On Wed, Jan 21, 2026 at 09:32:37PM +0530, Vinod Koul wrote: > On 19-01-26, 23:26, Koichiro Den wrote: > > 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. > > Strictly speaking slave config should be used for peripheral transfers. > For memcpy users (this seems more like that), I would argue slave config > does not make much sense.
It is not memcpy because one side address is not visible. It is really hard to define the difference between memcpy and slave transfer because - some slave transfer use MMIO, both side address increase, not like tranditional FIFO. it makes more like memcpy. - althougth it look like memcpy, but some slave have limitation, like need 4 bytpe alignment, there are limitation about burst length each time. Generally, memcpy have not such limitation (except from dmaengine itself). - slave address may not visialable at one side system. So dw-edma don't use prep_memcpy, which use prep_sg to do data transfer. Frank > > -- > ~Vinod
