int mite_sync_input_dma(struct mite_channel *mite_chan, comedi_async * async) { int count; unsigned int nbytes, old_alloc_count; const unsigned bytes_per_scan = cfc_bytes_per_scan(async->subdevice); old_alloc_count = async->buf_write_alloc_count; // write alloc as much as we can comedi_buf_write_alloc(async, async->prealloc_bufsz); nbytes = mite_bytes_written_to_memory_lb(mite_chan); if ((int)(mite_bytes_written_to_memory_ub(mite_chan) - old_alloc_count) > 0) { rt_printk("mite: DMA overwrite of free area\n"); async->events |= COMEDI_CB_OVERFLOW; return -1; } count = nbytes - async->buf_write_count; /* it's possible count will be negative due to * conservative value returned by mite_bytes_written_to_memory_lb */ if (count <= 0) { return 0; } comedi_buf_write_free(async, count); async->scan_progress += count; if (async->scan_progress >= bytes_per_scan) { async->scan_progress %= bytes_per_scan; async->events |= COMEDI_CB_EOS; } async->events |= COMEDI_CB_BLOCK; return 0; }
int mite_sync_input_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s) { struct comedi_async *async = s->async; int count; unsigned int nbytes, old_alloc_count; old_alloc_count = async->buf_write_alloc_count; /* write alloc as much as we can */ comedi_buf_write_alloc(s, async->prealloc_bufsz); nbytes = mite_bytes_written_to_memory_lb(mite_chan); if ((int)(mite_bytes_written_to_memory_ub(mite_chan) - old_alloc_count) > 0) { dev_warn(s->device->class_dev, "mite: DMA overwrite of free area\n"); async->events |= COMEDI_CB_OVERFLOW; return -1; } count = nbytes - async->buf_write_count; /* * it's possible count will be negative due to conservative value * returned by mite_bytes_written_to_memory_lb */ if (count <= 0) return 0; comedi_buf_write_free(s, count); comedi_inc_scan_progress(s, count); async->events |= COMEDI_CB_BLOCK; return 0; }