diff options
| -rw-r--r-- | drivers/mailbox/mailbox.c | 28 | ||||
| -rw-r--r-- | include/linux/mailbox_client.h | 1 | ||||
| -rw-r--r-- | include/linux/mailbox_controller.h | 4 |
3 files changed, 33 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c index 08ce9a1ab53a..6abb35ff49fa 100644 --- a/drivers/mailbox/mailbox.c +++ b/drivers/mailbox/mailbox.c @@ -284,6 +284,34 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg) EXPORT_SYMBOL_GPL(mbox_send_message); /** + * mbox_flush - flush a mailbox channel + * @chan: mailbox channel to flush + * @timeout: time, in milliseconds, to allow the flush operation to succeed + * + * Mailbox controllers that need to work in atomic context can implement the + * ->flush() callback to busy loop until a transmission has been completed. + * The implementation must call mbox_chan_txdone() upon success. Clients can + * call the mbox_flush() function at any time after mbox_send_message() to + * flush the transmission. After the function returns success, the mailbox + * transmission is guaranteed to have completed. + * + * Returns: 0 on success or a negative error code on failure. + */ +int mbox_flush(struct mbox_chan *chan, unsigned long timeout) +{ + int ret; + + if (!chan->mbox->ops->flush) + return -ENOTSUPP; + + ret = chan->mbox->ops->flush(chan, timeout); + if (ret < 0) + tx_tick(chan, ret); + + return ret; +} + +/** * mbox_request_channel - Request a mailbox channel. * @cl: Identity of the client requesting the channel. * @index: Index of mailbox specifier in 'mboxes' property. diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h index 44348710953f..faa7da3c9c8b 100644 --- a/include/linux/mailbox_client.h +++ b/include/linux/mailbox_client.h @@ -44,6 +44,7 @@ struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl, const char *name); struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index); int mbox_send_message(struct mbox_chan *chan, void *mssg); +int mbox_flush(struct mbox_chan *chan, unsigned long timeout); void mbox_client_txdone(struct mbox_chan *chan, int r); /* atomic */ bool mbox_client_peek_data(struct mbox_chan *chan); /* atomic */ void mbox_free_channel(struct mbox_chan *chan); /* may sleep */ diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h index 9b0b21207345..4994a438444c 100644 --- a/include/linux/mailbox_controller.h +++ b/include/linux/mailbox_controller.h @@ -24,6 +24,9 @@ struct mbox_chan; * transmission of data is reported by the controller via * mbox_chan_txdone (if it has some TX ACK irq). It must not * sleep. + * @flush: Called when a client requests transmissions to be blocking but + * the context doesn't allow sleeping. Typically the controller + * will implement a busy loop waiting for the data to flush out. * @startup: Called when a client requests the chan. The controller * could ask clients for additional parameters of communication * to be provided via client's chan_data. This call may @@ -46,6 +49,7 @@ struct mbox_chan; */ struct mbox_chan_ops { int (*send_data)(struct mbox_chan *chan, void *data); + int (*flush)(struct mbox_chan *chan, unsigned long timeout); int (*startup)(struct mbox_chan *chan); void (*shutdown)(struct mbox_chan *chan); bool (*last_tx_done)(struct mbox_chan *chan); |