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Date: Fri, 5 Feb 2016 18:19:22 -0500
From: Alexandre Bounine <alexandre.bounine@....com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexandre Bounine <alexandre.bounine@....com>,
Matt Porter <mporter@...nel.crashing.org>,
Aurelien Jacquiot <a-jacquiot@...com>,
Andre van Herk <andre.van.herk@...drive-technologies.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 06/30] 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 <alexandre.bounine@....com>
Cc: Matt Porter <mporter@...nel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@...com>
Cc: Andre van Herk <andre.van.herk@...drive-technologies.com>
Cc: linux-kernel@...r.kernel.org
---
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 f81d011..d675a44 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 4729594..500e1e0 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);
--
1.7.8.4
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