}
/*
- * 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
+ * atc_get_desc_by_cookie - get the descriptor of a cookie
+ * @atchan: the DMA channel
+ * @cookie: the cookie to get the descriptor for
*/
-static struct at_desc *atc_get_current_descriptors(struct at_dma_chan *atchan,
- u32 dscr_addr)
+static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan,
+ dma_cookie_t cookie)
{
- struct at_desc *desc, *_desc, *child, *desc_cur = NULL;
+ struct at_desc *desc, *_desc;
- 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_safe(desc, _desc, &atchan->queue, desc_node) {
+ if (desc->txd.cookie == cookie)
+ return desc;
+ }
- list_for_each_entry(child, &desc->tx_list, desc_node) {
- if (child->lli.dscr == dscr_addr) {
- desc_cur = child;
- break;
- }
- }
+ list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
+ if (desc->txd.cookie == cookie)
+ return desc;
}
- return desc_cur;
+ return NULL;
}
-/*
- * atc_get_bytes_left -
- * Get the number of bytes residue in dma buffer,
- * @chan: the channel we want to start
+/**
+ * atc_calc_bytes_left - calculates the number of bytes left according to the
+ * value read from CTRLA.
+ *
+ * @current_len: the number of bytes left before reading CTRLA
+ * @ctrla: the value of CTRLA
+ * @desc: the descriptor containing the transfer width
+ */
+static inline int atc_calc_bytes_left(int current_len, u32 ctrla,
+ struct at_desc *desc)
+{
+ return current_len - ((ctrla & ATC_BTSIZE_MAX) << desc->tx_width);
+}
+
+/**
+ * atc_calc_bytes_left_from_reg - calculates the number of bytes left according
+ * to the current value of CTRLA.
+ *
+ * @current_len: the number of bytes left before reading CTRLA
+ * @atchan: the channel to read CTRLA for
+ * @desc: the descriptor containing the transfer width
*/
-static int atc_get_bytes_left(struct dma_chan *chan)
+static inline int atc_calc_bytes_left_from_reg(int current_len,
+ struct at_dma_chan *atchan, struct at_desc *desc)
+{
+ u32 ctrla = channel_readl(atchan, CTRLA);
+
+ return atc_calc_bytes_left(current_len, ctrla, desc);
+}
+
+/**
+ * atc_get_bytes_left - get the number of bytes residue for a cookie
+ * @chan: DMA channel
+ * @cookie: transaction identifier to check status of
+ */
+static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
{
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;
+ struct at_desc *desc;
+ int ret;
+ u32 ctrla, dscr;
/*
- * Initialize necessary values in the first time.
- * remain_desc record remain desc length.
+ * If the cookie doesn't match to the currently running transfer then
+ * we can return the total length of the associated DMA transfer,
+ * because it is still queued.
*/
- if (atchan->remain_desc == 0)
- /* First descriptor embedds the transaction length */
- atchan->remain_desc = desc_first->len;
+ desc = atc_get_desc_by_cookie(atchan, cookie);
+ if (desc == NULL)
+ return -EINVAL;
+ else if (desc != desc_first)
+ return desc->total_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;
- }
+ /* cookie matches to the currently running transfer */
+ ret = desc_first->total_len;
+
+ if (desc_first->lli.dscr) {
+ /* hardware linked list transfer */
+
+ /*
+ * Calculate the residue by removing the length of the child
+ * descriptors already transferred from the total length.
+ * To get the current child descriptor we can use the value of
+ * the channel's DSCR register and compare it against the value
+ * of the hardware linked list structure of each child
+ * descriptor.
+ */
- count = (desc_cur->lli.ctrla & ATC_BTSIZE_MAX)
- << desc_first->tx_width;
- if (atchan->remain_desc < count) {
- ret = -EINVAL;
- goto out;
+ ctrla = channel_readl(atchan, CTRLA);
+ rmb(); /* ensure CTRLA is read before DSCR */
+ dscr = channel_readl(atchan, DSCR);
+
+ /* for the first descriptor we can be more accurate */
+ if (desc_first->lli.dscr == dscr)
+ return atc_calc_bytes_left(ret, ctrla, desc_first);
+
+ ret -= desc_first->len;
+ list_for_each_entry(desc, &desc_first->tx_list, desc_node) {
+ if (desc->lli.dscr == dscr)
+ break;
+
+ ret -= desc->len;
}
- atchan->remain_desc -= count;
- ret = atchan->remain_desc;
- } else {
/*
- * Get residual bytes when current
- * descriptor transfer in progress.
+ * For the last descriptor in the chain we can calculate
+ * the remaining bytes using the channel's register.
+ * Note that the transfer width of the first and last
+ * descriptor may differ.
*/
- count = (channel_readl(atchan, CTRLA) & ATC_BTSIZE_MAX)
- << (desc_first->tx_width);
- ret = atchan->remain_desc - count;
+ if (!desc->lli.dscr)
+ ret = atc_calc_bytes_left_from_reg(ret, atchan, desc);
+ } else {
+ /* single transfer */
+ ret = atc_calc_bytes_left_from_reg(ret, atchan, desc_first);
}
- /*
- * Check fifo empty.
- */
- if (!(dma_readl(atdma, CHSR) & AT_DMA_EMPT(chan_id)))
- atc_issue_pending(chan);
-out:
return ret;
}
/* 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;
}
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
+ desc->len = xfer_count << src_width;
atc_desc_chain(&first, &prev, desc);
}
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
- first->len = len;
+ first->total_len = len;
+
+ /* set transfer width for the calculation of the residue */
first->tx_width = src_width;
+ prev->tx_width = src_width;
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
| ATC_SRC_WIDTH(mem_width)
| len >> mem_width;
desc->lli.ctrlb = ctrlb;
+ desc->len = len;
atc_desc_chain(&first, &prev, desc);
total_len += len;
| ATC_DST_WIDTH(mem_width)
| len >> reg_width;
desc->lli.ctrlb = ctrlb;
+ desc->len = len;
atc_desc_chain(&first, &prev, desc);
total_len += len;
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
- first->len = total_len;
+ first->total_len = total_len;
+
+ /* set transfer width for the calculation of the residue */
first->tx_width = reg_width;
+ prev->tx_width = reg_width;
/* first link descriptor of list is responsible of flags */
first->txd.flags = flags; /* client is in control of this ack */
| ATC_FC_MEM2PER
| ATC_SIF(atchan->mem_if)
| ATC_DIF(atchan->per_if);
+ desc->len = period_len;
break;
case DMA_DEV_TO_MEM:
| ATC_FC_PER2MEM
| ATC_SIF(atchan->per_if)
| ATC_DIF(atchan->mem_if);
+ desc->len = period_len;
break;
default:
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
- first->len = buf_len;
+ first->total_len = buf_len;
first->tx_width = reg_width;
return &first->txd;
spin_lock_irqsave(&atchan->lock, flags);
/* Get number of bytes left in the active transactions */
- bytes = atc_get_bytes_left(chan);
+ bytes = atc_get_bytes_left(chan, cookie);
spin_unlock_irqrestore(&atchan->lock, flags);
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);
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");
}
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