| Message ID | 150369477557.6962.17597022285367797559.stgit@djiang5-desk3.ch.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 25/08/17 21:59, Dave Jiang wrote: > Adding a dmaengine transaction operation that allows copy to/from a > scatterlist and a flat buffer. Apologies if I'm late to the party, but doesn't DMA_SG already cover this use-case? As far as I can see, all this does is save the caller from setting up a single-entry scatterlist to describe the buffer - even if such a simplified interface is justified it seems like something that could be implemented as a wrapper around dmaengine_prep_dma_sg() rather than the providers having to implement a whole extra callback. Robin. > > Signed-off-by: Dave Jiang <dave.jiang@intel.com> > --- > Documentation/dmaengine/provider.txt | 3 +++ > drivers/dma/dmaengine.c | 2 ++ > include/linux/dmaengine.h | 19 +++++++++++++++++++ > 3 files changed, 24 insertions(+) > > diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt > index a75f52f..6241e36 100644 > --- a/Documentation/dmaengine/provider.txt > +++ b/Documentation/dmaengine/provider.txt > @@ -181,6 +181,9 @@ Currently, the types available are: > - Used by the client drivers to register a callback that will be > called on a regular basis through the DMA controller interrupt > > + * DMA_MEMCPY_SG > + - The device supports scatterlist to/from memory. > + > * DMA_PRIVATE > - The devices only supports slave transfers, and as such isn't > available for async transfers. > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > index 428b141..4d2c4e1 100644 > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -937,6 +937,8 @@ int dma_async_device_register(struct dma_device *device) > !device->device_prep_dma_memset); > BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) && > !device->device_prep_dma_interrupt); > + BUG_ON(dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && > + !device->device_prep_dma_memcpy_sg); > BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && > !device->device_prep_dma_cyclic); > BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index 64fbd38..0c91411 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -67,6 +67,7 @@ enum dma_transaction_type { > DMA_PQ_VAL, > DMA_MEMSET, > DMA_MEMSET_SG, > + DMA_MEMCPY_SG, > DMA_INTERRUPT, > DMA_PRIVATE, > DMA_ASYNC_TX, > @@ -692,6 +693,7 @@ struct dma_filter { > * @device_prep_dma_pq_val: prepares a pqzero_sum operation > * @device_prep_dma_memset: prepares a memset operation > * @device_prep_dma_memset_sg: prepares a memset operation over a scatter list > + * @device_prep_dma_memcpy_sg: prepares memcpy between scatterlist and buffer > * @device_prep_dma_interrupt: prepares an end of chain interrupt operation > * @device_prep_slave_sg: prepares a slave dma operation > * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. > @@ -768,6 +770,10 @@ struct dma_device { > struct dma_async_tx_descriptor *(*device_prep_dma_memset_sg)( > struct dma_chan *chan, struct scatterlist *sg, > unsigned int nents, int value, unsigned long flags); > + struct dma_async_tx_descriptor *(*device_prep_dma_memcpy_sg)( > + struct dma_chan *chan, > + struct scatterlist *sg, unsigned int sg_nents, > + dma_addr_t buf, bool to_sg, unsigned long flags); > struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( > struct dma_chan *chan, unsigned long flags); > > @@ -899,6 +905,19 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy( > len, flags); > } > > +static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy_sg( > + struct dma_chan *chan, struct scatterlist *sg, > + unsigned int sg_nents, dma_addr_t buf, bool to_sg, > + unsigned long flags) > +{ > + if (!chan || !chan->device || > + !chan->device->device_prep_dma_memcpy_sg) > + return NULL; > + > + return chan->device->device_prep_dma_memcpy_sg(chan, sg, sg_nents, > + buf, to_sg, flags); > +} > + > /** > * dmaengine_terminate_all() - Terminate all active DMA transfers > * @chan: The channel for which to terminate the transfers >
