Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
---
drivers/rpmsg/Kconfig | 24 ++
drivers/rpmsg/Makefile | 2 +
drivers/rpmsg/imx_rpmsg.c | 542 +++++++++++++++++++++++++++++++++++++
drivers/rpmsg/imx_rpmsg_pingpong.c | 100 +++++++
include/linux/imx_rpmsg.h | 43 +++
5 files changed, 711 insertions(+)
create mode 100644 drivers/rpmsg/imx_rpmsg.c
create mode 100644 drivers/rpmsg/imx_rpmsg_pingpong.c
create mode 100644 include/linux/imx_rpmsg.h
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index d0322b4..636460e 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -55,4 +55,28 @@ config RPMSG_VIRTIO
select RPMSG
select VIRTIO
+config HAVE_IMX_RPMSG
+ bool "IMX RPMSG driver on the AMP SOCs"
+ default y
+ depends on IMX_MBOX
+ select RPMSG_VIRTIO
+ help
+ Say y here to enable support for the iMX Rpmsg Driver providing
+ communication channels to remote processors in iMX asymmetric
+ multiprocessing (AMP) platforms.
+
+ Especially, it is mandatory required when the partition reset is
+ required on some iMX AMP platforms.
+
+config IMX_RPMSG_PINGPONG
+ tristate "IMX RPMSG pingpong driver -- loadable modules only"
+ default m
+ depends on HAVE_IMX_RPMSG && m
+ help
+ One 32bit unsigned int data transactions demoe between the A core
+ and the remote M core on the iMX AMP platforms.
+
+ Only the module mode is supported here, the demo would be kicked off
+ immediately when this module is insmoded.
+
endmenu
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 9aa8595..9c6fce5 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -6,3 +6,5 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_NATIVE) += qcom_glink_native.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
+obj-$(CONFIG_HAVE_IMX_RPMSG) += imx_rpmsg.o
+obj-$(CONFIG_IMX_RPMSG_PINGPONG) += imx_rpmsg_pingpong.o
diff --git a/drivers/rpmsg/imx_rpmsg.c b/drivers/rpmsg/imx_rpmsg.c
new file mode 100644
index 0000000..58888d1
--- /dev/null
+++ b/drivers/rpmsg/imx_rpmsg.c
@@ -0,0 +1,542 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <linux/circ_buf.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/of_device.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/platform_device.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_ring.h>
+#include <linux/imx_rpmsg.h>
+#include "rpmsg_internal.h"
+
+enum imx_rpmsg_variants {
+ IMX8MQ,
+ IMX8QXP,
+};
+
+struct imx_virdev {
+ struct virtio_device vdev;
+ unsigned int vring[2];
+ struct virtqueue *vq[2];
+ int base_vq_id;
+ int num_of_vqs;
+ struct imx_rpmsg_vproc *rpdev;
+};
+
+struct imx_rpmsg_vproc {
+ struct mbox_client cl;
+ struct mbox_client cl_rxdb;
+ struct mbox_chan *tx_ch;
+ struct mbox_chan *rx_ch;
+ struct mbox_chan *rxdb_ch;
+ enum imx_rpmsg_variants variant;
+ int vdev_nums;
+ int first_notify;
+ u32 flags;
+#define MAX_VDEV_NUMS 8
+ struct imx_virdev *ivdev[MAX_VDEV_NUMS];
+ struct delayed_work rpmsg_work;
+ struct circ_buf rx_buffer;
+ spinlock_t mu_lock;
+ struct notifier_block proc_nb;
+ struct platform_device *pdev;
+};
+
+#define RPMSG_NUM_BUFS (512)
+#define RPMSG_BUF_SIZE (512)
+#define RPMSG_BUFS_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
+#define RPMSG_VRING_ALIGN (4096)
+#define RPMSG_RING_SIZE ((DIV_ROUND_UP(vring_size(RPMSG_NUM_BUFS / 2, \
+ RPMSG_VRING_ALIGN), PAGE_SIZE)) * PAGE_SIZE)
+
+#define to_imx_virdev(vd) container_of(vd, struct imx_virdev, vdev)
+
+/*
+ * 1: indicated that remote processor is ready from re-initialization.
+ * Clear this bit after the RPMSG restore is finished at master side.
