Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

dma-jz4780.c residue reporting fixes (to fix jz4770 audio underruns) #1

Merged
merged 5 commits into from
Jul 2, 2018
Merged

dma-jz4780.c residue reporting fixes (to fix jz4770 audio underruns) #1

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
a31f080
dmaengine: dma-jz4780: Add missing residue DTC mask
senquack Jul 2, 2018
6474d93
dmaengine: dma-jz4780: Simplify jz4780_dma_desc_residue()
senquack Jul 2, 2018
b671af5
dmaengine: dma-jz4780: Set DTCn reg explicitly
senquack Jul 2, 2018
9250509
dmaengine: dma-jz4780: Further residue status fix
senquack Jul 2, 2018
b66bc50
dmaengine: dma-jz4780: Use dma_set_residue()
senquack Jul 2, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
34 changes: 20 additions & 14 deletions drivers/dma/dma-jz4780.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -528,6 +528,15 @@ static void jz4780_dma_begin(struct jz4780_dma_chan *jzchan)
jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DRT,
jzchan->transfer_type);

/*
* Set the transfer count. This is redundant for a descriptor-driven
* transfer. However, there can be a delay between the transfer start
* time and when DTCn reg contains the new transfer count. Setting
* it explicitly ensures residue is computed correctly at all times.
*/
jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DTC,
jzchan->desc->desc[jzchan->curr_hwdesc].dtc);

/* Write descriptor address and initiate descriptor fetch. */
desc_phys = jzchan->desc->desc_phys +
(jzchan->curr_hwdesc * sizeof(*jzchan->desc->desc));
Expand Down Expand Up @@ -605,21 +614,17 @@ static size_t jz4780_dma_desc_residue(struct jz4780_dma_chan *jzchan,
struct jz4780_dma_desc *desc, unsigned int next_sg)
{
struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
unsigned int residue, count;
unsigned int count = 0;
unsigned int i;

residue = 0;

for (i = next_sg; i < desc->count; i++)
residue += desc->desc[i].dtc << jzchan->transfer_shift;
count += desc->desc[i].dtc & 0xffffff;

if (next_sg != 0) {
count = jz4780_dma_chn_readl(jzdma, jzchan->id,
if (next_sg != 0)
count += jz4780_dma_chn_readl(jzdma, jzchan->id,
JZ_DMA_REG_DTC);
residue += count << jzchan->transfer_shift;
}

return residue;
return count << jzchan->transfer_shift;
}

static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan,
Expand All @@ -629,6 +634,7 @@ static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan,
struct virt_dma_desc *vdesc;
enum dma_status status;
unsigned long flags;
unsigned long residue = 0;

status = dma_cookie_status(chan, cookie, txstate);
if ((status == DMA_COMPLETE) || (txstate == NULL))
Expand All @@ -639,13 +645,13 @@ static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan,
vdesc = vchan_find_desc(&jzchan->vchan, cookie);
if (vdesc) {
/* On the issued list, so hasn't been processed yet */
txstate->residue = jz4780_dma_desc_residue(jzchan,
residue = jz4780_dma_desc_residue(jzchan,
to_jz4780_dma_desc(vdesc), 0);
} else if (cookie == jzchan->desc->vdesc.tx.cookie) {
txstate->residue = jz4780_dma_desc_residue(jzchan, jzchan->desc,
(jzchan->curr_hwdesc + 1) % jzchan->desc->count);
} else
txstate->residue = 0;
residue = jz4780_dma_desc_residue(jzchan, jzchan->desc,
jzchan->curr_hwdesc + 1);
}
dma_set_residue(txstate, residue);

if (vdesc && jzchan->desc && vdesc == &jzchan->desc->vdesc
&& jzchan->desc->status & (JZ_DMA_DCS_AR | JZ_DMA_DCS_HLT))
Expand Down