dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

The same information could be extracted from the struct dma_chan.
The patch introduces helper function dwc_get_data_width() as well.

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>

2 files changed, 20 insertions, 10 deletions

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index e5378b5741be..154952abc2e9 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -73,6 +73,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
  */
 #define NR_DESCS_PER_CHANNEL    64
 
+#define SRC_MASTER      0
+#define DST_MASTER      1
+
+static inline unsigned int dwc_get_data_width(struct dma_chan *chan, int master)
+{
+        struct dw_dma *dw = to_dw_dma(chan->device);
+        struct dw_dma_slave *dws = chan->private;
+
+        if (master == SRC_MASTER)
+                return dw->data_width[dwc_get_sms(dws)];
+        else if (master == DST_MASTER)
+                return dw->data_width[dwc_get_dms(dws)];
+
+        return 0;
+}
+
 /*----------------------------------------------------------------------*/
 
 /*
@@ -701,7 +717,6 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
                 size_t len, unsigned long flags)
 {
         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
-        struct dw_dma_slave     *dws = chan->private;
         struct dw_desc          *desc;
         struct dw_desc          *first;
         struct dw_desc          *prev;
@@ -724,8 +739,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 
         dwc->direction = DMA_MEM_TO_MEM;
 
-        data_width = min_t(unsigned int, dwc->dw->data_width[dwc_get_sms(dws)],
-                                         dwc->dw->data_width[dwc_get_dms(dws)]);
+        data_width = min_t(unsigned int, dwc_get_data_width(chan, SRC_MASTER),
+                           dwc_get_data_width(chan, DST_MASTER));
 
         src_width = dst_width = min_t(unsigned int, data_width,
                                       dwc_fast_fls(src | dest | len));
@@ -790,7 +805,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
                 unsigned long flags, void *context)
 {
         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
-        struct dw_dma_slave     *dws = chan->private;
         struct dma_slave_config *sconfig = &dwc->dma_sconfig;
         struct dw_desc          *prev;
         struct dw_desc          *first;
@@ -824,7 +838,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
                 ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
                         DWC_CTLL_FC(DW_DMA_FC_D_M2P);
 
-                data_width = dwc->dw->data_width[dwc_get_sms(dws)];
+                data_width = dwc_get_data_width(chan, SRC_MASTER);
 
                 for_each_sg(sgl, sg, sg_len, i) {
                         struct dw_desc  *desc;
@@ -887,7 +901,7 @@ slave_sg_todev_fill_desc:
                 ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
                         DWC_CTLL_FC(DW_DMA_FC_D_P2M);
 
-                data_width = dwc->dw->data_width[dwc_get_dms(dws)];
+                data_width = dwc_get_data_width(chan, DST_MASTER);
 
                 for_each_sg(sgl, sg, sg_len, i) {
                         struct dw_desc  *desc;
@@ -1739,7 +1753,6 @@ static int dw_probe(struct platform_device *pdev)
 
                 channel_clear_bit(dw, CH_EN, dwc->mask);
 
-                dwc->dw = dw;
                 dwc->direction = DMA_TRANS_NONE;
 
                 /* hardware configuration */
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index f9532c29b808..577f2dd35882 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -214,9 +214,6 @@ struct dw_dma_chan {
 
         /* configuration passed via DMA_SLAVE_CONFIG */
         struct dma_slave_config dma_sconfig;
-
-        /* backlink to dw_dma */
-        struct dw_dma           *dw;
 };
 
 static inline struct dw_dma_chan_regs __iomem *