/**
* mei_read - the read function.
*
* @file: pointer to file structure
* @ubuf: pointer to user buffer
* @length: buffer length
* @offset: data offset in buffer
*
* Return: >=0 data length on success , <0 on error
*/
static ssize_t mei_read(struct file *file, char __user *ubuf,
size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
struct mei_device *dev;
struct mei_cl_cb *cb = NULL;
int rets;
int err;
if (WARN_ON(!cl || !cl->dev))
return -ENODEV;
dev = cl->dev;
mutex_lock(&dev->device_lock);
if (dev->dev_state != MEI_DEV_ENABLED) {
rets = -ENODEV;
goto out;
}
if (length == 0) {
rets = 0;
goto out;
}
if (ubuf == NULL) {
rets = -EMSGSIZE;
goto out;
}
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
}
cb = mei_cl_read_cb(cl, file);
if (cb)
goto copy_buffer;
if (*offset > 0)
*offset = 0;
err = mei_cl_read_start(cl, length, file);
if (err && err != -EBUSY) {
cl_dbg(dev, cl, "mei start read failure status = %d\n", err);
rets = err;
goto out;
}
if (list_empty(&cl->rd_completed) && !waitqueue_active(&cl->rx_wait)) {
if (file->f_flags & O_NONBLOCK) {
rets = -EAGAIN;
goto out;
}
mutex_unlock(&dev->device_lock);
if (wait_event_interruptible(cl->rx_wait,
(!list_empty(&cl->rd_completed)) ||
(!mei_cl_is_connected(cl)))) {
if (signal_pending(current))
return -EINTR;
return -ERESTARTSYS;
}
mutex_lock(&dev->device_lock);
if (!mei_cl_is_connected(cl)) {
rets = -EBUSY;
goto out;
}
}
cb = mei_cl_read_cb(cl, file);
if (!cb) {
rets = 0;
goto out;
}
copy_buffer:
/* now copy the data to user space */
if (cb->status) {
rets = cb->status;
cl_dbg(dev, cl, "read operation failed %d\n", rets);
goto free;
}
cl_dbg(dev, cl, "buf.size = %zu buf.idx = %zu offset = %lld\n",
cb->buf.size, cb->buf_idx, *offset);
if (*offset >= cb->buf_idx) {
rets = 0;
goto free;
}
/* length is being truncated to PAGE_SIZE,
* however buf_idx may point beyond that */
length = min_t(size_t, length, cb->buf_idx - *offset);
if (copy_to_user(ubuf, cb->buf.data + *offset, length)) {
dev_dbg(dev->dev, "failed to copy data to userland\n");
rets = -EFAULT;
goto free;
}
rets = length;
*offset += length;
/* not all data was read, keep the cb */
if (*offset < cb->buf_idx)
goto out;
free:
mei_io_cb_free(cb);
*offset = 0;
out:
cl_dbg(dev, cl, "end mei read rets = %d\n", rets);
mutex_unlock(&dev->device_lock);
return rets;
}
/**
* mei_read - the read function.
*
* @file: pointer to file structure
* @ubuf: pointer to user buffer
* @length: buffer length
* @offset: data offset in buffer
*
* returns >=0 data length on success , <0 on error
*/
static ssize_t mei_read(struct file *file, char __user *ubuf,
size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
struct mei_cl_cb *cb_pos = NULL;
struct mei_cl_cb *cb = NULL;
struct mei_device *dev;
int rets;
int err;
if (WARN_ON(!cl || !cl->dev))
return -ENODEV;
dev = cl->dev;
mutex_lock(&dev->device_lock);
if (dev->dev_state != MEI_DEV_ENABLED) {
rets = -ENODEV;
goto out;
}
if (length == 0) {
rets = 0;
goto out;
}
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
}
if (cl->read_cb) {
cb = cl->read_cb;
/* read what left */
if (cb->buf_idx > *offset)
goto copy_buffer;
/* offset is beyond buf_idx we have no more data return 0 */
if (cb->buf_idx > 0 && cb->buf_idx <= *offset) {
rets = 0;
goto free;
}
/* Offset needs to be cleaned for contiguous reads*/
if (cb->buf_idx == 0 && *offset > 0)
*offset = 0;
} else if (*offset > 0) {
*offset = 0;
}
err = mei_cl_read_start(cl, length);
if (err && err != -EBUSY) {
dev_dbg(&dev->pdev->dev,
"mei start read failure with status = %d\n", err);
rets = err;
goto out;
}
if (MEI_READ_COMPLETE != cl->reading_state &&
!waitqueue_active(&cl->rx_wait)) {
if (file->f_flags & O_NONBLOCK) {
rets = -EAGAIN;
goto out;
}
mutex_unlock(&dev->device_lock);
if (wait_event_interruptible(cl->rx_wait,
MEI_READ_COMPLETE == cl->reading_state ||
mei_cl_is_transitioning(cl))) {
if (signal_pending(current))
return -EINTR;
return -ERESTARTSYS;
}
mutex_lock(&dev->device_lock);
if (mei_cl_is_transitioning(cl)) {
rets = -EBUSY;
goto out;
}
}
cb = cl->read_cb;
if (!cb) {
rets = -ENODEV;
goto out;
}
if (cl->reading_state != MEI_READ_COMPLETE) {
rets = 0;
goto out;
}
/* now copy the data to user space */
copy_buffer:
dev_dbg(&dev->pdev->dev, "buf.size = %d buf.idx= %ld\n",
cb->response_buffer.size, cb->buf_idx);
if (length == 0 || ubuf == NULL || *offset > cb->buf_idx) {
rets = -EMSGSIZE;
goto free;
}
/* length is being truncated to PAGE_SIZE,
* however buf_idx may point beyond that */
length = min_t(size_t, length, cb->buf_idx - *offset);
if (copy_to_user(ubuf, cb->response_buffer.data + *offset, length)) {
dev_dbg(&dev->pdev->dev, "failed to copy data to userland\n");
rets = -EFAULT;
goto free;
}
rets = length;
*offset += length;
if ((unsigned long)*offset < cb->buf_idx)
goto out;
free:
cb_pos = mei_cl_find_read_cb(cl);
/* Remove entry from read list */
if (cb_pos)
list_del(&cb_pos->list);
mei_io_cb_free(cb);
cl->reading_state = MEI_IDLE;
cl->read_cb = NULL;
out:
dev_dbg(&dev->pdev->dev, "end mei read rets= %d\n", rets);
mutex_unlock(&dev->device_lock);
return rets;
}
/**
* mei_read - the read function.
