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path: root/drivers/dma/at_hdmac.c
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Diffstat (limited to 'drivers/dma/at_hdmac.c')
-rw-r--r--drivers/dma/at_hdmac.c153
1 files changed, 60 insertions, 93 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 5a50423b7378..858bd64f1313 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -256,6 +256,8 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
ATC_SPIP_BOUNDARY(first->boundary));
channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) |
ATC_DPIP_BOUNDARY(first->boundary));
+ /* Don't allow CPU to reorder channel enable. */
+ wmb();
dma_writel(atdma, CHER, atchan->mask);
vdbg_dump_regs(atchan);
@@ -316,7 +318,8 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
struct at_desc *desc_first = atc_first_active(atchan);
struct at_desc *desc;
int ret;
- u32 ctrla, dscr, trials;
+ u32 ctrla, dscr;
+ unsigned int i;
/*
* If the cookie doesn't match to the currently running transfer then
@@ -386,7 +389,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
dscr = channel_readl(atchan, DSCR);
rmb(); /* ensure DSCR is read before CTRLA */
ctrla = channel_readl(atchan, CTRLA);
- for (trials = 0; trials < ATC_MAX_DSCR_TRIALS; ++trials) {
+ for (i = 0; i < ATC_MAX_DSCR_TRIALS; ++i) {
u32 new_dscr;
rmb(); /* ensure DSCR is read after CTRLA */
@@ -412,7 +415,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
rmb(); /* ensure DSCR is read before CTRLA */
ctrla = channel_readl(atchan, CTRLA);
}
- if (unlikely(trials >= ATC_MAX_DSCR_TRIALS))
+ if (unlikely(i == ATC_MAX_DSCR_TRIALS))
return -ETIMEDOUT;
/* for the first descriptor we can be more accurate */
@@ -462,18 +465,6 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
if (!atc_chan_is_cyclic(atchan))
dma_cookie_complete(txd);
- /* If the transfer was a memset, free our temporary buffer */
- if (desc->memset_buffer) {
- dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
- desc->memset_paddr);
- desc->memset_buffer = false;
- }
-
- /* move children to free_list */
- list_splice_init(&desc->tx_list, &atchan->free_list);
- /* move myself to free_list */
- list_move(&desc->desc_node, &atchan->free_list);
-
spin_unlock_irqrestore(&atchan->lock, flags);
dma_descriptor_unmap(txd);
@@ -483,42 +474,20 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
dmaengine_desc_get_callback_invoke(txd, NULL);
dma_run_dependencies(txd);
-}
-
-/**
- * atc_complete_all - finish work for all transactions
- * @atchan: channel to complete transactions for
- *
- * Eventually submit queued descriptors if any
- *
- * Assume channel is idle while calling this function
- * Called with atchan->lock held and bh disabled
- */
-static void atc_complete_all(struct at_dma_chan *atchan)
-{
- struct at_desc *desc, *_desc;
- LIST_HEAD(list);
- unsigned long flags;
-
- dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
spin_lock_irqsave(&atchan->lock, flags);
-
- /*
- * Submit queued descriptors ASAP, i.e. before we go through
- * the completed ones.
- */
- if (!list_empty(&atchan->queue))
- atc_dostart(atchan, atc_first_queued(atchan));
- /* empty active_list now it is completed */
- list_splice_init(&atchan->active_list, &list);
- /* empty queue list by moving descriptors (if any) to active_list */
- list_splice_init(&atchan->queue, &atchan->active_list);
-
+ /* move children to free_list */
+ list_splice_init(&desc->tx_list, &atchan->free_list);
+ /* add myself to free_list */
+ list_add(&desc->desc_node, &atchan->free_list);
spin_unlock_irqrestore(&atchan->lock, flags);
- list_for_each_entry_safe(desc, _desc, &list, desc_node)
- atc_chain_complete(atchan, desc);
+ /* If the transfer was a memset, free our temporary buffer */
+ if (desc->memset_buffer) {
+ dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
+ desc->memset_paddr);
+ desc->memset_buffer = false;
+ }
}
/**
@@ -527,26 +496,28 @@ static void atc_complete_all(struct at_dma_chan *atchan)
*/
static void atc_advance_work(struct at_dma_chan *atchan)
{
+ struct at_desc *desc;
unsigned long flags;
- int ret;
dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
spin_lock_irqsave(&atchan->lock, flags);
- ret = atc_chan_is_enabled(atchan);
- spin_unlock_irqrestore(&atchan->lock, flags);
- if (ret)
- return;
-
- if (list_empty(&atchan->active_list) ||
- list_is_singular(&atchan->active_list))
- return atc_complete_all(atchan);
+ if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list))
+ return spin_unlock_irqrestore(&atchan->lock, flags);
- atc_chain_complete(atchan, atc_first_active(atchan));
+ desc = atc_first_active(atchan);
+ /* Remove the transfer node from the active list. */
+ list_del_init(&desc->desc_node);
+ spin_unlock_irqrestore(&atchan->lock, flags);
