本帖最后由 gztwdz4379 于 2025-9-10 10:30 编辑
前言:
在多核异构架构成为工业SoC主流方案的当下,芯驰D9360凭借其Cortex-A55与Cortex-R5的协同设计,在需同时处理复杂应用与实时任务的场景中表现突出。本文将以眺望电子Core-D9360平台为例,详解如何利用RPMSG与VirtIO机制实现A核与R核间的可靠通信,并提供关键代码实现与调试方法。
图 1 Core-D9360 核心板
一、通信基础:RPMSG框架
RPMSG(Remote Processor Messaging)是Linux内核中用于处理器间通信的框架,采用virtio + rpmsg + IPCC三层架构实现: ●virtio:提供虚拟化队列管理 ●rpmsg:实现消息封装与路由 ●IPCC:硬件中断控制器
在Core-D9360核心板中,A55核运行Linux,R5核运行RTOS,两者通过虚拟通道(VirtIO ring buffer)进行数据传输,支持双向、异步、多通道通信。
图 2 核间通讯架构
二、核心代码实现
2.1 添加例程驱动 RTOS系统的例程添加在SDK/source/ssdk/examples/kunlun/drivers下,分别创建Kconfig和rules.mk文件,其中Kconfig文件内容如下:
rules.mk文件内容如下:
返回上一层目录下,在Kconfig下添加talowe驱动模块的初始状态和图形界面类型,添加内容如下:
在rules.mk文件下,添加如下内容:
MODULES += $(LOCAL_DIR)/talowe: 如果配置选项 CONFIG_TALOWE_TEST为 "y",则会将$(LOCAL_DIR)/talowe添加到变量MODULES中。当启用了"talowe test"功能时,会将$(LOCAL_DIR)/talowe模块添加到模块列表中。 2.2 R5核发送机制实现 将rpmsg目录下的rpmsg_test.c文件复制到talowe.c文件中,该驱动描述如何通过RPMSG协议进行核间通信。我们可以在此程序基础上加入自己的协议。 以下是R5核发送"Talowe:RtoA"字符串到A55核,并打印出接收到的信息的函数。 - <font color="#000000" face="微软雅黑" size="3">void send_receive_string(rpmsg_channel_t channel, const char *message) {
- int max_payload;
- struct dcf_ccm_hdr *snd_pkg;
- struct dcf_ccm_hdr *rcv_pkg;
- status_t ret;
- max_payload = rpmsg_channel_max_payload(channel);
- snd_pkg = osAlloc(max_payload);
- rcv_pkg = osAlloc(max_payload);
- ASSERT(snd_pkg && rcv_pkg);
- memset(snd_pkg, 0x0, max_payload);
- memset(rcv_pkg, 0x0, max_payload);
- snd_pkg->dmsg.msg_type = COMM_MSG_CCM_ECHO;
- snd_pkg->dmsg.opflags |= DCF_MSGF_TMS;
- snd_pkg->dmsg.msg_len = sizeof(struct dcf_ccm_hdr) - sizeof(struct dcf_message);
- strncpy(snd_pkg->data, message, max_payload - sizeof(struct dcf_ccm_hdr));
- ret = rpmsg_channel_send(channel, RPMSG_ECHO_EPT_ADDR, snd_pkg, max_payload, 3000);
- if (ret == RPMSG_SUCCESS) {
- printf("Sent: %s\n", message);
- } else {
- printf("Failed to send message\n");
- }
- int received_len;
- ret = rpmsg_channel_recv(channel, rcv_pkg, max_payload, &received_len, 3000);
- if (ret == RPMSG_SUCCESS) {
- printf("Received: %s\n", rcv_pkg->data);
- } else {
- printf("Failed to receive message\n");
- }
- osFree(snd_pkg);
- osFree(rcv_pkg);
- }</font>
将以上函数添加至talowe.c文件内,并在主函数rpmsg_test编写调用该函数条件,如下: - <font color="#000000" face="微软雅黑" size="3">const char* message_to_send = "Talowe:RtoA";
- static int rpmsg_test(int argc, char *argv[])
- {
- int test_case = -1;
- int type, rproc, times;
- ......
- else if (!strcmp(argv[0], "perf")) {
- test_case = 3;
- type = atoi(argv[1]);
- rproc = atoi(argv[2]);
- times = atoi(argv[3]);
- }
- else if(!strcmp(argv[0], "send")) {
- test_case = 4;
- type = atoi(argv[1]);
- rproc = atoi(argv[2]);
- times = atoi(argv[3]);
- }
- else {
- printf("Unknown cmd %s\n", argv[0]);
- goto exit;
- }
- ......
- ......
- case 3:
- do_rpmsg_perf_test(channel, times);
- break;
- case 4:
- send_receive_string(channel, message_to_send);
- break;
- default:
- printf("Unknown case %d\n", test_case);
- break;
- }
- </font>
加入串口打印提示: - <font color="#000000" face="微软雅黑" size="3">static void rpmsg_test_show(void)
- {
- printf("\nList rpmsg communicate with remote:\n");
- printf("\tType\t\t\tRemote-Proc\n");
- ......
