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/* Lattice Mico32 timer model.
Contributed by Jon Beniston <jon@beniston.com>
Copyright (C) 2009-2021 Free Software Foundation, Inc.
This file is part of GDB.
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/>. */
/* This must come before any other includes. */
#include "defs.h"
#include "sim-main.h"
#include "hw-main.h"
#include "sim-assert.h"
struct lm32timer
{
unsigned base; /* Base address of this timer. */
unsigned limit; /* Limit address of this timer. */
unsigned int status;
unsigned int control;
unsigned int period;
unsigned int snapshot;
struct hw_event *event;
};
/* Timer registers. */
#define LM32_TIMER_STATUS 0x0
#define LM32_TIMER_CONTROL 0x4
#define LM32_TIMER_PERIOD 0x8
#define LM32_TIMER_SNAPSHOT 0xc
/* Timer ports. */
enum
{
INT_PORT
};
static const struct hw_port_descriptor lm32timer_ports[] = {
{"int", INT_PORT, 0, output_port},
{}
};
static void
do_timer_event (struct hw *me, void *data)
{
struct lm32timer *timer = hw_data (me);
/* Is timer started? */
if (timer->control & 0x4)
{
if (timer->snapshot)
{
/* Decrement timer. */
timer->snapshot--;
}
else if (timer->control & 1)
{
/* Restart timer. */
timer->snapshot = timer->period;
}
}
/* Generate interrupt when timer is at 0, and interrupt enable is 1. */
if ((timer->snapshot == 0) && (timer->control & 1))
{
/* Generate interrupt. */
hw_port_event (me, INT_PORT, 1);
}
/* If timer is started, schedule another event to decrement the timer again. */
if (timer->control & 4)
hw_event_queue_schedule (me, 1, do_timer_event, 0);
}
static unsigned
lm32timer_io_write_buffer (struct hw *me,
const void *source,
int space, unsigned_word base, unsigned nr_bytes)
{
struct lm32timer *timers = hw_data (me);
int timer_reg;
const unsigned char *source_bytes = source;
int value = 0;
HW_TRACE ((me, "write to 0x%08lx length %d with 0x%x", (long) base,
(int) nr_bytes, value));
if (nr_bytes == 4)
value = (source_bytes[0] << 24)
| (source_bytes[1] << 16) | (source_bytes[2] << 8) | (source_bytes[3]);
else
hw_abort (me, "write with invalid number of bytes: %d", nr_bytes);
timer_reg = base - timers->base;
switch (timer_reg)
{
case LM32_TIMER_STATUS:
timers->status = value;
break;
case LM32_TIMER_CONTROL:
timers->control = value;
if (timers->control & 0x4)
{
/* Timer is started. */
hw_event_queue_schedule (me, 1, do_timer_event, 0);
}
break;
case LM32_TIMER_PERIOD:
timers->period = value;
break;
default:
hw_abort (me, "invalid register address: 0x%x.", timer_reg);
}
return nr_bytes;
}
static unsigned
lm32timer_io_read_buffer (struct hw *me,
void *dest,
int space, unsigned_word base, unsigned nr_bytes)
{
struct lm32timer *timers = hw_data (me);
int timer_reg;
int value;
unsigned char *dest_bytes = dest;
HW_TRACE ((me, "read 0x%08lx length %d", (long) base, (int) nr_bytes));
timer_reg = base - timers->base;
switch (timer_reg)
{
case LM32_TIMER_STATUS:
value = timers->status;
break;
case LM32_TIMER_CONTROL:
value = timers->control;
break;
case LM32_TIMER_PERIOD:
value = timers->period;
break;
case LM32_TIMER_SNAPSHOT:
value = timers->snapshot;
break;
default:
hw_abort (me, "invalid register address: 0x%x.", timer_reg);
}
if (nr_bytes == 4)
{
dest_bytes[0] = value >> 24;
dest_bytes[1] = value >> 16;
dest_bytes[2] = value >> 8;
dest_bytes[3] = value;
}
else
hw_abort (me, "read of unsupported number of bytes: %d", nr_bytes);
return nr_bytes;
}
static void
attach_lm32timer_regs (struct hw *me, struct lm32timer *timers)
{
unsigned_word attach_address;
int attach_space;
unsigned attach_size;
reg_property_spec reg;
if (hw_find_property (me, "reg") == NULL)
hw_abort (me, "Missing \"reg\" property");
if (!hw_find_reg_array_property (me, "reg", 0, ®))
hw_abort (me, "\"reg\" property must contain three addr/size entries");
hw_unit_address_to_attach_address (hw_parent (me),
®.address,
&attach_space, &attach_address, me);
timers->base = attach_address;
hw_unit_size_to_attach_size (hw_parent (me), ®.size, &attach_size, me);
timers->limit = attach_address + (attach_size - 1);
hw_attach_address (hw_parent (me),
0, attach_space, attach_address, attach_size, me);
}
static void
lm32timer_finish (struct hw *me)
{
struct lm32timer *timers;
int i;
timers = HW_ZALLOC (me, struct lm32timer);
set_hw_data (me, timers);
set_hw_io_read_buffer (me, lm32timer_io_read_buffer);
set_hw_io_write_buffer (me, lm32timer_io_write_buffer);
set_hw_ports (me, lm32timer_ports);
/* Attach ourself to our parent bus. */
attach_lm32timer_regs (me, timers);
/* Initialize the timers. */
timers->status = 0;
timers->control = 0;
timers->period = 0;
timers->snapshot = 0;
}
const struct hw_descriptor dv_lm32timer_descriptor[] = {
{"lm32timer", lm32timer_finish,},
{NULL},
};
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