[Qemu-devel] [PATCH 1/5] CAN bus simple messages transport implementation for QEMU

[pisa]

From: Pavel Pisa <address@hidden>

The CanBusState state structure is created for each
emulated CAN channel. Individual clients/emulated
CAN interfaces or host interface connection registers
to the bus by CanBusClientState structure.

Connection to the real host CAN bus network through
SocketCAN network interface is available only for Linux
host system. Mechanism is generic so more options
can follow.

Implementation is as simple as possible, no migration,
messages prioritization and queuing considered for now.
But it is intended to be extended when need arises.

Development repository and more documentation at

https://gitlab.fel.cvut.cz/canbus/qemu-canbus

The work is based on Jin Yang GSoC 2013 work funded
by Google and mentored in frame of RTEMS project GSoC
slot donated to QEMU.

Rewritten for QEMU-2.0+ versions and architecture cleanup
by Pavel Pisa (Czech Technical University in Prague).

Signed-off-by: Pavel Pisa <address@hidden>
---
 default-configs/pci.mak |   1 +
 hw/Makefile.objs        |   1 +
 hw/can/Makefile.objs    |   3 +
 hw/can/can_core.c       | 374 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/can/can_emu.h   | 133 +++++++++++++++++
 5 files changed, 512 insertions(+)
 create mode 100644 hw/can/Makefile.objs
 create mode 100644 hw/can/can_core.c
 create mode 100644 include/can/can_emu.h

