dmaengine: ste_dma40: Convert data_width from register bit format to value

When a DMA client requests and configures a DMA channel, it requests
data_width in Bytes. The DMA40 driver then swiftly converts it over to
the necessary register bit value. Unfortunately, for any subsequent
calculations we have to shift '1' by the bit pattern (1 << data_width)
times to make any sense of it.

This patch flips the semantics on its head and only converts the value
to its respective register bit pattern when writing to registers. This
way we can use the true data_width (in Bytes) value.

Cc: Dan Williams <djbw@fb.com>
Cc: Per Forlin <per.forlin@stericsson.com>
Cc: Rabin Vincent <rabin@rab.in>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 25 insertions, 38 deletions

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 483da1660eae..76c255fcdc2d 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -80,11 +80,11 @@ struct stedma40_chan_cfg dma40_memcpy_conf_phy = {
         .mode = STEDMA40_MODE_PHYSICAL,
         .dir = DMA_MEM_TO_MEM,
 
-        .src_info.data_width = STEDMA40_BYTE_WIDTH,
+        .src_info.data_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
         .src_info.psize = STEDMA40_PSIZE_PHY_1,
         .src_info.flow_ctrl = STEDMA40_NO_FLOW_CTRL,
 
-        .dst_info.data_width = STEDMA40_BYTE_WIDTH,
+        .dst_info.data_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
         .dst_info.psize = STEDMA40_PSIZE_PHY_1,
         .dst_info.flow_ctrl = STEDMA40_NO_FLOW_CTRL,
 };
@@ -94,11 +94,11 @@ struct stedma40_chan_cfg dma40_memcpy_conf_log = {
         .mode = STEDMA40_MODE_LOGICAL,
         .dir = DMA_MEM_TO_MEM,
 
-        .src_info.data_width = STEDMA40_BYTE_WIDTH,
+        .src_info.data_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
         .src_info.psize = STEDMA40_PSIZE_LOG_1,
         .src_info.flow_ctrl = STEDMA40_NO_FLOW_CTRL,
 
-        .dst_info.data_width = STEDMA40_BYTE_WIDTH,
+        .dst_info.data_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
         .dst_info.psize = STEDMA40_PSIZE_LOG_1,
         .dst_info.flow_ctrl = STEDMA40_NO_FLOW_CTRL,
 };
@@ -1005,20 +1005,21 @@ static int d40_psize_2_burst_size(bool is_log, int psize)
 
 /*
  * The dma only supports transmitting packages up to
- * STEDMA40_MAX_SEG_SIZE << data_width. Calculate the total number of
- * dma elements required to send the entire sg list
+ * STEDMA40_MAX_SEG_SIZE * data_width, where data_width is stored in Bytes.
+ *
+ * Calculate the total number of dma elements required to send the entire sg list.
  */
 static int d40_size_2_dmalen(int size, u32 data_width1, u32 data_width2)
 {
         int dmalen;
         u32 max_w = max(data_width1, data_width2);
         u32 min_w = min(data_width1, data_width2);
-        u32 seg_max = ALIGN(STEDMA40_MAX_SEG_SIZE << min_w, 1 << max_w);
+        u32 seg_max = ALIGN(STEDMA40_MAX_SEG_SIZE * min_w, max_w);
 
         if (seg_max > STEDMA40_MAX_SEG_SIZE)
-                seg_max -= (1 << max_w);
+                seg_max -= max_w;
 
-        if (!IS_ALIGNED(size, 1 << max_w))
+        if (!IS_ALIGNED(size, max_w))
                 return -EINVAL;
 
         if (size <= seg_max)
@@ -1464,7 +1465,7 @@ static u32 d40_residue(struct d40_chan *d40c)
                           >> D40_SREG_ELEM_PHY_ECNT_POS;
         }
 
-        return num_elt * (1 << d40c->dma_cfg.dst_info.data_width);
+        return num_elt * d40c->dma_cfg.dst_info.data_width;
 }
 
 static bool d40_tx_is_linked(struct d40_chan *d40c)
@@ -1784,9 +1785,9 @@ static int d40_validate_conf(struct d40_chan *d40c,
         }
 
         if (d40_psize_2_burst_size(is_log, conf->src_info.psize) *
-            (1 << conf->src_info.data_width) !=
+            conf->src_info.data_width !=
             d40_psize_2_burst_size(is_log, conf->dst_info.psize) *
-            (1 << conf->dst_info.data_width)) {
+            conf->dst_info.data_width) {
                 /*
                  * The DMAC hardware only supports
                  * src (burst x width) == dst (burst x width)
@@ -2673,33 +2674,10 @@ static void d40_terminate_all(struct dma_chan *chan)
 static int
 dma40_config_to_halfchannel(struct d40_chan *d40c,
                             struct stedma40_half_channel_info *info,
-                            enum dma_slave_buswidth width,
                             u32 maxburst)
 {
-        enum stedma40_periph_data_width addr_width;
         int psize;
 
-        switch (width) {
-        case DMA_SLAVE_BUSWIDTH_1_BYTE:
-                addr_width = STEDMA40_BYTE_WIDTH;
-                break;
-        case DMA_SLAVE_BUSWIDTH_2_BYTES:
-                addr_width = STEDMA40_HALFWORD_WIDTH;
-                break;
-        case DMA_SLAVE_BUSWIDTH_4_BYTES:
-                addr_width = STEDMA40_WORD_WIDTH;
-                break;
-        case DMA_SLAVE_BUSWIDTH_8_BYTES:
-                addr_width = STEDMA40_DOUBLEWORD_WIDTH;
-                break;
-        default:
-                dev_err(d40c->base->dev,
-                        "illegal peripheral address width "
-                        "requested (%d)\n",
-                        width);
-                return -EINVAL;
-        }
-
         if (chan_is_logical(d40c)) {
                 if (maxburst >= 16)
                         psize = STEDMA40_PSIZE_LOG_16;
@@ -2720,7 +2698,6 @@ dma40_config_to_halfchannel(struct d40_chan *d40c,
                         psize = STEDMA40_PSIZE_PHY_1;
         }
 
-        info->data_width = addr_width;
         info->psize = psize;
         info->flow_ctrl = STEDMA40_NO_FLOW_CTRL;
 
@@ -2804,14 +2781,24 @@ static int d40_set_runtime_config(struct dma_chan *chan,
                 src_maxburst = dst_maxburst * dst_addr_width / src_addr_width;
         }
 
+        /* Only valid widths are; 1, 2, 4 and 8. */
+        if (src_addr_width <= DMA_SLAVE_BUSWIDTH_UNDEFINED ||
+            src_addr_width >  DMA_SLAVE_BUSWIDTH_8_BYTES   ||
+            dst_addr_width <= DMA_SLAVE_BUSWIDTH_UNDEFINED ||
+            dst_addr_width >  DMA_SLAVE_BUSWIDTH_8_BYTES   ||
+            ((src_addr_width > 1) && (src_addr_width & 1)) ||
+            ((dst_addr_width > 1) && (dst_addr_width & 1)))
+                return -EINVAL;
+
+        cfg->src_info.data_width = src_addr_width;
+        cfg->dst_info.data_width = dst_addr_width;
+
         ret = dma40_config_to_halfchannel(d40c, &cfg->src_info,
-                                          src_addr_width,
                                           src_maxburst);
         if (ret)
                 return ret;
 
         ret = dma40_config_to_halfchannel(d40c, &cfg->dst_info,
-                                          dst_addr_width,
                                           dst_maxburst);
         if (ret)
                 return ret;