Hi,
i've been slowly looking at bringing dma for some of the lesser sunxis,
and have reached the point where i'm unsure what to do next beyond
testing the functionality w/spreading SoC-specific hacks "for testing"..
now even if i will manage to shove it partly under _bus_dma_tag, it will
not be usable w/o a hack/special-casing either, so that lead to looking
at implementing ofw_dmac, which i can't finish because i can't decide on
it's interface, i mean there's too many completely new pieces to me in
the puzzle after all, o and the naming; ofw_dma or ofw_dmac? can't pick.
DT-binding properties for the generic dma-controller did seem simple,
and in my case the Allwinner A10 DMA Controller follows those, but w/o
knowing better continuing would likely be waste of my time:)
currently i have something like this in sys/dev/ofw/ofw_dmac.h:
struct dma_controller {
int dc_node;
/*
* Pointer to struct x_bus_space_tag, containing
* another _cookie to struct x_softc of our parent.
*/
void *dc_cookie;
/* claim/disown channel|w/e controller specific */
void (*dc_claim)(void *. uint32_t *, int);
/* dc_cookie, &cells[1], disown:0|claim:1 */
LIST_ENTRY(dma_controller) dc_list;
uint32_t dc_phandle;
uint32_t dc_cells;
#ifdef notyet
uint32_t dc_channels;
uint32_t dc_requests;
#endif
};
void dmac_register(struct dma_controller *);
/*
* does return the number of entries in the "dmas" property,
* and the bus_dma_tag_t for client to use.
*/
int dmac_register_client(int, bus_dma_tag_t *);
void dmac_claim(int, const char *);
void dmac_claim_idx(int, int);
void dmac_disown(int, const char *);
void dmac_disown_idx(int, int);
for clients that'd be quite simple to use to get more specific
bus_dma_tag than given in fdt_attach_args, so ie. in drivers
used across different dma controllers, im hoping above might
work w/clients calling _register_client unconditionally? or?
any input more than welcome:)
-Artturi
