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// See LICENSE for license details.
#include "htif.h"
#include "atomic.h"
#include "mtrap.h"
#include "fdt.h"
#include "syscall.h"
#include <string.h>
extern uint64_t __htif_base;
volatile uint64_t tohost __attribute__((section(".htif")));
volatile uint64_t fromhost __attribute__((section(".htif")));
volatile int htif_console_buf;
static spinlock_t htif_lock = SPINLOCK_INIT;
uintptr_t htif;
#define TOHOST(base_int) (uint64_t *)(base_int + TOHOST_OFFSET)
#define FROMHOST(base_int) (uint64_t *)(base_int + FROMHOST_OFFSET)
#define TOHOST_OFFSET ((uintptr_t)tohost - (uintptr_t)__htif_base)
#define FROMHOST_OFFSET ((uintptr_t)fromhost - (uintptr_t)__htif_base)
static void __check_fromhost()
{
uint64_t fh = fromhost;
if (!fh)
return;
fromhost = 0;
// this should be from the console
assert(FROMHOST_DEV(fh) == 1);
switch (FROMHOST_CMD(fh)) {
case 0:
htif_console_buf = 1 + (uint8_t)FROMHOST_DATA(fh);
break;
case 1:
break;
default:
assert(0);
}
}
static void __set_tohost(uintptr_t dev, uintptr_t cmd, uintptr_t data)
{
while (tohost)
__check_fromhost();
tohost = TOHOST_CMD(dev, cmd, data);
}
int htif_console_getchar()
{
#if __riscv_xlen == 32
// HTIF devices are not supported on RV32
return -1;
#endif
spinlock_lock(&htif_lock);
__check_fromhost();
int ch = htif_console_buf;
if (ch >= 0) {
htif_console_buf = -1;
__set_tohost(1, 0, 0);
}
spinlock_unlock(&htif_lock);
return ch - 1;
}
static void do_tohost_fromhost(uintptr_t dev, uintptr_t cmd, uintptr_t data)
{
spinlock_lock(&htif_lock);
__set_tohost(dev, cmd, data);
while (1) {
uint64_t fh = fromhost;
if (fh) {
if (FROMHOST_DEV(fh) == dev && FROMHOST_CMD(fh) == cmd) {
fromhost = 0;
break;
}
__check_fromhost();
}
}
spinlock_unlock(&htif_lock);
}
void htif_syscall(uintptr_t arg)
{
do_tohost_fromhost(0, 0, arg);
}
void htif_console_putchar(uint8_t ch)
{
#if __riscv_xlen == 32
// HTIF devices are not supported on RV32, so proxy a write system call
volatile uint64_t magic_mem[8];
magic_mem[0] = SYS_write;
magic_mem[1] = 1;
magic_mem[2] = (uintptr_t)&ch;
magic_mem[3] = 1;
do_tohost_fromhost(0, 0, (uintptr_t)magic_mem);
#else
spinlock_lock(&htif_lock);
__set_tohost(1, 1, ch);
spinlock_unlock(&htif_lock);
#endif
}
void htif_poweroff()
{
while (1) {
spinlock_lock(&htif_lock);
__set_tohost(0, 0, 1);
spinlock_unlock(&htif_lock);
}
}
struct htif_scan
{
int compat;
};
static void htif_open(const struct fdt_scan_node *node, void *extra)
{
struct htif_scan *scan = (struct htif_scan *)extra;
memset(scan, 0, sizeof(*scan));
}
static void htif_prop(const struct fdt_scan_prop *prop, void *extra)
{
struct htif_scan *scan = (struct htif_scan *)extra;
if (!strcmp(prop->name, "compatible") && fdt_string_list_index(prop, "ucb,htif0") >= 0) {
scan->compat = 1;
}
}
static void htif_done(const struct fdt_scan_node *node, void *extra)
{
struct htif_scan *scan = (struct htif_scan *)extra;
if (!scan->compat) return;
htif = 1;
}
void query_htif(uintptr_t fdt)
{
struct fdt_cb cb;
struct htif_scan scan;
memset(&cb, 0, sizeof(cb));
cb.open = htif_open;
cb.prop = htif_prop;
cb.done = htif_done;
cb.extra = &scan;
fdt_scan(fdt, &cb);
}
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