Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/13 Barry Song 21cn...@gmail.com: 2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. i think it should be handled by this patch but not a new one. and i also think xfer_template is a bad name for a structure which is an API. i'd like to add namespace for it and rename it to dma_genxfer. or have any good suggestion? i'd like to send this together with BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) !device-device_prep_dma_genxfer) as v2. -barry -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On 15 September 2011 12:01, Barry Song 21cn...@gmail.com wrote: 2011/9/13 Barry Song 21cn...@gmail.com: 2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. i think it should be handled by this patch but not a new one. and i also think xfer_template is a bad name for a structure which is an API. i'd like to add namespace for it and rename it to dma_genxfer. or have any good suggestion? I think xfer_template is better - which stresses the usage as having prepared templates of transfers and only change src/dst address before submitting. 'device_prep_dma_genxfer' is the API which is already named so. i'd like to send this together with BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) !device-device_prep_dma_genxfer) as v2. Is there no change other than skipping check for SLAVE when using this api ? -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/15 Jassi Brar jaswinder.si...@linaro.org: On 15 September 2011 12:01, Barry Song 21cn...@gmail.com wrote: 2011/9/13 Barry Song 21cn...@gmail.com: 2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. i think it should be handled by this patch but not a new one. and i also think xfer_template is a bad name for a structure which is an API. i'd like to add namespace for it and rename it to dma_genxfer. or have any good suggestion? I think xfer_template is better - which stresses the usage as having prepared templates of transfers and only change src/dst address before submitting. 'device_prep_dma_genxfer' is the API which is already named so. sorry i can't agree that. device_prep_dma_genxfer is an API, xfer_template is a data structure which will be seen by users, client drivers. it at least needs a namespace. Otherwise, people someday maybe add another xfer. i'd like to send this together with BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) !device-device_prep_dma_genxfer) as v2. Is there no change other than skipping check for SLAVE when using this api ? -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/15 Jassi Brar jaswinder.si...@linaro.org: On 15 September 2011 12:01, Barry Song 21cn...@gmail.com wrote: 2011/9/13 Barry Song 21cn...@gmail.com: 2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. i think it should be handled by this patch but not a new one. and i also think xfer_template is a bad name for a structure which is an API. i'd like to add namespace for it and rename it to dma_genxfer. or have any good suggestion? I think xfer_template is better - which stresses the usage as having prepared templates of transfers and only change src/dst address before submitting. 'device_prep_dma_genxfer' is the API which is already named so. i'd like to send this together with BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) !device-device_prep_dma_genxfer) as v2. Is there no change other than skipping check for SLAVE when using this api ? another change i want to do is a simple xfer alloc helper so that every driver doesn't need a long line to alloc this struct with a zero length array: struct xfer_template *alloc_xfer_template(size_t frame_size) { kzalloc(sizeof(struct xfer_template) + sizeof(struct data_chunk) * frame_size); } Then client can fill xt.sgl[0].size xt.sgl[0].icg xt.sgl[1].size xt.sgl[1].icg ... xt.sgl[x].size xt.sgl[x].icg but xfer_template and data_chunk will have namespace. -barry -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/13 Barry Song 21cn...@gmail.com: 2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 12 September 2011 21:56, Barry Song 21cn...@gmail.com wrote: Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org anyway, this API needs a real user to prove why it needs to exist. prima2 can be the 1st(?, 2nd if TI uses) user of this API. let's try to see what the driver will be with this api. Then we might figure out more about what it should be. Did you discover any issue with the api? no until now, but i need to test as i said since there is nobody else has used it before. so i just hold the formal ACK for a moment. Because only three days ago you said { Jassi, you might think my reply as an ACK to [PATCH] DMAEngine: Define generic transfer request api. } if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, then the validation check in dma_async_device_register(): BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) !device-device_prep_slave_sg); is wrong to me. How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); The api met your requirements easily not because I know them already, but because I designed the api to be as generic as practically possible. -barry -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. thanks. -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 13 September 2011 13:16, Barry Song 21cn...