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path: root/drivers/misc/mei/hw-virtio.c
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Diffstat (limited to 'drivers/misc/mei/hw-virtio.c')
-rw-r--r--drivers/misc/mei/hw-virtio.c874
1 files changed, 874 insertions, 0 deletions
diff --git a/drivers/misc/mei/hw-virtio.c b/drivers/misc/mei/hw-virtio.c
new file mode 100644
index 000000000000..899dc1c5e7ca
--- /dev/null
+++ b/drivers/misc/mei/hw-virtio.c
@@ -0,0 +1,874 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2018-2020, Intel Corporation.
+ */
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/scatterlist.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ids.h>
+#include <linux/atomic.h>
+
+#include "mei_dev.h"
+#include "hbm.h"
+#include "client.h"
+
+#define MEI_VIRTIO_RPM_TIMEOUT 500
+/* ACRN virtio device types */
+#ifndef VIRTIO_ID_MEI
+#define VIRTIO_ID_MEI 0xFFFE /* virtio mei */
+#endif
+
+/**
+ * struct mei_virtio_cfg - settings passed from the virtio backend
+ * @buf_depth: read buffer depth in slots (4bytes)
+ * @hw_ready: hw is ready for operation
+ * @host_reset: synchronize reset with virtio backend
+ * @reserved: reserved for alignment
+ * @fw_status: FW status
+ */
+struct mei_virtio_cfg {
+ u32 buf_depth;
+ u8 hw_ready;
+ u8 host_reset;
+ u8 reserved[2];
+ u32 fw_status[MEI_FW_STATUS_MAX];
+} __packed;
+
+struct mei_virtio_hw {
+ struct mei_device mdev;
+ char name[32];
+
+ struct virtqueue *in;
+ struct virtqueue *out;
+
+ bool host_ready;
+ struct work_struct intr_handler;
+
+ u32 *recv_buf;
+ u8 recv_rdy;
+ size_t recv_sz;
+ u32 recv_idx;
+ u32 recv_len;
+
+ /* send buffer */
+ atomic_t hbuf_ready;
+ const void *send_hdr;
+ const void *send_buf;
+
+ struct mei_virtio_cfg cfg;
+};
+
+#define to_virtio_hw(_dev) container_of(_dev, struct mei_virtio_hw, mdev)
+
+/**
+ * mei_virtio_fw_status() - read status register of mei
+ * @dev: mei device
+ * @fw_status: fw status register values
+ *
+ * Return: always 0
+ */
+static int mei_virtio_fw_status(struct mei_device *dev,
+ struct mei_fw_status *fw_status)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ fw_status->count = MEI_FW_STATUS_MAX;
+ virtio_cread_bytes(vdev, offsetof(struct mei_virtio_cfg, fw_status),
+ fw_status->status, sizeof(fw_status->status));
+ return 0;
+}
+
+/**
+ * mei_virtio_pg_state() - translate internal pg state
+ * to the mei power gating state
+ * There is no power management in ACRN mode always return OFF
+ * @dev: mei device
+ *
+ * Return:
+ * * MEI_PG_OFF - if aliveness is on (always)
+ * * MEI_PG_ON - (never)
+ */
+static inline enum mei_pg_state mei_virtio_pg_state(struct mei_device *dev)
+{
+ return MEI_PG_OFF;
+}
+
+/**
+ * mei_virtio_hw_config() - configure hw dependent settings
+ *
+ * @dev: mei device
+ *
+ * Return: always 0
+ */
+static int mei_virtio_hw_config(struct mei_device *dev)
+{
+ return 0;
+}
+
+/**
+ * mei_virtio_hbuf_empty_slots() - counts write empty slots.
+ * @dev: the device structure
+ *
+ * Return: always return frontend buf size if buffer is ready, 0 otherwise
+ */
+static int mei_virtio_hbuf_empty_slots(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ return (atomic_read(&hw->hbuf_ready) == 1) ? hw->cfg.buf_depth : 0;
+}
+
+/**
+ * mei_virtio_hbuf_is_ready() - checks if write buffer is ready
+ * @dev: the device structure
+ *
+ * Return: true if hbuf is ready
+ */
+static bool mei_virtio_hbuf_is_ready(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ return atomic_read(&hw->hbuf_ready) == 1;
+}
+
+/**
+ * mei_virtio_hbuf_max_depth() - returns depth of FE write buffer.