On 08/30/2017 11:18 AM, Robin Murphy wrote: > On 25/08/17 21:59, Dave Jiang wrote: >> Adding a dmaengine transaction operation that allows copy to/from a >> scatterlist and a flat buffer. > > Apologies if I'm late to the party, but doesn't DMA_SG already cover > this use-case? As far as I can see, all this does is save the caller > from setting up a single-entry scatterlist to describe the buffer - even > if such a simplified interface is justified it seems like something that > could be implemented as a wrapper around dmaengine_prep_dma_sg() rather > than the providers having to implement a whole extra callback. > DMA_SG is queued to be removed in 4.14. There is no in kernel consumer for the code. > Robin. > >> >> Signed-off-by: Dave Jiang <dave.jiang@intel.com> >> --- >> Documentation/dmaengine/provider.txt | 3 +++ >> drivers/dma/dmaengine.c | 2 ++ >> include/linux/dmaengine.h | 19 +++++++++++++++++++ >> 3 files changed, 24 insertions(+) >> >> diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt >> index a75f52f..6241e36 100644 >> --- a/Documentation/dmaengine/provider.txt >> +++ b/Documentation/dmaengine/provider.txt >> @@ -181,6 +181,9 @@ Currently, the types available are: >> - Used by the client drivers to register a callback that will be >> called on a regular basis through the DMA controller interrupt >> >> + * DMA_MEMCPY_SG >> + - The device supports scatterlist to/from memory. >> + >> * DMA_PRIVATE >> - The devices only supports slave transfers, and as such isn't >> available for async transfers. >> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c >> index 428b141..4d2c4e1 100644 >> --- a/drivers/dma/dmaengine.c >> +++ b/drivers/dma/dmaengine.c >> @@ -937,6 +937,8 @@ int dma_async_device_register(struct dma_device *device) >> !device->device_prep_dma_memset); >> BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) && >> !device->device_prep_dma_interrupt); >> + BUG_ON(dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && >> + !device->device_prep_dma_memcpy_sg); >> BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && >> !device->device_prep_dma_cyclic); >> BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && >> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h >> index 64fbd38..0c91411 100644 >> --- a/include/linux/dmaengine.h >> +++ b/include/linux/dmaengine.h >> @@ -67,6 +67,7 @@ enum dma_transaction_type { >> DMA_PQ_VAL, >> DMA_MEMSET, >> DMA_MEMSET_SG, >> + DMA_MEMCPY_SG, >> DMA_INTERRUPT, >> DMA_PRIVATE, >> DMA_ASYNC_TX, >> @@ -692,6 +693,7 @@ struct dma_filter { >> * @device_prep_dma_pq_val: prepares a pqzero_sum operation >> * @device_prep_dma_memset: prepares a memset operation >> * @device_prep_dma_memset_sg: prepares a memset operation over a scatter list >> + * @device_prep_dma_memcpy_sg: prepares memcpy between scatterlist and buffer >> * @device_prep_dma_interrupt: prepares an end of chain interrupt operation >> * @device_prep_slave_sg: prepares a slave dma operation >> * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. >> @@ -768,6 +770,10 @@ struct dma_device { >> struct dma_async_tx_descriptor *(*device_prep_dma_memset_sg)( >> struct dma_chan *chan, struct scatterlist *sg, >> unsigned int nents, int value, unsigned long flags); >> + struct dma_async_tx_descriptor *(*device_prep_dma_memcpy_sg)( >> + struct dma_chan *chan, >> + struct scatterlist *sg, unsigned int sg_nents, >> + dma_addr_t buf, bool to_sg, unsigned long flags); >> struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( >> struct dma_chan *chan, unsigned long flags); >> >> @@ -899,6 +905,19 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy( >> len, flags); >> } >> >> +static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy_sg( >> + struct dma_chan *chan, struct scatterlist *sg, >> + unsigned int sg_nents, dma_addr_t buf, bool to_sg, >> + unsigned long flags) >> +{ >> + if (!chan || !chan->device || >> + !chan->device->device_prep_dma_memcpy_sg) >> + return NULL; >> + >> + return chan->device->device_prep_dma_memcpy_sg(chan, sg, sg_nents, >> + buf, to_sg, flags); >> +} >> + >> /** >> * dmaengine_terminate_all() - Terminate all active DMA transfers >> * @chan: The channel for which to terminate the transfers >>
