261 lines
8.8 KiB
C
261 lines
8.8 KiB
C
/*
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* QEMU RISC-V Host Target Interface (HTIF) Emulation
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*
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* Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
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* Copyright (c) 2017-2018 SiFive, Inc.
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*
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* This provides HTIF device emulation for QEMU. At the moment this allows
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* for identical copies of bbl/linux to run on both spike and QEMU.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2 or later, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "qemu/log.h"
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#include "hw/sysbus.h"
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#include "hw/char/serial.h"
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#include "chardev/char.h"
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#include "chardev/char-fe.h"
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#include "hw/riscv/riscv_htif.h"
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#include "qemu/timer.h"
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#include "qemu/error-report.h"
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#define RISCV_DEBUG_HTIF 0
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#define HTIF_DEBUG(fmt, ...) \
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do { \
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if (RISCV_DEBUG_HTIF) { \
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qemu_log_mask(LOG_TRACE, "%s: " fmt "\n", __func__, ##__VA_ARGS__);\
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} \
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} while (0)
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static uint64_t fromhost_addr, tohost_addr;
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static int address_symbol_set;
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void htif_symbol_callback(const char *st_name, int st_info, uint64_t st_value,
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uint64_t st_size)
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{
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if (strcmp("fromhost", st_name) == 0) {
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address_symbol_set |= 1;
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fromhost_addr = st_value;
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if (st_size != 8) {
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error_report("HTIF fromhost must be 8 bytes");
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exit(1);
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}
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} else if (strcmp("tohost", st_name) == 0) {
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address_symbol_set |= 2;
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tohost_addr = st_value;
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if (st_size != 8) {
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error_report("HTIF tohost must be 8 bytes");
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exit(1);
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}
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}
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}
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/*
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* Called by the char dev to see if HTIF is ready to accept input.
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*/
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static int htif_can_recv(void *opaque)
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{
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return 1;
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}
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/*
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* Called by the char dev to supply input to HTIF console.
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* We assume that we will receive one character at a time.
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*/
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static void htif_recv(void *opaque, const uint8_t *buf, int size)
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{
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HTIFState *htifstate = opaque;
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if (size != 1) {
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return;
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}
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/* TODO - we need to check whether mfromhost is zero which indicates
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the device is ready to receive. The current implementation
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will drop characters */
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uint64_t val_written = htifstate->pending_read;
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uint64_t resp = 0x100 | *buf;
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htifstate->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
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}
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/*
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* Called by the char dev to supply special events to the HTIF console.
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* Not used for HTIF.
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*/
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static void htif_event(void *opaque, QEMUChrEvent event)
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{
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}
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static int htif_be_change(void *opaque)
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{
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HTIFState *s = opaque;
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qemu_chr_fe_set_handlers(&s->chr, htif_can_recv, htif_recv, htif_event,
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htif_be_change, s, NULL, true);
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return 0;
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}
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static void htif_handle_tohost_write(HTIFState *htifstate, uint64_t val_written)
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{
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uint8_t device = val_written >> 56;
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uint8_t cmd = val_written >> 48;
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uint64_t payload = val_written & 0xFFFFFFFFFFFFULL;
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int resp = 0;
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HTIF_DEBUG("mtohost write: device: %d cmd: %d what: %02" PRIx64
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" -payload: %016" PRIx64 "\n", device, cmd, payload & 0xFF, payload);
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/*
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* Currently, there is a fixed mapping of devices:
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* 0: riscv-tests Pass/Fail Reporting Only (no syscall proxy)
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* 1: Console
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*/
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if (unlikely(device == 0x0)) {
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/* frontend syscall handler, shutdown and exit code support */
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if (cmd == 0x0) {
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if (payload & 0x1) {
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/* exit code */
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int exit_code = payload >> 1;
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exit(exit_code);
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} else {
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qemu_log_mask(LOG_UNIMP, "pk syscall proxy not supported\n");
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}
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} else {
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qemu_log("HTIF device %d: unknown command\n", device);
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}
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} else if (likely(device == 0x1)) {
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/* HTIF Console */
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if (cmd == 0x0) {
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/* this should be a queue, but not yet implemented as such */
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htifstate->pending_read = val_written;
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htifstate->env->mtohost = 0; /* clear to indicate we read */