+ * @dev: the device structure
+ *
+ * Return: size of frontend write buffer in bytes
+ */
+static u32 mei_virtio_hbuf_depth(const struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ return hw->cfg.buf_depth;
+}
+
+/**
+ * mei_virtio_intr_clear() - clear and stop interrupts
+ * @dev: the device structure
+ */
+static void mei_virtio_intr_clear(struct mei_device *dev)
+{
+ /*
+ * In our virtio solution, there are two types of interrupts,
+ * vq interrupt and config change interrupt.
+ * 1) start/reset rely on virtio config changed interrupt;
+ * 2) send/recv rely on virtio virtqueue interrupts.
+ * They are all virtual interrupts. So, we don't have corresponding
+ * operation to do here.
+ */
+}
+
+/**
+ * mei_virtio_intr_enable() - enables mei BE virtqueues callbacks
+ * @dev: the device structure
+ */
+static void mei_virtio_intr_enable(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ virtio_config_enable(vdev);
+
+ virtqueue_enable_cb(hw->in);
+ virtqueue_enable_cb(hw->out);
+}
+
+/**
+ * mei_virtio_intr_disable() - disables mei BE virtqueues callbacks
+ *
+ * @dev: the device structure
+ */
+static void mei_virtio_intr_disable(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ virtio_config_disable(vdev);
+
+ virtqueue_disable_cb(hw->in);
+ virtqueue_disable_cb(hw->out);
+}
+
+/**
+ * mei_virtio_synchronize_irq() - wait for pending IRQ handlers for all
+ * virtqueue
+ * @dev: the device structure
+ */
+static void mei_virtio_synchronize_irq(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ /*
+ * Now, all IRQ handlers are converted to workqueue.
+ * Change synchronize irq to flush this work.
+ */
+ flush_work(&hw->intr_handler);
+}
+
+static void mei_virtio_free_outbufs(struct mei_virtio_hw *hw)
+{
+ kfree(hw->send_hdr);
+ kfree(hw->send_buf);
+ hw->send_hdr = NULL;
+ hw->send_buf = NULL;
+}
+
+/**
+ * mei_virtio_write_message() - writes a message to mei virtio back-end service.
+ * @dev: the device structure
+ * @hdr: mei header of message
+ * @hdr_len: header length
+ * @data: message payload will be written
+ * @data_len: message payload length
+ *
+ * Return:
+ * * 0: on success
+ * * -EIO: if write has failed
+ * * -ENOMEM: on memory allocation failure
+ */
+static int mei_virtio_write_message(struct mei_device *dev,
+ const void *hdr, size_t hdr_len,
+ const void *data, size_t data_len)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct scatterlist sg[2];
+ const void *hbuf, *dbuf;
+ int ret;
+
+ if (WARN_ON(!atomic_add_unless(&hw->hbuf_ready, -1, 0)))
+ return -EIO;
+
+ hbuf = kmemdup(hdr, hdr_len, GFP_KERNEL);
+ hw->send_hdr = hbuf;
+
+ dbuf = kmemdup(data, data_len, GFP_KERNEL);
+ hw->send_buf = dbuf;
+
+ if (!hbuf || !dbuf) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ sg_init_table(sg, 2);
+ sg_set_buf(&sg[0], hbuf, hdr_len);
+ sg_set_buf(&sg[1], dbuf, data_len);
+
+ ret = virtqueue_add_outbuf(hw->out, sg, 2, hw, GFP_KERNEL);
+ if (ret) {
+ dev_err(dev->dev, "failed to add outbuf\n");
+ goto fail;
+ }
+
+ virtqueue_kick(hw->out);
+ return 0;
+fail:
+
+ mei_virtio_free_outbufs(hw);
+
+ return ret;
+}
+
+/**
+ * mei_virtio_count_full_read_slots() - counts read full slots.
+ * @dev: the device structure
+ *
+ * Return: -EOVERFLOW if overflow, otherwise filled slots count
+ */
+static int mei_virtio_count_full_read_slots(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ if (hw->recv_idx > hw->recv_len)
+ return -EOVERFLOW;
+
+ return hw->recv_len - hw->recv_idx;
+}
+
+/**
+ * mei_virtio_read_hdr() - Reads 32bit dword from mei virtio receive buffer
+ *
+ * @dev: the device structure
+ *
+ * Return: 32bit dword of receive buffer (u32)
+ */
+static inline u32 mei_virtio_read_hdr(const struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ WARN_ON(hw->cfg.buf_depth < hw->recv_idx + 1);
+
+ return hw->recv_buf[hw->recv_idx++];
+}
+
+static int mei_virtio_read(struct mei_device *dev, unsigned char *buffer,
+ unsigned long len)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ u32 slots = mei_data2slots(len);
+
+ if (WARN_ON(hw->cfg.buf_depth < hw->recv_idx + slots))
+ return -EOVERFLOW;
+
+ /*
+ * Assumption: There is only one MEI message in recv_buf each time.
