/**
* mei_amthif_read - read data from AMTHIF client
*
* @dev: the device structure
* @file: pointer to file object
* @ubuf: pointer to user data in user space
* @length: data length to read
* @offset: data read offset
*
* Locking: called under "dev->device_lock" lock
*
* Return:
* returned data length on success,
* zero if no data to read,
* negative on failure.
*/
int mei_amthif_read(struct mei_device *dev, struct file *file,
char __user *ubuf, size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
struct mei_cl_cb *cb;
int rets;
int wait_ret;
dev_dbg(dev->dev, "checking amthif data\n");
cb = mei_cl_read_cb(cl, file);
/* Check for if we can block or not*/
if (cb == NULL && file->f_flags & O_NONBLOCK)
return -EAGAIN;
dev_dbg(dev->dev, "waiting for amthif data\n");
while (cb == NULL) {
/* unlock the Mutex */
mutex_unlock(&dev->device_lock);
wait_ret = wait_event_interruptible(cl->rx_wait,
!list_empty(&cl->rd_completed) ||
!mei_cl_is_connected(cl));
/* Locking again the Mutex */
mutex_lock(&dev->device_lock);
if (wait_ret)
return -ERESTARTSYS;
if (!mei_cl_is_connected(cl)) {
rets = -ENODEV;
goto out;
}
cb = mei_cl_read_cb(cl, file);
}
if (cb->status) {
rets = cb->status;
dev_dbg(dev->dev, "read operation failed %d\n", rets);
goto free;
}
dev_dbg(dev->dev, "Got amthif data\n");
/* if the whole message will fit remove it from the list */
if (cb->buf_idx >= *offset && length >= (cb->buf_idx - *offset))
list_del_init(&cb->list);
else if (cb->buf_idx <= *offset) {
/* end of the message has been reached */
list_del_init(&cb->list);
rets = 0;
goto free;
}
/* else means that not full buffer will be read and do not
* remove message from deletion list
*/
dev_dbg(dev->dev, "amthif cb->buf.size - %zu cb->buf_idx - %zu\n",
cb->buf.size, cb->buf_idx);
/* length is being truncated to PAGE_SIZE, however,
* the buf_idx may point beyond */
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;
} else {
rets = length;
if ((*offset + length) < cb->buf_idx) {
*offset += length;
goto out;
}
}
free:
dev_dbg(dev->dev, "free amthif cb memory.\n");
*offset = 0;
mei_io_cb_free(cb);
out:
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
*
* 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;
bool nonblock = !!(file->f_flags & O_NONBLOCK);
int rets;
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;
}
cb = mei_cl_read_cb(cl, file);
if (cb)
goto copy_buffer;
if (*offset > 0)
*offset = 0;
rets = mei_cl_read_start(cl, length, file);
if (rets && rets != -EBUSY) {
cl_dbg(dev, cl, "mei start read failure status = %d\n", rets);
goto out;
}
if (nonblock) {
rets = -EAGAIN;
goto out;
}
if (rets == -EBUSY &&
!mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, file)) {
rets = -ENOMEM;
goto out;
}
do {
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 = -ENODEV;
goto out;
}
cb = mei_cl_read_cb(cl, file);
} while (!cb);
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
*
* 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 (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
}
cb = mei_cl_read_cb(cl, file);
if (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, 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) {
if (mei_cl_is_fixed_address(cl) && dev->allow_fixed_address) {
cb = mei_cl_read_cb(cl, NULL);
if (cb)
goto copy_buffer;
}
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 = %d buf.idx = %ld\n",
cb->buf.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->buf.data + *offset, length)) {
dev_dbg(dev->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:
mei_io_cb_free(cb);
out:
cl_dbg(dev, cl, "end mei read rets = %d\n", rets);
mutex_unlock(&dev->device_lock);
return rets;
}