+ */
+#define REMOTE_IS_READY BIT(0)
+/* 1: Use reserved memory region as DMA pool */
+#define SPECIFIC_DMA_POOL BIT(1)
+
+struct imx_rpmsg_vq_info {
+ __u16 num; /* number of entries in the virtio_ring */
+ __u16 vq_id; /* a globaly unique index of this virtqueue */
+ void *addr; /* address where we mapped the virtio ring */
+ struct imx_rpmsg_vproc *rpdev;
+};
+
+static u64 imx_rpmsg_get_features(struct virtio_device *vdev)
+{
+ /* VIRTIO_RPMSG_F_NS has been made private */
+ return 1 << 0;
+}
+
+static int imx_rpmsg_finalize_features(struct virtio_device *vdev)
+{
+ /* Give virtio_ring a chance to accept features */
+ vring_transport_features(vdev);
+ return 0;
+}
+
+/* kick the remote processor, and let it know which virtqueue to poke at */
+static bool imx_rpmsg_notify(struct virtqueue *vq)
+{
+ int ret;
+ unsigned long flags;
+ unsigned int mu_rpmsg = 0;
+ struct imx_rpmsg_vq_info *rpvq = vq->priv;
+ struct imx_rpmsg_vproc *rpdev = rpvq->rpdev;
+
+ mu_rpmsg = rpvq->vq_id << 16;
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ /*
+ * Send the index of the triggered virtqueue as the mu payload.
+ * Use the timeout MU send message here.
+ * Since that M4 core may not be loaded, and the first MSG may
+ * not be handled by M4 when multi-vdev is enabled.
+ * To make sure that the message wound't be discarded when M4
+ * is running normally or in the suspend mode. Only use
+ * the timeout mechanism by the first notify when the vdev is
+ * registered.
+ * ~14ms is required by M4 ready to process the MU message from
+ * cold boot. Set the wait time 20ms here.
+ */
+ if (unlikely(rpdev->first_notify > 0)) {
+ rpdev->first_notify--;
+ rpdev->cl.tx_tout = 20;
+ ret = mbox_send_message(rpdev->tx_ch, &mu_rpmsg);
+ if (ret < 0)
+ return false;
+ } else {
+ rpdev->cl.tx_tout = 0;
+ ret = mbox_send_message(rpdev->tx_ch, &mu_rpmsg);
+ if (ret < 0)
+ return false;
+ }
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+
+ return true;
+}
+
+static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
+ unsigned int index,
+ void (*callback)(struct virtqueue *vq),
+ const char *name,
+ bool ctx)
+{
+ struct imx_virdev *virdev = to_imx_virdev(vdev);
+ struct imx_rpmsg_vproc *rpdev = virdev->rpdev;
+ struct platform_device *pdev = rpdev->pdev;
+ struct device *dev = &pdev->dev;
+ struct imx_rpmsg_vq_info *rpvq;
+ struct virtqueue *vq;
+ int err;
+
+ rpvq = kmalloc(sizeof(*rpvq), GFP_KERNEL);
+ if (!rpvq)
+ return ERR_PTR(-ENOMEM);
+
+ /* ioremap'ing normal memory, so we cast away sparse's complaints */
+ rpvq->addr = (__force void *) ioremap_nocache(virdev->vring[index],
+ RPMSG_RING_SIZE);
+ if (!rpvq->addr) {
+ err = -ENOMEM;
+ goto free_rpvq;
+ }
+
+ memset_io(rpvq->addr, 0, RPMSG_RING_SIZE);
+
+ dev_dbg(dev, "vring%d: phys 0x%x, virt 0x%p\n",
+ index, virdev->vring[index], rpvq->addr);
+
+ vq = vring_new_virtqueue(index, RPMSG_NUM_BUFS / 2, RPMSG_VRING_ALIGN,
+ vdev, true, ctx,
+ rpvq->addr,
+ imx_rpmsg_notify, callback,
+ name);
+ if (!vq) {
+ dev_err(dev, "vring_new_virtqueue failed\n");
+ err = -ENOMEM;
+ goto unmap_vring;
+ }
+
+ virdev->vq[index] = vq;
+ vq->priv = rpvq;
+ /* system-wide unique id for this virtqueue */
+ rpvq->vq_id = virdev->base_vq_id + index;
+ rpvq->rpdev = rpdev;
+
+ return vq;
+
+unmap_vring:
+ /* iounmap normal memory, so make sparse happy */
+ iounmap((__force void __iomem *) rpvq->addr);
+free_rpvq:
+ kfree(rpvq);
+ return ERR_PTR(err);
+}
+
+static void imx_rpmsg_del_vqs(struct virtio_device *vdev)
+{
+ struct virtqueue *vq, *n;
+
