dmaengine: mv_xor: Add support for scatter-gather DMA mode
authorStefan Roese <sr@denx.de>
Wed, 26 Oct 2016 08:10:25 +0000 (10:10 +0200)
committerVinod Koul <vinod.koul@intel.com>
Fri, 25 Nov 2016 05:46:36 +0000 (11:16 +0530)
This patch adds memory to memory scatter-gather support to the Marvell
mv_or DMA driver.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Marcin Wojtas <mw@semihalf.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
drivers/dma/mv_xor.c
drivers/dma/mv_xor.h

index 23f7528..b0d09d9 100644 (file)
@@ -68,6 +68,36 @@ static void mv_desc_init(struct mv_xor_desc_slot *desc,
        hw_desc->byte_count = byte_count;
 }
 
+/* Populate the descriptor */
+static void mv_xor_config_sg_ll_desc(struct mv_xor_desc_slot *desc,
+                                    dma_addr_t dma_src, dma_addr_t dma_dst,
+                                    u32 len, struct mv_xor_desc_slot *prev)
+{
+       struct mv_xor_desc *hw_desc = desc->hw_desc;
+
+       hw_desc->status = XOR_DESC_DMA_OWNED;
+       hw_desc->phy_next_desc = 0;
+       /* Configure for XOR with only one src address -> MEMCPY */
+       hw_desc->desc_command = XOR_DESC_OPERATION_XOR | (0x1 << 0);
+       hw_desc->phy_dest_addr = dma_dst;
+       hw_desc->phy_src_addr[0] = dma_src;
+       hw_desc->byte_count = len;
+
+       if (prev) {
+               struct mv_xor_desc *hw_prev = prev->hw_desc;
+
+               hw_prev->phy_next_desc = desc->async_tx.phys;
+       }
+}
+
+static void mv_xor_desc_config_eod(struct mv_xor_desc_slot *desc)
+{
+       struct mv_xor_desc *hw_desc = desc->hw_desc;
+
+       /* Enable end-of-descriptor interrupt */
+       hw_desc->desc_command |= XOR_DESC_EOD_INT_EN;
+}
+
 static void mv_desc_set_mode(struct mv_xor_desc_slot *desc)
 {
        struct mv_xor_desc *hw_desc = desc->hw_desc;
@@ -228,8 +258,13 @@ mv_chan_clean_completed_slots(struct mv_xor_chan *mv_chan)
        list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,
                                 node) {
 
-               if (async_tx_test_ack(&iter->async_tx))
+               if (async_tx_test_ack(&iter->async_tx)) {
                        list_move_tail(&iter->node, &mv_chan->free_slots);
+                       if (!list_empty(&iter->sg_tx_list)) {
+                               list_splice_tail_init(&iter->sg_tx_list,
+                                                       &mv_chan->free_slots);
+                       }
+               }
        }
        return 0;
 }
@@ -244,11 +279,20 @@ mv_desc_clean_slot(struct mv_xor_desc_slot *desc,
        /* the client is allowed to attach dependent operations
         * until 'ack' is set
         */
-       if (!async_tx_test_ack(&desc->async_tx))
+       if (!async_tx_test_ack(&desc->async_tx)) {
                /* move this slot to the completed_slots */
                list_move_tail(&desc->node, &mv_chan->completed_slots);
-       else
+               if (!list_empty(&desc->sg_tx_list)) {
+                       list_splice_tail_init(&desc->sg_tx_list,
+                                             &mv_chan->completed_slots);
+               }
+       } else {
                list_move_tail(&desc->node, &mv_chan->free_slots);
+               if (!list_empty(&desc->sg_tx_list)) {
+                       list_splice_tail_init(&desc->sg_tx_list,
+                                             &mv_chan->free_slots);
+               }
+       }
 
        return 0;
 }
@@ -450,6 +494,7 @@ static int mv_xor_alloc_chan_resources(struct dma_chan *chan)
                dma_async_tx_descriptor_init(&slot->async_tx, chan);
                slot->async_tx.tx_submit = mv_xor_tx_submit;
                INIT_LIST_HEAD(&slot->node);
+               INIT_LIST_HEAD(&slot->sg_tx_list);
                dma_desc = mv_chan->dma_desc_pool;
                slot->async_tx.phys = dma_desc + idx * MV_XOR_SLOT_SIZE;
                slot->idx = idx++;
@@ -617,6 +662,132 @@ mv_xor_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
        return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags);
 }
 
