On 23 January 2013 14:42, Andy Shevchenko
<[email protected]> wrote:
> Ah, you mean the dma_cookie_status returns DMA_SUCCESS in case
> active_list is empty, don't you?
Bingo!!
> Yesterday I spent in testing of different approaches. First of all, the
> calculation of the sent amount is nicer when ctlhi/ctllo is used and it
> works fine. But the approach, when we substract length of sent
> descriptors, is losing data. Namely, we have no information how big is
> the master descriptor (it has total length of the entire chain). So, I'm
> thinking how to solve this one. Otherwise it seems simpler than mine
> first idea.
I was planning to give you another review comment which i thought i will
give later :)
It looks to be a bit wrong to have individual lengths in all descriptors leaving
the first one :)
This is the descriptor struct:
struct dw_desc {
/* FIRST values the hardware uses */
struct dw_lli lli;
/* THEN values for driver housekeeping */
struct list_head desc_node;
struct list_head tx_list;
struct dma_async_tx_descriptor txd;
size_t len;
};
Firstly i believe we can have a union of both list_heads as only one is used
at any time. Can you patch it down?
Second to solve your problem, you can add another field here: total_len.
I know it will consume 4 bytes per desc but i think that's the drawback we need
to accept.
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