static ssize_t tpm_write(struct file *file, const char __user *buf,
size_t size, loff_t *off)
{
struct file_priv *priv = file->private_data;
size_t in_size = size;
ssize_t out_size;
/* cannot perform a write until the read has cleared
either via tpm_read or a user_read_timer timeout.
This also prevents splitted buffered writes from blocking here.
*/
if (atomic_read(&priv->data_pending) != 0)
return -EBUSY;
if (in_size > TPM_BUFSIZE)
return -E2BIG;
mutex_lock(&priv->buffer_mutex);
if (copy_from_user
(priv->data_buffer, (void __user *) buf, in_size)) {
mutex_unlock(&priv->buffer_mutex);
return -EFAULT;
}
/* atomic tpm command send and result receive. We only hold the ops
* lock during this period so that the tpm can be unregistered even if
* the char dev is held open.
*/
if (tpm_try_get_ops(priv->chip)) {
mutex_unlock(&priv->buffer_mutex);
return -EPIPE;
}
out_size = tpm_transmit(priv->chip, priv->data_buffer,
sizeof(priv->data_buffer));
tpm_put_ops(priv->chip);
if (out_size < 0) {
mutex_unlock(&priv->buffer_mutex);
return out_size;
}
atomic_set(&priv->data_pending, out_size);
mutex_unlock(&priv->buffer_mutex);
/* Set a timeout by which the reader must come claim the result */
mod_timer(&priv->user_read_timer, jiffies + (60 * HZ));
return in_size;
}
ssize_t tpm_common_write(struct file *file, const char __user *buf,
size_t size, loff_t *off)
{
struct file_priv *priv = file->private_data;
int ret = 0;
if (size > TPM_BUFSIZE)
return -E2BIG;
mutex_lock(&priv->buffer_mutex);
/* Cannot perform a write until the read has cleared either via
* tpm_read or a user_read_timer timeout. This also prevents split
* buffered writes from blocking here.
*/
if ((!priv->response_read && priv->response_length) ||
priv->command_enqueued) {
ret = -EBUSY;
goto out;
}
if (copy_from_user(priv->data_buffer, buf, size)) {
ret = -EFAULT;
goto out;
}
if (size < 6 ||
size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
ret = -EINVAL;
goto out;
}
/* atomic tpm command send and result receive. We only hold the ops
* lock during this period so that the tpm can be unregistered even if
* the char dev is held open.
*/
if (tpm_try_get_ops(priv->chip)) {
ret = -EPIPE;
goto out;
}
priv->response_length = 0;
priv->response_read = false;
*off = 0;
/*
* If in nonblocking mode schedule an async job to send
* the command return the size.
* In case of error the err code will be returned in
* the subsequent read call.
*/
if (file->f_flags & O_NONBLOCK) {
priv->command_enqueued = true;
queue_work(tpm_dev_wq, &priv->async_work);
mutex_unlock(&priv->buffer_mutex);
return size;
}
ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer));
tpm_put_ops(priv->chip);
if (ret > 0) {
priv->response_length = ret;
mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
ret = size;
}
out:
mutex_unlock(&priv->buffer_mutex);
return ret;
}