On Sun, Jan 18, 2026 at 10:54:07PM +0900, Koichiro Den wrote: > A remote eDMA provider may need to expose the linked-list (LL) memory > region that was configured by platform glue (typically at boot), so the > peer (host) can map it and operate the remote view of the controller. > > Export dw_edma_chan_get_ll_region() to return the LL region associated > with a given dma_chan.
This informaiton passed from dwc epc driver. Is it possible to get it from EPC driver. Frank > > Signed-off-by: Koichiro Den <[email protected]> > --- > drivers/dma/dw-edma/dw-edma-core.c | 26 ++++++++++++++++++++++++++ > include/linux/dma/edma.h | 14 ++++++++++++++ > 2 files changed, 40 insertions(+) > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c > b/drivers/dma/dw-edma/dw-edma-core.c > index 0eb8fc1dcc34..c4fb66a9b5f5 100644 > --- a/drivers/dma/dw-edma/dw-edma-core.c > +++ b/drivers/dma/dw-edma/dw-edma-core.c > @@ -1209,6 +1209,32 @@ int dw_edma_chan_register_notify(struct dma_chan > *dchan, > } > EXPORT_SYMBOL_GPL(dw_edma_chan_register_notify); > > +int dw_edma_chan_get_ll_region(struct dma_chan *dchan, > + struct dw_edma_region *region) > +{ > + struct dw_edma_chip *chip; > + struct dw_edma_chan *chan; > + > + if (!dchan || !region || !dchan->device) > + return -ENODEV; > + > + chan = dchan2dw_edma_chan(dchan); > + if (!chan) > + return -ENODEV; > + > + chip = chan->dw->chip; > + if (!(chip->flags & DW_EDMA_CHIP_LOCAL)) > + return -EINVAL; > + > + if (chan->dir == EDMA_DIR_WRITE) > + *region = chip->ll_region_wr[chan->id]; > + else > + *region = chip->ll_region_rd[chan->id]; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(dw_edma_chan_get_ll_region); > + > MODULE_LICENSE("GPL v2"); > MODULE_DESCRIPTION("Synopsys DesignWare eDMA controller core driver"); > MODULE_AUTHOR("Gustavo Pimentel <[email protected]>"); > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h > index 3c538246de07..c9ec426e27ec 100644 > --- a/include/linux/dma/edma.h > +++ b/include/linux/dma/edma.h > @@ -153,6 +153,14 @@ bool dw_edma_chan_ignore_irq(struct dma_chan *chan); > int dw_edma_chan_register_notify(struct dma_chan *chan, > void (*cb)(struct dma_chan *chan, void *user), > void *user); > + > +/** > + * dw_edma_chan_get_ll_region - get linked list (LL) memory for a dma_chan > + * @chan: the target DMA channel > + * @region: output parameter returning the corresponding LL region > + */ > +int dw_edma_chan_get_ll_region(struct dma_chan *chan, > + struct dw_edma_region *region); > #else > static inline int dw_edma_probe(struct dw_edma_chip *chip) > { > @@ -182,6 +190,12 @@ static inline int dw_edma_chan_register_notify(struct > dma_chan *chan, > { > return -ENODEV; > } > + > +static inline int dw_edma_chan_get_ll_region(struct dma_chan *chan, > + struct dw_edma_region *region) > +{ > + return -EINVAL; > +} > #endif /* CONFIG_DW_EDMA */ > > struct pci_epc; > -- > 2.51.0 >
