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Date: Thu, 4 Mar 2010 14:31:58 +0100
From: Linus Walleij <linus.walleij@...ricsson.com>
To: Dan Williams <dan.j.williams@...el.com>,
linux-kernel@...r.kernel.org
Cc: Linus Walleij <linus.walleij@...ricsson.com>
Subject: [PATCH 2/2] DMAENGINE: COH 901 318 fix bytesleft
This makes the function to get the number of bytes left in the
ongoing DMA transaction actually work: the old code did not take
neither lli:s nor queued jobs into account. Also fix a missing
spinlock while we're at it.
Signed-off-by: Linus Walleij <linus.walleij@...ricsson.com>
---
drivers/dma/coh901318.c | 97 +++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 89 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index 20889c9..672517b 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -408,25 +408,101 @@ coh901318_first_queued(struct coh901318_chan *cohc)
return d;
}
+static inline u32 coh901318_get_bytes_in_lli(struct coh901318_lli *in_lli)
+{
+ struct coh901318_lli *lli = in_lli;
+ u32 bytes = 0;
+
+ while (lli) {
+ bytes += lli->control & COH901318_CX_CTRL_TC_VALUE_MASK;
+ lli = lli->virt_link_addr;
+ }
+ return bytes;
+}
+
/*
- * DMA start/stop controls
+ * Get the number of bytes left to transfer on this channel,
+ * it is unwise to call this before stopping the channel for
+ * absolute measures, but for a rough guess you can still call
+ * it.
*/
u32 coh901318_get_bytes_left(struct dma_chan *chan)
{
- unsigned long flags;
- u32 ret;
struct coh901318_chan *cohc = to_coh901318_chan(chan);
+ struct coh901318_desc *cohd;
+ struct list_head *pos;
+ unsigned long flags;
+ u32 left = 0;
+ int i = 0;
spin_lock_irqsave(&cohc->lock, flags);
- /* Read transfer count value */
- ret = readl(cohc->base->virtbase +
- COH901318_CX_CTRL+COH901318_CX_CTRL_SPACING *
- cohc->id) & COH901318_CX_CTRL_TC_VALUE_MASK;
+ /*
+ * If there are many queued jobs, we iterate and add the
+ * size of them all. We take a special look on the first
+ * job though, since it is probably active.
+ */
+ list_for_each(pos, &cohc->active) {
+ /*
+ * The first job in the list will be working on the
+ * hardware. The job can be stopped but still active,
+ * so that the transfer counter is somewhere inside
+ * the buffer.
+ */
+ cohd = list_entry(pos, struct coh901318_desc, node);
+
+ if (i == 0) {
+ struct coh901318_lli *lli;
+ dma_addr_t ladd;
+
+ pr_err("DMA count first entry\n");
+ /* Read current transfer count value */
+ left = readl(cohc->base->virtbase +
+ COH901318_CX_CTRL +
+ COH901318_CX_CTRL_SPACING * cohc->id) &
+ COH901318_CX_CTRL_TC_VALUE_MASK;
+
+ /* See if the transfer is linked... */
+ ladd = readl(cohc->base->virtbase +
+ COH901318_CX_LNK_ADDR +
+ COH901318_CX_LNK_ADDR_SPACING *
+ cohc->id) &
+ ~COH901318_CX_LNK_LINK_IMMEDIATE;
+ /* Single transaction */
+ if (!ladd)
+ continue;
+
+ /*
+ * Linked transaction, follow the lli, find the
+ * currently processing lli, and proceed to the next
+ */
+ lli = cohd->lli;
+ while (lli && lli->link_addr != ladd)
+ lli = lli->virt_link_addr;
+
+ if (lli)
+ lli = lli->virt_link_addr;
+
+ /*
+ * Follow remaining lli links around to count the total
+ * number of bytes left
+ */
+ left += coh901318_get_bytes_in_lli(lli);
+ } else {
+ left += coh901318_get_bytes_in_lli(cohd->lli);
+ }
+ i++;
+ }
+
+ /* Also count bytes in the queued jobs */
+ list_for_each(pos, &cohc->queue) {
+ cohd = list_entry(pos, struct coh901318_desc, node);
+ left += coh901318_get_bytes_in_lli(cohd->lli);
+ }
spin_unlock_irqrestore(&cohc->lock, flags);
- return ret;
+ return left;
}
EXPORT_SYMBOL(coh901318_get_bytes_left);
@@ -831,6 +907,7 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
static int coh901318_alloc_chan_resources(struct dma_chan *chan)
{
struct coh901318_chan *cohc = to_coh901318_chan(chan);
+ unsigned long flags;
dev_vdbg(COHC_2_DEV(cohc), "[%s] DMA channel %d\n",
__func__, cohc->id);
@@ -838,11 +915,15 @@ static int coh901318_alloc_chan_resources(struct dma_chan *chan)
if (chan->client_count > 1)
return -EBUSY;
+ spin_lock_irqsave(&cohc->lock, flags);
+
coh901318_config(cohc, NULL);
cohc->allocated = 1;
cohc->completed = chan->cookie = 1;
+ spin_unlock_irqrestore(&cohc->lock, flags);
+
return 1;
}
--
1.6.3.3
--
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