dmaengine: dw_dmac: simplify master selection

The patch to add the common DMA binding added a dummy dw_dma_slave
structure into the dw_dma_chan structure in order to configure the
masters correctly. It turns out that this can be simplified if we
pick the DMA masters in the dwc_alloc_chan_resources function instead
and save them in the dw_dma_chan structure directly.

This could be simplified further once all users that today use
dw_dma_slave for configuration get converted to device tree based
setup instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

2 files changed, 33 insertions, 48 deletions

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 274fd7dd81f6..951ef5bc8afb 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -49,29 +49,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
         return slave ? slave->src_master : 1;
 }
 
-#define SRC_MASTER      0
-#define DST_MASTER      1
-
-static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
+static inline void dwc_set_masters(struct dw_dma_chan *dwc)
 {
-        struct dw_dma *dw = to_dw_dma(chan->device);
-        struct dw_dma_slave *dws = chan->private;
-        unsigned int m;
-
-        if (master == SRC_MASTER)
-                m = dwc_get_sms(dws);
-        else
-                m = dwc_get_dms(dws);
+        struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+        struct dw_dma_slave *dws = dwc->chan.private;
+        unsigned char mmax = dw->nr_masters - 1;
 
-        return min_t(unsigned int, dw->nr_masters - 1, m);
+        if (dwc->request_line == ~0) {
+                dwc->src_master = min_t(unsigned char, mmax, dwc_get_sms(dws));
+                dwc->dst_master = min_t(unsigned char, mmax, dwc_get_dms(dws));
+        }
 }
 
 #define DWC_DEFAULT_CTLLO(_chan) ({                             \
                 struct dw_dma_chan *_dwc = to_dw_dma_chan(_chan);       \
                 struct dma_slave_config *_sconfig = &_dwc->dma_sconfig; \
                 bool _is_slave = is_slave_direction(_dwc->direction);   \
-                int _dms = dwc_get_master(_chan, DST_MASTER);           \
-                int _sms = dwc_get_master(_chan, SRC_MASTER);           \
                 u8 _smsize = _is_slave ? _sconfig->src_maxburst :       \
                         DW_DMA_MSIZE_16;                        \
                 u8 _dmsize = _is_slave ? _sconfig->dst_maxburst :       \
@@ -81,8 +74,8 @@ static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
                  | DWC_CTLL_SRC_MSIZE(_smsize)                  \
                  | DWC_CTLL_LLP_D_EN                            \
                  | DWC_CTLL_LLP_S_EN                            \
-                 | DWC_CTLL_DMS(_dms)                           \
-                 | DWC_CTLL_SMS(_sms));                         \
+                 | DWC_CTLL_DMS(_dwc->dst_master)               \
+                 | DWC_CTLL_SMS(_dwc->src_master));             \
         })
 
 /*
@@ -92,13 +85,6 @@ static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
  */
 #define NR_DESCS_PER_CHANNEL    64
 
-static inline unsigned int dwc_get_data_width(struct dma_chan *chan, int master)
-{
-        struct dw_dma *dw = to_dw_dma(chan->device);
-
-        return dw->data_width[dwc_get_master(chan, master)];
-}
-
 /*----------------------------------------------------------------------*/
 
 static struct device *chan2dev(struct dma_chan *chan)
@@ -172,13 +158,7 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
         if (dwc->initialized == true)
                 return;
 
-        if (dws && dws->cfg_hi == ~0 && dws->cfg_lo == ~0) {
-                /* Autoconfigure based on request line from DT */
-                if (dwc->direction == DMA_MEM_TO_DEV)
-                        cfghi = DWC_CFGH_DST_PER(dwc->request_line);
-                else if (dwc->direction == DMA_DEV_TO_MEM)
-                        cfghi = DWC_CFGH_SRC_PER(dwc->request_line);
-        } else if (dws) {
+        if (dws) {
                 /*
                  * We need controller-specific data to set up slave
                  * transfers.
@@ -189,9 +169,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
                 cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
         } else {
                 if (dwc->direction == DMA_MEM_TO_DEV)
-                        cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id);
+                        cfghi = DWC_CFGH_DST_PER(dwc->request_line);
                 else if (dwc->direction == DMA_DEV_TO_MEM)
-                        cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id);
+                        cfghi = DWC_CFGH_SRC_PER(dwc->request_line);
         }
 