@gmail.com wrote: if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com one issue i noticed is with a device_prep_dma_genxfer, i don't need device_prep_slave_sg any more, Yeah, the damengine would need to adapt to the fact that these interleaved tranfers could be Mem-Mem as well as Mem-Dev (even though yours could be only one type, but some dmacs could do both). How about: BUG_ON(dma_has_cap(DMA_MEMCPY, device-cap_mask) - !device-device_prep_dma_memcpy); + !device-device_prep_dma_memcpy + !device-device_prep_dma_genxfer); BUG_ON(dma_has_cap(DMA_SLAVE, device-cap_mask) - !device-device_prep_slave_sg); + !device-device_prep_slave_sg + !device-device_prep_dma_genxfer); Seems ok, but please modify in a way you think is best and submit a patch on top of this new api. Then it'll be easier to evaluate everything. i think it should be handled by this patch but not a new one. thanks. -barry -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org anyway, this API needs a real user to prove why it needs to exist. prima2 can be the 1st(?, 2nd if TI uses) user of this API. let's try to see what the driver will be with this api. Then we might figure out more about what it should be. --- include/linux/dmaengine.h | 73 + 1 files changed, 73 insertions(+), 0 deletions(-) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 8fbf40e..74f3ae0 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -76,6 +76,76 @@ enum dma_transaction_type { /* last transaction type for creation of the capabilities mask */ #define DMA_TX_TYPE_END (DMA_CYCLIC + 1) +/** + * Generic Transfer Request + * + * A chunk is collection of contiguous bytes to be transfered. + * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG). + * ICGs may or maynot change between chunks. + * A FRAME is the smallest series of contiguous {chunk,icg} pairs, + * that when repeated an integral number of times, specifies the transfer. + * A transfer template is specification of a Frame, the number of times + * it is to be repeated and other per-transfer attributes. + * + * Practically, a client driver would have ready a template for each + * type of transfer it is going to need during its lifetime and + * set only 'src_start' and 'dst_start' before submitting the requests. + * + * + * | Frame-1 | Frame-2 | ~ | Frame-'numf' | + * |==.===...=...|==.===...=...| ~ |==.===...=...| + * + * == Chunk size + * ... ICG + */ + +/** + * struct data_chunk - Element of scatter-gather list that makes a frame. + * @size: Number of bytes to read from source. + * size_dst := fn(op, size_src), so doesn't mean much for destination. + * @icg: Number of bytes to jump after last src/dst address of this + * chunk and before first src/dst address for next chunk. + * Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false. + * Ignored for src(assumed 0), if src_inc is true and src_sgl is false. + */ +struct data_chunk { + size_t size; + size_t icg; +}; + +/** + * struct xfer_template - Template to convey DMAC the transfer pattern + * and attributes. + * @op: The operation to perform on source data before writing it on + * to destination address. + * @src_start: Bus address of source for the first chunk. + * @dst_start: Bus address of destination for the first chunk. + * @src_inc: If the source address increments after reading from it. + * @dst_inc: If the destination address increments after writing to it. + * @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read). + * Otherwise, source is read contiguously (icg ignored). + * Ignored if src_inc is false. + * @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write). + * Otherwise, destination is filled contiguously (icg ignored). + * Ignored if dst_inc is false. + * @frm_irq: If the client expects DMAC driver to do callback after each frame. + * @numf: Number of frames in this template. + * @frame_size: Number of chunks in a frame i.e, size of sgl[]. + * @sgl: Array of {chunk,icg} pairs that make up a frame. + */ +struct xfer_template { + enum dma_transaction_type op; + dma_addr_t src_start; + dma_addr_t dst_start; + bool src_inc; + bool dst_inc; + bool src_sgl; + bool dst_sgl; + bool frm_irq; + size_t numf; + size_t frame_size; + struct data_chunk sgl[0]; +}; /** * enum dma_ctrl_flags - DMA flags to augment operation preparation, @@ -432,6 +502,7 @@ struct dma_tx_state { * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. * The function takes a buffer of size buf_len. The callback function will * be called after period_len bytes have been transferred. + * @device_prep_dma_genxfer: Transfer expression in a generic way. * @device_control: manipulate all pending operations on a channel, returns * zero or error code
Re: [PATCH] DMAEngine: Define generic transfer request api
