atmel-mci: fix initialization of dma slave data

The conversion of atmel-mci to dma_request_channel missed the
initialization of the channel dma_slave information.  The filter_fn passed
to dma_request_channel is responsible for initializing the channel's
private data.  This implementation has the additional benefit of enabling
a generic client-channel data passing mechanism.

Reviewed-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 9 insertions, 7 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a58993011edb..280a9d263eb3 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -518,6 +518,7 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v
                                        dma_chan_name(chan), err);
                         else
                                 break;
+                        chan->private = NULL;
                         chan = NULL;
                 }
         }
@@ -536,6 +537,7 @@ void dma_release_channel(struct dma_chan *chan)
         WARN_ONCE(chan->client_count != 1,
                   "chan reference count %d != 1\n", chan->client_count);
         dma_chan_put(chan);
+        chan->private = NULL;
         mutex_unlock(&dma_list_mutex);
 }
 EXPORT_SYMBOL_GPL(dma_release_channel);
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 6b702cc46b3d..a97c07eef7ec 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -560,7 +560,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
                 unsigned long flags)
 {
         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
-        struct dw_dma_slave     *dws = dwc->dws;
+        struct dw_dma_slave     *dws = chan->private;
         struct dw_desc          *prev;
         struct dw_desc          *first;
         u32                     ctllo;
@@ -790,7 +790,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
         cfghi = DWC_CFGH_FIFO_MODE;
         cfglo = 0;
 
-        dws = dwc->dws;
+        dws = chan->private;
         if (dws) {
                 /*
                  * We need controller-specific data to set up slave
@@ -866,7 +866,6 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
         spin_lock_bh(&dwc->lock);
         list_splice_init(&dwc->free_list, &list);
         dwc->descs_allocated = 0;
-        dwc->dws = NULL;
 
         /* Disable interrupts */
         channel_clear_bit(dw, MASK.XFER, dwc->mask);
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 00fdd187bb0c..b252b202c5cf 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -139,8 +139,6 @@ struct dw_dma_chan {
         struct list_head        queue;
         struct list_head        free_list;
 
-        struct dw_dma_slave     *dws;
-
         unsigned int            descs_allocated;
 };
 
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 76bfe16c09b1..2b1196e6142c 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1548,9 +1548,10 @@ static bool filter(struct dma_chan *chan, void *slave)
 {
         struct dw_dma_slave *dws = slave;
 
-        if (dws->dma_dev == chan->device->dev)
+        if (dws->dma_dev == chan->device->dev) {
+                chan->private = dws;
                 return true;
-        else
+        } else
                 return false;
 }
 #endif
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 3e68469c1885..f0413845f20e 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -121,6 +121,7 @@ struct dma_chan_percpu {
  * @local: per-cpu pointer to a struct dma_chan_percpu
  * @client-count: how many clients are using this channel
  * @table_count: number of appearances in the mem-to-mem allocation table
+ * @private: private data for certain client-channel associations
  */
 struct dma_chan {
         struct dma_device *device;
@@ -134,6 +135,7 @@ struct dma_chan {
         struct dma_chan_percpu *local;
         int client_count;
         int table_count;
+        void *private;
 };
 
 /**