this feature has been supported in kernel 3.9-rc5, this contain the following patches. Please evalutate if it can be backported to raring kernel.
1. commit b801479bb6f5b66f5a35feaa72451ac5ac152ef5 Author: Heikki Krogerus <email address hidden> Date: Thu Oct 18 17:34:08 2012 +0300
dmaengine: dw_dmac: amend description and indentation
2. commit 21d43f49cb5e132e74bde9e34ac0760f79ab85a9 Author: Andy Shevchenko <email address hidden> Date: Thu Oct 18 17:34:09 2012 +0300
dw_dmac: change dev_printk() to corresponding macros
3.commit 6168d5670bd764557b5e06b1842964a44cf34a45 Author: Andy Shevchenko <email address hidden> Date: Thu Oct 18 17:34:10 2012 +0300
dw_dmac: don't call platform_get_drvdata twice
4. commit ba84bd7146b9244de0ce04cdc668521a73f5336f Author: Andy Shevchenko <email address hidden> Date: Thu Oct 18 17:34:11 2012 +0300
dw_dmac: change dev_crit to dev_WARN in dwc_handle_error
5. commit e63a47a361e03eaf79e0f2f6cdaca8e7679d1867 Author: Andy Shevchenko <email address hidden> Date: Thu Oct 18 17:34:12 2012 +0300
dw_dmac: introduce to_dw_desc() macro
6. commit 123de543414bce42da9729071962d4a9512612c8 Author: Andy Shevchenko <email address hidden> Date: Wed Jan 9 10:17:01 2013 +0200
dw_dmac: absence of pdata isn't critical when autocfg is set
7. commit cbd65312ba6b508e994d40729e84a51301870bcc Author: Andy Shevchenko <email address hidden> Date: Wed Jan 9 10:17:11 2013 +0200
dw_dmac: check for mapping errors
8. commit 21e93c1e7dae0e8b1914a522c331f0f7763fa89d Author: Andy Shevchenko <email address hidden> Date: Wed Jan 9 10:17:12 2013 +0200
dw_dmac: remove redundant check
9. commit f5c6a7df35b04db906577e90fa5e133e56433bcf Author: Andy Shevchenko <email address hidden> Date: Wed Jan 9 10:17:13 2013 +0200
dw_dmac: update tx_node_active in dwc_do_single_block
10. commit 21fe3c5245647d200a7ba25d42b80d21c578a8dc Author: Andy Shevchenko <email address hidden> Date: Wed Jan 9 10:17:14 2013 +0200
dma: dw_dmac: add dwc_chan_pause and dwc_chan_resume
11. commit 61cc13a51bcff737ce02d2047834171c0365b00d Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:52:56 2013 +0200
dmaengine: introduce is_slave_direction function
12. commit 782bc950d84e404422ba21008fd51ee894c8d231 Author: Sascha Hauer <email address hidden> Date: Thu Sep 30 13:56:32 2010 +0000
dmaengine: add possibility for cyclic transfers
13. commit f44b92f4dd2f6caf326b149e0b9636a1d4e50184 Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:52:58 2013 +0200
dma: dw_dmac: check direction properly in dw_dma_cyclic_prep
14. commit 0efcdb20f4a83967c99da3d3bef9018f86532fae Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:52:59 2013 +0200
dma: ep93xx_dma: reuse is_slave_direction helper
15. commit 5127c4f8a314b798459985d93f7829cf9cf9bbc3 Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:53:00 2013 +0200
dma: ipu_idmac: reuse is_slave_direction helper
16. commit a725dcc0342b4d9ffc6ae4aedc2973d902aabeb1 Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:53:01 2013 +0200
dma: ste_dma40: reuse is_slave_direction helper
17. commit 01126856ff4f7d4cc5899c208fd4d3c7d0a2b83a Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:53:02 2013 +0200
dw_dmac: call .probe after we have a device in place
18. commit 0fdb567fc72da906e230ce7e2aae2feba260a6be Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:53:03 2013 +0200
dw_dmac: store direction in the custom channel structure
19. commit 495aea4b571d1b7f77883f87754247b115627f68 Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 11:11:41 2013 +0200
dw_dmac: make usage of dw_dma_slave optional
20. commit 23d5f4ec9de43dbc73a42f1483d9339b907c3dff Author: Andy Shevchenko <email address hidden> Date: Thu Jan 10 10:53:05 2013 +0200
dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous
21. commit f8122a82d2eae8ef42de48829deed0ca9d9e1f17 Author: Andy Shevchenko <email address hidden> Date: Wed Jan 16 15:48:50 2013 +0200