+ list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
+ struct imx_rpmsg_vq_info *rpvq = vq->priv;
+
+ iounmap(rpvq->addr);
+ vring_del_virtqueue(vq);
+ kfree(rpvq);
+ }
+}
+
+static int imx_rpmsg_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+ struct virtqueue *vqs[],
+ vq_callback_t *callbacks[],
+ const char * const names[],
+ const bool *ctx,
+ struct irq_affinity *desc)
+{
+ struct imx_virdev *virdev = to_imx_virdev(vdev);
+ int i, err;
+
+ /* we maintain two virtqueues per remote processor (for RX and TX) */
+ if (nvqs != 2)
+ return -EINVAL;
+
+ for (i = 0; i < nvqs; ++i) {
+ vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i],
+ ctx ? ctx[i] : false);
+ if (IS_ERR(vqs[i])) {
+ err = PTR_ERR(vqs[i]);
+ goto error;
+ }
+ }
+
+ virdev->num_of_vqs = nvqs;
+ return 0;
+
+error:
+ imx_rpmsg_del_vqs(vdev);
+ return err;
+}
+
+static void imx_rpmsg_reset(struct virtio_device *vdev)
+{
+ dev_dbg(&vdev->dev, "reset !\n");
+}
+
+static u8 imx_rpmsg_get_status(struct virtio_device *vdev)
+{
+ return 0;
+}
+
+static void imx_rpmsg_set_status(struct virtio_device *vdev, u8 status)
+{
+ dev_dbg(&vdev->dev, "%s new status: %d\n", __func__, status);
+}
+
+static void imx_rpmsg_vproc_release(struct device *dev)
+{
+ /* this handler is provided so driver core doesn't yell at us */
+}
+
+static struct virtio_config_ops imx_rpmsg_config_ops = {
+ .get_features = imx_rpmsg_get_features,
+ .finalize_features = imx_rpmsg_finalize_features,
+ .find_vqs = imx_rpmsg_find_vqs,
+ .del_vqs = imx_rpmsg_del_vqs,
+ .reset = imx_rpmsg_reset,
+ .set_status = imx_rpmsg_set_status,
+ .get_status = imx_rpmsg_get_status,
+};
+
+static const struct of_device_id imx_rpmsg_dt_ids[] = {
+ { .compatible = "fsl,imx8mq-rpmsg", .data = (void *)IMX8MQ, },
+ { .compatible = "fsl,imx8qxp-rpmsg", .data = (void *)IMX8QXP, },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx_rpmsg_dt_ids);
+
+static int set_vring_phy_buf(struct platform_device *pdev,
+ struct imx_rpmsg_vproc *rpdev, int vdev_nums)
+{
+ struct resource *res;
+ resource_size_t size;
+ unsigned int start, end;
+ int i, ret = 0;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (res) {
+ size = resource_size(res);
+ start = res->start;
+ end = res->start + size;
+ for (i = 0; i < vdev_nums; i++) {
+ rpdev->ivdev[i] = kzalloc(sizeof(struct imx_virdev),
+ GFP_KERNEL);
+ if (!rpdev->ivdev[i])
+ return -ENOMEM;
+
+ rpdev->ivdev[i]->vring[0] = start;
+ rpdev->ivdev[i]->vring[1] = start + 0x8000;
+ start += 0x10000;
+ if (start > end) {
+ dev_err(&pdev->dev,
+ "Too small memory size %x!\n",
+ (u32)size);
+ ret = -EINVAL;
+ break;
+ }
+ }
+ } else {
+ return -ENOMEM;
+ }
+
+ return ret;
+}
+
+static void rpmsg_work_handler(struct work_struct *work)
+{
+ u32 message;
+ unsigned long flags;
+ struct imx_virdev *virdev;
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct imx_rpmsg_vproc *rpdev = container_of(dwork,
+ struct imx_rpmsg_vproc, rpmsg_work);
+ struct circ_buf *cb = &rpdev->rx_buffer;
+ struct platform_device *pdev = rpdev->pdev;
+ struct device *dev = &pdev->dev;
+
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ /* handle all incoming mu message */
+ while (CIRC_CNT(cb->head, cb->tail, PAGE_SIZE)) {
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+ message = (u32) cb->buf[cb->tail];
+ virdev = rpdev->ivdev[(message >> 16) / 2];
+
+ dev_dbg(dev, "%s msg: 0x%x\n", __func__, message);
+ message = message >> 16;
+ message -= virdev->base_vq_id;
+
+ /*
+ * Currently both PENDING_MSG and explicit-virtqueue-index
+ * messaging are supported.