On 12 September 2011 21:56, Barry Song 21cn...@gmail.com wrote: Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org anyway, this API needs a real user to prove why it needs to exist. prima2 can be the 1st(?, 2nd if TI uses) user of this API. let's try to see what the driver will be with this api. Then we might figure out more about what it should be. Did you discover any issue with the api? Because only three days ago you said { Jassi, you might think my reply as an ACK to [PATCH] DMAEngine: Define generic transfer request api. } The api met your requirements easily not because I know them already, but because I designed the api to be as generic as practically possible. -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/9/13 Jassi Brar jaswinder.si...@linaro.org: On 12 September 2011 21:56, Barry Song 21cn...@gmail.com wrote: Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org anyway, this API needs a real user to prove why it needs to exist. prima2 can be the 1st(?, 2nd if TI uses) user of this API. let's try to see what the driver will be with this api. Then we might figure out more about what it should be. Did you discover any issue with the api? no until now, but i need to test as i said since there is nobody else has used it before. so i just hold the formal ACK for a moment. Because only three days ago you said { Jassi, you might think my reply as an ACK to [PATCH] DMAEngine: Define generic transfer request api. } if test pass, to the patch, and even for the moment, to the API's idea Acked-by: Barry Song baohua.s...@csr.com The api met your requirements easily not because I know them already, but because I designed the api to be as generic as practically possible. -barry -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On Aug 19, 2011, at 9:43 AM, Koul, Vinod wrote: On Tue, 2011-08-16 at 15:06 +0200, Linus Walleij wrote: On Tue, Aug 16, 2011 at 2:56 PM, Koul, Vinod vinod.k...@intel.com wrote: Currently we have two approaches to solve this problem first being the DMA_STRIDE_CONFIG proposed by Linus W, I feel this one is better approach as this can give client ability to configure each transfer rather than set for the channel. Linus W, do you agree? I think Sundaram is in the position of doing some heavy work on using one or the other of the API:s, and I think he is better suited than anyone else of us to select what scheme to use, in the end he's going to write the first code using the API. And Unfortunately TI folks don't seem to care about this discussion :( Haven't seen anything on this from them, or on previous RFC by Jassi IIRC, Sundaram went on holiday. I suspect he cares a lot about this discussion as he has a session on the topic at LPC. -Matt -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On Tue, 2011-08-16 at 15:06 +0200, Linus Walleij wrote: On Tue, Aug 16, 2011 at 2:56 PM, Koul, Vinod vinod.k...@intel.com wrote: Currently we have two approaches to solve this problem first being the DMA_STRIDE_CONFIG proposed by Linus W, I feel this one is better approach as this can give client ability to configure each transfer rather than set for the channel. Linus W, do you agree? I think Sundaram is in the position of doing some heavy work on using one or the other of the API:s, and I think he is better suited than anyone else of us to select what scheme to use, in the end he's going to write the first code using the API. And Unfortunately TI folks don't seem to care about this discussion :( Haven't seen anything on this from them, or on previous RFC by Jassi -- ~Vinod -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
2011/8/19 Koul, Vinod vinod.k...@intel.com: On Tue, 2011-08-16 at 15:06 +0200, Linus Walleij wrote: On Tue, Aug 16, 2011 at 2:56 PM, Koul, Vinod vinod.k...@intel.com wrote: I think Sundaram is in the position of doing some heavy work on using one or the other of the API:s, and I think he is better suited than anyone else of us to select what scheme to use, in the end he's going to write the first code using the API. And Unfortunately TI folks don't seem to care about this discussion :( Haven't seen anything on this from them, or on previous RFC by Jassi Well if there is no code usig the API then there is no rush in merging it either I guess. Whenever someone (TI or Samsung) cook some driver patches they can choose their approach. Thanks, Linus Walleij -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On 19 August 2011 22:58, Koul, Vinod vinod.k...@intel.com wrote: On Fri, 2011-08-19 at 21:16 +0530, Jassi Brar wrote: On 19 August 2011 19:49, Linus Walleij linus.ml.wall...@gmail.com wrote: 2011/8/19 Koul, Vinod vinod.k...@intel.com: On Tue, 2011-08-16 at 15:06 +0200, Linus Walleij wrote: On Tue, Aug 16, 2011 at 2:56 PM, Koul, Vinod vinod.k...@intel.com wrote: I think Sundaram is in the position of doing some heavy work on using one or the other of the API:s, and I think he is better suited than anyone else of us to select what scheme to use, in the end he's going to write the first code using the API. And Unfortunately TI folks don't seem to care about this discussion :( Haven't seen anything on this from them, or on previous RFC by Jassi Well if there is no code usig the API then there is no rush in merging it either I guess. Whenever someone (TI or Samsung) cook some driver patches they can choose their approach. No, it's not a matter of choice. If that were the case, Sundaram already proposed a TI specific flag. Why wait for him to tell his choice again? You might, but I can't molest my sensibility to believe that a Vendor specific flag could be better than a generic solution. Not here at least, where the overhead