dw_dmac: allocate dma descriptors from DMA_COHERENT memory
22. commit 5be10f349bc0a2f3dd2ab6417ffe29746403984c Author: Andy Shevchenko <email address hidden> Date: Thu Jan 17 10:03:01 2013 +0200
dw_dmac: don't exceed AHB master number in dwc_get_data_width
23. commit 77bcc497c60ec62dbb84abc809a6e218d53409e9 Author: Andy Shevchenko <email address hidden> Date: Fri Jan 18 14:14:15 2013 +0200
dw_dmac: move soft LLP code from tasklet to dwc_scan_descriptors
24. commit 985a6c7dcf309378b91d16cdbdb0909479f99c33 Author: Andy Shevchenko <email address hidden> Date: Fri Jan 18 17:10:59 2013 +0200
dw_dmac: print out DW_PARAMS and DWC_PARAMS when debug
25. commit fdf475fa40f1468cf43a72b270f74dc6a4a5c905 Author: Andy Shevchenko <email address hidden> Date: Fri Jan 25 11:48:00 2013 +0200
dw_dmac: remove unnecessary tx_list field in dw_dma_chan
26. commit 30d38a3286b140ae8cea84a93cde1f112e352aaf Author: Andy Shevchenko <email address hidden> Date: Fri Jan 25 11:48:01 2013 +0200
dw_dmac: introduce total_len field in struct dw_desc
27. commit 176dcec50f3f0bc46f11b983c1a3bbc2dd3514fd Author: Andy Shevchenko <email address hidden> Date: Fri Jan 25 11:48:02 2013 +0200
dw_dmac: fill individual length of descriptor
28. commit 4702d5244ca947263e8b7eb2ba6d8721e80c46e2 Author: Andy Shevchenko <email address hidden> Date: Fri Jan 25 11:48:03 2013 +0200
dw_dmac: return proper residue value
29. commit 877e86f28385407f05c5aa4e397d4ccb3233f01a Author: Andy Shevchenko <email address hidden> Date: Thu Feb 14 10:41:09 2013 +0200
dw_dmac: apply default dma_mask if needed
30. commit cfdf5b6cc5985014a7ce891093f4fd0ae2d27ca6 Author: Mika Westerberg <email address hidden> Date: Thu Feb 7 17:36:28 2013 +0200
dw_dmac: add support for Lynxpoint DMA controllers
31. commit bce95c63ef1bcf528ea45c41505eb4c21560d92d Author: Andy Shevchenko <email address hidden> Date: Wed Feb 20 13:52:17 2013 +0200
dw_dmac: adjust slave_id accordingly to request line base
this feature has been supported in kernel 3.9-rc5, this contain the following patches. Please evalutate if it can be backported to raring kernel.
1. commit b801479bb6f5b66 f5a35feaa72451a c5ac152ef5
Author: Heikki Krogerus <email address hidden>
Date: Thu Oct 18 17:34:08 2012 +0300
dmaengine: dw_dmac: amend description and indentation
2. commit 21d43f49cb5e132 e74bde9e34ac076 0f79ab85a9
Author: Andy Shevchenko <email address hidden>
Date: Thu Oct 18 17:34:09 2012 +0300
dw_dmac: change dev_printk() to corresponding macros
3.commit 6168d5670bd7645 57b5e06b1842964 a44cf34a45
Author: Andy Shevchenko <email address hidden>
Date: Thu Oct 18 17:34:10 2012 +0300
dw_dmac: don't call platform_ get_drvdata twice
4. commit ba84bd7146b9244 de0ce04cdc66852 1a73f5336f
Author: Andy Shevchenko <email address hidden>
Date: Thu Oct 18 17:34:11 2012 +0300
dw_dmac: change dev_crit to dev_WARN in dwc_handle_error
5. commit e63a47a361e03ea f79e0f2f6cdaca8 e7679d1867
Author: Andy Shevchenko <email address hidden>
Date: Thu Oct 18 17:34:12 2012 +0300
dw_dmac: introduce to_dw_desc() macro
6. commit 123de543414bce4 2da9729071962d4 a9512612c8
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 9 10:17:01 2013 +0200
dw_dmac: absence of pdata isn't critical when autocfg is set
7. commit cbd65312ba6b508 e994d40729e84a5 1301870bcc
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 9 10:17:11 2013 +0200
dw_dmac: check for mapping errors
8. commit 21e93c1e7dae0e8 b1914a522c331f0 f7763fa89d
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 9 10:17:12 2013 +0200
dw_dmac: remove redundant check
9. commit f5c6a7df35b04db 906577e90fa5e13 3e56433bcf
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 9 10:17:13 2013 +0200
dw_dmac: update tx_node_active in dwc_do_single_block
10. commit 21fe3c5245647d2 00a7ba25d42b80d 21c578a8dc
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 9 10:17:14 2013 +0200
dma: dw_dmac: add dwc_chan_pause and dwc_chan_resume