On 30/08/17 19:25, Dave Jiang wrote: > On 08/30/2017 11:18 AM, Robin Murphy wrote: >> On 25/08/17 21:59, Dave Jiang wrote: >>> Adding a dmaengine transaction operation that allows copy to/from a >>> scatterlist and a flat buffer. >> >> Apologies if I'm late to the party, but doesn't DMA_SG already cover >> this use-case? As far as I can see, all this does is save the caller >> from setting up a single-entry scatterlist to describe the buffer - even >> if such a simplified interface is justified it seems like something that >> could be implemented as a wrapper around dmaengine_prep_dma_sg() rather >> than the providers having to implement a whole extra callback. >> > > DMA_SG is queued to be removed in 4.14. There is no in kernel consumer > for the code. Ah, I see, that's what I was missing. So we're effectively just replacing that interface with a more pragmatic alternative - that makes sense. Thanks, Robin. >>> >>> Signed-off-by: Dave Jiang <dave.jiang@intel.com> >>> --- >>> Documentation/dmaengine/provider.txt | 3 +++ >>> drivers/dma/dmaengine.c | 2 ++ >>> include/linux/dmaengine.h | 19 +++++++++++++++++++ >>> 3 files changed, 24 insertions(+) >>> >>> diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt >>> index a75f52f..6241e36 100644 >>> --- a/Documentation/dmaengine/provider.txt >>> +++ b/Documentation/dmaengine/provider.txt >>> @@ -181,6 +181,9 @@ Currently, the types available are: >>> - Used by the client drivers to register a callback that will be >>> called on a regular basis through the DMA controller interrupt >>> >>> + * DMA_MEMCPY_SG >>> + - The device supports scatterlist to/from memory. >>> + >>> * DMA_PRIVATE >>> - The devices only supports slave transfers, and as such isn't >>> available for async transfers. >>> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c >>> index 428b141..4d2c4e1 100644 >>> --- a/drivers/dma/dmaengine.c >>> +++ b/drivers/dma/dmaengine.c >>> @@ -937,6 +937,8 @@ int dma_async_device_register(struct dma_device *device) >>> !device->device_prep_dma_memset); >>> BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) && >>> !device->device_prep_dma_interrupt); >>> + BUG_ON(dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && >>> + !device->device_prep_dma_memcpy_sg); >>> BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && >>> !device->device_prep_dma_cyclic); >>> BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && >>> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h >>> index 64fbd38..0c91411 100644 >>> --- a/include/linux/dmaengine.h >>> +++ b/include/linux/dmaengine.h >>> @@ -67,6 +67,7 @@ enum dma_transaction_type { >>> DMA_PQ_VAL, >>> DMA_MEMSET, >>> DMA_MEMSET_SG, >>> + DMA_MEMCPY_SG, >>> DMA_INTERRUPT, >>> DMA_PRIVATE, >>> DMA_ASYNC_TX, >>> @@ -692,6 +693,7 @@ struct dma_filter { >>> * @device_prep_dma_pq_val: prepares a pqzero_sum operation >>> * @device_prep_dma_memset: prepares a memset operation >>> * @device_prep_dma_memset_sg: prepares a memset operation over a scatter list >>> + * @device_prep_dma_memcpy_sg: prepares memcpy between scatterlist and buffer >>> * @device_prep_dma_interrupt: prepares an end of chain interrupt operation >>> * @device_prep_slave_sg: prepares a slave dma operation >>> * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. >>> @@ -768,6 +770,10 @@ struct dma_device { >>> struct dma_async_tx_descriptor *(*device_prep_dma_memset_sg)( >>> struct dma_chan *chan, struct scatterlist *sg, >>> unsigned int nents, int value, unsigned long flags); >>> + struct dma_async_tx_descriptor *(*device_prep_dma_memcpy_sg)( >>> + struct dma_chan *chan, >>> + struct scatterlist *sg, unsigned int sg_nents, >>> + dma_addr_t buf, bool to_sg, unsigned long flags); >>> struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( >>> struct dma_chan *chan, unsigned long flags); >>> >>> @@ -899,6 +905,19 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy( >>> len, flags); >>> } >>> >>> +static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy_sg( >>> + struct dma_chan *chan, struct scatterlist *sg, >>> + unsigned int sg_nents, dma_addr_t buf, bool to_sg, >>> + unsigned long flags) >>> +{ >>> + if (!chan || !chan->device || >>> + !chan->device->device_prep_dma_memcpy_sg) >>> + return NULL; >>> + >>> + return chan->device->device_prep_dma_memcpy_sg(chan, sg, sg_nents, >>> + buf, to_sg, flags); >>> +} >>> + >>> /** >>> * dmaengine_terminate_all() - Terminate all active DMA transfers >>> * @chan: The channel for which to terminate the transfers >>>