+ atc_chain_complete(atchan, desc);
/* advance work */
spin_lock_irqsave(&atchan->lock, flags);
- atc_dostart(atchan, atc_first_active(atchan));
+ if (!list_empty(&atchan->active_list)) {
+ desc = atc_first_queued(atchan);
+ list_move_tail(&desc->desc_node, &atchan->active_list);
+ atc_dostart(atchan, desc);
+ }
spin_unlock_irqrestore(&atchan->lock, flags);
}
@@ -558,6 +529,7 @@ static void atc_advance_work(struct at_dma_chan *atchan)
static void atc_handle_error(struct at_dma_chan *atchan)
{
struct at_desc *bad_desc;
+ struct at_desc *desc;
struct at_desc *child;
unsigned long flags;
@@ -570,13 +542,12 @@ static void atc_handle_error(struct at_dma_chan *atchan)
bad_desc = atc_first_active(atchan);
list_del_init(&bad_desc->desc_node);
- /* As we are stopped, take advantage to push queued descriptors
- * in active_list */
- list_splice_init(&atchan->queue, atchan->active_list.prev);
-
/* Try to restart the controller */
- if (!list_empty(&atchan->active_list))
- atc_dostart(atchan, atc_first_active(atchan));
+ if (!list_empty(&atchan->active_list)) {
+ desc = atc_first_queued(atchan);
+ list_move_tail(&desc->desc_node, &atchan->active_list);
+ atc_dostart(atchan, desc);
+ }
/*
* KERN_CRITICAL may seem harsh, but since this only happens
@@ -691,19 +662,11 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
spin_lock_irqsave(&atchan->lock, flags);
cookie = dma_cookie_assign(tx);
- if (list_empty(&atchan->active_list)) {
- dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
- desc->txd.cookie);
- atc_dostart(atchan, desc);
- list_add_tail(&desc->desc_node, &atchan->active_list);
- } else {
- dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
- desc->txd.cookie);
- list_add_tail(&desc->desc_node, &atchan->queue);
- }
-
+ list_add_tail(&desc->desc_node, &atchan->queue);
spin_unlock_irqrestore(&atchan->lock, flags);
+ dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
+ desc->txd.cookie);
return cookie;
}
@@ -1445,11 +1408,8 @@ static int atc_terminate_all(struct dma_chan *chan)
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma *atdma = to_at_dma(chan->device);
int chan_id = atchan->chan_common.chan_id;
- struct at_desc *desc, *_desc;
unsigned long flags;
- LIST_HEAD(list);
-
dev_vdbg(chan2dev(chan), "%s\n", __func__);
/*
@@ -1468,19 +1428,15 @@ static int atc_terminate_all(struct dma_chan *chan)
cpu_relax();
/* active_list entries will end up before queued entries */
- list_splice_init(&atchan->queue, &list);
- list_splice_init(&atchan->active_list, &list);
-
- spin_unlock_irqrestore(&atchan->lock, flags);
-
- /* Flush all pending and queued descriptors */
- list_for_each_entry_safe(desc, _desc, &list, desc_node)
- atc_chain_complete(atchan, desc);
+ list_splice_tail_init(&atchan->queue, &atchan->free_list);
+ list_splice_tail_init(&atchan->active_list, &atchan->free_list);
clear_bit(ATC_IS_PAUSED, &atchan->status);
/* if channel dedicated to cyclic operations, free it */
clear_bit(ATC_IS_CYCLIC, &atchan->status);
+ spin_unlock_irqrestore(&atchan->lock, flags);
+
return 0;
}
@@ -1535,20 +1491,26 @@ atc_tx_status(struct dma_chan *chan,
}
/**
- * atc_issue_pending - try to finish work
+ * atc_issue_pending - takes the first transaction descriptor in the pending
+ * queue and starts the transfer.
* @chan: target DMA channel
*/
static void atc_issue_pending(struct dma_chan *chan)
{
- struct at_dma_chan *atchan = to_at_dma_chan(chan);
+ struct at_dma_chan *atchan = to_at_dma_chan(chan);
+ struct at_desc *desc;
+ unsigned long flags;
dev_vdbg(chan2dev(chan), "issue_pending\n");
- /* Not needed for cyclic transfers */
- if (atc_chan_is_cyclic(atchan))
- return;
+ spin_lock_irqsave(&atchan->lock, flags);
+ if (atc_chan_is_enabled(atchan) || list_empty(&atchan->queue))
+ return spin_unlock_irqrestore(&atchan->lock, flags);
- atc_advance_work(atchan);
+ desc = atc_first_queued(atchan);
+ list_move_tail(&desc->desc_node, &atchan->active_list);
+ atc_dostart(atchan, desc);
+ spin_unlock_irqrestore(&atchan->lock, flags);
}
/**
@@ -1966,7 +1928,11 @@ static int __init at_dma_probe(struct platform_device *pdev)
dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "",
plat_dat->nr_channels);
- dma_async_device_register(&atdma->dma_common);
+ err = dma_async_device_register(&atdma->dma_common);
+ if (err) {
+ dev_err(&pdev->dev, "Unable to register: %d.\n", err);
+ goto err_dma_async_device_register;
+ }
/*
* Do not return an error if the dmac node is not present in order to
@@ -1986,6 +1952,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
err_of_dma_controller_register:
dma_async_device_unregister(&atdma->dma_common);
+err_dma_async_device_register:
dma_pool_destroy(atdma->memset_pool);
err_memset_pool_create:
dma_pool_destroy(atdma->dma_desc_pool);