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pfpu.c
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pfpu.c
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/*
* Milkymist VJ SoC (Software)
* Copyright (C) 2007, 2008, 2009, 2010 Sebastien Bourdeauducq
*
* 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, version 3 of the License.
*
* 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 <irq.h>
#include <hw/interrupts.h>
#include <hw/pfpu.h>
#include <hal/pfpu.h>
#define PFPU_TASKQ_SIZE 4 /* < must be a power of 2 */
#define PFPU_TASKQ_MASK (PFPU_TASKQ_SIZE-1)
static struct pfpu_td *queue[PFPU_TASKQ_SIZE];
static unsigned int produce;
static unsigned int consume;
static unsigned int level;
static int cts;
void pfpu_init()
{
unsigned int mask;
/* Reset PFPU */
CSR_PFPU_CTL = 0;
irq_ack(IRQ_PFPU);
produce = 0;
consume = 0;
level = 0;
cts = 1;
mask = irq_getmask();
mask |= IRQ_PFPU;
irq_setmask(mask);
printf("FPU: programmable floating point unit initialized\n");
}
static void load_program(pfpu_instruction *program, int size)
{
int page;
int word;
volatile pfpu_instruction *pfpu_prog = (pfpu_instruction *)CSR_PFPU_CODEBASE;
for(page=0;page<(PFPU_PROGSIZE/PFPU_PAGESIZE);page++) {
for(word=0;word<PFPU_PAGESIZE;word++) {
if(size == 0) return;
pfpu_prog[word] = *program;
program++;
size--;
}
}
}
static void load_registers(float *registers)
{
volatile float *pfpu_regs = (float *)CSR_PFPU_DREGBASE;
int i;
for(i=PFPU_SPREG_COUNT;i<PFPU_REG_COUNT;i++)
pfpu_regs[i] = registers[i];
}
static void update_registers(float *registers)
{
volatile float *pfpu_regs = (float *)CSR_PFPU_DREGBASE;
int i;
for(i=PFPU_SPREG_COUNT;i<PFPU_REG_COUNT;i++)
registers[i] = pfpu_regs[i];
}
static void pfpu_start(struct pfpu_td *td)
{
load_program(td->program, td->progsize);
load_registers(td->registers);
CSR_PFPU_MESHBASE = (unsigned int)td->output;
CSR_PFPU_HMESHLAST = td->hmeshlast;
CSR_PFPU_VMESHLAST = td->vmeshlast;
CSR_PFPU_CTL = PFPU_CTL_START;
}
void pfpu_isr()
{
if(queue[consume]->update)
update_registers(queue[consume]->registers);
if(queue[consume]->invalidate) {
asm volatile( /* Invalidate Level-1 data cache */
"wcsr DCC, r0\n"
"nop\n"
);
}
queue[consume]->callback(queue[consume]);
consume = (consume + 1) & PFPU_TASKQ_MASK;
level--;
irq_ack(IRQ_PFPU);
if(level > 0)
pfpu_start(queue[consume]);
else
cts = 1;
}
int pfpu_submit_task(struct pfpu_td *td)
{
unsigned int oldmask;
oldmask = irq_getmask();
irq_setmask(oldmask & (~IRQ_PFPU));
if(level >= PFPU_TASKQ_SIZE) {
irq_setmask(oldmask);
printf("FPU: taskq overflow\n");
return 0;
}
queue[produce] = td;
produce = (produce + 1) & PFPU_TASKQ_MASK;
level++;
if(cts) {
cts = 0;
pfpu_start(td);
}
irq_setmask(oldmask);
return 1;
}