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/* SPDX-License-Identifier: copyleft-next-0.3.1 */
/* Copyright 2023 Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
#include <stdbool.h>
#include <gran/bus/simple_bus.h>
#include <gran/vec.h>
struct bus_region {
uint64_t addr;
uint64_t size;
struct component *component;
};
struct simple_bus {
struct component component;
struct vec regions;
struct component *send;
struct packet pkt;
bool busy;
};
static struct bus_region *find_bus_region(struct simple_bus *bus, uint64_t addr)
{
foreach_vec(i, bus->regions) {
struct bus_region *r = vec_at(&bus->regions, i);
if (addr >= r->addr && addr < (r->addr + r->size))
return r;
}
return NULL;
}
static stat simple_bus_clock(struct simple_bus *bus)
{
if (bus->busy) {
stat r = SEND(bus, bus->send, bus->pkt);
if (r == EBUSY)
return OK;
bus->busy = false;
return r;
}
return OK;
}
static stat simple_bus_receive(struct simple_bus *bus, struct component *from, struct packet pkt)
{
if (bus->busy)
return EBUSY;
bus->busy = true;
struct bus_region *region = find_bus_region(bus, pkt.to);
if (!region) {
warn("illegal address on bus %s at %" PRIuPTR,
bus->component.name, pkt.to);
bus->send = from;
bus->pkt = response(pkt);
set_flags(&bus->pkt, PACKET_ERROR);
return OK;
}
bus->send = region->component;
bus->pkt = pkt;
return OK;
}
static void simple_bus_destroy(struct simple_bus *bus)
{
vec_destroy(&bus->regions);
free(bus);
}
struct component *create_simple_bus()
{
struct simple_bus *bus = calloc(1, sizeof(struct simple_bus));
if (!bus)
return NULL;
bus->component.receive = (receive_callback)simple_bus_receive;
bus->component.clock = (clock_callback)simple_bus_clock;
bus->component.destroy = (destroy_callback)simple_bus_destroy;
bus->regions = vec_create(sizeof(struct bus_region));
return (struct component *)bus;
}
stat simple_bus_add(struct component *bus, struct component *component,
uint64_t addr, uint64_t size)
{
struct simple_bus *b = (struct simple_bus *)bus;
struct bus_region *found = find_bus_region(b, addr);
if (!found) found = find_bus_region(b, addr + size);
if (found) {
error("%s overlaps with %s at %" PRIuPTR,
found->component->name,
component->name,
found->addr
);
return EEXISTS;
}
struct bus_region new = (struct bus_region){
.component = component,
.addr = addr,
.size = size
};
vect_append(struct bus_region, b->regions, &new);
return OK;
}
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