Christoph, Alan,
> If it is allocating / freeing this memory all the time in the hot path
> it should really use a dma pool (see include/ilinux/dmapool.h).
> The dma coherent APIs aren't really built for being called in the
> hot path.
hcd_buffer_free uses a combination of dma pools and dma coher
On Sat, Mar 03, 2018 at 09:22:35AM +0100, Fredrik Noring wrote:
> Critically, it performs the following calls:
If it is allocating / freeing this memory all the time in the hot path
it should really use a dma pool (see include/ilinux/dmapool.h).
The dma coherent APIs aren't really built for being
Hi Christoph,
> Why do you want to free coherent dma allocations from irq context?
> They generally are a long-term resource that as a rule of thumb should
> be allocated in ->probe and freed in ->remove.
The device specific HCD only does dma_declare_coherent_memory (with
HCD_LOCAL_MEM) in ->prob
Hi Robin,
> Historically, that particular line of code appears to date back to commit
> aa24886e379d (and tracking it's ancestry was quite fun).
>
> Now, I'm sure not all of the considerations of 11-and-a-half years ago still
> apply, but one certainly does: ARM* still uses non-cacheable mappings
