On Sun, Jan 18, 2026 at 12:03:19PM -0500, Frank Li wrote: > On Sun, Jan 18, 2026 at 10:54:04PM +0900, Koichiro Den wrote: > > DesignWare EP eDMA can generate interrupts both locally and remotely > > (LIE/RIE). Remote eDMA users need to decide, per channel, whether > > completions should be handled locally, remotely, or both. Unless > > carefully configured, the endpoint and host would race to ack the > > interrupt. > > > > Introduce a per-channel interrupt routing mode and export small APIs to > > configure and query it. Update v0 programming so that RIE and local > > done/abort interrupt masking follow the selected mode. The default mode > > keeps the original behavior, so unless the new APIs are explicitly used, > > no functional changes. > > > > Signed-off-by: Koichiro Den <[email protected]> > > --- > > drivers/dma/dw-edma/dw-edma-core.c | 52 +++++++++++++++++++++++++++ > > drivers/dma/dw-edma/dw-edma-core.h | 2 ++ > > drivers/dma/dw-edma/dw-edma-v0-core.c | 26 +++++++++----- > > include/linux/dma/edma.h | 44 +++++++++++++++++++++++ > > 4 files changed, 116 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c > > b/drivers/dma/dw-edma/dw-edma-core.c > > index b9d59c3c0cb4..059b3996d383 100644 > > --- a/drivers/dma/dw-edma/dw-edma-core.c > > +++ b/drivers/dma/dw-edma/dw-edma-core.c > > @@ -768,6 +768,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, > > u32 wr_alloc, u32 rd_alloc) > > chan->configured = false; > > chan->request = EDMA_REQ_NONE; > > chan->status = EDMA_ST_IDLE; > > + chan->irq_mode = DW_EDMA_CH_IRQ_DEFAULT; > > > > if (chan->dir == EDMA_DIR_WRITE) > > chan->ll_max = (chip->ll_region_wr[chan->id].sz / > > EDMA_LL_SZ); > > @@ -1062,6 +1063,57 @@ int dw_edma_remove(struct dw_edma_chip *chip) > > } > > EXPORT_SYMBOL_GPL(dw_edma_remove); > > > > +int dw_edma_chan_irq_config(struct dma_chan *dchan, > > + enum dw_edma_ch_irq_mode mode) > > +{ > > + struct dw_edma_chan *chan; > > + > > + switch (mode) { > > + case DW_EDMA_CH_IRQ_DEFAULT: > > + case DW_EDMA_CH_IRQ_LOCAL: > > + case DW_EDMA_CH_IRQ_REMOTE: > > + break; > > + default: > > + return -EINVAL; > > + } > > + > > + if (!dchan || !dchan->device) > > + return -ENODEV; > > + > > + chan = dchan2dw_edma_chan(dchan); > > + if (!chan) > > + return -ENODEV; > > + > > + chan->irq_mode = mode; > > + > > + dev_vdbg(chan->dw->chip->dev, "Channel: %s[%u] set irq_mode=%u\n", > > + str_write_read(chan->dir == EDMA_DIR_WRITE), > > + chan->id, mode); > > + > > + return 0; > > +} > > +EXPORT_SYMBOL_GPL(dw_edma_chan_irq_config); > > + > > +bool dw_edma_chan_ignore_irq(struct dma_chan *dchan) > > +{ > > + struct dw_edma_chan *chan; > > + struct dw_edma *dw; > > + > > + if (!dchan || !dchan->device) > > + return false; > > + > > + chan = dchan2dw_edma_chan(dchan); > > + if (!chan) > > + return false; > > + > > + dw = chan->dw; > > + if (dw->chip->flags & DW_EDMA_CHIP_LOCAL) > > + return chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE; > > + else > > + return chan->irq_mode == DW_EDMA_CH_IRQ_LOCAL; > > +} > > +EXPORT_SYMBOL_GPL(dw_edma_chan_ignore_irq); > > + > > MODULE_LICENSE("GPL