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/*
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2010-2020, The Regents of the University of California
* (Regents). All Rights Reserved.
*/
#include <sbi/riscv_locks.h>
#include <sbi_utils/sys/htif.h>
#define HTIF_DATA_BITS 48
#define HTIF_DATA_MASK ((1ULL << HTIF_DATA_BITS) - 1)
#define HTIF_DATA_SHIFT 0
#define HTIF_CMD_BITS 8
#define HTIF_CMD_MASK ((1ULL << HTIF_CMD_BITS) - 1)
#define HTIF_CMD_SHIFT 48
#define HTIF_DEV_BITS 8
#define HTIF_DEV_MASK ((1ULL << HTIF_DEV_BITS) - 1)
#define HTIF_DEV_SHIFT 56
#define HTIF_DEV_SYSTEM 0
#define HTIF_DEV_CONSOLE 1
#define HTIF_CONSOLE_CMD_GETC 0
#define HTIF_CONSOLE_CMD_PUTC 1
#if __riscv_xlen == 64
# define TOHOST_CMD(dev, cmd, payload) \
(((uint64_t)(dev) << HTIF_DEV_SHIFT) | \
((uint64_t)(cmd) << HTIF_CMD_SHIFT) | \
(uint64_t)(payload))
#else
# define TOHOST_CMD(dev, cmd, payload) ({ \
if ((dev) || (cmd)) __builtin_trap(); \
(payload); })
#endif
#define FROMHOST_DEV(fromhost_value) \
((uint64_t)((fromhost_value) >> HTIF_DEV_SHIFT) & HTIF_DEV_MASK)
#define FROMHOST_CMD(fromhost_value) \
((uint64_t)((fromhost_value) >> HTIF_CMD_SHIFT) & HTIF_CMD_MASK)
#define FROMHOST_DATA(fromhost_value) \
((uint64_t)((fromhost_value) >> HTIF_DATA_SHIFT) & HTIF_DATA_MASK)
#define PK_SYS_write 64
volatile uint64_t tohost __attribute__((section(".htif")));
volatile uint64_t fromhost __attribute__((section(".htif")));
static int htif_console_buf;
static spinlock_t htif_lock = SPIN_LOCK_INITIALIZER;
static void __check_fromhost()
{
uint64_t fh = fromhost;
if (!fh)
return;
fromhost = 0;
/* this should be from the console */
if (FROMHOST_DEV(fh) != HTIF_DEV_CONSOLE)
__builtin_trap();
switch (FROMHOST_CMD(fh)) {
case HTIF_CONSOLE_CMD_GETC:
htif_console_buf = 1 + (uint8_t)FROMHOST_DATA(fh);
break;
case HTIF_CONSOLE_CMD_PUTC:
break;
default:
__builtin_trap();
}
}
static void __set_tohost(uint64_t dev, uint64_t cmd, uint64_t data)
{
while (tohost)
__check_fromhost();
tohost = TOHOST_CMD(dev, cmd, data);
}
#if __riscv_xlen == 32
static void do_tohost_fromhost(uint64_t dev, uint64_t cmd, uint64_t data)
{
spin_lock(&htif_lock);
__set_tohost(HTIF_DEV_SYSTEM, cmd, data);
while (1) {
uint64_t fh = fromhost;
if (fh) {
if (FROMHOST_DEV(fh) == HTIF_DEV_SYSTEM &&
FROMHOST_CMD(fh) == cmd) {
fromhost = 0;
break;
}
__check_fromhost();
}
}
spin_unlock(&htif_lock);
}
void htif_putc(char ch)
{
/* HTIF devices are not supported on RV32, so do a proxy write call */
volatile uint64_t magic_mem[8];
magic_mem[0] = PK_SYS_write;
magic_mem[1] = HTIF_DEV_CONSOLE;
magic_mem[2] = (uint64_t)(uintptr_t)&ch;
magic_mem[3] = HTIF_CONSOLE_CMD_PUTC;
do_tohost_fromhost(HTIF_DEV_SYSTEM, 0, (uint64_t)(uintptr_t)magic_mem);
}
#else
void htif_putc(char ch)
{
spin_lock(&htif_lock);
__set_tohost(HTIF_DEV_CONSOLE, HTIF_CONSOLE_CMD_PUTC, ch);
spin_unlock(&htif_lock);
}
#endif
int htif_getc(void)
{
int ch;
#if __riscv_xlen == 32
/* HTIF devices are not supported on RV32 */
return -1;
#endif
spin_lock(&htif_lock);
__check_fromhost();
ch = htif_console_buf;
if (ch >= 0) {
htif_console_buf = -1;
__set_tohost(HTIF_DEV_CONSOLE, HTIF_CONSOLE_CMD_GETC, 0);
}
spin_unlock(&htif_lock);
return ch - 1;
}
int htif_system_down(u32 type)
{
while (1) {
fromhost = 0;
tohost = 1;
}
}
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