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-rw-r--r--drivers/dma/at_hdmac.c130
-rw-r--r--drivers/dma/at_hdmac_regs.h3
2 files changed, 115 insertions, 18 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 4c101a9dd3cb..5ce89368a8db 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -54,6 +54,7 @@ MODULE_PARM_DESC(init_nr_desc_per_channel,
/* prototypes */
static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
+static void atc_issue_pending(struct dma_chan *chan);
/*----------------------------------------------------------------------*/
@@ -230,6 +231,94 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
vdbg_dump_regs(atchan);
}
+/*
+ * atc_get_current_descriptors -
+ * locate the descriptor which equal to physical address in DSCR
+ * @atchan: the channel we want to start
+ * @dscr_addr: physical descriptor address in DSCR
+ */
+static struct at_desc *atc_get_current_descriptors(struct at_dma_chan *atchan,
+ u32 dscr_addr)
+{
+ struct at_desc *desc, *_desc, *child, *desc_cur = NULL;
+
+ list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
+ if (desc->lli.dscr == dscr_addr) {
+ desc_cur = desc;
+ break;
+ }
+
+ list_for_each_entry(child, &desc->tx_list, desc_node) {
+ if (child->lli.dscr == dscr_addr) {
+ desc_cur = child;
+ break;
+ }
+ }
+ }
+
+ return desc_cur;
+}
+
+/*
+ * atc_get_bytes_left -
+ * Get the number of bytes residue in dma buffer,
+ * @chan: the channel we want to start
+ */
+static int atc_get_bytes_left(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_first = atc_first_active(atchan);
+ struct at_desc *desc_cur;
+ int ret = 0, count = 0;
+
+ /*
+ * Initialize necessary values in the first time.
+ * remain_desc record remain desc length.
+ */
+ if (atchan->remain_desc == 0)
+ /* First descriptor embedds the transaction length */
+ atchan->remain_desc = desc_first->len;
+
+ /*
+ * This happens when current descriptor transfer complete.
+ * The residual buffer size should reduce current descriptor length.
+ */
+ if (unlikely(test_bit(ATC_IS_BTC, &atchan->status))) {
+ clear_bit(ATC_IS_BTC, &atchan->status);
+ desc_cur = atc_get_current_descriptors(atchan,
+ channel_readl(atchan, DSCR));
+ if (!desc_cur) {
+ ret = -EINVAL;
+ goto out;
+ }
+ atchan->remain_desc -= (desc_cur->lli.ctrla & ATC_BTSIZE_MAX)
+ << (desc_first->tx_width);
+ if (atchan->remain_desc < 0) {
+ ret = -EINVAL;
+ goto out;
+ } else
+ ret = atchan->remain_desc;
+ } else {
+ /*
+ * Get residual bytes when current
+ * descriptor transfer in progress.
+ */
+ count = (channel_readl(atchan, CTRLA) & ATC_BTSIZE_MAX)
+ << (desc_first->tx_width);
+ ret = atchan->remain_desc - count;
+ }
+ /*
+ * Check fifo empty.
+ */
+ if (!(dma_readl(atdma, CHSR) & AT_DMA_EMPT(chan_id)))
+ atc_issue_pending(chan);
+
+out:
+ return ret;
+}
+
/**
* atc_chain_complete - finish work for one transaction chain
* @atchan: channel we work on
@@ -496,6 +585,8 @@ static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
/* Give information to tasklet */
set_bit(ATC_IS_ERROR, &atchan->status);
}
+ if (pending & AT_DMA_BTC(i))
+ set_bit(ATC_IS_BTC, &atchan->status);
tasklet_schedule(&atchan->tasklet);
ret = IRQ_HANDLED;
}
@@ -1035,34 +1126,35 @@ atc_tx_status(struct dma_chan *chan,
struct dma_tx_state *txstate)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
- dma_cookie_t last_used;
- dma_cookie_t last_complete;
unsigned long flags;
enum dma_status ret;
-
- spin_lock_irqsave(&atchan->lock, flags);
+ int bytes = 0;
ret = dma_cookie_status(chan, cookie, txstate);
- if (ret != DMA_SUCCESS) {
- atc_cleanup_descriptors(atchan);
+ if (ret == DMA_SUCCESS)
+ return ret;
+ /*
+ * There's no point calculating the residue if there's
+ * no txstate to store the value.
+ */
+ if (!txstate)
+ return DMA_ERROR;
- ret = dma_cookie_status(chan, cookie, txstate);
- }
+ spin_lock_irqsave(&atchan->lock, flags);
- last_complete = chan->completed_cookie;
- last_used = chan->cookie;
+ /* Get number of bytes left in the active transactions */
+ bytes = atc_get_bytes_left(chan);
spin_unlock_irqrestore(&atchan->lock, flags);
- if (ret != DMA_SUCCESS)
- dma_set_residue(txstate, atc_first_active(atchan)->len);
-
- if (atc_chan_is_paused(atchan))
- ret = DMA_PAUSED;
+ if (unlikely(bytes < 0)) {
+ dev_vdbg(chan2dev(chan), "get residual bytes error\n");
+ return DMA_ERROR;
+ } else
+ dma_set_residue(txstate, bytes);
- dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d (d%d, u%d)\n",
- ret, cookie, last_complete ? last_complete : 0,
- last_used ? last_used : 0);
+ dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %d\n",
+ ret, cookie, bytes);
return ret;
}
@@ -1146,6 +1238,7 @@ static int atc_alloc_chan_resources(struct dma_chan *chan)
spin_lock_irqsave(&atchan->lock, flags);
atchan->descs_allocated = i;
+ atchan->remain_desc = 0;
list_splice(&tmp_list, &atchan->free_list);
dma_cookie_init(chan);
spin_unlock_irqrestore(&atchan->lock, flags);
@@ -1188,6 +1281,7 @@ static void atc_free_chan_resources(struct dma_chan *chan)
list_splice_init(&atchan->free_list, &list);
atchan->descs_allocated = 0;
atchan->status = 0;
+ atchan->remain_desc = 0;
dev_vdbg(chan2dev(chan), "free_chan_resources: done\n");
}
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index 3679933fb646..f31d647acdfa 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -213,6 +213,7 @@ txd_to_at_desc(struct dma_async_tx_descriptor *txd)
enum atc_status {
ATC_IS_ERROR = 0,
ATC_IS_PAUSED = 1,
+ ATC_IS_BTC = 2,
ATC_IS_CYCLIC = 24,
};
@@ -230,6 +231,7 @@ enum atc_status {
* @save_cfg: configuration register that is saved on suspend/resume cycle
* @save_dscr: for cyclic operations, preserve next descriptor address in
* the cyclic list on suspend/resume cycle
+ * @remain_desc: to save remain desc length
* @dma_sconfig: configuration for slave transfers, passed via DMA_SLAVE_CONFIG
* @lock: serializes enqueue/dequeue operations to descriptors lists
* @active_list: list of descriptors dmaengine is being running on
@@ -248,6 +250,7 @@ struct at_dma_chan {
struct tasklet_struct tasklet;
u32 save_cfg;
u32 save_dscr;
+ u32 remain_desc;
struct dma_slave_config dma_sconfig;
spinlock_t lock;