dmaengine: ti: k3-udma: Move the TR counter calculation to helper function

Move the TR counter parameter configuration code out from the prep_memcpy
callback to a helper function to allow a generic re-usable code for other
TR based transfers.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20200214091441.27535-4-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index cb9259e104b4b45aea3c3849c39b5d0aeae47ee0..9b00013d6f633c51f4b8949e5734c80e417b7424 100644 (file)
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -2029,6 +2029,51 @@ static struct udma_desc *udma_alloc_tr_desc(struct udma_chan *uc,
        return d;
 }
 
+/**
+ * udma_get_tr_counters - calculate TR counters for a given length
+ * @len: Length of the trasnfer
+ * @align_to: Preferred alignment
+ * @tr0_cnt0: First TR icnt0
+ * @tr0_cnt1: First TR icnt1
+ * @tr1_cnt0: Second (if used) TR icnt0
+ *
+ * For len < SZ_64K only one TR is enough, tr1_cnt0 is not updated
+ * For len >= SZ_64K two TRs are used in a simple way:
+ * First TR: SZ_64K-alignment blocks (tr0_cnt0, tr0_cnt1)
+ * Second TR: the remaining length (tr1_cnt0)
+ *
+ * Returns the number of TRs the length needs (1 or 2)
+ * -EINVAL if the length can not be supported
+ */
+static int udma_get_tr_counters(size_t len, unsigned long align_to,
+                               u16 *tr0_cnt0, u16 *tr0_cnt1, u16 *tr1_cnt0)
+{
+       if (len < SZ_64K) {
+               *tr0_cnt0 = len;
+               *tr0_cnt1 = 1;
+
+               return 1;
+       }
+
+       if (align_to > 3)
+               align_to = 3;
+
+realign:
+       *tr0_cnt0 = SZ_64K - BIT(align_to);
+       if (len / *tr0_cnt0 >= SZ_64K) {
+               if (align_to) {
+                       align_to--;
+                       goto realign;
+               }
+               return -EINVAL;
+       }
+
+       *tr0_cnt1 = len / *tr0_cnt0;
+       *tr1_cnt0 = len % *tr0_cnt0;
+
+       return 2;
+}
+
 static struct udma_desc *
 udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
                      unsigned int sglen, enum dma_transfer_direction dir,
@@ -2581,29 +2626,12 @@ udma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
                return NULL;
        }
 
-       if (len < SZ_64K) {
-               num_tr = 1;
-               tr0_cnt0 = len;
-               tr0_cnt1 = 1;
-       } else {
-               unsigned long align_to = __ffs(src | dest);
-
-               if (align_to > 3)
-                       align_to = 3;
-               /*
-                * Keep simple: tr0: SZ_64K-alignment blocks,
-                *              tr1: the remaining
-                */
-               num_tr = 2;
-               tr0_cnt0 = (SZ_64K - BIT(align_to));
-               if (len / tr0_cnt0 >= SZ_64K) {
-                       dev_err(uc->ud->dev, "size %zu is not supported\n",
-                               len);
-                       return NULL;
-               }
-
-               tr0_cnt1 = len / tr0_cnt0;
-               tr1_cnt0 = len % tr0_cnt0;
+       num_tr = udma_get_tr_counters(len, __ffs(src | dest), &tr0_cnt0,
+                                     &tr0_cnt1, &tr1_cnt0);
+       if (num_tr < 0) {
+               dev_err(uc->ud->dev, "size %zu is not supported\n",
+                       len);
+               return NULL;
        }
 
        d = udma_alloc_tr_desc(uc, tr_size, num_tr, DMA_MEM_TO_MEM);