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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Catalin Patulea
* Copyright (C) 2008 by Maurus Cuelenaere
* Copyright (C) 2009 by Karl Kurbjun
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "registers.h"
#include "arm.h"
#include "ipc.h"
/* Size of data buffer in words (16 bit) */
#define DSP_BUFFER_SIZE (0x1000)
/* Put the "data" buffer in it's own .dma section so that it can
* be handled in the linker.cmd. */
#pragma DATA_SECTION (data, ".dma")
/* This is the "data" buffer on the DSP side used for SARAM to McBSP (IIS) */
static signed short data[DSP_BUFFER_SIZE];
/* These two describe the location of the buffer on the ARM (set in DSPHINT) */
volatile unsigned short sdem_addrh;
volatile unsigned short sdem_addrl;
/* This is the size of the ARM buffer (set in DSPHINT) */
volatile unsigned short sdem_dsp_size;
/* These two variables keep track of the buffer level in the DSP, dsp_level,
* (SARAM to McBSP) and the level on the ARM buffer (sdem_level).
* sdem_level is used in the main firmware to keep track of the current
* playback status. dsp_level is only used in this function. */
static unsigned short dsp_level;
volatile unsigned short sdem_level;
/* This is used to keep track of the last SDRAM to SARAM transfer */
static unsigned short last_size;
/* This tells us which half of the DSP buffer (data) is free */
static unsigned short dma0_unlocked;
/* This is used by the ARM to flag playback status and start/stop the DMA
* transfers. */
volatile unsigned short dma0_stopped;
/* This is used to effectively flag whether the ARM has new data ready or not */
short waiting;
/* rebuffer sets up the next SDRAM to SARAM transfer and tells the ARM when DMA
* needs a new buffer.
*
* Note: The upper limit on larger buffers is the size of a short. If larger
* buffer sizes are needed the code on the ARM side needs to be changed to
* update a full long.
*/
void rebuffer(void)
{
unsigned long sdem_addr;
if(dma0_stopped==1 || dma0_stopped==2) /* Stop / Pause */
{
/* Stop MCBSP DMA0 */
DMPREC &= 0xFFFE;
/* Shut the transmitter down */
audiohw_stop();
/* Stop the HPIB transfer if it is running */
DMA_TRG = 0;
/* Reset the following variables for DMA restart */
sdem_level = 0;
dsp_level = 0;
last_size = 0;
return;
}
/* If the sdem_level is equal to the buffer size the ARM code gave
* (sdem_dsp_size) then reset the size and ask the arm for another buffer
*/
if(sdem_level == sdem_dsp_size)
{
sdem_level=0;
/* Get a new buffer (location and size) from ARM */
status.msg = MSG_REFILL;
waiting=1;
/* trigger DSPHINT on the ARM */
int_arm();
}
if(!waiting)
{
/* Size is in bytes (but forced 32 bit transfers). Comparison is
* against DSP_BUFFER_SIZE because it is in words and this needs to
* compare against half the total size in bytes. */
if( dsp_level + sdem_dsp_size - sdem_level > DSP_BUFFER_SIZE)
{
last_size = DSP_BUFFER_SIZE - dsp_level;
}
else
{
last_size = sdem_dsp_size - sdem_level;
}
/* DSP addresses are 16 bit (word). dsp_level is in bytes so it needs to
* be converted to words. */
DSP_ADDRL = (unsigned short)data + dma0_unlocked + (dsp_level >> 1);
DSP_ADDRH = 0;
/* SDRAM addresses are 8 bit (byte)
* Warning: These addresses are forced to 32 bit alignment!
*/
sdem_addr = ((unsigned long)sdem_addrh << 16 | sdem_addrl) + sdem_level;
SDEM_ADDRL = sdem_addr & 0xffff;
SDEM_ADDRH = sdem_addr >> 16;
/* Set the size of the SDRAM to SARAM transfer (demac transfer) */
DMA_SIZE = last_size;
DMA_CTRL = 0;
/* These are just debug signals that are not used/needed right now */
status.payload.refill._DMA_TRG = DMA_TRG;
status.payload.refill._SDEM_ADDRH = SDEM_ADDRH;
status.payload.refill._SDEM_ADDRL = SDEM_ADDRL;
status.payload.refill._DSP_ADDRH = DSP_ADDRH;
status.payload.refill._DSP_ADDRL = DSP_ADDRL;
/* Start the demac transfer */
DMA_TRG = 1;
}
}
/* This interupt handler is for the SARAM (on DSP) to McBSP IIS DMA transfer.
* It interupts at 1/2 empty and empty so that we can start filling a new buffer
* from SDRAM when a half is free. dsp_level should always be full when this
* interupt occurs except for the initial start. */
interrupt void handle_dma0(void)
{
/* Byte offset to half-buffer locked by DMA0.
0 for top, DSP_BUFFER_SIZE/2 for bottom */
unsigned short dma0_locked;
IFR = 1 << 6;
/* DMSRC0 is the beginning of the DMA0-locked SARAM half-buffer. */
DMSA = 0x00 /* DMSRC0 (banked register, see page 133 of SPRU302B */;
/* Note that these address offsets (dma0_locked and dma0_unlocked are in
* words. */
dma0_locked = DMSDN & (DSP_BUFFER_SIZE>>1);
dma0_unlocked = dma0_locked ^ (DSP_BUFFER_SIZE>>1);
dsp_level = 0;
/* Start the SDRAM to SARAM copy */
rebuffer();
}
/* This interupt handler runs every time a DMA transfer is complete from SDRAM
* to the SARAM buffer. It is used to update the SARAM buffer level
* (dsp_level), the SDRAM buffer level (sdem_level) and to rebuffer if the dsp
* buffer is not full. */
interrupt void handle_dmac(void) {
IFR = 1 << 11; /* Clear interrupt */
/* dsp_level and sdem_level are in bytes */
dsp_level += last_size;
sdem_level += last_size;
/* compare to DSP_BUFFER_SIZE without a divide because it is in words and
* we want half the total size in bytes. */
if(dsp_level < DSP_BUFFER_SIZE)
{
rebuffer();
}
}
void dma_init(void) {
/* Initialize some of the global variables to known values avoiding the
* .cinit section. */
dsp_level = 0;
sdem_level = 0;
last_size = 0;
dma0_unlocked = 0;
dma0_stopped = 1;
waiting = 0;
/* Configure SARAM to McBSP DMA */
/* Event XEVT0, 32-bit transfers, 0 frame count */
DMSFC0 = 2 << 12 | 1 << 11;
/* Interrupts generated, Half and full buffer.
* ABU mode, From data space with postincrement, to data space with no
* change
*/
DMMCR0 = 1 << 14 | 1 << 13 |
1 << 12 | 1 << 8 | 1 << 6 | 1;
/* Set the source (incrementing) location */
DMSRC0 = (unsigned short)&data;
/* Set the destination (static) location to the McBSP IIS interface */
DMDST0 = (unsigned short)&DXR20;
/* Set the size of the buffer */
DMCTR0 = sizeof(data);
/* Setup DMA0 interrupts and start the transfer */
DMPREC = 2 << 6;
}
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