+ * Backend service need follow this rule too.
+ */
+ memcpy(buffer, hw->recv_buf + hw->recv_idx, len);
+ hw->recv_idx += slots;
+
+ return 0;
+}
+
+static bool mei_virtio_pg_is_enabled(struct mei_device *dev)
+{
+ return false;
+}
+
+static bool mei_virtio_pg_in_transition(struct mei_device *dev)
+{
+ return false;
+}
+
+static void mei_virtio_add_recv_buf(struct mei_virtio_hw *hw)
+{
+ struct scatterlist sg;
+
+ if (hw->recv_rdy) /* not needed */
+ return;
+
+ /* refill the recv_buf to IN virtqueue to get next message */
+ sg_init_one(&sg, hw->recv_buf, mei_slots2data(hw->cfg.buf_depth));
+ hw->recv_len = 0;
+ hw->recv_idx = 0;
+ hw->recv_rdy = 1;
+ virtqueue_add_inbuf(hw->in, &sg, 1, hw->recv_buf, GFP_KERNEL);
+ virtqueue_kick(hw->in);
+}
+
+/**
+ * mei_virtio_hw_is_ready() - check whether the BE(hw) has turned ready
+ * @dev: mei device
+ * Return: bool
+ */
+static bool mei_virtio_hw_is_ready(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ virtio_cread(vdev, struct mei_virtio_cfg,
+ hw_ready, &hw->cfg.hw_ready);
+
+ dev_dbg(dev->dev, "hw ready %d\n", hw->cfg.hw_ready);
+
+ return hw->cfg.hw_ready;
+}
+
+/**
+ * mei_virtio_hw_reset - resets virtio hw.
+ *
+ * @dev: the device structure
+ * @intr_enable: virtio use data/config callbacks
+ *
+ * Return: 0 on success an error code otherwise
+ */
+static int mei_virtio_hw_reset(struct mei_device *dev, bool intr_enable)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ dev_dbg(dev->dev, "hw reset\n");
+
+ dev->recvd_hw_ready = false;
+ hw->host_ready = false;
+ atomic_set(&hw->hbuf_ready, 0);
+ hw->recv_len = 0;
+ hw->recv_idx = 0;
+
+ hw->cfg.host_reset = 1;
+ virtio_cwrite(vdev, struct mei_virtio_cfg,
+ host_reset, &hw->cfg.host_reset);
+
+ mei_virtio_hw_is_ready(dev);
+
+ if (intr_enable)
+ mei_virtio_intr_enable(dev);
+
+ return 0;
+}
+
+/**
+ * mei_virtio_hw_reset_release() - release device from the reset
+ * @dev: the device structure
+ */
+static void mei_virtio_hw_reset_release(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ struct virtio_device *vdev = dev_to_virtio(dev->dev);
+
+ dev_dbg(dev->dev, "hw reset release\n");
+ hw->cfg.host_reset = 0;
+ virtio_cwrite(vdev, struct mei_virtio_cfg,
+ host_reset, &hw->cfg.host_reset);
+}
+
+/**
+ * mei_virtio_hw_ready_wait() - wait until the virtio(hw) has turned ready
+ * or timeout is reached
+ * @dev: mei device
+ *
+ * Return: 0 on success, error otherwise
+ */
+static int mei_virtio_hw_ready_wait(struct mei_device *dev)
+{
+ mutex_unlock(&dev->device_lock);
+ wait_event_timeout(dev->wait_hw_ready,
+ dev->recvd_hw_ready,
+ mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT));
+ mutex_lock(&dev->device_lock);
+ if (!dev->recvd_hw_ready) {
+ dev_err(dev->dev, "wait hw ready failed\n");
+ return -ETIMEDOUT;
+ }
+
+ dev->recvd_hw_ready = false;
+ return 0;
+}
+
+/**
+ * mei_virtio_hw_start() - hw start routine
+ * @dev: mei device
+ *
+ * Return: 0 on success, error otherwise
+ */
+static int mei_virtio_hw_start(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+ int ret;
+
+ dev_dbg(dev->dev, "hw start\n");
+ mei_virtio_hw_reset_release(dev);
+
+ ret = mei_virtio_hw_ready_wait(dev);