diff --git a/default-configs/pci.mak b/default-configs/pci.mak
index e514bdef42..bbe11887a1 100644
--- a/default-configs/pci.mak
+++ b/default-configs/pci.mak
@@ -31,6 +31,7 @@ CONFIG_ESP_PCI=y
 CONFIG_SERIAL=y
 CONFIG_SERIAL_ISA=y
 CONFIG_SERIAL_PCI=y
+CONFIG_CAN_CORE=y
 CONFIG_IPACK=y
 CONFIG_WDT_IB6300ESB=y
 CONFIG_PCI_TESTDEV=y
diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index cf4cb2010b..9d84b8faaa 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -6,6 +6,7 @@ devices-dirs-$(CONFIG_SOFTMMU) += block/
 devices-dirs-$(CONFIG_SOFTMMU) += bt/
 devices-dirs-$(CONFIG_SOFTMMU) += char/
 devices-dirs-$(CONFIG_SOFTMMU) += cpu/
+devices-dirs-$(CONFIG_SOFTMMU) += can/
 devices-dirs-$(CONFIG_SOFTMMU) += display/
 devices-dirs-$(CONFIG_SOFTMMU) += dma/
 devices-dirs-$(CONFIG_SOFTMMU) += gpio/
diff --git a/hw/can/Makefile.objs b/hw/can/Makefile.objs
new file mode 100644
index 0000000000..9afb45679f
--- /dev/null
+++ b/hw/can/Makefile.objs
@@ -0,0 +1,3 @@
+# CAN bus interfaces emulation and infrastructure
+
+common-obj-$(CONFIG_CAN_CORE) += can_core.o
diff --git a/hw/can/can_core.c b/hw/can/can_core.c
new file mode 100644
index 0000000000..783aa888db
--- /dev/null
+++ b/hw/can/can_core.c
@@ -0,0 +1,374 @@
+/*
+ * CAN common CAN bus emulation support
+ *
+ * Copyright (c) 2013-2014 Jin Yang
+ * Copyright (c) 2014 Pavel Pisa
+ *
+ * Initial development supported by Google GSoC 2013 from RTEMS project slot
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to 
deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "chardev/char.h"
+#include "qemu/sockets.h"
+#include "qemu/error-report.h"
+#include "hw/hw.h"
+#include "can/can_emu.h"
+
+#ifndef DEBUG_CAN
+#define DEBUG_CAN 0
+#endif /*DEBUG_CAN*/
+
+/*
+ * The option to connect individual CAN busses
+ * to the host CAN interface is operating system
+ * and CAN drivers infrastructure specific.
+ *
+ * Linux SocketCAN support is implemented for now.
+ * If more otions are added later, then they can be
+ * moved to separate files.
+ */
+#ifdef __linux__
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/can.h>
+#include <linux/can/raw.h>
+
+#define NUM_FILTER        4
+#define CAN_READ_BUF_LEN  5
+typedef struct {
+    CanBusClientState  bus_client;
+    qemu_can_filter    rfilter[NUM_FILTER];
+    can_err_mask_t     err_mask;
+
+    qemu_can_frame     buf[CAN_READ_BUF_LEN];
+    int                bufcnt;
+    int                bufptr;
+
+    int                fd;
+} CanBusHostConnectState;
+
+#endif /*__linux__*/
+
+static QTAILQ_HEAD(, CanBusState) can_buses =
+    QTAILQ_HEAD_INITIALIZER(can_buses);
+
+CanBusState *can_bus_find_by_name(const char *name, bool create_missing)
+{
+    CanBusState *bus;
+
+    if (name == NULL) {
+        name = "canbus0";
+    }
+
+    QTAILQ_FOREACH(bus, &can_buses, next) {
+        if (!strcmp(bus->name, name)) {
+            return bus;
+        }
+    }
+
+    if (!create_missing) {
+        return 0;
+    }
+
+    bus = g_malloc0(sizeof(*bus));
+    if (bus == NULL) {
+        return NULL;
+    }
+
+    QTAILQ_INIT(&bus->clients);
+
+    bus->name = g_strdup(name);
+
+    QTAILQ_INSERT_TAIL(&can_buses, bus, next);
+    return bus;
+}
+
+int can_bus_insert_client(CanBusState *bus, CanBusClientState *client)
+{
+    client->bus = bus;
+    QTAILQ_INSERT_TAIL(&bus->clients, client, next);
+    return 0;
+}
+
+int can_bus_remove_client(CanBusClientState *client)
+{
+    CanBusState *bus = client->bus;
+    if (bus == NULL) {
+        return 0;
+    }
+
+    QTAILQ_REMOVE(&bus->clients, client, next);
+    client->bus = NULL;
+    return 1;
+}
+
+ssize_t can_bus_client_send(CanBusClientState *client,
+             const struct qemu_can_frame *frames, size_t frames_cnt)
+{
+    int ret = 0;
+    CanBusState *bus = client->bus;
+    CanBusClientState *peer;
+    if (bus == NULL) {
+        return -1;
+    }
+
+    QTAILQ_FOREACH(peer, &bus->clients, next) {
+        if (peer->info->can_receive(peer)) {
+            if (peer == client) {
+                /* No loopback support for now */
+                continue;
+            }
+            if (peer->info->receive(peer, frames, frames_cnt) > 0) {
+                ret = 1;
+            }
+        }
+    }
+
+    return ret;
+}
+
+int can_bus_client_set_filters(CanBusClientState *client,
+             const struct qemu_can_filter *filters, size_t filters_cnt)
+{
+    return 0;
+}
+
+static void can_display_msg(struct qemu_can_frame *msg)
+{
+    int i;
+
+    fprintf(stderr, "%03X [%01d]:", (msg->can_id & 0x1fffffff), msg->can_dlc);
+    for (i = 0; i < msg->can_dlc; i++) {
+        fprintf(stderr, "  %02X", msg->data[i]);
+    }
+    fprintf(stderr, "\n");
+}
+
+#ifdef __linux__
