[alsa-devel] [PATCH 1/2][RFC] dmaengine: rcar-audmapp: calculate chcr via src/dst addr

[Kuninori Morimoto]

Hi Geert

> >> +static u32 audmapp_addr_to_id(struct device *dev, u32 addr)
> >> +{
> >> +     struct id_addr_table ssi_id_table[] = {
> 
> static const, so they don't get copied to the stack on every invocation.

Indeed, thanks

> >> +             {0x00, 0x0000}, /* SSI00 */
> >> +             {0x01, 0x0400}, /* SSI01 */
> >> +             {0x02, 0x0800}, /* SSI02 */
> >> +             {0x03, 0x0C00}, /* SSI03 */
> >> +             {0x04, 0x1000}, /* SSI10 */
> >> +             {0x05, 0x1400}, /* SSI11 */
> >> +             {0x06, 0x1800}, /* SSI12 */
> >> +             {0x07, 0x1C00}, /* SSI13 */
> >> +             {0x08, 0x2000}, /* SSI20 */
> >
> > Isn't the address part here the physical address of the FIFO,
> 
> Yes they are.
> 
> > which can be different for each implementation that contains
> > an audmapp device?
> 
> Fortunately they're identical for all (current) members of the R-Car Gen2
> family.
> 
> Morimoto-san: Are the base addresses configured in DT?
> I did a quick search for 0xec300000, 0xec320000, 0xec40000,
> 0xec420000, and 0xec000000,  and couldn't find them in DT, only in
> source code (comments). They must come from somewhere?
> Note that I didn't follow the sound binding discussions that closely.

This base addresses are specified from sound driver.
 - sound driver specifies src/dst address by DMAEngine API
 - audmapp find necessary ID from src/dst address

Best regards
---
Kuninori Morimoto