On 12/03/2014 05:47 AM, Padma Venkat wrote:
Hi Lars,
[snip]
+
+ ret = dma_cookie_status(chan, cookie, txstate);
+ if (ret == DMA_COMPLETE || !txstate)
+ return ret;
+
+ used = txstate->used;
+
+ spin_lock_irqsave(&pch->lock, flags);
+ sar = readl(regs + SA(thrd->id));
+ dar = readl(regs + DA(thrd->id));
+
+ list_for_each_entry(desc, &pch->work_list, node) {
+ if (desc->status == BUSY) {
+ current_c = desc->txd.cookie;
+ if (first) {
+ first_c = desc->txd.cookie;
+ first = false;
+ }
+
+ if (first_c < current_c)
+ residue += desc->px.bytes;
+ else {
+ if (desc->rqcfg.src_inc && pl330_src_addr_in_desc(desc, sar)) {
+ residue += desc->px.bytes;
+ residue -= sar - desc->px.src_addr;
+ } else if (desc->rqcfg.dst_inc && pl330_dst_addr_in_desc(desc, dar))
{
+ residue += desc->px.bytes;
+ residue -= dar - desc->px.dst_addr;
+ }
+ }
+ } else if (desc->status == PREP)
+ residue += desc->px.bytes;
+
+ if (desc->txd.cookie == used)
+ break;
+ }
+ spin_unlock_irqrestore(&pch->lock, flags);
+ dma_set_residue(txstate, residue);
+ return ret;
}
[snip]
Any comment on this patch?
Well it doesn't break audio, but I don't think it has the correct haviour
for all cases yet.
OK. Any way of testing other cases like scatter-gather and memcopy. I
verified memcopy in dmatest but it seems not doing anything with
residue bytes.
E.g. I think your current patch fails if more than one transfer has been
submitted. In that case you'll count the bytes for all of them rather than
just the one requested.
Again, the semantics are that it should return the progress of the transfer
for which the allocation function returned the cookie that is passe to this
May be my understanding is wrong. For clarification..In the
snd_dmaengine_pcm_pointer it is subtracting the residue bytes from the
total buffer bytes not from period bytes. So how it expects
the progress of the transfer of the passed cookie which just holds period bytes?
The issue that makes implementing this correctly for the pl330 driver
complicated is that the driver allocates one cookie per segment/period, but
the external API works with one cookie per transfer. All those cookies that
are assigned to the segments/periods that are not the first in a transfer
are not externally visible.
dmaengine_prep_slave_sg() and friends create a transfer and return
descriptor for this transfer with a single cookie. If that cookie is passed
to dmaengine_tx_status() the function is supposed to report the progress on
that one transfer that was previously allocated and returned that cookie
number. residue is the total number of bytes that are still left to to be
processed for that transfer.
I've started reworking the pl330 driver to only have a single cookie per
transfer, instead of one per period/segment. This makes implementing the
residue reporting a lot easier. I never finished that work though, but I can
try to see if I can revive it next week.
- Lars
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