+ * Whatever approach is taken, at this point message contains
+ * the index of the vring which was just triggered.
+ */
+ if (message < virdev->num_of_vqs)
+ vring_interrupt(message, virdev->vq[message]);
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ cb->tail = CIRC_ADD(cb->tail, PAGE_SIZE, 4);
+ }
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+}
+
+static int imx_rpmsg_partition_notify(struct notifier_block *nb,
+ unsigned long event, void *group)
+{
+ /* Reserved for the partition reset. */
+ return 0;
+}
+
+static void imx_rpmsg_rxdb_callback(struct mbox_client *c, void *msg)
+{
+ unsigned long flags;
+ struct imx_rpmsg_vproc *rpdev = container_of(c,
+ struct imx_rpmsg_vproc, cl);
+
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ rpdev->flags |= REMOTE_IS_READY;
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+}
+
+static int imx_rpmsg_rxdb_channel_init(struct imx_rpmsg_vproc *rpdev)
+{
+ struct platform_device *pdev = rpdev->pdev;
+ struct device *dev = &pdev->dev;
+ struct mbox_client *cl;
+ int ret = 0;
+
+ cl = &rpdev->cl_rxdb;
+ cl->dev = dev;
+ cl->rx_callback = imx_rpmsg_rxdb_callback;
+
+ /*
+ * RX door bell is used to receive the ready signal from remote
+ * after the partition reset of A core.
+ */
+ rpdev->rxdb_ch = mbox_request_channel_byname(cl, "rxdb");
+ if (IS_ERR(rpdev->rxdb_ch)) {
+ ret = PTR_ERR(rpdev->rxdb_ch);
+ dev_err(cl->dev, "failed to request mbox chan rxdb, ret %d\n",
+ ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+static void imx_rpmsg_rx_callback(struct mbox_client *c, void *msg)
+{
+ int buf_space;
+ unsigned long flags;
+ u32 *data = msg;
+ struct imx_rpmsg_vproc *rpdev = container_of(c,
+ struct imx_rpmsg_vproc, cl);
+ struct circ_buf *cb = &rpdev->rx_buffer;
+
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ buf_space = CIRC_SPACE(cb->head, cb->tail, PAGE_SIZE);
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+ if (unlikely(!buf_space)) {
+ dev_err(c->dev, "RPMSG RX overflow!\n");
+ return;
+ }
+ spin_lock_irqsave(&rpdev->mu_lock, flags);
+ cb->buf[cb->head] = *data;
+ cb->head = CIRC_ADD(cb->head, PAGE_SIZE, 4);
+ spin_unlock_irqrestore(&rpdev->mu_lock, flags);
+
+ schedule_delayed_work(&(rpdev->rpmsg_work), 0);
+}
+
+static int imx_rpmsg_probe(struct platform_device *pdev)
+{
+ int j, ret = 0;
+ char *buf;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = pdev->dev.of_node;
+ struct imx_rpmsg_vproc *rpdev;
+ struct mbox_client *cl;
+
+ buf = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ rpdev = devm_kzalloc(dev, sizeof(*rpdev), GFP_KERNEL);
+ if (!rpdev)
+ return -ENOMEM;
+
+ rpdev->proc_nb.notifier_call = imx_rpmsg_partition_notify;
+ rpdev->variant = (enum imx_rpmsg_variants)of_device_get_match_data(dev);
+ rpdev->rx_buffer.buf = buf;
+ rpdev->rx_buffer.head = 0;
+ rpdev->rx_buffer.tail = 0;
+
+ cl = &rpdev->cl;
+ cl->dev = dev;
+ cl->tx_block = false;
+ cl->tx_tout = 20;
+ cl->knows_txdone = false;
+ cl->rx_callback = imx_rpmsg_rx_callback;