+ if (ret)
+ return ret;
+
+ mei_virtio_add_recv_buf(hw);
+ atomic_set(&hw->hbuf_ready, 1);
+ dev_dbg(dev->dev, "hw is ready\n");
+ hw->host_ready = true;
+
+ return 0;
+}
+
+/**
+ * mei_virtio_host_is_ready() - check whether the FE has turned ready
+ * @dev: mei device
+ *
+ * Return: bool
+ */
+static bool mei_virtio_host_is_ready(struct mei_device *dev)
+{
+ struct mei_virtio_hw *hw = to_virtio_hw(dev);
+
+ dev_dbg(dev->dev, "host ready %d\n", hw->host_ready);
+
+ return hw->host_ready;
+}
+
+/**
+ * mei_virtio_data_in() - The callback of recv virtqueue of virtio mei
+ * @vq: receiving virtqueue
+ */
+static void mei_virtio_data_in(struct virtqueue *vq)
+{
+ struct mei_virtio_hw *hw = vq->vdev->priv;
+
+ /* disable interrupts (enabled again from in the interrupt worker) */
+ virtqueue_disable_cb(hw->in);
+
+ schedule_work(&hw->intr_handler);
+}
+
+/**
+ * mei_virtio_data_out() - The callback of send virtqueue of virtio mei
+ * @vq: transmitting virtqueue
+ */
+static void mei_virtio_data_out(struct virtqueue *vq)
+{
+ struct mei_virtio_hw *hw = vq->vdev->priv;
+
+ schedule_work(&hw->intr_handler);
+}
+
+static void mei_virtio_intr_handler(struct work_struct *work)
+{
+ struct mei_virtio_hw *hw =
+ container_of(work, struct mei_virtio_hw, intr_handler);
+ struct mei_device *dev = &hw->mdev;
+ LIST_HEAD(complete_list);
+ s32 slots;
+ int rets = 0;
+ void *data;
+ unsigned int len;
+
+ mutex_lock(&dev->device_lock);
+
+ if (dev->dev_state == MEI_DEV_DISABLED) {
+ dev_warn(dev->dev, "Interrupt in disabled state.\n");
+ mei_virtio_intr_disable(dev);
+ goto end;
+ }
+
+ /* check if ME wants a reset */
+ if (!mei_hw_is_ready(dev) && dev->dev_state != MEI_DEV_RESETTING) {
+ dev_warn(dev->dev, "BE service not ready: resetting.\n");
+ schedule_work(&dev->reset_work);
+ goto end;
+ }
+
+ /* check if we need to start the dev */
+ if (!mei_host_is_ready(dev)) {
+ if (mei_hw_is_ready(dev)) {
+ dev_dbg(dev->dev, "we need to start the dev.\n");
+ dev->recvd_hw_ready = true;
+ wake_up(&dev->wait_hw_ready);
+ } else {
+ dev_warn(dev->dev, "Spurious Interrupt\n");
+ }
+ goto end;
+ }
+
+ /* read */
+ if (hw->recv_rdy) {
+ data = virtqueue_get_buf(hw->in, &len);
+ if (!data || !len) {
+ dev_dbg(dev->dev, "No data %d", len);
+ } else {
+ dev_dbg(dev->dev, "data_in %d\n", len);
+ WARN_ON(data != hw->recv_buf);
+ hw->recv_len = mei_data2slots(len);
+ hw->recv_rdy = 0;
+ }
+ }
+
+ /* write */
+ if (!atomic_read(&hw->hbuf_ready)) {
+ if (!virtqueue_get_buf(hw->out, &len)) {
+ dev_warn(dev->dev, "Failed to getbuf\n");
+ } else {
+ mei_virtio_free_outbufs(hw);
+ atomic_inc(&hw->hbuf_ready);
+ }
+ }
+
+ /* check slots available for reading */
+ slots = mei_count_full_read_slots(dev);
+ while (slots > 0) {
+ dev_dbg(dev->dev, "slots to read = %08x\n", slots);
+ rets = mei_irq_read_handler(dev, &complete_list, &slots);
+
+ if (rets &&
+ (dev->dev_state != MEI_DEV_RESETTING &&
+ dev->dev_state != MEI_DEV_POWER_DOWN)) {
+ dev_err(dev->dev, "mei_irq_read_handler ret = %d.\n",
+ rets);
+ schedule_work(&dev->reset_work);
+ goto end;
+ }
+ }
+
+ dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
+
+ mei_irq_write_handler(dev, &complete_list);