+
+static void can_bus_host_read(void *opaque)
+{
+    CanBusHostConnectState *c;
+    c = (CanBusHostConnectState *)opaque;
+
+    /* CAN_READ_BUF_LEN for multiple messages syscall is possible for future */
+    c->bufcnt = read(c->fd, c->buf, sizeof(qemu_can_frame));
+    if (c->bufcnt < 0) {
+        perror("CAN bus host read");
+        return;
+    }
+
+    can_bus_client_send(&c->bus_client, c->buf, 1);
+
+    if (DEBUG_CAN) {
+        can_display_msg(c->buf); /* Just display the first one. */
+    }
+}
+
+static int can_bus_host_can_receive(CanBusClientState *client)
+{
+    CanBusHostConnectState *c;
+    c = container_of(client, CanBusHostConnectState, bus_client);
+
+    if (c->fd < 0) {
+        return -1;
+    }
+
+    return 1;
+}
+
+static ssize_t can_bus_host_receive(CanBusClientState *client,
+                            const qemu_can_frame *frames, size_t frames_cnt)
+{
+    CanBusHostConnectState *c;
+    c = container_of(client, CanBusHostConnectState, bus_client);
+    size_t len = sizeof(qemu_can_frame);
+    int res;
+
+    if (c->fd < 0) {
+        return -1;
+    }
+
+    res = write(c->fd, frames, len);
+
+    if (!res) {
+        fprintf(stderr, "CAN bus write to host device zero length\n");
+        return -1;
+    }
+
+    /* send frame */
+    if (res != len) {
+        perror("CAN bus write to host device error");
+        return -1;
+    }
+
+    return 1;
+}
+
+static void can_bus_host_cleanup(CanBusClientState *client)
+{
+    CanBusHostConnectState *c;
+    c = container_of(client, CanBusHostConnectState, bus_client);
+
+    if (c->fd >= 0) {
+        qemu_set_fd_handler(c->fd, NULL, NULL, c);
+        close(c->fd);
+        c->fd = -1;
+    }
+}
+
+static int can_bus_host_set_filters(CanBusClientState *client,
+                   const struct qemu_can_filter *filters, size_t filters_cnt)
+{
+    CanBusHostConnectState *c;
+    c = container_of(client, CanBusHostConnectState, bus_client);
+
+    int i;
+
+    if (filters_cnt > 4) {
+        return -1;
+    }
+
+    if (DEBUG_CAN) {
+        for (i = 0; i < filters_cnt; i++) {
+            fprintf(stderr, "[%i]  id=0x%08x maks=0x%08x\n",
+                   i, filters[i].can_id, filters[i].can_mask);
+        }
+    }
+
+    setsockopt(c->fd, SOL_CAN_RAW, CAN_RAW_FILTER,
+               filters, filters_cnt * sizeof(qemu_can_filter));
+
+    return 0;
+}
+
+static void can_bus_host_update_read_handler(CanBusHostConnectState *c)
+{
+    if (c->fd >= 0) {
+        qemu_set_fd_handler(c->fd, can_bus_host_read, NULL, c);
+    }
+}
+
+static CanBusClientInfo can_bus_host_bus_client_info = {
+    .can_receive = can_bus_host_can_receive,
+    .receive = can_bus_host_receive,
+    .cleanup = can_bus_host_cleanup,
+    .poll = NULL
+};
+
+static
+CanBusHostConnectState *can_bus_host_connect_new(const char *host_dev_name)
+{
+    int s; /* can raw socket */
+    CanBusHostConnectState    *c;
+    struct sockaddr_can addr;
+    struct ifreq ifr;
+
+    c = g_malloc0(sizeof(CanBusHostConnectState));
+    if (c == NULL) {
+        goto fail1;
+    }
+
+    c->fd = -1;
+
+    /* open socket */
+    s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
+    if (s < 0) {
+        perror("socket");
+        goto fail;
+    }
+
+    addr.can_family = AF_CAN;
+    memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
+    strcpy(ifr.ifr_name, host_dev_name);
+    if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
+        perror("SIOCGIFINDEX");
+        goto fail;
+    }
+    addr.can_ifindex = ifr.ifr_ifindex;
+
+    c->err_mask = 0xffffffff; /* Receive error frame. */
+    setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER,
+                   &c->err_mask, sizeof(c->err_mask));
+
+    /* Receive all data frame. If |= CAN_INV_FILTER no data. */
+    c->rfilter[0].can_id = 0;
+    c->rfilter[0].can_mask = 0;
+    c->rfilter[0].can_mask &= ~CAN_ERR_FLAG;
+    setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER,
+                   c->rfilter, sizeof(struct qemu_can_filter));
+
+    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        perror("bind");
+        goto fail;
+    }
+
+    c->fd = s;
+
+    c->bus_client.info = &can_bus_host_bus_client_info;
+
+    can_bus_host_update_read_handler(c);
+
+    return c;
+
+fail:
+    can_bus_host_cleanup(&c->bus_client);
+    g_free(c);
+fail1:
+
+    return NULL;
+}
+
+int can_bus_connect_to_host_device(CanBusState *bus, const char *host_dev_name)
+{
+    CanBusHostConnectState *c;
+
+    c = can_bus_host_connect_new(host_dev_name);
+    if (c == NULL) {
+        error_report("CAN bus setup of host connect to \"%s\" failed",
+                      host_dev_name);
