diff options
Diffstat (limited to 'hw/riscv/riscv_htif.c')
| -rw-r--r-- | hw/riscv/riscv_htif.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/hw/riscv/riscv_htif.c b/hw/riscv/riscv_htif.c new file mode 100644 index 0000000000..3e17f30251 --- /dev/null +++ b/hw/riscv/riscv_htif.c @@ -0,0 +1,258 @@ +/* + * QEMU RISC-V Host Target Interface (HTIF) Emulation + * + * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu + * Copyright (c) 2017-2018 SiFive, Inc. + * + * This provides HTIF device emulation for QEMU. At the moment this allows + * for identical copies of bbl/linux to run on both spike and QEMU. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2 or later, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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/>. + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "qemu/log.h" +#include "hw/sysbus.h" +#include "hw/char/serial.h" +#include "chardev/char.h" +#include "chardev/char-fe.h" +#include "hw/riscv/riscv_htif.h" +#include "qemu/timer.h" +#include "exec/address-spaces.h" +#include "qemu/error-report.h" + +#define RISCV_DEBUG_HTIF 0 +#define HTIF_DEBUG(fmt, ...) \ + do { \ + if (RISCV_DEBUG_HTIF) { \ + qemu_log_mask(LOG_TRACE, "%s: " fmt "\n", __func__, ##__VA_ARGS__);\ + } \ + } while (0) + +static uint64_t fromhost_addr, tohost_addr; + +void htif_symbol_callback(const char *st_name, int st_info, uint64_t st_value, + uint64_t st_size) +{ + if (strcmp("fromhost", st_name) == 0) { + fromhost_addr = st_value; + if (st_size != 8) { + error_report("HTIF fromhost must be 8 bytes"); + exit(1); + } + } else if (strcmp("tohost", st_name) == 0) { + tohost_addr = st_value; + if (st_size != 8) { + error_report("HTIF tohost must be 8 bytes"); + exit(1); + } + } +} + +/* + * Called by the char dev to see if HTIF is ready to accept input. + */ +static int htif_can_recv(void *opaque) +{ + return 1; +} + +/* + * Called by the char dev to supply input to HTIF console. + * We assume that we will receive one character at a time. + */ +static void htif_recv(void *opaque, const uint8_t *buf, int size) +{ + HTIFState *htifstate = opaque; + + if (size != 1) { + return; + } + + /* TODO - we need to check whether mfromhost is zero which indicates + the device is ready to receive. The current implementation + will drop characters */ + + uint64_t val_written = htifstate->pending_read; + uint64_t resp = 0x100 | *buf; + + htifstate->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16); +} + +/* + * Called by the char dev to supply special events to the HTIF console. + * Not used for HTIF. + */ +static void htif_event(void *opaque, int event) +{ + +} + +static int htif_be_change(void *opaque) +{ + HTIFState *s = opaque; + + qemu_chr_fe_set_handlers(&s->chr, htif_can_recv, htif_recv, htif_event, + htif_be_change, s, NULL, true); + + return 0; +} + +static void htif_handle_tohost_write(HTIFState *htifstate, uint64_t val_written) +{ + uint8_t device = val_written >> 56; + uint8_t cmd = val_written >> 48; + uint64_t payload = val_written & 0xFFFFFFFFFFFFULL; + int resp = 0; + + HTIF_DEBUG("mtohost write: device: %d cmd: %d what: %02" PRIx64 + " -payload: %016" PRIx64 "\n", device, cmd, payload & 0xFF, payload); + + /* + * Currently, there is a fixed mapping of devices: + * 0: riscv-tests Pass/Fail Reporting Only (no syscall proxy) + * 1: Console + */ + if (unlikely(device == 0x0)) { + /* frontend syscall handler, shutdown and exit code support */ + if (cmd == 0x0) { + if (payload & 0x1) { + /* exit code */ + int exit_code = payload >> 1; + exit(exit_code); + } else { + qemu_log_mask(LOG_UNIMP, "pk syscall proxy not supported\n"); + } + } else { + qemu_log("HTIF device %d: unknown command\n", device); + } + } else if (likely(device == 0x1)) { + /* HTIF Console */ + if (cmd == 0x0) { + /* this should be a queue, but not yet implemented as such */ + htifstate->pending_read = val_written; + htifstate->env->mtohost = 0; /* clear to indicate we read */ + return; + } else if (cmd == 0x1) { + qemu_chr_fe_write(&htifstate->chr, (uint8_t *)&payload, 1); + resp = 0x100 | (uint8_t)payload; + } else { + qemu_log("HTIF device %d: unknown command\n", device); + } + } else { + qemu_log("HTIF unknown device or command\n"); + HTIF_DEBUG("device: %d cmd: %d what: %02" PRIx64 + " payload: %016" PRIx64, device, cmd, payload & 0xFF, payload); + } + /* + * - latest bbl does not set fromhost to 0 if there is a value in tohost + * - with this code enabled, qemu hangs waiting for fromhost to go to 0 + * - with this code disabled, qemu works with bbl priv v1.9.1 and v1.10 + * - HTIF needs protocol documentation and a more complete state machine + + while (!htifstate->fromhost_inprogress && + htifstate->env->mfromhost != 0x0) { + } + */ + htifstate->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16); + htifstate->env->mtohost = 0; /* clear to indicate we read */ +} + +#define TOHOST_OFFSET1 (htifstate->tohost_offset) +#define TOHOST_OFFSET2 (htifstate->tohost_offset + 4) +#define FROMHOST_OFFSET1 (htifstate->fromhost_offset) +#define FROMHOST_OFFSET2 (htifstate->fromhost_offset + 4) + +/* CPU wants to read an HTIF register */ +static uint64_t htif_mm_read(void *opaque, hwaddr addr, unsigned size) +{ + HTIFState *htifstate = opaque; + if (addr == TOHOST_OFFSET1) { + return htifstate->env->mtohost & 0xFFFFFFFF; + } else if (addr == TOHOST_OFFSET2) { + return (htifstate->env->mtohost >> 32) & 0xFFFFFFFF; + } else if (addr == FROMHOST_OFFSET1) { + return htifstate->env->mfromhost & 0xFFFFFFFF; + } else if (addr == FROMHOST_OFFSET2) { + return (htifstate->env->mfromhost >> 32) & 0xFFFFFFFF; + } else { + qemu_log("Invalid htif read: address %016" PRIx64 "\n", + (uint64_t)addr); + return 0; + } +} + +/* CPU wrote to an HTIF register */ +static void htif_mm_write(void *opaque, hwaddr addr, + uint64_t value, unsigned size) +{ + HTIFState *htifstate = opaque; + if (addr == TOHOST_OFFSET1) { + if (htifstate->env->mtohost == 0x0) { + htifstate->allow_tohost = 1; + htifstate->env->mtohost = value & 0xFFFFFFFF; + } else { + htifstate->allow_tohost = 0; + } + } else if (addr == TOHOST_OFFSET2) { + if (htifstate->allow_tohost) { + htifstate->env->mtohost |= value << 32; + htif_handle_tohost_write(htifstate, htifstate->env->mtohost); + } + } else if (addr == FROMHOST_OFFSET1) { + htifstate->fromhost_inprogress = 1; + htifstate->env->mfromhost = value & 0xFFFFFFFF; + } else if (addr == FROMHOST_OFFSET2) { + htifstate->env->mfromhost |= value << 32; + htifstate->fromhost_inprogress = 0; + } else { + qemu_log("Invalid htif write: address %016" PRIx64 "\n", + (uint64_t)addr); + } +} + +static const MemoryRegionOps htif_mm_ops = { + .read = htif_mm_read, + .write = htif_mm_write, +}; + +HTIFState *htif_mm_init(MemoryRegion *address_space, MemoryRegion *main_mem, + CPURISCVState *env, Chardev *chr) +{ + uint64_t base = MIN(tohost_addr, fromhost_addr); + uint64_t size = MAX(tohost_addr + 8, fromhost_addr + 8) - base; + uint64_t tohost_offset = tohost_addr - base; + uint64_t fromhost_offset = fromhost_addr - base; + + HTIFState *s = g_malloc0(sizeof(HTIFState)); + s->address_space = address_space; + s->main_mem = main_mem; + s->main_mem_ram_ptr = memory_region_get_ram_ptr(main_mem); + s->env = env; + s->tohost_offset = tohost_offset; + s->fromhost_offset = fromhost_offset; + s->pending_read = 0; + s->allow_tohost = 0; + s->fromhost_inprogress = 0; + qemu_chr_fe_init(&s->chr, chr, &error_abort); + qemu_chr_fe_set_handlers(&s->chr, htif_can_recv, htif_recv, htif_event, + htif_be_change, s, NULL, true); + if (base) { + memory_region_init_io(&s->mmio, NULL, &htif_mm_ops, s, + TYPE_HTIF_UART, size); + memory_region_add_subregion(address_space, base, &s->mmio); + } + + return s; +} |