+
+ dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
+
+ mei_irq_compl_handler(dev, &complete_list);
+
+ mei_virtio_add_recv_buf(hw);
+
+end:
+ if (dev->dev_state != MEI_DEV_DISABLED) {
+ if (!virtqueue_enable_cb(hw->in))
+ schedule_work(&hw->intr_handler);
+ }
+
+ mutex_unlock(&dev->device_lock);
+}
+
+static void mei_virtio_config_changed(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw = vdev->priv;
+ struct mei_device *dev = &hw->mdev;
+
+ virtio_cread(vdev, struct mei_virtio_cfg,
+ hw_ready, &hw->cfg.hw_ready);
+
+ if (dev->dev_state == MEI_DEV_DISABLED) {
+ dev_dbg(dev->dev, "disabled state don't start\n");
+ return;
+ }
+
+ /* Run intr handler once to handle reset notify */
+ schedule_work(&hw->intr_handler);
+}
+
+static void mei_virtio_remove_vqs(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw = vdev->priv;
+
+ virtqueue_detach_unused_buf(hw->in);
+ hw->recv_len = 0;
+ hw->recv_idx = 0;
+ hw->recv_rdy = 0;
+
+ virtqueue_detach_unused_buf(hw->out);
+
+ mei_virtio_free_outbufs(hw);
+
+ vdev->config->del_vqs(vdev);
+}
+
+/*
+ * There are two virtqueues, one is for send and another is for recv.
+ */
+static int mei_virtio_init_vqs(struct mei_virtio_hw *hw,
+ struct virtio_device *vdev)
+{
+ struct virtqueue *vqs[2];
+
+ vq_callback_t *cbs[] = {
+ mei_virtio_data_in,
+ mei_virtio_data_out,
+ };
+ static const char * const names[] = {
+ "in",
+ "out",
+ };
+ int ret;
+
+ ret = virtio_find_vqs(vdev, 2, vqs, cbs, names, NULL);
+ if (ret)
+ return ret;
+
+ hw->in = vqs[0];
+ hw->out = vqs[1];
+
+ return 0;
+}
+
+static const struct mei_hw_ops mei_virtio_ops = {
+ .fw_status = mei_virtio_fw_status,
+ .pg_state = mei_virtio_pg_state,
+
+ .host_is_ready = mei_virtio_host_is_ready,
+
+ .hw_is_ready = mei_virtio_hw_is_ready,
+ .hw_reset = mei_virtio_hw_reset,
+ .hw_config = mei_virtio_hw_config,
+ .hw_start = mei_virtio_hw_start,
+
+ .pg_in_transition = mei_virtio_pg_in_transition,
+ .pg_is_enabled = mei_virtio_pg_is_enabled,
+
+ .intr_clear = mei_virtio_intr_clear,
+ .intr_enable = mei_virtio_intr_enable,
+ .intr_disable = mei_virtio_intr_disable,
+ .synchronize_irq = mei_virtio_synchronize_irq,
+
+ .hbuf_free_slots = mei_virtio_hbuf_empty_slots,
+ .hbuf_is_ready = mei_virtio_hbuf_is_ready,
+ .hbuf_depth = mei_virtio_hbuf_depth,
+
+ .write = mei_virtio_write_message,
+
+ .rdbuf_full_slots = mei_virtio_count_full_read_slots,
+ .read_hdr = mei_virtio_read_hdr,
+ .read = mei_virtio_read,
+};
+
+static int mei_virtio_probe(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw;
+ int ret;
+
+ hw = devm_kzalloc(&vdev->dev, sizeof(*hw), GFP_KERNEL);
+ if (!hw)
+ return -ENOMEM;
+
+ vdev->priv = hw;
+
+ INIT_WORK(&hw->intr_handler, mei_virtio_intr_handler);
+
+ ret = mei_virtio_init_vqs(hw, vdev);
+ if (ret)
+ goto vqs_failed;
+
+ virtio_cread(vdev, struct mei_virtio_cfg,
+ buf_depth, &hw->cfg.buf_depth);
+
+ hw->recv_buf = kzalloc(mei_slots2data(hw->cfg.buf_depth), GFP_KERNEL);
+ if (!hw->recv_buf) {
+ ret = -ENOMEM;
+ goto hbuf_failed;
+ }
+ atomic_set(&hw->hbuf_ready, 0);
+
+ virtio_device_ready(vdev);
+
+ mei_device_init(&hw->mdev, &vdev->dev, &mei_virtio_ops);
+
+ pm_runtime_get_noresume(&vdev->dev);