+
+ rpdev->tx_ch = mbox_request_channel_byname(cl, "tx");
+ if (IS_ERR(rpdev->tx_ch)) {
+ ret = PTR_ERR(rpdev->tx_ch);
+ goto err_chl;
+ }
+ rpdev->rx_ch = mbox_request_channel_byname(cl, "rx");
+ if (IS_ERR(rpdev->rx_ch)) {
+ ret = PTR_ERR(rpdev->rx_ch);
+ goto err_chl;
+ }
+
+ spin_lock_init(&rpdev->mu_lock);
+ INIT_DELAYED_WORK(&(rpdev->rpmsg_work), rpmsg_work_handler);
+ ret = of_property_read_u32(np, "vdev-nums", &rpdev->vdev_nums);
+ if (ret)
+ rpdev->vdev_nums = 1;
+ if (rpdev->vdev_nums > MAX_VDEV_NUMS) {
+ dev_err(dev, "vdev-nums exceed the max %d\n", MAX_VDEV_NUMS);
+ ret = -EINVAL;
+ goto err_chl;
+ }
+ rpdev->first_notify = rpdev->vdev_nums;
+
+ ret = set_vring_phy_buf(pdev, rpdev, rpdev->vdev_nums);
+ if (ret) {
+ dev_err(dev, "No vring buffer.\n");
+ ret = -ENOMEM;
+ goto err_chl;
+ }
+ if (of_reserved_mem_device_init(dev)) {
+ dev_dbg(dev, "dev doesn't have specific DMA pool.\n");
+ rpdev->flags &= (~SPECIFIC_DMA_POOL);
+ } else {
+ rpdev->flags |= SPECIFIC_DMA_POOL;
+ }
+
+ for (j = 0; j < rpdev->vdev_nums; j++) {
+ dev_dbg(dev, "%s rpdev vdev%d: vring0 0x%x, vring1 0x%x\n",
+ __func__, rpdev->vdev_nums,
+ rpdev->ivdev[j]->vring[0],
+ rpdev->ivdev[j]->vring[1]);
+ rpdev->ivdev[j]->vdev.id.device = VIRTIO_ID_RPMSG;
+ rpdev->ivdev[j]->vdev.config = &imx_rpmsg_config_ops;
+ rpdev->pdev = pdev;
+ rpdev->ivdev[j]->vdev.dev.parent = &pdev->dev;
+ rpdev->ivdev[j]->vdev.dev.release = imx_rpmsg_vproc_release;
+ rpdev->ivdev[j]->base_vq_id = j * 2;
+ rpdev->ivdev[j]->rpdev = rpdev;
+
+ ret = register_virtio_device(&rpdev->ivdev[j]->vdev);
+ if (ret) {
+ dev_err(dev, "%s failed to register rpdev: %d\n",
+ __func__, ret);
+ goto err_out;
+ }
+ }
+ /* Initialize the RX doorbell channel. */
+ ret = imx_rpmsg_rxdb_channel_init(rpdev);
+ if (ret)
+ goto err_out;
+
+ return ret;
+
+err_out:
+ if (rpdev->flags & SPECIFIC_DMA_POOL)
+ of_reserved_mem_device_release(dev);
+err_chl:
+ if (!IS_ERR(rpdev->rxdb_ch))
+ mbox_free_channel(rpdev->rxdb_ch);
+ if (!IS_ERR(rpdev->tx_ch))
+ mbox_free_channel(rpdev->tx_ch);
+ if (!IS_ERR(rpdev->rx_ch))
+ mbox_free_channel(rpdev->rx_ch);
+ return ret;
+}
+
+static struct platform_driver imx_rpmsg_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "imx-rpmsg",
+ .of_match_table = imx_rpmsg_dt_ids,
+ },
+ .probe = imx_rpmsg_probe,
+};
+
+static int __init imx_rpmsg_init(void)
+{
+ int ret;
+
+ ret = platform_driver_register(&imx_rpmsg_driver);
+ if (ret)
+ pr_err("Unable to initialize rpmsg driver\n");
+ else
+ pr_info("imx rpmsg driver is registered.\n");
+
+ return ret;
+}
+
+MODULE_DESCRIPTION("iMX remote processor messaging virtio device");
+MODULE_LICENSE("GPL v2");
+arch_initcall(imx_rpmsg_init);
diff --git a/drivers/rpmsg/imx_rpmsg_pingpong.c b/drivers/rpmsg/imx_rpmsg_pingpong.c
new file mode 100644
index 0000000..b028914
--- /dev/null
+++ b/drivers/rpmsg/imx_rpmsg_pingpong.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/virtio.h>
+#include <linux/rpmsg.h>
+
+#define MSG "hello world!"