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return;
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} else if (cmd == 0x1) {
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qemu_chr_fe_write(&htifstate->chr, (uint8_t *)&payload, 1);
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resp = 0x100 | (uint8_t)payload;
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} else {
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qemu_log("HTIF device %d: unknown command\n", device);
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}
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} else {
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qemu_log("HTIF unknown device or command\n");
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HTIF_DEBUG("device: %d cmd: %d what: %02" PRIx64
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" payload: %016" PRIx64, device, cmd, payload & 0xFF, payload);
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}
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/*
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* - latest bbl does not set fromhost to 0 if there is a value in tohost
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* - with this code enabled, qemu hangs waiting for fromhost to go to 0
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* - with this code disabled, qemu works with bbl priv v1.9.1 and v1.10
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* - HTIF needs protocol documentation and a more complete state machine
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while (!htifstate->fromhost_inprogress &&
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htifstate->env->mfromhost != 0x0) {
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}
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*/
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htifstate->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
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htifstate->env->mtohost = 0; /* clear to indicate we read */
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}
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#define TOHOST_OFFSET1 (htifstate->tohost_offset)
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#define TOHOST_OFFSET2 (htifstate->tohost_offset + 4)
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#define FROMHOST_OFFSET1 (htifstate->fromhost_offset)
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#define FROMHOST_OFFSET2 (htifstate->fromhost_offset + 4)
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/* CPU wants to read an HTIF register */
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static uint64_t htif_mm_read(void *opaque, hwaddr addr, unsigned size)
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{
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HTIFState *htifstate = opaque;
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if (addr == TOHOST_OFFSET1) {
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return htifstate->env->mtohost & 0xFFFFFFFF;
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} else if (addr == TOHOST_OFFSET2) {
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return (htifstate->env->mtohost >> 32) & 0xFFFFFFFF;
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} else if (addr == FROMHOST_OFFSET1) {
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return htifstate->env->mfromhost & 0xFFFFFFFF;
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} else if (addr == FROMHOST_OFFSET2) {
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return (htifstate->env->mfromhost >> 32) & 0xFFFFFFFF;
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} else {
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qemu_log("Invalid htif read: address %016" PRIx64 "\n",
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(uint64_t)addr);
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return 0;
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}
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}
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/* CPU wrote to an HTIF register */
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static void htif_mm_write(void *opaque, hwaddr addr,
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uint64_t value, unsigned size)
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{
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HTIFState *htifstate = opaque;
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if (addr == TOHOST_OFFSET1) {
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if (htifstate->env->mtohost == 0x0) {
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htifstate->allow_tohost = 1;
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htifstate->env->mtohost = value & 0xFFFFFFFF;
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} else {
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htifstate->allow_tohost = 0;
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}
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} else if (addr == TOHOST_OFFSET2) {
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if (htifstate->allow_tohost) {
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htifstate->env->mtohost |= value << 32;
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htif_handle_tohost_write(htifstate, htifstate->env->mtohost);
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}
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} else if (addr == FROMHOST_OFFSET1) {
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htifstate->fromhost_inprogress = 1;
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htifstate->env->mfromhost = value & 0xFFFFFFFF;
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} else if (addr == FROMHOST_OFFSET2) {
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htifstate->env->mfromhost |= value << 32;
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htifstate->fromhost_inprogress = 0;
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} else {
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qemu_log("Invalid htif write: address %016" PRIx64 "\n",
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(uint64_t)addr);
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}
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}
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static const MemoryRegionOps htif_mm_ops = {
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.read = htif_mm_read,
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.write = htif_mm_write,
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};
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HTIFState *htif_mm_init(MemoryRegion *address_space, MemoryRegion *main_mem,
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CPURISCVState *env, Chardev *chr)
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{
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uint64_t base = MIN(tohost_addr, fromhost_addr);
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uint64_t size = MAX(tohost_addr + 8, fromhost_addr + 8) - base;
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uint64_t tohost_offset = tohost_addr - base;
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uint64_t fromhost_offset = fromhost_addr - base;
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HTIFState *s = g_malloc0(sizeof(HTIFState));
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s->address_space = address_space;
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s->main_mem = main_mem;
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s->main_mem_ram_ptr = memory_region_get_ram_ptr(main_mem);
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s->env = env;
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s->tohost_offset = tohost_offset;
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s->fromhost_offset = fromhost_offset;
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s->pending_read = 0;
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s->allow_tohost = 0;
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s->fromhost_inprogress = 0;
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qemu_chr_fe_init(&s->chr, chr, &error_abort);
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qemu_chr_fe_set_handlers(&s->chr, htif_can_recv, htif_recv, htif_event,
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htif_be_change, s, NULL, true);
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if (address_symbol_set == 3) {
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memory_region_init_io(&s->mmio, NULL, &htif_mm_ops, s,
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TYPE_HTIF_UART, size);
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memory_region_add_subregion_overlap(address_space, base,
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&s->mmio, 1);
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}
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return s;
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}
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