dmaengine/amba-pl08x: Add prep_single_byte_llis() routine
Viresh Kumar [Fri, 5 Aug 2011 10:02:39 +0000 (15:02 +0530)]
Code for creating single byte llis is present at several places. Create a
routine to avoid code redundancy.

Also, we don't need one lli per single byte transfer, we can have single lli to
do all single byte transfer.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/amba-pl08x.c

index e5930d5..45d8a5d 100644 (file)
@@ -559,6 +559,14 @@ static void pl08x_fill_lli_for_desc(struct pl08x_lli_build_data *bd,
        bd->remainder -= len;
 }
 
+static inline void prep_byte_width_lli(struct pl08x_lli_build_data *bd,
+               u32 *cctl, u32 len, int num_llis, size_t *total_bytes)
+{
+       *cctl = pl08x_cctl_bits(*cctl, 1, 1, len);
+       pl08x_fill_lli_for_desc(bd, num_llis, len, *cctl);
+       (*total_bytes) += len;
+}
+
 /*
  * This fills in the table of LLIs for the transfer descriptor
  * Note that we assume we never have to change the burst sizes
@@ -570,7 +578,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
        struct pl08x_bus_data *mbus, *sbus;
        struct pl08x_lli_build_data bd;
        int num_llis = 0;
-       u32 cctl;
+       u32 cctl, early_bytes = 0;
        size_t max_bytes_per_lli, total_bytes = 0;
        struct pl08x_lli *llis_va;
 
@@ -619,29 +627,27 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
                 mbus == &bd.srcbus ? "src" : "dst",
                 sbus == &bd.srcbus ? "src" : "dst");
 
-       if (txd->len < mbus->buswidth) {
-               /* Less than a bus width available - send as single bytes */
-               while (bd.remainder) {
-                       dev_vdbg(&pl08x->adev->dev,
-                                "%s single byte LLIs for a transfer of "
-                                "less than a bus width (remain 0x%08x)\n",
-                                __func__, bd.remainder);
-                       cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
-                       pl08x_fill_lli_for_desc(&bd, num_llis++, 1, cctl);
-                       total_bytes++;
-               }
-       } else {
-               /* Make one byte LLIs until master bus is aligned */
-               while ((mbus->addr) % (mbus->buswidth)) {
-                       dev_vdbg(&pl08x->adev->dev,
-                               "%s adjustment lli for less than bus width "
-                                "(remain 0x%08x)\n",
-                                __func__, bd.remainder);
-                       cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
-                       pl08x_fill_lli_for_desc(&bd, num_llis++, 1, cctl);
-                       total_bytes++;
-               }
+       /*
+        * Send byte by byte for following cases
+        * - Less than a bus width available
+        * - until master bus is aligned
+        */
+       if (bd.remainder < mbus->buswidth)
+               early_bytes = bd.remainder;
+       else if ((mbus->addr) % (mbus->buswidth)) {
+               early_bytes = mbus->buswidth - (mbus->addr) % (mbus->buswidth);
+               if ((bd.remainder - early_bytes) < mbus->buswidth)
+                       early_bytes = bd.remainder;
+       }
+
+       if (early_bytes) {
+               dev_vdbg(&pl08x->adev->dev, "%s byte width LLIs "
+                               "(remain 0x%08x)\n", __func__, bd.remainder);
+               prep_byte_width_lli(&bd, &cctl, early_bytes, num_llis++,
+                               &total_bytes);
+       }
 
+       if (bd.remainder) {
                /*
                 * Master now aligned
                 * - if slave is not then we must set its width down
@@ -692,13 +698,12 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
                /*
                 * Send any odd bytes
                 */
-               while (bd.remainder) {
-                       cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
+               if (bd.remainder) {
                        dev_vdbg(&pl08x->adev->dev,
-                               "%s align with boundary, single odd byte (remain %zu)\n",
+                               "%s align with boundary, send odd bytes (remain %zu)\n",
                                __func__, bd.remainder);
-                       pl08x_fill_lli_for_desc(&bd, num_llis++, 1, cctl);
-                       total_bytes++;
+                       prep_byte_width_lli(&bd, &cctl, bd.remainder,
+                                       num_llis++, &total_bytes);
                }
        }