+static unsigned int rpmsg_pingpong;
+
+static int rpmsg_pingpong_cb(struct rpmsg_device *rpdev, void *data, int len,
+ void *priv, u32 src)
+{
+ int err;
+
+ /* reply */
+ rpmsg_pingpong = *(unsigned int *)data;
+ pr_info("get %d (src: 0x%x)\n", rpmsg_pingpong, src);
+
+ /* pingpongs should not live forever */
+ if (rpmsg_pingpong > 100) {
+ dev_info(&rpdev->dev, "goodbye!\n");
+ return 0;
+ }
+ rpmsg_pingpong++;
+ err = rpmsg_sendto(rpdev->ept, (void *)(&rpmsg_pingpong), 4, src);
+
+ if (err)
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", err);
+
+ return err;
+}
+
+static int rpmsg_pingpong_probe(struct rpmsg_device *rpdev)
+{
+ int err;
+
+ dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
+ rpdev->src, rpdev->dst);
+
+ /*
+ * send a message to our remote processor, and tell remote
+ * processor about this channel
+ */
+ err = rpmsg_send(rpdev->ept, MSG, strlen(MSG));
+ if (err) {
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", err);
+ return err;
+ }
+
+ rpmsg_pingpong = 0;
+ err = rpmsg_sendto(rpdev->ept, (void *)(&rpmsg_pingpong),
+ 4, rpdev->dst);
+ if (err) {
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", err);
+ return err;
+ }
+
+ return 0;
+}
+
+static void rpmsg_pingpong_remove(struct rpmsg_device *rpdev)
+{
+ dev_info(&rpdev->dev, "rpmsg pingpong driver is removed\n");
+}
+
+static struct rpmsg_device_id rpmsg_driver_pingpong_id_table[] = {
+ { .name = "rpmsg-openamp-demo-channel" },
+ { .name = "rpmsg-openamp-demo-channel-1" },
+ { },
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_pingpong_id_table);
+
+static struct rpmsg_driver rpmsg_pingpong_driver = {
+ .drv.name = KBUILD_MODNAME,
+ .drv.owner = THIS_MODULE,
+ .id_table = rpmsg_driver_pingpong_id_table,
+ .probe = rpmsg_pingpong_probe,
+ .callback = rpmsg_pingpong_cb,
+ .remove = rpmsg_pingpong_remove,
+};
+
+static int __init init(void)
+{
+ return register_rpmsg_driver(&rpmsg_pingpong_driver);
+}
+
+static void __exit fini(void)
+{
+ unregister_rpmsg_driver(&rpmsg_pingpong_driver);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("iMX virtio remote processor messaging pingpong driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/imx_rpmsg.h b/include/linux/imx_rpmsg.h
new file mode 100644
index 0000000..e0d5e97
--- /dev/null
+++ b/include/linux/imx_rpmsg.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 NXP.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * @file linux/imx_rpmsg.h
+ *
+ * @brief Global header file for iMX RPMSG
+ *
+ * @ingroup RPMSG
+ */
+#ifndef __LINUX_IMX_RPMSG_H__
+#define __LINUX_IMX_RPMSG_H__
+
+/* Category define */
+#define IMX_RMPSG_LIFECYCLE 1
+#define IMX_RPMSG_PMIC 2
+#define IMX_RPMSG_AUDIO 3
+#define IMX_RPMSG_KEY 4
+#define IMX_RPMSG_GPIO 5
+#define IMX_RPMSG_RTC 6
+#define IMX_RPMSG_SENSOR 7
+/* rpmsg version */
+#define IMX_RMPSG_MAJOR 1
+#define IMX_RMPSG_MINOR 0
+
+#define CIRC_ADD(idx, size, value) (((idx) + (value)) & ((size) - 1))
+
+struct imx_rpmsg_head {
+ u8 cate;
+ u8 major;
+ u8 minor;
+ u8 type;
+ u8 cmd;
+ u8 reserved[5];
+} __packed;
+
+#endif /* __LINUX_IMX_RPMSG_H__ */
