Some of the comments about my earlier EDMA patches touched on issues
in that programming interface, like:
- The single call to allocate DMA resources is overly complex.
- Its programming model doesn't match the hardware well: talking
about master vs. slave, not channels and parameter RAM; confusing
those two resource types (especially when allocating); etc.
- Since the calls used a "davinci_" prefix, they wouldn't be very
appropriate for the DMA in the OMAP-L137 chip.
These patches address those issues by restructuring resource allocation
so there are now separate alloc/free calls for both kinds of resources;
and renaming everything. The resulting calls are also put into groups
that reflect the interface structure. From the header;
/* alloc/free DMA channels and their dedicated parameter RAM slots */
int edma_alloc_channel(int channel,
void (*callback)(unsigned channel, u16 ch_status, void *data),
void *data, enum dma_event_q);
void edma_free_channel(unsigned channel);
/* alloc/free parameter RAM slots */
int edma_alloc_slot(int slot);
void edma_free_slot(unsigned slot);
/* calls that operate on part of a parameter RAM slot */
void edma_set_src(unsigned slot, dma_addr_t src_port,
enum address_mode mode, enum fifo_width);
void edma_set_dest(unsigned slot, dma_addr_t dest_port,
enum address_mode mode, enum fifo_width);
void edma_get_position(unsigned slot, dma_addr_t *src, dma_addr_t *dst);
void edma_set_src_index(unsigned slot, s16 src_bidx, s16 src_cidx);
void edma_set_dest_index(unsigned slot, s16 dest_bidx, s16 dest_cidx);
void edma_set_transfer_params(unsigned slot, u16 acnt, u16 bcnt, u16 ccnt,
u16 bcnt_rld, enum sync_dimension sync_mode);
void edma_link(unsigned from, unsigned to);
void edma_unlink(unsigned from);
/* calls that operate on an entire parameter RAM slot */
void edma_write_slot(unsigned slot, const struct edmacc_param *params);
void edma_read_slot(unsigned slot, struct edmacc_param *params);
/* channel control operations */
int edma_start(unsigned channel);
void edma_stop(unsigned channel);
void edma_clean_channel(unsigned channel);
void edma_pause(unsigned channel);
void edma_resume(unsigned channel);
So, my two cents: merge these. Then the EDMA support is fair game to
merge to mainline -- there's much worse there already! -- although some
cleanups (enums and other symbols etc) may still be wanted.
Then the MMC/SD driver can merge, and the audio driver will be able to
build (and run!) in mainline.
- Dave
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