Hi Vinod, On 31.08.2017 12:57, Robin Murphy wrote: > On 30/08/17 19:25, Dave Jiang wrote: >> On 08/30/2017 11:18 AM, Robin Murphy wrote: >>> On 25/08/17 21:59, Dave Jiang wrote: >>>> Adding a dmaengine transaction operation that allows copy to/from a >>>> scatterlist and a flat buffer. >>> >>> Apologies if I'm late to the party, but doesn't DMA_SG already cover >>> this use-case? As far as I can see, all this does is save the caller >>> from setting up a single-entry scatterlist to describe the buffer - even >>> if such a simplified interface is justified it seems like something that >>> could be implemented as a wrapper around dmaengine_prep_dma_sg() rather >>> than the providers having to implement a whole extra callback. >>> >> >> DMA_SG is queued to be removed in 4.14. There is no in kernel consumer >> for the code. > > Ah, I see, that's what I was missing. So we're effectively just > replacing that interface with a more pragmatic alternative - that makes > sense. What are the plans with this new DMA_MEMCPY_SG interface? When will it hit mainline or is something missing? Thanks, Stefan
On Mon, Nov 13, 2017 at 09:28:46AM +0100, Stefan Roese wrote: > Hi Vinod, > > On 31.08.2017 12:57, Robin Murphy wrote: > >On 30/08/17 19:25, Dave Jiang wrote: > >>On 08/30/2017 11:18 AM, Robin Murphy wrote: > >>>On 25/08/17 21:59, Dave Jiang wrote: > >>>>Adding a dmaengine transaction operation that allows copy to/from a > >>>>scatterlist and a flat buffer. > >>> > >>>Apologies if I'm late to the party, but doesn't DMA_SG already cover > >>>this use-case? As far as I can see, all this does is save the caller > >>>from setting up a single-entry scatterlist to describe the buffer - even > >>>if such a simplified interface is justified it seems like something that > >>>could be implemented as a wrapper around dmaengine_prep_dma_sg() rather > >>>than the providers having to implement a whole extra callback. > >>> > >> > >>DMA_SG is queued to be removed in 4.14. There is no in kernel consumer > >>for the code. > > > >Ah, I see, that's what I was missing. So we're effectively just > >replacing that interface with a more pragmatic alternative - that makes > >sense. > > What are the plans with this new DMA_MEMCPY_SG interface? When will it > hit mainline or is something missing? The old one was removed in 4.14 so if you have a usage feel free to send a patch to add this with usage. Thanks
Hi Vinod, On 15.11.2017 16:52, Vinod Koul wrote: > On Mon, Nov 13, 2017 at 09:28:46AM +0100, Stefan Roese wrote: >> Hi Vinod, >> >> On 31.08.2017 12:57, Robin Murphy wrote: >>> On 30/08/17 19:25, Dave Jiang wrote: >>>> On 08/30/2017 11:18 AM, Robin Murphy wrote: >>>>> On 25/08/17 21:59, Dave Jiang wrote: >>>>>> Adding a dmaengine transaction operation that allows copy to/from a >>>>>> scatterlist and a flat buffer. >>>>> >>>>> Apologies if I'm late to the party, but doesn't DMA_SG already cover >>>>> this use-case? As far as I can see, all this does is save the caller >>>> >from setting up a single-entry scatterlist to describe the buffer - even >>>>> if such a simplified interface is justified it seems like something that >>>>> could be implemented as a wrapper around dmaengine_prep_dma_sg() rather >>>>> than the providers having to implement a whole extra callback. >>>>> >>>> >>>> DMA_SG is queued to be removed in 4.14. There is no in kernel consumer >>>> for the code. >>> >>> Ah, I see, that's what I was missing. So we're effectively just >>> replacing that interface with a more pragmatic alternative - that makes >>> sense. >> >> What are the plans with this new DMA_MEMCPY_SG interface? When will it >> hit mainline or is something missing? > > The old one was removed in 4.14 so if you have a usage feel free to send a > patch to add this with usage. No, its not the "old one" (DMA_SG) but the "new one" (DMA_MEMCPY_SG) I'm referring to (this email thread). My impression was, that this new interface has (or will get) in-kernel users and will be pulled at some time. Thanks, Stefan
