librpitx/src/fmdmasync.cpp

77 lines
2.5 KiB
C++

/*
Copyright (C) 2018 Evariste COURJAUD F5OEO
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "stdio.h"
#include "fmdmasync.h"
#include "gpio.h" //for definition of registers
fmdmasync::fmdmasync(int Channel,uint32_t FifoSize):dma(Channel,FifoSize*2,FifoSize)
{
SetDmaAlgo();
FillMemory(12,1472);
}
fmdmasync::~fmdmasync()
{
}
void fmdmasync::SetDmaAlgo()
{
dma_cb_t *cbp = cbarray;
for (uint32_t samplecnt = 0; samplecnt < cbsize/2; samplecnt++) { //cbsize/2 because we have 2 CB by sample
// Write a frequency sample
cbp->info = BCM2708_DMA_NO_WIDE_BURSTS | BCM2708_DMA_WAIT_RESP ;
cbp->src = mem_virt_to_phys(&usermem[samplecnt]);
cbp->dst = 0x7E000000 + (GPCLK_DIV<<2) + CLK_BASE ;
cbp->length = 4;
cbp->stride = 0;
cbp->next = mem_virt_to_phys(cbp + 1);
//fprintf(stderr,"cbp : sample %x src %x dest %x next %x\n",samplecnt,cbp->src,cbp->dst,cbp->next);
cbp++;
// Delay
cbp->info = /*BCM2708_DMA_SRC_IGNOR | */BCM2708_DMA_NO_WIDE_BURSTS | BCM2708_DMA_WAIT_RESP | BCM2708_DMA_D_DREQ | BCM2708_DMA_PER_MAP(DREQ_PWM);
cbp->src = mem_virt_to_phys(cbarray); // Data is not important as we use it only to feed the PWM
cbp->dst = 0x7E000000 + (PWM_FIFO<<2) + PWM_BASE ;
cbp->length = 4;
cbp->stride = 0;
cbp->next = mem_virt_to_phys(cbp + 1);
//fprintf(stderr,"cbp : sample %x src %x dest %x next %x\n",samplecnt,cbp->src,cbp->dst,cbp->next);
cbp++;
}
cbp--;
cbp->next = mem_virt_to_phys(cbarray); // We loop to the first CB
//fprintf(stderr,"Last cbp : src %x dest %x next %x\n",cbp->src,cbp->dst,cbp->next);
}
void fmdmasync::FillMemory(uint32_t FreqDivider,uint32_t FreqFractionnal)
{
for (uint32_t samplecnt = 0; samplecnt < usermemsize; samplecnt++)
{
usermem[samplecnt]=0x5A000000 | ((FreqDivider)<<12) | FreqFractionnal;
FreqFractionnal=(FreqFractionnal+1)%4096;
if (FreqFractionnal==0) FreqDivider++;
}
}