From 7096f36e5388beb06b80576d3ccc3a0df2760035 Mon Sep 17 00:00:00 2001 From: Kedareswara rao Appana Date: Fri, 26 Feb 2016 19:33:51 +0530 Subject: [PATCH] dmaengine: xilinx_vdma: Improve SG engine handling The current driver allows user to queue up multiple segments on to a single transaction descriptor. User will submit this single desc and in the issue_pending() we decode multiple segments and submit to SG HW engine. We free up the allocated_desc when it is submitted to the HW. Existing code prevents the user to prepare multiple trasactions at same time as we are overwrite with the allocated_desc. The best utilization of HW SG engine would happen if we collate the pending list when we start dma this patch updates the same. Signed-off-by: Kedareswara rao Appana Signed-off-by: Vinod Koul --- drivers/dma/xilinx/xilinx_vdma.c | 127 ++++++++++++++++++------------- 1 file changed, 72 insertions(+), 55 deletions(-) diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c index 6f4b5017ca3b..06bffec934d2 100644 --- a/drivers/dma/xilinx/xilinx_vdma.c +++ b/drivers/dma/xilinx/xilinx_vdma.c @@ -190,8 +190,7 @@ struct xilinx_vdma_tx_descriptor { * @desc_offset: TX descriptor registers offset * @lock: Descriptor operation lock * @pending_list: Descriptors waiting - * @active_desc: Active descriptor - * @allocated_desc: Allocated descriptor + * @active_list: Descriptors ready to submit * @done_list: Complete descriptors * @common: DMA common channel * @desc_pool: Descriptors pool @@ -206,6 +205,7 @@ struct xilinx_vdma_tx_descriptor { * @tasklet: Cleanup work after irq * @config: Device configuration info * @flush_on_fsync: Flush on Frame sync + * @desc_pendingcount: Descriptor pending count */ struct xilinx_vdma_chan { struct xilinx_vdma_device *xdev; @@ -213,8 +213,7 @@ struct xilinx_vdma_chan { u32 desc_offset; spinlock_t lock; struct list_head pending_list; - struct xilinx_vdma_tx_descriptor *active_desc; - struct xilinx_vdma_tx_descriptor *allocated_desc; + struct list_head active_list; struct list_head done_list; struct dma_chan common; struct dma_pool *desc_pool; @@ -229,6 +228,7 @@ struct xilinx_vdma_chan { struct tasklet_struct tasklet; struct xilinx_vdma_config config; bool flush_on_fsync; + u32 desc_pendingcount; }; /** @@ -342,19 +342,11 @@ static struct xilinx_vdma_tx_descriptor * xilinx_vdma_alloc_tx_descriptor(struct xilinx_vdma_chan *chan) { struct xilinx_vdma_tx_descriptor *desc; - unsigned long flags; - - if (chan->allocated_desc) - return chan->allocated_desc; desc = kzalloc(sizeof(*desc), GFP_KERNEL); if (!desc) return NULL; - spin_lock_irqsave(&chan->lock, flags); - chan->allocated_desc = desc; - spin_unlock_irqrestore(&chan->lock, flags); - INIT_LIST_HEAD(&desc->segments); return desc; @@ -412,9 +404,7 @@ static void xilinx_vdma_free_descriptors(struct xilinx_vdma_chan *chan) xilinx_vdma_free_desc_list(chan, &chan->pending_list); xilinx_vdma_free_desc_list(chan, &chan->done_list); - - xilinx_vdma_free_tx_descriptor(chan, chan->active_desc); - chan->active_desc = NULL; + xilinx_vdma_free_desc_list(chan, &chan->active_list); spin_unlock_irqrestore(&chan->lock, flags); } @@ -614,25 +604,26 @@ static void xilinx_vdma_start(struct xilinx_vdma_chan *chan) static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan) { struct xilinx_vdma_config *config = &chan->config; - struct xilinx_vdma_tx_descriptor *desc; + struct xilinx_vdma_tx_descriptor *desc, *tail_desc; unsigned long flags; u32 reg; - struct xilinx_vdma_tx_segment *head, *tail = NULL; + struct xilinx_vdma_tx_segment *tail_segment; if (chan->err) return; spin_lock_irqsave(&chan->lock, flags); - /* There's already an active descriptor, bail out. */ - if (chan->active_desc) - goto out_unlock; - if (list_empty(&chan->pending_list)) goto out_unlock; desc = list_first_entry(&chan->pending_list, struct xilinx_vdma_tx_descriptor, node); + tail_desc = list_last_entry(&chan->pending_list, + struct xilinx_vdma_tx_descriptor, node); + + tail_segment = list_last_entry(&tail_desc->segments, + struct xilinx_vdma_tx_segment, node); /* If it is SG mode and hardware is busy, cannot submit */ if (chan->has_sg && xilinx_vdma_is_running(chan) && @@ -645,14 +636,9 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan) * If hardware is idle, then all descriptors on the running lists are * done, start new transfers */ - if (chan->has_sg) { - head = list_first_entry(&desc->segments, - struct xilinx_vdma_tx_segment, node); - tail = list_entry(desc->segments.prev, - struct xilinx_vdma_tx_segment, node); - - vdma_ctrl_write(chan, XILINX_VDMA_REG_CURDESC, head->phys); - } + if (chan->has_sg) + vdma_ctrl_write(chan, XILINX_VDMA_REG_CURDESC, + desc->async_tx.phys); /* Configure the hardware using info in the config structure */ reg = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR); @@ -694,12 +680,15 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan) /* Start the transfer */ if (chan->has_sg) { - vdma_ctrl_write(chan, XILINX_VDMA_REG_TAILDESC, tail->phys); + vdma_ctrl_write(chan, XILINX_VDMA_REG_TAILDESC, + tail_segment->phys); } else { struct xilinx_vdma_tx_segment *segment, *last = NULL; int i = 0; - list_for_each_entry(segment, &desc->segments, node) { + list_for_each_entry(desc, &chan->pending_list, node) { + segment = list_first_entry(&desc->segments, + struct xilinx_vdma_tx_segment, node); vdma_desc_write(chan, XILINX_VDMA_REG_START_ADDRESS(i++), segment->hw.buf_addr); @@ -716,8 +705,8 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan) vdma_desc_write(chan, XILINX_VDMA_REG_VSIZE, last->hw.vsize); } - list_del(&desc->node); - chan->active_desc = desc; + list_splice_tail_init(&chan->pending_list, &chan->active_list); + chan->desc_pendingcount = 0; out_unlock: spin_unlock_irqrestore(&chan->lock, flags); @@ -742,21 +731,19 @@ static void xilinx_vdma_issue_pending(struct dma_chan *dchan) */ static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan) { - struct xilinx_vdma_tx_descriptor *desc; + struct xilinx_vdma_tx_descriptor *desc, *next; unsigned long flags; spin_lock_irqsave(&chan->lock, flags); - desc = chan->active_desc; - if (!desc) { - dev_dbg(chan->dev, "no running descriptors\n"); + if (list_empty(&chan->active_list)) goto out_unlock; - } - - dma_cookie_complete(&desc->async_tx); - list_add_tail(&desc->node, &chan->done_list); - chan->active_desc = NULL; + list_for_each_entry_safe(desc, next, &chan->active_list, node) { + list_del(&desc->node); + dma_cookie_complete(&desc->async_tx); + list_add_tail(&desc->node, &chan->done_list); + } out_unlock: spin_unlock_irqrestore(&chan->lock, flags); @@ -878,6 +865,44 @@ static irqreturn_t xilinx_vdma_irq_handler(int irq, void *data) return IRQ_HANDLED; } +/** + * append_desc_queue - Queuing descriptor + * @chan: Driver specific dma channel + * @desc: dma transaction descriptor + */ +static void append_desc_queue(struct xilinx_vdma_chan *chan, + struct xilinx_vdma_tx_descriptor *desc) +{ + struct xilinx_vdma_tx_segment *tail_segment; + struct xilinx_vdma_tx_descriptor *tail_desc; + + if (list_empty(&chan->pending_list)) + goto append; + + /* + * Add the hardware descriptor to the chain of hardware descriptors + * that already exists in memory. + */ + tail_desc = list_last_entry(&chan->pending_list, + struct xilinx_vdma_tx_descriptor, node); + tail_segment = list_last_entry(&tail_desc->segments, + struct xilinx_vdma_tx_segment, node); + tail_segment->hw.next_desc = (u32)desc->async_tx.phys; + + /* + * Add the software descriptor and all children to the list + * of pending transactions + */ +append: + list_add_tail(&desc->node, &chan->pending_list); + chan->desc_pendingcount++; + + if (unlikely(chan->desc_pendingcount > chan->num_frms)) { + dev_dbg(chan->dev, "desc pendingcount is too high\n"); + chan->desc_pendingcount = chan->num_frms; + } +} + /** * xilinx_vdma_tx_submit - Submit DMA transaction * @tx: Async transaction descriptor @@ -906,11 +931,8 @@ static dma_cookie_t xilinx_vdma_tx_submit(struct dma_async_tx_descriptor *tx) cookie = dma_cookie_assign(tx); - /* Append the transaction to the pending transactions queue. */ - list_add_tail(&desc->node, &chan->pending_list); - - /* Free the allocated desc */ - chan->allocated_desc = NULL; + /* Put this transaction onto the tail of the pending queue */ + append_desc_queue(chan, desc); spin_unlock_irqrestore(&chan->lock, flags); @@ -973,13 +995,6 @@ xilinx_vdma_dma_prep_interleaved(struct dma_chan *dchan, else hw->buf_addr = xt->src_start; - /* Link the previous next descriptor to current */ - if (!list_empty(&desc->segments)) { - prev = list_last_entry(&desc->segments, - struct xilinx_vdma_tx_segment, node); - prev->hw.next_desc = segment->phys; - } - /* Insert the segment into the descriptor segments list. */ list_add_tail(&segment->node, &desc->segments); @@ -988,7 +1003,7 @@ xilinx_vdma_dma_prep_interleaved(struct dma_chan *dchan, /* Link the last hardware descriptor with the first. */ segment = list_first_entry(&desc->segments, struct xilinx_vdma_tx_segment, node); - prev->hw.next_desc = segment->phys; + desc->async_tx.phys = segment->phys; return &desc->async_tx; @@ -1127,10 +1142,12 @@ static int xilinx_vdma_chan_probe(struct xilinx_vdma_device *xdev, chan->dev = xdev->dev; chan->xdev = xdev; chan->has_sg = xdev->has_sg; + chan->desc_pendingcount = 0x0; spin_lock_init(&chan->lock); INIT_LIST_HEAD(&chan->pending_list); INIT_LIST_HEAD(&chan->done_list); + INIT_LIST_HEAD(&chan->active_list); /* Retrieve the channel properties from the device tree */ has_dre = of_property_read_bool(node, "xlnx,include-dre"); -- 2.30.2