         channel_writel(dwc, CFG_LO, cfglo);
@@ -745,6 +725,7 @@ 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           *dw = to_dw_dma(chan->device);
         struct dw_desc          *desc;
         struct dw_desc          *first;
         struct dw_desc          *prev;
@@ -767,8 +748,8 @@ 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_get_data_width(chan, SRC_MASTER),
-                           dwc_get_data_width(chan, DST_MASTER));
+        data_width = min_t(unsigned int, dw->data_width[dwc->src_master],
+                           dw->data_width[dwc->dst_master]);
 
         src_width = dst_width = min_t(unsigned int, data_width,
                                       dwc_fast_fls(src | dest | len));
@@ -826,6 +807,7 @@ 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           *dw = to_dw_dma(chan->device);
         struct dma_slave_config *sconfig = &dwc->dma_sconfig;
         struct dw_desc          *prev;
         struct dw_desc          *first;
@@ -859,7 +841,7 @@ 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_get_data_width(chan, SRC_MASTER);
+                data_width = dw->data_width[dwc->src_master];
 
                 for_each_sg(sgl, sg, sg_len, i) {
                         struct dw_desc  *desc;
@@ -919,7 +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_get_data_width(chan, DST_MASTER);
+                data_width = dw->data_width[dwc->dst_master];
 
                 for_each_sg(sgl, sg, sg_len, i) {
                         struct dw_desc  *desc;
@@ -1020,6 +1002,10 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
         memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
         dwc->direction = sconfig->direction;
 
+        /* Take the request line from slave_id member */
+        if (dwc->request_line == ~0)
+                dwc->request_line = sconfig->slave_id;
+
         convert_burst(&dwc->dma_sconfig.src_maxburst);
         convert_burst(&dwc->dma_sconfig.dst_maxburst);
         convert_slave_id(dwc);
@@ -1170,6 +1156,8 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
          * doesn't mean what you think it means), and status writeback.
          */
 
+        dwc_set_masters(dwc);
+
         spin_lock_irqsave(&dwc->lock, flags);
         i = dwc->descs_allocated;
         while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -1227,6 +1215,7 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
         list_splice_init(&dwc->free_list, &list);
         dwc->descs_allocated = 0;
         dwc->initialized = false;
+        dwc->request_line = ~0;
 
         /* Disable interrupts */
         channel_clear_bit(dw, MASK.XFER, dwc->mask);
@@ -1254,23 +1243,15 @@ struct dw_dma_of_filter_args {
 static bool dw_dma_of_filter(struct dma_chan *chan, void *param)
 {
         struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
-        struct dw_dma *dw = to_dw_dma(chan->device);
         struct dw_dma_of_filter_args *fargs = param;
-        struct dw_dma_slave *dws = &dwc->slave;
 
         /* Ensure the device matches our channel */
         if (chan->device != &fargs->dw->dma)
                 return false;
 
-        dws->dma_dev    = dw->dma.dev;
-        dws->cfg_hi     = ~0;
-        dws->cfg_lo     = ~0;
-        dws->src_master = fargs->src;
-        dws->dst_master = fargs->dst;
-
         dwc->request_line = fargs->req;
-
-        chan->private = dws;
+        dwc->src_master = fargs->src;
+        dwc->dst_master = fargs->dst;
 
         return true;
 }
@@ -1784,6 +1765,7 @@ static int dw_probe(struct platform_device *pdev)
                 channel_clear_bit(dw, CH_EN, dwc->mask);
 
                 dwc->direction = DMA_TRANS_NONE;
+                dwc->request_line = ~0;
 
                 /* Hardware configuration */
                 if (autocfg) {
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 4d02c3669b75..9b0e12e85e31 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -212,8 +212,11 @@ struct dw_dma_chan {
         /* hardware configuration */
         unsigned int            block_size;
         bool                    nollp;
+
+        /* custom slave configuration */
         unsigned int            request_line;
-        struct dw_dma_slave     slave;
+        unsigned char           src_master;
+        unsigned char           dst_master;
 
         /* configuration passed via DMA_SLAVE_CONFIG */
         struct dma_slave_config dma_sconfig;