On 11/15/2017 09:13 AM, Stefan Roese wrote: > Hi Vinod, > > On 15.11.2017 16:52, Vinod Koul wrote: >> On Mon, Nov 13, 2017 at 09:28:46AM +0100, Stefan Roese wrote: >>> Hi Vinod, >>> >>> On 31.08.2017 12:57, Robin Murphy wrote: >>>> On 30/08/17 19:25, Dave Jiang wrote: >>>>> On 08/30/2017 11:18 AM, Robin Murphy wrote: >>>>>> On 25/08/17 21:59, Dave Jiang wrote: >>>>>>> Adding a dmaengine transaction operation that allows copy to/from a >>>>>>> scatterlist and a flat buffer. >>>>>> >>>>>> Apologies if I'm late to the party, but doesn't DMA_SG already cover >>>>>> this use-case? As far as I can see, all this does is save the caller >>>>> >from setting up a single-entry scatterlist to describe the buffer - even >>>>>> if such a simplified interface is justified it seems like something that >>>>>> could be implemented as a wrapper around dmaengine_prep_dma_sg() rather >>>>>> than the providers having to implement a whole extra callback. >>>>>> >>>>> >>>>> DMA_SG is queued to be removed in 4.14. There is no in kernel consumer >>>>> for the code. >>>> >>>> Ah, I see, that's what I was missing. So we're effectively just >>>> replacing that interface with a more pragmatic alternative - that makes >>>> sense. >>> >>> What are the plans with this new DMA_MEMCPY_SG interface? When will it >>> hit mainline or is something missing? >> >> The old one was removed in 4.14 so if you have a usage feel free to send a >> patch to add this with usage. > > No, its not the "old one" (DMA_SG) but the "new one" (DMA_MEMCPY_SG) > I'm referring to (this email thread). My impression was, that this > new interface has (or will get) in-kernel users and will be pulled at > some time. > Decided to hold off on the submission for now. If you need it and have an upstream consumer for it, feel free to push the change.
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index a75f52f..6241e36 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt @@ -181,6 +181,9 @@ Currently, the types available are: - Used by the client drivers to register a callback that will be called on a regular basis through the DMA controller interrupt + * DMA_MEMCPY_SG + - The device supports scatterlist to/from memory. + * DMA_PRIVATE - The devices only supports slave transfers, and as such isn't available for async transfers. diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 428b141..4d2c4e1 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -937,6 +937,8 @@ int dma_async_device_register(struct dma_device *device) !device->device_prep_dma_memset); BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt); + BUG_ON(dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && + !device->device_prep_dma_memcpy_sg); BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic); BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 64fbd38..0c91411 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -67,6 +67,7 @@ enum dma_transaction_type { DMA_PQ_VAL, DMA_MEMSET, DMA_MEMSET_SG, + DMA_MEMCPY_SG, DMA_INTERRUPT, DMA_PRIVATE, DMA_ASYNC_TX, @@ -692,6 +693,7 @@ struct dma_filter { * @device_prep_dma_pq_val: prepares a pqzero_sum operation * @device_prep_dma_memset: prepares a memset operation * @device_prep_dma_memset_sg: prepares a memset operation over a scatter list + * @device_prep_dma_memcpy_sg: prepares memcpy between scatterlist and buffer * @device_prep_dma_interrupt: prepares an end of chain interrupt operation * @device_prep_slave_sg: prepares a slave dma operation * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. @@ -768,6 +770,10 @@ struct dma_device { struct dma_async_tx_descriptor *(*device_prep_dma_memset_sg)( struct dma_chan *chan, struct scatterlist *sg, unsigned int nents, int value, unsigned long flags); + struct dma_async_tx_descriptor *(*device_prep_dma_memcpy_sg)( + struct dma_chan *chan, + struct scatterlist *sg, unsigned int sg_nents, + dma_addr_t buf, bool to_sg, unsigned long flags); struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( struct dma_chan *chan, unsigned long flags); @@ -899,6 +905,19 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy( len, flags); } +static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy_sg( + struct dma_chan *chan, struct scatterlist *sg, + unsigned int sg_nents, dma_addr_t buf, bool to_sg, + unsigned long flags) +{ + if (!chan || !chan->device || + !chan->device->device_prep_dma_memcpy_sg) + return NULL; + + return chan->device->device_prep_dma_memcpy_sg(chan, sg, sg_nents, + buf, to_sg, flags); +} + /** * dmaengine_terminate_all() - Terminate all active DMA transfers * @chan: The channel for which to terminate the transfers
Adding a dmaengine transaction operation that allows copy to/from a scatterlist and a flat buffer. Signed-off-by: Dave Jiang <dave.jiang@intel.com> --- Documentation/dmaengine/provider.txt | 3 +++ drivers/dma/dmaengine.c | 2 ++ include/linux/dmaengine.h | 19 +++++++++++++++++++ 3 files changed, 24 insertions(+)