From d2a321f37ed49de86058b5daaf50a11d3ee2d61f Mon Sep 17 00:00:00 2001 From: Alexandre Bounine Date: Tue, 22 Mar 2016 14:25:57 -0700 Subject: [PATCH] rapidio/tsi721_dma: fix pending transaction queue handling Fix pending DMA request queue handling to avoid broken ordering during concurrent request submissions. Signed-off-by: Alexandre Bounine Cc: Matt Porter Cc: Aurelien Jacquiot Cc: Andre van Herk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rapidio/devices/tsi721.h | 2 +- drivers/rapidio/devices/tsi721_dma.c | 60 ++++++++++++++-------------- 2 files changed, 32 insertions(+), 30 deletions(-) diff --git a/drivers/rapidio/devices/tsi721.h b/drivers/rapidio/devices/tsi721.h index f81d01149b39..d675a44ffc17 100644 --- a/drivers/rapidio/devices/tsi721.h +++ b/drivers/rapidio/devices/tsi721.h @@ -674,7 +674,7 @@ struct tsi721_bdma_chan { struct dma_chan dchan; struct tsi721_tx_desc *tx_desc; spinlock_t lock; - struct list_head active_list; + struct tsi721_tx_desc *active_tx; struct list_head queue; struct list_head free_list; struct tasklet_struct tasklet; diff --git a/drivers/rapidio/devices/tsi721_dma.c b/drivers/rapidio/devices/tsi721_dma.c index 47295940a868..500e1e044c36 100644 --- a/drivers/rapidio/devices/tsi721_dma.c +++ b/drivers/rapidio/devices/tsi721_dma.c @@ -63,14 +63,6 @@ struct tsi721_tx_desc *to_tsi721_desc(struct dma_async_tx_descriptor *txd) return container_of(txd, struct tsi721_tx_desc, txd); } -static inline -struct tsi721_tx_desc *tsi721_dma_first_active( - struct tsi721_bdma_chan *bdma_chan) -{ - return list_first_entry(&bdma_chan->active_list, - struct tsi721_tx_desc, desc_node); -} - static int tsi721_bdma_ch_init(struct tsi721_bdma_chan *bdma_chan, int bd_num) { struct tsi721_dma_desc *bd_ptr; @@ -534,23 +526,30 @@ entry_done: return err; } -static void tsi721_advance_work(struct tsi721_bdma_chan *bdma_chan) +static void tsi721_advance_work(struct tsi721_bdma_chan *bdma_chan, + struct tsi721_tx_desc *desc) { - struct tsi721_tx_desc *desc; int err; dev_dbg(bdma_chan->dchan.device->dev, "%s: Enter\n", __func__); + if (!tsi721_dma_is_idle(bdma_chan)) + return; + /* - * If there are any new transactions in the queue add them - * into the processing list - */ - if (!list_empty(&bdma_chan->queue)) - list_splice_init(&bdma_chan->queue, &bdma_chan->active_list); + * If there is no data transfer in progress, fetch new descriptor from + * the pending queue. + */ + + if (desc == NULL && bdma_chan->active_tx == NULL && + !list_empty(&bdma_chan->queue)) { + desc = list_first_entry(&bdma_chan->queue, + struct tsi721_tx_desc, desc_node); + list_del_init((&desc->desc_node)); + bdma_chan->active_tx = desc; + } - /* Start new transaction (if available) */ - if (!list_empty(&bdma_chan->active_list)) { - desc = tsi721_dma_first_active(bdma_chan); + if (desc) { err = tsi721_submit_sg(desc); if (!err) tsi721_start_dma(bdma_chan); @@ -581,6 +580,10 @@ static void tsi721_dma_tasklet(unsigned long data) dev_err(bdma_chan->dchan.device->dev, "%s: DMA ERROR - DMAC%d_STS = 0x%x\n", __func__, bdma_chan->id, dmac_sts); + + spin_lock(&bdma_chan->lock); + bdma_chan->active_tx = NULL; + spin_unlock(&bdma_chan->lock); } if (dmac_int & TSI721_DMAC_INT_STFULL) { @@ -594,7 +597,7 @@ static void tsi721_dma_tasklet(unsigned long data) tsi721_clr_stat(bdma_chan); spin_lock(&bdma_chan->lock); - desc = tsi721_dma_first_active(bdma_chan); + desc = bdma_chan->active_tx; if (desc->sg_len == 0) { dma_async_tx_callback callback = NULL; @@ -606,14 +609,15 @@ static void tsi721_dma_tasklet(unsigned long data) callback = desc->txd.callback; param = desc->txd.callback_param; } - list_move(&desc->desc_node, &bdma_chan->free_list); + list_add(&desc->desc_node, &bdma_chan->free_list); + bdma_chan->active_tx = NULL; spin_unlock(&bdma_chan->lock); if (callback) callback(param); spin_lock(&bdma_chan->lock); } - tsi721_advance_work(bdma_chan); + tsi721_advance_work(bdma_chan, bdma_chan->active_tx); spin_unlock(&bdma_chan->lock); } @@ -720,9 +724,6 @@ static void tsi721_free_chan_resources(struct dma_chan *dchan) if (bdma_chan->bd_base == NULL) return; - BUG_ON(!list_empty(&bdma_chan->active_list)); - BUG_ON(!list_empty(&bdma_chan->queue)); - tsi721_bdma_interrupt_enable(bdma_chan, 0); bdma_chan->active = false; tsi721_sync_dma_irq(bdma_chan); @@ -745,11 +746,11 @@ static void tsi721_issue_pending(struct dma_chan *dchan) dev_dbg(dchan->device->dev, "%s: Enter\n", __func__); + spin_lock_bh(&bdma_chan->lock); if (tsi721_dma_is_idle(bdma_chan) && bdma_chan->active) { - spin_lock_bh(&bdma_chan->lock); - tsi721_advance_work(bdma_chan); - spin_unlock_bh(&bdma_chan->lock); + tsi721_advance_work(bdma_chan, NULL); } + spin_unlock_bh(&bdma_chan->lock); } static @@ -839,7 +840,8 @@ static int tsi721_terminate_all(struct dma_chan *dchan) } while ((dmac_int & TSI721_DMAC_INT_SUSP) == 0); } - list_splice_init(&bdma_chan->active_list, &list); + if (bdma_chan->active_tx) + list_add(&bdma_chan->active_tx->desc_node, &list); list_splice_init(&bdma_chan->queue, &list); list_for_each_entry_safe(desc, _d, &list, desc_node) @@ -875,7 +877,7 @@ int tsi721_register_dma(struct tsi721_device *priv) spin_lock_init(&bdma_chan->lock); - INIT_LIST_HEAD(&bdma_chan->active_list); + bdma_chan->active_tx = NULL; INIT_LIST_HEAD(&bdma_chan->queue); INIT_LIST_HEAD(&bdma_chan->free_list); -- 2.20.1