+        exit(1);
+    }
+
+    if (can_bus_insert_client(bus, &c->bus_client) < 0) {
+        error_report("CAN host device \"%s\" connect to bus \"%s\" failed",
+                      host_dev_name, bus->name);
+        exit(1);
+    }
+
+    if (0) {
+        /*
+         * Not used there or as a CanBusHostConnectState method
+         * for now but included there for documentation purposes
+         * and to suppress warning.
+         */
+        can_bus_host_set_filters(&c->bus_client, NULL, 0);
+    }
+
+    return 0;
+}
+
+#else /*__linux__*/
+int can_bus_connect_to_host_device(CanBusState *bus, const char *name)
+{
+    error_report("CAN bus connect to host device not supported on this 
system");
+    exit(1);
+}
+#endif /*__linux__*/
diff --git a/include/can/can_emu.h b/include/can/can_emu.h
new file mode 100644
index 0000000000..86b35aef32
--- /dev/null
+++ b/include/can/can_emu.h
@@ -0,0 +1,133 @@
+/*
+ * CAN common CAN bus emulation support
+ *
+ * Copyright (c) 2013-2014 Jin Yang
+ * Copyright (c) 2014 Pavel Pisa
+ *
+ * Initial development supported by Google GSoC 2013 from RTEMS project slot
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to 
deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef NET_CAN_EMU_H
+#define NET_CAN_EMU_H
+
+#include "qemu/queue.h"
+
+/* NOTE: the following two structures is copied from <linux/can.h>. */
+
+/*
+ * Controller Area Network Identifier structure
+ *
+ * bit 0-28    : CAN identifier (11/29 bit)
+ * bit 29      : error frame flag (0 = data frame, 1 = error frame)
+ * bit 30      : remote transmission request flag (1 = rtr frame)
+ * bit 31      : frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
+ */
+typedef uint32_t qemu_canid_t;
+
+#if defined(__GNUC__) || defined(__linux__)
+    #define QEMU_CAN_FRAME_DATA_ALIGN __attribute__((aligned(8)))
+#else
+    #define QEMU_CAN_FRAME_DATA_ALIGN
+#endif
+
+typedef struct qemu_can_frame {
+    qemu_canid_t    can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
+    uint8_t         can_dlc; /* data length code: 0 .. 8 */
+    uint8_t         data[8] QEMU_CAN_FRAME_DATA_ALIGN;
+} qemu_can_frame;
+
+/**
+ * struct qemu_can_filter - CAN ID based filter in can_register().
+ * @can_id:   relevant bits of CAN ID which are not masked out.
+ * @can_mask: CAN mask (see description)
+ *
+ * Description:
+ * A filter matches, when
+ *
+ *          <received_can_id> & mask == can_id & mask
+ *
+ * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
+ * filter for error message frames (CAN_ERR_FLAG bit set in mask).
+ */
+typedef struct qemu_can_filter {
+    qemu_canid_t    can_id;
+    qemu_canid_t    can_mask;
+} qemu_can_filter;
+
+#define CAN_INV_FILTER 0x20000000U /* to be set in qemu_can_filter.can_id */
+
+typedef struct CanBusClientState CanBusClientState;
+typedef struct CanBusState CanBusState;
+
+typedef void (CanBusClientPoll)(CanBusClientState *, bool enable);
+typedef int (CanBusClientCanReceive)(CanBusClientState *);
+typedef ssize_t (CanBusClientReceive)(CanBusClientState *,
+                 const struct qemu_can_frame *frames, size_t frames_cnt);
+typedef void (CanBusClientCleanup) (CanBusClientState *);
+typedef void (CanBusClientDestructor)(CanBusClientState *);
+
+typedef struct CanBusClientInfo {
+    /*CanBusClientOptionsKind type;*/
+    size_t size;
+    CanBusClientCanReceive *can_receive;
+    CanBusClientReceive *receive;
+    CanBusClientCleanup *cleanup;
+    CanBusClientPoll *poll;
+} CanBusClientInfo;
+
+struct CanBusClientState {
+    CanBusClientInfo *info;
+    CanBusState *bus;
+    int link_down;
+    QTAILQ_ENTRY(CanBusClientState) next;
+    CanBusClientState *peer;
+    /*CanBusQueue *incoming_queue;*/
+    char *model;
+    char *name;
+    /*unsigned receive_disabled : 1;*/
+    CanBusClientDestructor *destructor;
+    /*unsigned int queue_index;*/
+    /*unsigned rxfilter_notify_enabled:1;*/
+};
+
+struct CanBusState {
+    char *name;
+    QTAILQ_HEAD(, CanBusClientState) clients;
+    QTAILQ_ENTRY(CanBusState) next;
+};
+
+CanBusState *can_bus_find_by_name(const char *name, bool create_missing);
+
+int can_bus_insert_client(CanBusState *bus, CanBusClientState *client);
+
+int can_bus_remove_client(CanBusClientState *client);
+
+ssize_t can_bus_client_send(CanBusClientState *,
+                            const struct qemu_can_frame *frames,
+                            size_t frames_cnt);
+
+int can_bus_client_set_filters(CanBusClientState *,
+                               const struct qemu_can_filter *filters,
+                               size_t filters_cnt);
+
+int can_bus_connect_to_host_device(CanBusState *bus, const char 
*host_dev_name);
+
+#endif
-- 
2.11.0