From: Xiang Wang <[email protected]> In some of our drivers (e.g. UART) we may stop a running DMA before it finishes. So we need APIs to know how many bytes have been transferred.
Signed-off-by: Xiang Wang <[email protected]> --- drivers/dma/mmp_pdma.c | 88 +++++++++++++++++++++++++++++++++++++++++++---- 1 files changed, 80 insertions(+), 8 deletions(-) diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c index c26699f..57cd047 100644 --- a/drivers/dma/mmp_pdma.c +++ b/drivers/dma/mmp_pdma.c @@ -104,7 +104,8 @@ struct mmp_pdma_chan { spinlock_t desc_lock; /* Descriptor list lock */ struct list_head chain_pending; /* Link descriptors queue for pending */ struct list_head chain_running; /* Link descriptors queue for running */ - bool idle; /* channel statue machine */ + enum dma_status status; /* channel status machine */ + u32 bytes_residue; struct dma_pool *desc_pool; /* Descriptors pool */ }; @@ -270,7 +271,7 @@ static void start_pending_queue(struct mmp_pdma_chan *chan) struct mmp_pdma_desc_sw *desc; /* still in running, irq will start the pending list */ - if (!chan->idle) { + if (chan->status == DMA_IN_PROGRESS) { dev_dbg(chan->dev, "DMA controller still busy\n"); return; } @@ -307,7 +308,64 @@ static void start_pending_queue(struct mmp_pdma_chan *chan) */ set_desc(chan->phy, desc->async_tx.phys); enable_chan(chan->phy); - chan->idle = false; + chan->status = DMA_IN_PROGRESS; + chan->bytes_residue = 0; +} + +/* + * Get the number of pending bytes. Should be called with desc_lock held + * because we are accessing desc list. + */ +static u32 mmp_pdma_get_bytes_residue(struct mmp_pdma_chan *chan) +{ + u32 reg, orig_pos, cur_pos, ddadr, residue = 0; + bool running_desc_found = false; + struct mmp_pdma_desc_sw *desc_sw; + + /* + * When a phy channel is unavailable, maybe it has been freed, return + * last stored value for safe. + */ + if (!chan->phy) + return chan->bytes_residue; + + reg = (chan->phy->idx << 4) + DDADR; + ddadr = readl_relaxed(chan->phy->base + reg); + + /* iterate over all descriptors to sum up the number of pending bytes */ + list_for_each_entry(desc_sw, &chan->chain_running, node) { + /* for the case of a running descriptor */ + if (desc_sw->desc.ddadr == ddadr && !running_desc_found) { + switch (chan->dir) { + case DMA_DEV_TO_MEM: + case DMA_MEM_TO_MEM: + reg = (chan->phy->idx << 4) + DTADR; + cur_pos = readl_relaxed(chan->phy->base + reg); + orig_pos = desc_sw->desc.dtadr; + break; + + case DMA_MEM_TO_DEV: + reg = (chan->phy->idx << 4) + DSADR; + cur_pos = readl_relaxed(chan->phy->base + reg); + orig_pos = desc_sw->desc.dsadr; + break; + + default: + cur_pos = 0; + orig_pos = 0; + } + residue = (u32)(desc_sw->desc.dcmd & DCMD_LENGTH) + + orig_pos - cur_pos; + running_desc_found = true; + continue; + } + + /* for the case of following un-started descriptors*/ + if (running_desc_found) + residue += (u32)(desc_sw->desc.dcmd & DCMD_LENGTH); + } + + return residue; } @@ -381,7 +439,7 @@ static int mmp_pdma_alloc_chan_resources(struct dma_chan *dchan) chan->phy->vchan = NULL; chan->phy = NULL; } - chan->idle = true; + chan->status = DMA_SUCCESS; chan->dev_addr = 0; return 1; } @@ -409,7 +467,7 @@ static void mmp_pdma_free_chan_resources(struct dma_chan *dchan) dma_pool_destroy(chan->desc_pool); chan->desc_pool = NULL; - chan->idle = true; + chan->status = DMA_SUCCESS; chan->dev_addr = 0; if (chan->phy) { chan->phy->vchan = NULL; @@ -588,9 +646,16 @@ static int mmp_pdma_control(struct dma_chan *dchan, enum dma_ctrl_cmd cmd, spin_lock_irqsave(&chan->desc_lock, flags); mmp_pdma_free_desc_list(chan, &chan->chain_pending); mmp_pdma_free_desc_list(chan, &chan->chain_running); + chan->bytes_residue = 0; spin_unlock_irqrestore(&chan->desc_lock, flags); - chan->idle = true; + chan->status = DMA_SUCCESS; break; + + case DMA_PAUSE: + disable_chan(chan->phy); + chan->status = DMA_PAUSED; + break; + case DMA_SLAVE_CONFIG: if (cfg->direction == DMA_DEV_TO_MEM) { chan->dcmd = DCMD_INCTRGADDR | DCMD_FLOWSRC; @@ -637,7 +702,9 @@ static enum dma_status mmp_pdma_tx_status(struct dma_chan *dchan, unsigned long flags; spin_lock_irqsave(&chan->desc_lock, flags); - ret = dma_cookie_status(dchan, cookie, txstate); + chan->bytes_residue = mmp_pdma_get_bytes_residue(chan); + dma_set_residue(txstate, chan->bytes_residue); + ret = chan->status; spin_unlock_irqrestore(&chan->desc_lock, flags); return ret; @@ -684,6 +751,8 @@ static void dma_do_tasklet(unsigned long data) dev_dbg(chan->dev, "completed_cookie=%d\n", cookie); } + /* update bytes_residue so that the user can query later on */ + chan->bytes_residue = mmp_pdma_get_bytes_residue(chan); /* * move the descriptors to a temporary list so we can drop the lock * during the entire cleanup operation @@ -691,7 +760,7 @@ static void dma_do_tasklet(unsigned long data) list_splice_tail_init(&chan->chain_running, &chain_cleanup); /* the hardware is now idle and ready for more */ - chan->idle = true; + chan->status = DMA_SUCCESS; /* Start any pending transactions automatically */ start_pending_queue(chan); @@ -750,6 +819,9 @@ static int mmp_pdma_chan_init(struct mmp_pdma_device *pdev, INIT_LIST_HEAD(&chan->chain_pending); INIT_LIST_HEAD(&chan->chain_running); + chan->status = DMA_SUCCESS; + chan->bytes_residue = 0; + /* register virt channel to dma engine */ list_add_tail(&chan->chan.device_node, &pdev->device.channels); -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