+ pm_runtime_set_active(&vdev->dev);
+ pm_runtime_enable(&vdev->dev);
+
+ ret = mei_start(&hw->mdev);
+ if (ret)
+ goto mei_start_failed;
+
+ pm_runtime_set_autosuspend_delay(&vdev->dev, MEI_VIRTIO_RPM_TIMEOUT);
+ pm_runtime_use_autosuspend(&vdev->dev);
+
+ ret = mei_register(&hw->mdev, &vdev->dev);
+ if (ret)
+ goto mei_failed;
+
+ pm_runtime_put(&vdev->dev);
+
+ return 0;
+
+mei_failed:
+ mei_stop(&hw->mdev);
+mei_start_failed:
+ mei_cancel_work(&hw->mdev);
+ mei_disable_interrupts(&hw->mdev);
+ kfree(hw->recv_buf);
+hbuf_failed:
+ vdev->config->del_vqs(vdev);
+vqs_failed:
+ return ret;
+}
+
+static int __maybe_unused mei_virtio_pm_runtime_idle(struct device *device)
+{
+ struct virtio_device *vdev = dev_to_virtio(device);
+ struct mei_virtio_hw *hw = vdev->priv;
+
+ dev_dbg(&vdev->dev, "rpm: mei_virtio : runtime_idle\n");
+
+ if (!hw)
+ return -ENODEV;
+
+ if (mei_write_is_idle(&hw->mdev))
+ pm_runtime_autosuspend(device);
+
+ return -EBUSY;
+}
+
+static int __maybe_unused mei_virtio_pm_runtime_suspend(struct device *device)
+{
+ return 0;
+}
+
+static int __maybe_unused mei_virtio_pm_runtime_resume(struct device *device)
+{
+ return 0;
+}
+
+static int __maybe_unused mei_virtio_freeze(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw = vdev->priv;
+
+ dev_dbg(&vdev->dev, "freeze\n");
+
+ if (!hw)
+ return -ENODEV;
+
+ mei_stop(&hw->mdev);
+ mei_disable_interrupts(&hw->mdev);
+ cancel_work_sync(&hw->intr_handler);
+ vdev->config->reset(vdev);
+ mei_virtio_remove_vqs(vdev);
+
+ return 0;
+}
+
+static int __maybe_unused mei_virtio_restore(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw = vdev->priv;
+ int ret;
+
+ dev_dbg(&vdev->dev, "restore\n");
+
+ if (!hw)
+ return -ENODEV;
+
+ ret = mei_virtio_init_vqs(hw, vdev);
+ if (ret)
+ return ret;
+
+ virtio_device_ready(vdev);
+
+ ret = mei_restart(&hw->mdev);
+ if (ret)
+ return ret;
+
+ /* Start timer if stopped in suspend */
+ schedule_delayed_work(&hw->mdev.timer_work, HZ);
+
+ return 0;
+}
+
+static const struct dev_pm_ops mei_virtio_pm_ops = {
+ SET_RUNTIME_PM_OPS(mei_virtio_pm_runtime_suspend,
+ mei_virtio_pm_runtime_resume,
+ mei_virtio_pm_runtime_idle)
+};
+
+static void mei_virtio_remove(struct virtio_device *vdev)
+{
+ struct mei_virtio_hw *hw = vdev->priv;
+
+ mei_stop(&hw->mdev);
+ mei_disable_interrupts(&hw->mdev);
+ cancel_work_sync(&hw->intr_handler);
+ mei_deregister(&hw->mdev);
+ vdev->config->reset(vdev);
+ mei_virtio_remove_vqs(vdev);
+ kfree(hw->recv_buf);
+ pm_runtime_disable(&vdev->dev);
+}
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_MEI, VIRTIO_DEV_ANY_ID },
+ { }
+};
+
+static struct virtio_driver mei_virtio_driver = {
+ .id_table = id_table,
+ .probe = mei_virtio_probe,
+ .remove = mei_virtio_remove,
+ .config_changed = mei_virtio_config_changed,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .owner = THIS_MODULE,
+ .pm = &mei_virtio_pm_ops,
+ },
+#ifdef CONFIG_PM_SLEEP
+ .freeze = mei_virtio_freeze,
+ .restore = mei_virtio_restore,
+#endif
+};
+
+module_virtio_driver(mei_virtio_driver);
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio MEI frontend driver");
+MODULE_LICENSE("GPL v2");