due to generality is not much. (though I can trim some 'futuristic' members from the 'struct xfer_template') Who said anything about adding a vendor flag solution, Not you, but to whom I replied - LinusW See https://lkml.org/lkml/2011/7/11/74 since TI are potential users of the API it would good to know i this fits there needs are not. I am super-interested to hear from TI guys. The generic api here rather supports the case Sundaram projected as 'most' general case. Look at the figure at end of https://lkml.org/lkml/2011/6/9/343 Maintainers might wait as long as they want, but there should never be an option to have vendor specific hacks. to me API looks decent after reading some specs of DMACs which support this mode. Pls send updated patch along with one driver which uses it. Should be good to go... That has been one problem with DMAEngine. People patch the API as they need stuff, rather than having had solid thought-out API that could be extended consistently. For ex, we ended up having _ten_ device_prep_dma_* callbacks, where as we could have done having had originally 1 (or maybe 2) 'generic' prepare callback with a 'enum dma_transaction_type op' argument. IMO it's rather good that I designed this API for a theoretical highly-capable DMAC, and not just the DMAC I've worked on - which would have constrained the api in future for other DMACs. -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] DMAEngine: Define generic transfer request api
On Fri, 2011-08-12 at 16:44 +0530, Jassi Brar wrote: Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org --- include/linux/dmaengine.h | 73 + 1 files changed, 73 insertions(+), 0 deletions(-) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 8fbf40e..74f3ae0 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -76,6 +76,76 @@ enum dma_transaction_type { /* last transaction type for creation of the capabilities mask */ #define DMA_TX_TYPE_END (DMA_CYCLIC + 1) +/** + * Generic Transfer Request + * + * A chunk is collection of contiguous bytes to be transfered. + * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG). + * ICGs may or maynot change between chunks. + * A FRAME is the smallest series of contiguous {chunk,icg} pairs, + * that when repeated an integral number of times, specifies the transfer. + * A transfer template is specification of a Frame, the number of times + * it is to be repeated and other per-transfer attributes. + * + * Practically, a client driver would have ready a template for each + * type of transfer it is going to need during its lifetime and + * set only 'src_start' and 'dst_start' before submitting the requests. + * + * + * | Frame-1| Frame-2 | ~ | Frame-'numf' | + * |==.===...=...|==.===...=...| ~ |==.===...=...| + * + *== Chunk size + *... ICG + */ + +/** + * struct data_chunk - Element of scatter-gather list that makes a frame. + * @size: Number of bytes to read from source. + * size_dst := fn(op, size_src), so doesn't mean much for destination. + * @icg: Number of bytes to jump after last src/dst address of this + *chunk and before first src/dst address for next chunk. + *Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false. + *Ignored for src(assumed 0), if src_inc is true and src_sgl is false. + */ +struct data_chunk { + size_t size; + size_t icg; +}; + +/** + * struct xfer_template - Template to convey DMAC the transfer pattern + *and attributes. + * @op: The operation to perform on source data before writing it on + *to destination address. + * @src_start: Bus address of source for the first chunk. + * @dst_start: Bus address of destination for the first chunk. + * @src_inc: If the source address increments after reading from it. + * @dst_inc: If the destination address increments after writing to it. + * @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read). + * Otherwise, source is read contiguously (icg ignored). + * Ignored if src_inc is false. + * @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write). + * Otherwise, destination is filled contiguously (icg ignored). + * Ignored if dst_inc is false. + * @frm_irq: If the client expects DMAC driver to do callback after each frame. + * @numf: Number of frames in this template. + * @frame_size: Number of chunks in a frame i.e, size of sgl[]. + * @sgl: Array of {chunk,icg} pairs that make up a frame. + */ +struct xfer_template { + enum dma_transaction_type op; + dma_addr_t src_start; + dma_addr_t dst_start; + bool src_inc; + bool dst_inc; + bool src_sgl; + bool dst_sgl; + bool frm_irq; + size_t numf; + size_t frame_size; + struct data_chunk sgl[0]; +}; /** * enum dma_ctrl_flags - DMA flags to augment operation preparation, @@ -432,6 +502,7 @@ struct dma_tx_state { * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. * The function takes a buffer of size buf_len. The callback function will * be called after period_len bytes have been transferred. + * @device_prep_dma_genxfer: Transfer expression in a generic way. * @device_control: manipulate all pending operations on a channel, returns * zero or error code * @device_tx_status: poll for transaction completion, the optional @@ -496,6 +567,8 @@ struct dma_device { struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)( struct dma_chan *chan,
