int mite_sync_output_dma(struct mite_channel *mite_chan, comedi_async * async) { int count; u32 nbytes_ub, nbytes_lb; unsigned int old_alloc_count; u32 stop_count = async->cmd.stop_arg * cfc_bytes_per_scan(async->subdevice); old_alloc_count = async->buf_read_alloc_count; // read alloc as much as we can comedi_buf_read_alloc(async, async->prealloc_bufsz); nbytes_lb = mite_bytes_read_from_memory_lb(mite_chan); if (async->cmd.stop_src == TRIG_COUNT && (int)(nbytes_lb - stop_count) > 0) nbytes_lb = stop_count; nbytes_ub = mite_bytes_read_from_memory_ub(mite_chan); if (async->cmd.stop_src == TRIG_COUNT && (int)(nbytes_ub - stop_count) > 0) nbytes_ub = stop_count; if ((int)(nbytes_ub - old_alloc_count) > 0) { rt_printk("mite: DMA underrun\n"); async->events |= COMEDI_CB_OVERFLOW; return -1; } count = nbytes_lb - async->buf_read_count; if (count <= 0) { return 0; } if (count) { comedi_buf_read_free(async, count); async->events |= COMEDI_CB_BLOCK; } return 0; }
int mite_sync_output_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s) { struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; u32 stop_count = cmd->stop_arg * comedi_bytes_per_scan(s); unsigned int old_alloc_count = async->buf_read_alloc_count; u32 nbytes_ub, nbytes_lb; int count; /* read alloc as much as we can */ comedi_buf_read_alloc(s, async->prealloc_bufsz); nbytes_lb = mite_bytes_read_from_memory_lb(mite_chan); if (cmd->stop_src == TRIG_COUNT && (int)(nbytes_lb - stop_count) > 0) nbytes_lb = stop_count; nbytes_ub = mite_bytes_read_from_memory_ub(mite_chan); if (cmd->stop_src == TRIG_COUNT && (int)(nbytes_ub - stop_count) > 0) nbytes_ub = stop_count; if ((int)(nbytes_ub - old_alloc_count) > 0) { dev_warn(s->device->class_dev, "mite: DMA underrun\n"); async->events |= COMEDI_CB_OVERFLOW; return -1; } count = nbytes_lb - async->buf_read_count; if (count <= 0) return 0; if (count) { comedi_buf_read_free(s, count); async->events |= COMEDI_CB_BLOCK; } return 0; }