_each_entry(dsg, &txd->dsg_list, node)
+                                bytes += dsg->len;
+                } else {
+                        bytes = pl08x_getbytes_chan(plchan);
+                }
+        }
+        spin_unlock_irqrestore(&plchan->vc.lock, flags);
+
+        /*
          * This cookie not complete yet
          * Get number of bytes left in the active transactions and queue
          */
-        dma_set_residue(txstate, pl08x_getbytes_chan(plchan));
+        dma_set_residue(txstate, bytes);
 
-        if (plchan->state == PL08X_CHAN_PAUSED)
-                return DMA_PAUSED;
+        if (plchan->state == PL08X_CHAN_PAUSED && ret == DMA_IN_PROGRESS)
+                ret = DMA_PAUSED;
 
         /* Whether waiting or running, we're in progress */
-        return DMA_IN_PROGRESS;
+        return ret;
 }
 
 /* PrimeCell DMA extension */