*
* @file: pointer to file structure
* @ubuf: pointer to user buffer
* @length: buffer length
* @offset: data offset in buffer
*
* returns >=0 data length on success , <0 on error
*/
static ssize_t mei_read(struct file *file, char __user *ubuf,
size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
struct mei_cl_cb *cb_pos = NULL;
struct mei_cl_cb *cb = NULL;
struct mei_device *dev;
int i;
int rets;
int err;
if (WARN_ON(!cl || !cl->dev))
return -ENODEV;
dev = cl->dev;
mutex_lock(&dev->device_lock);
if (dev->dev_state != MEI_DEV_ENABLED) {
rets = -ENODEV;
goto out;
}
if ((cl->sm_state & MEI_WD_STATE_INDEPENDENCE_MSG_SENT) == 0) {
/* Do not allow to read watchdog client */
i = mei_me_cl_by_uuid(dev, &mei_wd_guid);
if (i >= 0) {
struct mei_me_client *me_client = &dev->me_clients[i];
if (cl->me_client_id == me_client->client_id) {
rets = -EBADF;
goto out;
}
}
} else {
cl->sm_state &= ~MEI_WD_STATE_INDEPENDENCE_MSG_SENT;
}
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
}
if (cl->read_cb && cl->read_cb->buf_idx > *offset) {
cb = cl->read_cb;
goto copy_buffer;
} else if (cl->read_cb && cl->read_cb->buf_idx > 0 &&
cl->read_cb->buf_idx <= *offset) {
cb = cl->read_cb;
rets = 0;
goto free;
} else if ((!cl->read_cb || !cl->read_cb->buf_idx) && *offset > 0) {
/*Offset needs to be cleaned for contiguous reads*/
*offset = 0;
rets = 0;
goto out;
}
err = mei_cl_read_start(cl, length);
if (err && err != -EBUSY) {
dev_dbg(&dev->pdev->dev,
"mei start read failure with status = %d\n", err);
rets = err;
goto out;
}
if (MEI_READ_COMPLETE != cl->reading_state &&
!waitqueue_active(&cl->rx_wait)) {
if (file->f_flags & O_NONBLOCK) {
rets = -EAGAIN;
goto out;
}
mutex_unlock(&dev->device_lock);
if (wait_event_interruptible(cl->rx_wait,
(MEI_READ_COMPLETE == cl->reading_state ||
MEI_FILE_INITIALIZING == cl->state ||
MEI_FILE_DISCONNECTED == cl->state ||
MEI_FILE_DISCONNECTING == cl->state))) {
if (signal_pending(current))
return -EINTR;
return -ERESTARTSYS;
}
mutex_lock(&dev->device_lock);
if (MEI_FILE_INITIALIZING == cl->state ||
MEI_FILE_DISCONNECTED == cl->state ||
MEI_FILE_DISCONNECTING == cl->state) {
rets = -EBUSY;
goto out;
}
}
cb = cl->read_cb;
if (!cb) {
rets = -ENODEV;
goto out;
}
if (cl->reading_state != MEI_READ_COMPLETE) {
rets = 0;
goto out;
}
/* now copy the data to user space */
copy_buffer:
dev_dbg(&dev->pdev->dev, "buf.size = %d buf.idx= %ld\n",
cb->response_buffer.size, cb->buf_idx);
if (length == 0 || ubuf == NULL || *offset > cb->buf_idx) {
rets = -EMSGSIZE;
goto free;
}
/* length is being truncated to PAGE_SIZE,
* however buf_idx may point beyond that */
length = min_t(size_t, length, cb->buf_idx - *offset);
if (copy_to_user(ubuf, cb->response_buffer.data + *offset, length)) {
rets = -EFAULT;
goto free;
}
rets = length;
*offset += length;
if ((unsigned long)*offset < cb->buf_idx)
goto out;
free:
cb_pos = mei_cl_find_read_cb(cl);
/* Remove entry from read list */
if (cb_pos)
list_del(&cb_pos->list);
mei_io_cb_free(cb);
cl->reading_state = MEI_IDLE;
cl->read_cb = NULL;
out:
dev_dbg(&dev->pdev->dev, "end mei read rets= %d\n", rets);
mutex_unlock(&dev->device_lock);
return rets;
}