dmaengine: xgene-dma: Fix overwritting DMA tx ring

This patch fixes an over flow issue with the TX ring descriptor. Each
descriptor is 32B in size and an operation requires 2 of these
descriptors.

Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index 4c5dddaad2d59e5bfc2b79e462880091cbfa5ce2..8d57b1b12e411ef902d26af984e7d34a741a4cf2 100644 (file)
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -59,7 +59,6 @@
 #define XGENE_DMA_RING_MEM_RAM_SHUTDOWN                0xD070
 #define XGENE_DMA_RING_BLK_MEM_RDY             0xD074
 #define XGENE_DMA_RING_BLK_MEM_RDY_VAL         0xFFFFFFFF
-#define XGENE_DMA_RING_DESC_CNT(v)             (((v) & 0x0001FFFE) >> 1)
 #define XGENE_DMA_RING_ID_GET(owner, num)      (((owner) << 6) | (num))
 #define XGENE_DMA_RING_DST_ID(v)               ((1 << 10) | (v))
 #define XGENE_DMA_RING_CMD_OFFSET              0x2C
@@ -379,14 +378,6 @@ static u8 xgene_dma_encode_xor_flyby(u32 src_cnt)
        return flyby_type[src_cnt];
 }
 
-static u32 xgene_dma_ring_desc_cnt(struct xgene_dma_ring *ring)
-{
-       u32 __iomem *cmd_base = ring->cmd_base;
-       u32 ring_state = ioread32(&cmd_base[1]);
-
-       return XGENE_DMA_RING_DESC_CNT(ring_state);
-}
-
 static void xgene_dma_set_src_buffer(__le64 *ext8, size_t *len,
                                     dma_addr_t *paddr)
 {
@@ -659,15 +650,12 @@ static void xgene_dma_clean_running_descriptor(struct xgene_dma_chan *chan,
        dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
 }
 
-static int xgene_chan_xfer_request(struct xgene_dma_ring *ring,
-                                  struct xgene_dma_desc_sw *desc_sw)
+static void xgene_chan_xfer_request(struct xgene_dma_chan *chan,
+                                   struct xgene_dma_desc_sw *desc_sw)
 {
+       struct xgene_dma_ring *ring = &chan->tx_ring;
        struct xgene_dma_desc_hw *desc_hw;
 
-       /* Check if can push more descriptor to hw for execution */
-       if (xgene_dma_ring_desc_cnt(ring) > (ring->slots - 2))
-               return -EBUSY;
-
        /* Get hw descriptor from DMA tx ring */
        desc_hw = &ring->desc_hw[ring->head];
 
@@ -694,11 +682,13 @@ static int xgene_chan_xfer_request(struct xgene_dma_ring *ring,
                memcpy(desc_hw, &desc_sw->desc2, sizeof(*desc_hw));
        }
 
+       /* Increment the pending transaction count */
+       chan->pending += ((desc_sw->flags &
+                         XGENE_DMA_FLAG_64B_DESC) ? 2 : 1);
+
        /* Notify the hw that we have descriptor ready for execution */
        iowrite32((desc_sw->flags & XGENE_DMA_FLAG_64B_DESC) ?
                  2 : 1, ring->cmd);
-
-       return 0;
 }
 
 /**
@@ -710,7 +700,6 @@ static int xgene_chan_xfer_request(struct xgene_dma_ring *ring,
 static void xgene_chan_xfer_ld_pending(struct xgene_dma_chan *chan)
 {
        struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
-       int ret;
 
        /*
         * If the list of pending descriptors is empty, then we
@@ -735,18 +724,13 @@ static void xgene_chan_xfer_ld_pending(struct xgene_dma_chan *chan)
                if (chan->pending >= chan->max_outstanding)
                        return;
 
-               ret = xgene_chan_xfer_request(&chan->tx_ring, desc_sw);
-               if (ret)
-                       return;
+               xgene_chan_xfer_request(chan, desc_sw);
 
                /*
                 * Delete this element from ld pending queue and append it to
                 * ld running queue
                 */
                list_move_tail(&desc_sw->node, &chan->ld_running);
-
-               /* Increment the pending transaction count */
-               chan->pending++;
        }
 }
 
@@ -821,7 +805,8 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
                 * Decrement the pending transaction count
                 * as we have processed one
                 */
-               chan->pending--;
+               chan->pending -= ((desc_sw->flags &
+                                 XGENE_DMA_FLAG_64B_DESC) ? 2 : 1);
 
                /*
                 * Delete this node from ld running queue and append it to
@@ -1485,7 +1470,7 @@ static int xgene_dma_create_chan_rings(struct xgene_dma_chan *chan)
                 tx_ring->id, tx_ring->num, tx_ring->desc_vaddr);
 
        /* Set the max outstanding request possible to this channel */
-       chan->max_outstanding = rx_ring->slots;
+       chan->max_outstanding = tx_ring->slots;
 
        return ret;
 }