11. commit 61cc13a51bcff73 7ce02d204783417 1c0365b00d
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:52:56 2013 +0200
dmaengine: introduce is_slave_direction function
12. commit 782bc950d84e404 422ba21008fd51e e894c8d231
Author: Sascha Hauer <email address hidden>
Date: Thu Sep 30 13:56:32 2010 +0000
dmaengine: add possibility for cyclic transfers
13. commit f44b92f4dd2f6ca f326b149e0b9636 a1d4e50184
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:52:58 2013 +0200
dma: dw_dmac: check direction properly in dw_dma_cyclic_prep
14. commit 0efcdb20f4a8396 7c99da3d3bef901 8f86532fae
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:52:59 2013 +0200
dma: ep93xx_dma: reuse is_slave_direction helper
15. commit 5127c4f8a314b79 8459985d93f7829 cf9cf9bbc3
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:53:00 2013 +0200
dma: ipu_idmac: reuse is_slave_direction helper
16. commit a725dcc0342b4d9 ffc6ae4aedc2973 d902aabeb1
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:53:01 2013 +0200
dma: ste_dma40: reuse is_slave_direction helper
17. commit 01126856ff4f7d4 cc5899c208fd4d3 c7d0a2b83a
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:53:02 2013 +0200
dw_dmac: call .probe after we have a device in place
18. commit 0fdb567fc72da90 6e230ce7e2aae2f eba260a6be
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:53:03 2013 +0200
dw_dmac: store direction in the custom channel structure
19. commit 495aea4b571d1b7 f77883f87754247 b115627f68
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 11:11:41 2013 +0200
dw_dmac: make usage of dw_dma_slave optional
20. commit 23d5f4ec9de43db c73a42f1483d933 9b907c3dff
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 10 10:53:05 2013 +0200
dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous
21. commit f8122a82d2eae8e f42de48829deed0 ca9d9e1f17
Author: Andy Shevchenko <email address hidden>
Date: Wed Jan 16 15:48:50 2013 +0200
dw_dmac: allocate dma descriptors from DMA_COHERENT memory
22. commit 5be10f349bc0a2f 3dd2ab6417ffe29 746403984c
Author: Andy Shevchenko <email address hidden>
Date: Thu Jan 17 10:03:01 2013 +0200
dw_dmac: don't exceed AHB master number in dwc_get_data_width
23. commit 77bcc497c60ec62 dbb84abc809a6e2 18d53409e9
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 18 14:14:15 2013 +0200
dw_dmac: move soft LLP code from tasklet to dwc_scan_ descriptors
24. commit 985a6c7dcf30937 8b91d16cdbdb090 9479f99c33
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 18 17:10:59 2013 +0200
dw_dmac: print out DW_PARAMS and DWC_PARAMS when debug
25. commit fdf475fa40f1468 cf43a72b270f74d c6a4a5c905
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 25 11:48:00 2013 +0200
dw_dmac: remove unnecessary tx_list field in dw_dma_chan
26. commit 30d38a3286b140a e8cea84a93cde1f 112e352aaf
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 25 11:48:01 2013 +0200
dw_dmac: introduce total_len field in struct dw_desc
27. commit 176dcec50f3f0bc 46f11b983c1a3bb c2dd3514fd
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 25 11:48:02 2013 +0200
dw_dmac: fill individual length of descriptor
28. commit 4702d5244ca9472 63e8b7eb2ba6d87 21e80c46e2
Author: Andy Shevchenko <email address hidden>
Date: Fri Jan 25 11:48:03 2013 +0200
dw_dmac: return proper residue value
29. commit 877e86f28385407 f05c5aa4e397d4c cb3233f01a
Author: Andy Shevchenko <email address hidden>
Date: Thu Feb 14 10:41:09 2013 +0200
dw_dmac: apply default dma_mask if needed
30. commit cfdf5b6cc598501 4a7ce891093f4fd 0ae2d27ca6
Author: Mika Westerberg <email address hidden>
Date: Thu Feb 7 17:36:28 2013 +0200
dw_dmac: add support for Lynxpoint DMA controllers
31. commit bce95c63ef1bcf5 28ea45c41505eb4 c21560d92d
Author: Andy Shevchenko <email address hidden>
Date: Wed Feb 20 13:52:17 2013 +0200
dw_dmac: adjust slave_id accordingly to request line base