- ......
- printf("\trpmsg_test perf <type> <remote-proc> <times>\n");
- printf("\trpmsg_test send <type> <remote-proc> <times>\n");
- printf("\ne.g: test ping rpmsg.virtio 10 times with secure, use command:\n");
- printf("\trpmsg_test ping 0 1 10\n");
- }</font>
编辑如下文件:SDK/source/ssdk/ middleware/rpmsg_service/rpmsg_echo.c - <font color="#000000" face="微软雅黑" size="3">static int echo_channel_cb(void *data, int len, unsigned long src, void *arg)
- {
- rpmsg_channel_t chan = arg;
- struct dcf_ccm_hdr *ccm_pkg = data;
- const char *char_data = (char *)data;
- int ret = 0;
- if (ccm_pkg->dmsg.msg_type == COMM_MSG_CCM_ECHO) {
- ccm_pkg->time[2] = timer_get_current_time(g_syscnt_timer) * g_sdrv_syscnt_dev.cnt_per_us;
- ret = rpmsg_channel_send(chan, src, data, len, 1000);
- printf("Sending data (length %d): ", len);
- for (int i = 8; i < len; i++) {
- printf("%c ", char_data[i]);
- }
- printf("\n");
- }
- else if (ccm_pkg->dmsg.msg_type == COMM_MSG_CCM_ACK) {
- ret = rpmsg_channel_send(chan, src, (char *)"ACK", 4, 1000);
- ssdk_printf(SSDK_INFO,"send ACK\n");
- }
- else {
- ssdk_printf(SSDK_WARNING, "echo_channel_cb: unknown %d bytes from addr %ld\n", len, src);
- }
- if (ret != 0) {
- ssdk_printf(SSDK_WARNING, "echo_channel_cb: channel send failed\n");
- }
- return ret;
- }</font>
通过以下指令打开图形化配置界面,进入到Driver and Application Examples->Driver Example Support下,可以看到我们新加的talowe test Support驱动配置选项,需要关闭 RPMSG Example Application Support 选项,如下:
- <font color="#000000" face="微软雅黑" size="3">./tools/menuconfig.sh -b d9360_ref -p ref -c secure</font>
2.3 A55核发送数据到R5核 A55核Linux系统通过echo_test命令与R5核进行通讯,以下是该命令源码的文件位置:
自定义一个发送和接收字符串的函数,如下: - <font color="#000000" face="微软雅黑" size="3">
- int send_receive_string(int fd, const char *send_str,int ntimes, int seconds) {
- int i = 0, j = 0;
- int size, bytes_rcvd, bytes_sent;
- long elapse = 0;
- err_cnt = 0;
- i_payload = (struct _payload *)malloc(sizeof(struct _payload) + payload_max_size);
- r_payload = (struct _payload *)malloc(sizeof(struct _payload) + payload_max_size);
- if (i_payload == 0 || r_payload == 0) {
- printf("ERROR: Failed to allocate memory for payload.\n");
- return -1;
- }
- if (seconds)
- gettimeofday(&start_test, NULL);
- i_payload->magic = 0xA5;
- for (j = 0; j < ntimes; j++) {
- i_payload->num = i;
- i_payload->size = size;
- strcpy(i_payload->data, send_str);
- if (verbose)
- printf("\r\n sending payload number");
- if (verbose)
- printf(" %d of size %lu\r\n", i_payload->num, (sizeof(struct _payload)) + strlen(i_payload->data));
- bytes_sent = write(fd, i_payload, sizeof(struct _payload) + strlen(i_payload->data));
- if (bytes_sent <= 0) {
- if (verbose) {
- perror("\r\n Error sending data\n");
- break;
- } else
- fprintf(stderr, "#");
- err_cnt++;
- continue;
- }
- printf("send string:%s\n",i_payload->data);
- r_payload->num = 0;
- bytes_rcvd = read(fd, r_payload, sizeof(struct _payload) + payload_max_size);
- while (bytes_rcvd <= 0) {
- usleep(10000);
- bytes_rcvd = read(fd, r_payload, sizeof(struct _payload) + payload_max_size);
- }
- r_payload->data[bytes_rcvd] = '\0';
- printf("receive string:%s\n",r_payload->data);
- if (interval)
- sleep(interval);
- }
- free(i_payload);
- free(r_payload);
- return 0;
- }</font>
在main函数内添加新增函数条件,执行指令时实现A55核发送"Talowe:AtoR"字符串到R5核: - <font color="#000000" face="微软雅黑" size="3">
- int main(int argc, char *argv[])
- {
- int opt;
- char *rpmsg_dev = RPMSG_DEVICE_NAME;
- ......
- int test_second = 0;
- int send_char = 0;
- char *value_c;
- if (strstr(argv[0], "property")) {
- do_property_test(argc, argv);
- return 0;
- }
- ......
