Hi Liam, 2015-06-04 23:07 GMT+08:00 Liam Girdwood <liam.r.girdw...@linux.intel.com>:
> On Thu, 2015-06-04 at 14:10 +0800, li yuqian wrote: > > Hi Liam, > > > > 2015-06-03 16:55 GMT+08:00 Liam Girdwood > > <liam.r.girdw...@linux.intel.com>: > > On Tue, 2015-06-02 at 18:27 +0100, Strasser, Kevin wrote: > > > Hi Li, > > > > > > On 06/01/15 8:03 PM, li yuqian wrote: > > > > check those driver, and i can understand there are three > > parts for the LPE > > > > driver to working, special for the LPE firmware need to > > adde it. i can figure > > > > it out in the > > > > > > > https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/sound/soc/intel/sst-acpi.c?id=refs/tags/v4.0.4 > > > > line 249 and 250. > > > > > > > > but when i checked that sst-acpi.c, i found the baytrial > > sst is not support > > > > the DMA data transfer, see the resindex_dma_base = -1 in > > line 262 and line 51 > > > > /* DMA only valid when resindex_dma_base != -1*/ > > > > > > > > Am i correct? the MBM i2s does not support DMA data > > transfer? > > > > > > You are correct, the Bay Trail LPE driver does not use DMA. > > I think that is just > > > a driver limitation, and does not necessarily indicate that > > the hardware isn't > > > capable. > > > > > > Liam, can you provide any context here? > > > > > > The BYT audio DSP driver does not use DMA for loading the FW > > from host > > memory to DSP memory, but it does use DMA for audio playback > > and capture > > (controlled by the FW). The BYT audio driver just does a > > memcpy() of the > > FW from host to DSP memory. > > > > Liam > > > > > > > > Thanks, > > > Kevin > > > > > > Thanks for the explanation. is there more details information for that > > "controlled by FW"? such as what is the data width of FW required, is > > that fixed or user can change? in other words, should i use different > > that FW to do different data width, sync clock and sst clock? also, i > > found the TIZEN have some different FW for download in INTEL website > > in > > > https://downloadcenter.intel.com/download/23903/Intel-Atom-Processor-E3800-Series-Linux-support-package-LPE-Firmware-for-Tizen-IVI-3-0-M2-Kernel-3-10-LTSI, > can i use those FW to load to mainline kernel to support different mode of > LPE, such as the master/slave mode with different sync, main clock? > > > > It sounds like you have some different requirements to those supported > by the FW ? Can you be more specific ? The current FW can support 16bit > stereo at 48kHz with the codec as I2S slave. > > The FW wholly controls operation and configuration of the audio DMA and > SSP ports (the host does not touch these). The host allocates the DMA > buffers though. > > Btw, there are some new FW releases that are coming out soon that will > provide some more flexibility wrt SSP configuration. This may be able to > help with your requirements too. > > Thanks > > Liam > > > > thanks > > > Thank you. now i understand how is FW working. i project required the SSP working at 8KHZ sync, 2M main TDM bus clock, slave mode, will INTEL release such configure FW? i am expecting those new FW release ASAP ;) Thanks Yuqian
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