diff options
Diffstat (limited to 'sound/pci/cs46xx/imgs/cwcdma.asp')
| -rw-r--r-- | sound/pci/cs46xx/imgs/cwcdma.asp | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/sound/pci/cs46xx/imgs/cwcdma.asp b/sound/pci/cs46xx/imgs/cwcdma.asp new file mode 100644 index 00000000..a65e1193 --- /dev/null +++ b/sound/pci/cs46xx/imgs/cwcdma.asp @@ -0,0 +1,170 @@ +// +// Copyright(c) by Benny Sjostrand (benny@hostmobility.com) +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +// + + +// +// This code runs inside the DSP (cs4610, cs4612, cs4624, or cs4630), +// to compile it you need a tool named SPASM 3.0 and DSP code owned by +// Cirrus Logic(R). The SPASM program will generate a object file (cwcdma.osp), +// the "ospparser" tool will genereate the cwcdma.h file it's included from +// the cs46xx_lib.c file. +// +// +// The purpose of this code is very simple: make it possible to tranfser +// the samples 'as they are' with no alteration from a PCMreader +// SCB (DMA from host) to any other SCB. This is useful for AC3 through SPDIF. +// SRC (source rate converters) task always alters the samples in somehow, +// however it's from 48khz -> 48khz. +// The alterations are not audible, but AC3 wont work. +// +// ... +// | +// +---------------+ +// | AsynchFGTxSCB | +// +---------------+ +// | +// subListPtr +// | +// +--------------+ +// | DMAReader | +// +--------------+ +// | +// subListPtr +// | +// +-------------+ +// | PCMReader | +// +-------------+ +// (DMA from host) +// + +struct dmaSCB + { + long dma_reserved1[3]; + + short dma_reserved2:dma_outBufPtr; + + short dma_unused1:dma_unused2; + + long dma_reserved3[4]; + + short dma_subListPtr:dma_nextSCB; + short dma_SPBptr:dma_entryPoint; + + long dma_strmRsConfig; + long dma_strmBufPtr; + + long dma_reserved4; + + VolumeControl s2m_volume; + }; + +#export DMAReader +void DMAReader() +{ + execChild(); + r2 = r0->dma_subListPtr; + r1 = r0->nextSCB; + + rsConfig01 = r2->strmRsConfig; + // Load rsConfig for input buffer + + rsDMA01 = r2->basicReq.daw, , tb = Z(0 - rf); + // Load rsDMA in case input buffer is a DMA buffer Test to see if there is any data to transfer + + if (tb) goto execSibling_2ind1 after { + r5 = rf + (-1); + r6 = r1->dma_entryPoint; // r6 = entry point of sibling task + r1 = r1->dma_SPBptr, // r1 = pointer to sibling task's SPB + , ind = r6; // Load entry point of sibling task + } + + rsConfig23 = r0->dma_strmRsConfig; + // Load rsConfig for output buffer (never a DMA buffer) + + r4 = r0->dma_outBufPtr; + + rsa0 = r2->strmBufPtr; + // rsa0 = input buffer pointer + + for (i = r5; i >= 0; --i) + after { + rsa2 = r4; + // rsa2 = output buffer pointer + + nop; + nop; + } + //***************************** + // TODO: cycles to this point * + //***************************** + { + acc0 = (rsd0 = *rsa0++1); + // get sample + + nop; // Those "nop"'s are really uggly, but there's + nop; // something with DSP's pipelines which I don't + nop; // understand, resulting this code to fail without + // having those "nop"'s (Benny) + + rsa0?reqDMA = r2; + // Trigger DMA transfer on input stream, + // if needed to replenish input buffer + + nop; + // Yet another magic "nop" to make stuff work + + ,,r98 = acc0 $+>> 0; + // store sample in ALU + + nop; + // latency on load register. + // (this one is understandable) + + *rsa2++1 = r98; + // store sample in output buffer + + nop; // The same story + nop; // as above again ... + nop; + } + // TODO: cycles per loop iteration + + r2->strmBufPtr = rsa0,, ; + // Update the modified buffer pointers + + r4 = rsa2; + // Load output pointer position into r4 + + r2 = r0->nextSCB; + // Sibling task + + goto execSibling_2ind1 // takes 6 cycles + after { + r98 = r2->thisSPB:entryPoint; + // Load child routine entry and data address + + r1 = r9; + // r9 is r2->thisSPB + + r0->dma_outBufPtr = r4,, + // Store updated output buffer pointer + + ind = r8; + // r8 is r2->entryPoint + } +} |