- while ((opt = getopt(argc, argv, "a:d:n:cbpxvst:hi:lm:S:P:")) != -1) {
- switch (opt) {
- ......
- case 'v':
- verbose = 1;
- break;
- case 'c':
- send_char = 1;
- break;
- case 'b':
- benchmark = 1;
- break;
- ......
- default:
- printf("getopt return unsupported option: -%c\n", opt);
- usage("echo_test");
- break;
- }
- }
- else if (benchmark == 2) {
- iperf_test(fd, ntimes);
- } else if (benchmark == 3) {
- throughput_test(fd, ntimes, test_second);
- } else if( send_char == 1){
- const char *message_to_send = "Talowe:AtoR";
- int result = send_receive_string(fd, message_to_send,ntimes, test_second);
- if (result < 0) {
- printf("Error sending/receiving string.\n");
- }
- }
- else {
- if (test_second) {
- ntimes = 0x7fffffff;
- }
- ......
- return 0;
- }
- 在打印列表添加如下提示:
- static void usage(const char *cmd)
- {
- printf("This is s rpmsg echo test %s, MTU=%d\n", ECHO_TEST_VERSION, rpmsg_payload_test);
- ......
- printf("%s -v\t\t: Verbose mode\n", cmd);
- printf("%s -c [char]\t: send Talowe:AtoR\n", cmd);
- ......
- printf("echo_test -d soc:ipcc@0.ipcc-echo.-1.30 -x -t 10 ; Throughput test in average (Ack'd) in 10 seconds (print in 1 second)\n");
- exit(0);
- }</font>
编辑如下文件:SDK/source/linux/drivers/rpmsg/virtio_rpmsg_bus.c - <font color="#000000" face="微软雅黑" size="3">static int rpmsg_echo_cb(struct rpmsg_device *rpdev, void *data, int len,
- void *priv, u32 src)
- {
- struct dcf_message *msg = data;
- struct virtproc_info *vrp = priv;
- ......
- switch (msg->msg_type) {
- case COMM_MSG_CCM_ECHO:
- dev_err(dev,"virtio send susses");
- /* Add timestamp in the time[2] */
- ......
- break;
- case COMM_MSG_CCM_ACK:
- dev_err(dev,"rpmsg recv ACK");
- err = __send_offchannel_raw(vrp, RPMSG_ECHO_ADDR, src, "ACK", 4, true);
- ......
- break;
- default:
- /* No more action, just drop the packet */
- break;
- }
- return 0;
- }</font>
编辑如下文件:SDK/source/linux/drivers/rpmsg/semidrive_ipcc.c - <font color="#000000" face="微软雅黑" size="3">
- static int rpmsg_ipcc_echo_cb(struct rpmsg_device *rpdev, void *data, int len,
- void *priv, u32 src)
- {
- struct rpmsg_ipcc_device *vrp = priv;
- struct device *dev = vrp->dev;
- ......
- switch (dmsg->msg_type) {
- case COMM_MSG_CCM_ECHO:
- dev_err(dev,"ipcc send susses");
- /* Add timestamp in the time[2] */
- ......
- break;
- case COMM_MSG_CCM_ACK:
- dev_err(dev,"ipcc recv ACK");
- err = __send_offchannel_raw(vrp, RPMSG_ECHO_ADDR, src, "ACK", 4,true);
- ......
- break;
- default:
- /* No more action, just drop the packet */
- break;
- }
- return 0;
- }</font>
内核需打开以下配置: - <font color="#000000" face="微软雅黑" size="3">CONFIG_RPMSG=y
- CONFIG_RPMSG_CHAR=y
- CONFIG_RPMSG_VIRTIO=y
- CONFIG_RPMSG_SEMIDRIVE=y</font>
三、烧写测试验证
3.1 R5核向A55核发送信息 以下测试内容为R5核发送"Talowe:RtoA"字符串到A55核,A55核接收到字符串之后重新发送给R5核。 R5核: - <font color="#000000" face="微软雅黑" size="3">rpmsg_test send 0 3 1</font>
A55核:
3.2 A55核向R5发送信息 以下测试内容为A55核发送"Talowe:AtoR"字符串到R5核,R5核接收到字符串之后重新发送给A55核。 A55核: - <font color="#000000" face="微软雅黑" size="3">echo_test -d virtio0.rpmsg-echo.-1.30 -c 1</font>
R5核:
四、结语
通过RPMsg在单芯片上实现了这种高效的核间通信机制,使得异构多核SoC能够真正发挥"实时控制+高性能计算"的协同优势,成为工业4.0、自动驾驶、AIoT等领域的核心技术底座。 广州眺望电子科技有限公司推出Core-D9360核心板与EVM-D9载板外,还提供完整的SDK、编译指南、测试手册及技术文档,覆盖从环境搭建、代码编译、镜像烧写到功能验证的全流程,助力开发者快速实现产品化。 如果您希望获取完整核心板开发资料与产品价格,欢迎关注我们的公众号或官方淘宝店铺,联系获取!
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