+/**
+ * mv_xor_prep_dma_sg - prepare descriptors for a memory sg transaction
+ * @chan: DMA channel
+ * @dst_sg: Destination scatter list
+ * @dst_sg_len: Number of entries in destination scatter list
+ * @src_sg: Source scatter list
+ * @src_sg_len: Number of entries in source scatter list
+ * @flags: transfer ack flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *
+mv_xor_prep_dma_sg(struct dma_chan *chan, struct scatterlist *dst_sg,
+                  unsigned int dst_sg_len, struct scatterlist *src_sg,
+                  unsigned int src_sg_len, unsigned long flags)
+{
+       struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
+       struct mv_xor_desc_slot *new;
+       struct mv_xor_desc_slot *first = NULL;
+       struct mv_xor_desc_slot *prev = NULL;
+       size_t len, dst_avail, src_avail;
+       dma_addr_t dma_dst, dma_src;
+       int desc_cnt = 0;
+       int ret;
+
+       dev_dbg(mv_chan_to_devp(mv_chan),
+               "%s dst_sg_len: %d src_sg_len: %d flags: %ld\n",
+               __func__, dst_sg_len, src_sg_len, flags);
+
+       dst_avail = sg_dma_len(dst_sg);
+       src_avail = sg_dma_len(src_sg);
+
+       /* Run until we are out of scatterlist entries */
+       while (true) {
+               /* Allocate and populate the descriptor */
+               desc_cnt++;
+               new = mv_chan_alloc_slot(mv_chan);
+               if (!new) {
+                       dev_err(mv_chan_to_devp(mv_chan),
+                               "Out of descriptors (desc_cnt=%d)!\n",
+                               desc_cnt);
+                       goto err;
+               }
+
+               len = min_t(size_t, src_avail, dst_avail);
+               len = min_t(size_t, len, MV_XOR_MAX_BYTE_COUNT);
+               if (len == 0)
+                       goto fetch;
+
+               if (len < MV_XOR_MIN_BYTE_COUNT) {
+                       dev_err(mv_chan_to_devp(mv_chan),
+                               "Transfer size of %zu too small!\n", len);
+                       goto err;
+               }
+
+               dma_dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) -
+                       dst_avail;
+               dma_src = sg_dma_address(src_sg) + sg_dma_len(src_sg) -
+                       src_avail;
+
+               /* Check if a new window needs to get added for 'dst' */
+               ret = mv_xor_add_io_win(mv_chan, dma_dst);
+               if (ret)
+                       goto err;
+
+               /* Check if a new window needs to get added for 'src' */
+               ret = mv_xor_add_io_win(mv_chan, dma_src);
+               if (ret)
+                       goto err;
+
+               /* Populate the descriptor */
+               mv_xor_config_sg_ll_desc(new, dma_src, dma_dst, len, prev);
+               prev = new;
+               dst_avail -= len;
+               src_avail -= len;
+
+               if (!first)
+                       first = new;
+               else
+                       list_move_tail(&new->node, &first->sg_tx_list);
+
+fetch:
+               /* Fetch the next dst scatterlist entry */
+               if (dst_avail == 0) {
+                       if (dst_sg_len == 0)
+                               break;
+
+                       /* Fetch the next entry: if there are no more: done */
+                       dst_sg = sg_next(dst_sg);
+                       if (dst_sg == NULL)
+                               break;
+
+                       dst_sg_len--;
+                       dst_avail = sg_dma_len(dst_sg);
+               }
+
+               /* Fetch the next src scatterlist entry */
+               if (src_avail == 0) {
+                       if (src_sg_len == 0)
+                               break;
+
+                       /* Fetch the next entry: if there are no more: done */
+                       src_sg = sg_next(src_sg);
+                       if (src_sg == NULL)
+                               break;
+
+                       src_sg_len--;
+                       src_avail = sg_dma_len(src_sg);
+               }
+       }
+
+       /* Set the EOD flag in the last descriptor */
+       mv_xor_desc_config_eod(new);
+       first->async_tx.flags = flags;
+
+       return &first->async_tx;
+
+err:
+       /* Cleanup: Move all descriptors back into the free list */
+       spin_lock_bh(&mv_chan->lock);
+       mv_desc_clean_slot(first, mv_chan);
+       spin_unlock_bh(&mv_chan->lock);
+
+       return NULL;
+}
+
 static void mv_xor_free_chan_resources(struct dma_chan *chan)
 {
        struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
@@ -1083,6 +1254,8 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
                dma_dev->device_prep_dma_interrupt = mv_xor_prep_dma_interrupt;
        if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
                dma_dev->device_prep_dma_memcpy = mv_xor_prep_dma_memcpy;
+       if (dma_has_cap(DMA_SG, dma_dev->cap_mask))
+               dma_dev->device_prep_dma_sg = mv_xor_prep_dma_sg;
        if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
                dma_dev->max_xor = 8;
                dma_dev->device_prep_dma_xor = mv_xor_prep_dma_xor;
@@ -1132,10 +1305,11 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
                        goto err_free_irq;
        }
 
-       dev_info(&pdev->dev, "Marvell XOR (%s): ( %s%s%s)\n",
+       dev_info(&pdev->dev, "Marvell XOR (%s): ( %s%s%s%s)\n",
                 mv_chan->op_in_desc ? "Descriptor Mode" : "Registers Mode",
                 dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "xor " : "",
                 dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "cpy " : "",
+                dma_has_cap(DMA_SG, dma_dev->cap_mask) ? "sg " : "",
                 dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask) ? "intr " : "");
 
        dma_async_device_register(dma_dev);
@@ -1378,6 +1552,7 @@ static int mv_xor_probe(struct platform_device *pdev)
 
                        dma_cap_zero(cap_mask);
                        dma_cap_set(DMA_MEMCPY, cap_mask);
+                       dma_cap_set(DMA_SG, cap_mask);
                        dma_cap_set(DMA_XOR, cap_mask);
                        dma_cap_set(DMA_INTERRUPT, cap_mask);
 
index 88eeab2..cf921dd 100644 (file)
@@ -148,6 +148,7 @@ struct mv_xor_chan {
  */
 struct mv_xor_desc_slot {
        struct list_head        node;
+       struct list_head        sg_tx_list;
        enum dma_transaction_type       type;
        void                    *hw_desc;
        u16                     idx;