dbdma_command
struct dbdma_command;
typedef struct dbdma_command dbdma_command_t;
cmd = chan->sc_slots_pa + slot * sizeof(struct dbdma_command);
struct dbdma_command cmd;
branch_slot * sizeof(struct dbdma_command);
if (newslots > (PAGE_SIZE / sizeof(struct dbdma_command)))
struct dbdma_command *sc_slots;