v2"); > > MODULE_DESCRIPTION("Synopsys DesignWare eDMA controller core driver"); > > MODULE_AUTHOR("Gustavo Pimentel <[email protected]>"); > > diff --git a/drivers/dma/dw-edma/dw-edma-core.h > > b/drivers/dma/dw-edma/dw-edma-core.h > > index 71894b9e0b15..8458d676551a 100644 > > --- a/drivers/dma/dw-edma/dw-edma-core.h > > +++ b/drivers/dma/dw-edma/dw-edma-core.h > > @@ -81,6 +81,8 @@ struct dw_edma_chan { > > > > struct msi_msg msi; > > > > + enum dw_edma_ch_irq_mode irq_mode; > > + > > enum dw_edma_request request; > > enum dw_edma_status status; > > u8 configured; > > diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c > > b/drivers/dma/dw-edma/dw-edma-v0-core.c > > index 2850a9df80f5..80472148c335 100644 > > --- a/drivers/dma/dw-edma/dw-edma-v0-core.c > > +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c > > @@ -256,8 +256,10 @@ dw_edma_v0_core_handle_int(struct dw_edma_irq *dw_irq, > > enum dw_edma_dir dir, > > for_each_set_bit(pos, &val, total) { > > chan = &dw->chan[pos + off]; > > > > - dw_edma_v0_core_clear_done_int(chan); > > - done(chan); > > + if (!dw_edma_chan_ignore_irq(&chan->vc.chan)) { > > + dw_edma_v0_core_clear_done_int(chan); > > + done(chan); > > + } > > > > ret = IRQ_HANDLED; > > } > > @@ -267,8 +269,10 @@ dw_edma_v0_core_handle_int(struct dw_edma_irq *dw_irq, > > enum dw_edma_dir dir, > > for_each_set_bit(pos, &val, total) { > > chan = &dw->chan[pos + off]; > > > > - dw_edma_v0_core_clear_abort_int(chan); > > - abort(chan); > > + if (!dw_edma_chan_ignore_irq(&chan->vc.chan)) { > > + dw_edma_v0_core_clear_abort_int(chan); > > + abort(chan); > > + } > > > > ret = IRQ_HANDLED; > > } > > @@ -331,7 +335,8 @@ static void dw_edma_v0_core_write_chunk(struct > > dw_edma_chunk *chunk) > > j--; > > if (!j) { > > control |= DW_EDMA_V0_LIE; > > - if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL)) > > + if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) && > > + chan->irq_mode != DW_EDMA_CH_IRQ_LOCAL) > > control |= DW_EDMA_V0_RIE; > > } > > > > @@ -408,12 +413,17 @@ static void dw_edma_v0_core_start(struct > > dw_edma_chunk *chunk, bool first) > > break; > > } > > } > > - /* Interrupt unmask - done, abort */ > > + /* Interrupt mask/unmask - done, abort */ > > raw_spin_lock_irqsave(&dw->lock, flags); > > > > tmp = GET_RW_32(dw, chan->dir, int_mask); > > - tmp &= ~FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id)); > > - tmp &= ~FIELD_PREP(EDMA_V0_ABORT_INT_MASK, BIT(chan->id)); > > + if (chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE) { > > + tmp |= FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id)); > > + tmp |= FIELD_PREP(EDMA_V0_ABORT_INT_MASK, > > BIT(chan->id)); > > + } else { > > + tmp &= ~FIELD_PREP(EDMA_V0_DONE_INT_MASK, > > BIT(chan->id)); > > + tmp &= ~FIELD_PREP(EDMA_V0_ABORT_INT_MASK, > > BIT(chan->id)); > > + } > > SET_RW_32(dw, chan->dir, int_mask, tmp); > > /* Linked list error */ > > tmp = GET_RW_32(dw, chan->dir, linked_list_err_en); > > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h > > index ffad10ff2cd6..6f50165ac084 100644 > > --- a/include/linux/dma/edma.h > > +++ b/include/linux/dma/edma.h > > @@ -60,6 +60,23 @@ enum dw_edma_chip_flags { > > DW_EDMA_CHIP_LOCAL = BIT(0), > > }; > > > > +/* > > + * enum dw_edma_ch_irq_mode - per-channel interrupt routing control > > + * @DW_EDMA_CH_IRQ_DEFAULT: LIE=1/RIE=1, local interrupt unmasked > > + * @DW_EDMA_CH_IRQ_LOCAL: LIE=1/RIE=0 > > + * @DW_EDMA_CH_IRQ_REMOTE: LIE=1/RIE=1, local interrupt masked > > + * > > + * Some implementations require using LIE=1/RIE=1 with the local interrupt > > + * masked to generate a remote-only interrupt (rather than LIE=0/RIE=1). > > + * See the DesignWare endpoint databook 5.40, "Hint" below "Figure 8-22 > > + * Write Interrupt Generation". > > + */ > > +enum dw_edma_ch_irq_mode { > > + DW_EDMA_CH_IRQ_DEFAULT = 0, > > + DW_EDMA_CH_IRQ_LOCAL, > > + DW_EDMA_CH_IRQ_REMOTE, > > +}; > > + > > /** > > * struct dw_edma_chip - representation of DesignWare eDMA controller > > hardware > > * @dev: struct device of the eDMA controller > > @@ -105,6 +122,22 @@ struct dw_edma_chip { > > #if IS_REACHABLE(CONFIG_DW_EDMA) > > int dw_edma_probe(struct dw_edma_chip *chip); > > int dw_edma_remove(struct dw_edma_chip *chip); > > +/** > > + * dw_edma_chan_irq_config - configure per-channel interrupt routing > > + * @chan: DMA channel obtained from dma_request_channel() > > + * @mode: interrupt routing mode > > + * > > + * Returns 0 on success, -EINVAL for invalid @mode, or -ENODEV if @chan > > does > > + * not belong to the DesignWare eDMA driver. > > + */ > > +int dw_edma_chan_irq_config(struct dma_chan *chan, > > + enum dw_edma_ch_irq_mode mode); > > + > > +/** > > + * dw_edma_chan_ignore_irq - tell whether local IRQ handling should be > > ignored > > + * @chan: DMA channel obtained from dma_request_channel() > > + */ > > +bool dw_edma_chan_ignore_irq(struct dma_chan *chan); > > #else > > static inline int dw_edma_probe(struct dw_edma_chip *chip) > > { > > @@ -115,6 +148,17 @@ static inline int dw_edma_remove(struct dw_edma_chip > > *chip) > > { > > return 0; > > } > > + > > +static inline int dw_edma_chan_irq_config(struct dma_chan *chan, > > + enum dw_edma_ch_irq_mode mode) > > +{ > > + return -ENODEV; > > +} > > + > > +static inline bool dw_edma_chan_ignore_irq(struct dma_chan *chan) > > +{ > > + return false; > > +} > > I think it'd better go thought > > struct dma_slave_config { > ... > void *peripheral_config; > size_t peripheral_size; > > }; > > So DMA consumer can use standard DMAengine API, dmaengine_slave_config().
Using .peripheral_config wasn't something I had initially considered, but I agree that this is preferable in the sense that it avoids introducing the additional exported APIs. I'm not entirely sure whether it's clean to use it for non-peripheral settings in the strict sense, but there seem to be precedents such as stm32_mdma_dma_config, so I guess it seems acceptable. If I'm missing something, please correct me. I'll rework this part as you suggested. Thanks for the guidance. Koichiro > > Frank > > #endif /* CONFIG_DW_EDMA */ > > > > struct pci_epc; > > -- > > 2.51.0 > >