Re: [PATCH] DMAEngine: Define generic transfer request api
On Tue, Aug 16, 2011 at 2:56 PM, Koul, Vinod vinod.k...@intel.com wrote: Currently we have two approaches to solve this problem first being the DMA_STRIDE_CONFIG proposed by Linus W, I feel this one is better approach as this can give client ability to configure each transfer rather than set for the channel. Linus W, do you agree? I think Sundaram is in the position of doing some heavy work on using one or the other of the API:s, and I think he is better suited than anyone else of us to select what scheme to use, in the end he's going to write the first code using the API. Yours, Linus Walleij -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH] DMAEngine: Define generic transfer request api
Define a new api that could be used for doing fancy data transfers like interleaved to contiguous copy and vice-versa. Traditional SG_list based transfers tend to be very inefficient in such cases as where the interleave and chunk are only a few bytes, which call for a very condensed api to convey pattern of the transfer. This api supports all 4 variants of scatter-gather and contiguous transfer. Besides, it could also represent common operations like device_prep_dma_{cyclic, memset, memcpy} and maybe some more that I am not sure of. Of course, neither can this api help transfers that don't lend to DMA by nature, i.e, scattered tiny read/writes with no periodic pattern. Signed-off-by: Jassi Brar jaswinder.si...@linaro.org --- include/linux/dmaengine.h | 73 + 1 files changed, 73 insertions(+), 0 deletions(-) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 8fbf40e..74f3ae0 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -76,6 +76,76 @@ enum dma_transaction_type { /* last transaction type for creation of the capabilities mask */ #define DMA_TX_TYPE_END (DMA_CYCLIC + 1) +/** + * Generic Transfer Request + * + * A chunk is collection of contiguous bytes to be transfered. + * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG). + * ICGs may or maynot change between chunks. + * A FRAME is the smallest series of contiguous {chunk,icg} pairs, + * that when repeated an integral number of times, specifies the transfer. + * A transfer template is specification of a Frame, the number of times + * it is to be repeated and other per-transfer attributes. + * + * Practically, a client driver would have ready a template for each + * type of transfer it is going to need during its lifetime and + * set only 'src_start' and 'dst_start' before submitting the requests. + * + * + * | Frame-1| Frame-2 | ~ | Frame-'numf' | + * |==.===...=...|==.===...=...| ~ |==.===...=...| + * + *== Chunk size + *... ICG + */ + +/** + * struct data_chunk - Element of scatter-gather list that makes a frame. + * @size: Number of bytes to read from source. + * size_dst := fn(op, size_src), so doesn't mean much for destination. + * @icg: Number of bytes to jump after last src/dst address of this + * chunk and before first src/dst address for next chunk. + * Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false. + * Ignored for src(assumed 0), if src_inc is true and src_sgl is false. + */ +struct data_chunk { + size_t size; + size_t icg; +}; + +/** + * struct xfer_template - Template to convey DMAC the transfer pattern + * and attributes. + * @op: The operation to perform on source data before writing it on + * to destination address. + * @src_start: Bus address of source for the first chunk. + * @dst_start: Bus address of destination for the first chunk. + * @src_inc: If the source address increments after reading from it. + * @dst_inc: If the destination address increments after writing to it. + * @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read). + * Otherwise, source is read contiguously (icg ignored). + * Ignored if src_inc is false. + * @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write). + * Otherwise, destination is filled contiguously (icg ignored). + * Ignored if dst_inc is false. + * @frm_irq: If the client expects DMAC driver to do callback after each frame. + * @numf: Number of frames in this template. + * @frame_size: Number of chunks in a frame i.e, size of sgl[]. + * @sgl: Array of {chunk,icg} pairs that make up a frame. + */ +struct xfer_template { + enum dma_transaction_type op; + dma_addr_t src_start; + dma_addr_t dst_start; + bool src_inc; + bool dst_inc; + bool src_sgl; + bool dst_sgl; + bool frm_irq; + size_t numf; + size_t frame_size; + struct data_chunk sgl[0]; +}; /** * enum dma_ctrl_flags - DMA flags to augment operation preparation, @@ -432,6 +502,7 @@ struct dma_tx_state { * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. * The function takes a buffer of size buf_len. The callback function will * be called after period_len bytes have been transferred. + * @device_prep_dma_genxfer: Transfer expression in a generic way. * @device_control: manipulate all pending operations on a channel, returns * zero or error code * @device_tx_status: poll for transaction completion, the optional @@ -496,6 +567,8 @@ struct dma_device { struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)( struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_data_direction direction); +