| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #ifndef __MAILBOX_CONTROLLER_H |
| #define __MAILBOX_CONTROLLER_H |
| |
| #include <linux/of.h> |
| #include <linux/types.h> |
| #include <linux/hrtimer.h> |
| #include <linux/device.h> |
| #include <linux/completion.h> |
| |
| struct mbox_chan; |
| |
| /** |
| * struct mbox_chan_ops - methods to control mailbox channels |
| * @send_data: The API asks the MBOX controller driver, in atomic |
| * context try to transmit a message on the bus. Returns 0 if |
| * data is accepted for transmission, -EBUSY while rejecting |
| * if the remote hasn't yet read the last data sent. Actual |
| * 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 |
| * block. After this call the Controller must forward any |
| * data received on the chan by calling mbox_chan_received_data. |
| * The controller may do stuff that need to sleep. |
| * @shutdown: Called when a client relinquishes control of a chan. |
| * This call may block too. The controller must not forward |
| * any received data anymore. |
| * The controller may do stuff that need to sleep. |
| * @last_tx_done: If the controller sets 'txdone_poll', the API calls |
| * this to poll status of last TX. The controller must |
| * give priority to IRQ method over polling and never |
| * set both txdone_poll and txdone_irq. Only in polling |
| * mode 'send_data' is expected to return -EBUSY. |
| * The controller may do stuff that need to sleep/block. |
| * Used only if txdone_poll:=true && txdone_irq:=false |
| * @peek_data: Atomic check for any received data. Return true if controller |
| * has some data to push to the client. False otherwise. |
| */ |
| 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); |
| bool (*peek_data)(struct mbox_chan *chan); |
| }; |
| |
| /** |
| * struct mbox_controller - Controller of a class of communication channels |
| * @dev: Device backing this controller |
| * @ops: Operators that work on each communication chan |
| * @chans: Array of channels |
| * @num_chans: Number of channels in the 'chans' array. |
| * @txdone_irq: Indicates if the controller can report to API when |
| * the last transmitted data was read by the remote. |
| * Eg, if it has some TX ACK irq. |
| * @txdone_poll: If the controller can read but not report the TX |
| * done. Ex, some register shows the TX status but |
| * no interrupt rises. Ignored if 'txdone_irq' is set. |
| * @txpoll_period: If 'txdone_poll' is in effect, the API polls for |
| * last TX's status after these many millisecs |
| * @of_xlate: Controller driver specific mapping of channel via DT |
| * @poll_hrt: API private. hrtimer used to poll for TXDONE on all |
| * channels. |
| * @node: API private. To hook into list of controllers. |
| */ |
| struct mbox_controller { |
| struct device *dev; |
| const struct mbox_chan_ops *ops; |
| struct mbox_chan *chans; |
| int num_chans; |
| bool txdone_irq; |
| bool txdone_poll; |
| unsigned txpoll_period; |
| struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox, |
| const struct of_phandle_args *sp); |
| /* Internal to API */ |
| struct hrtimer poll_hrt; |
| struct list_head node; |
| }; |
| |
| /* |
| * The length of circular buffer for queuing messages from a client. |
| * 'msg_count' tracks the number of buffered messages while 'msg_free' |
| * is the index where the next message would be buffered. |
| * We shouldn't need it too big because every transfer is interrupt |
| * triggered and if we have lots of data to transfer, the interrupt |
| * latencies are going to be the bottleneck, not the buffer length. |
| * Besides, mbox_send_message could be called from atomic context and |
| * the client could also queue another message from the notifier 'tx_done' |
| * of the last transfer done. |
| * REVISIT: If too many platforms see the "Try increasing MBOX_TX_QUEUE_LEN" |
| * print, it needs to be taken from config option or somesuch. |
| */ |
| #define MBOX_TX_QUEUE_LEN 20 |
| |
| /** |
| * struct mbox_chan - s/w representation of a communication chan |
| * @mbox: Pointer to the parent/provider of this channel |
| * @txdone_method: Way to detect TXDone chosen by the API |
| * @cl: Pointer to the current owner of this channel |
| * @tx_complete: Transmission completion |
| * @active_req: Currently active request hook |
| * @msg_count: No. of mssg currently queued |
| * @msg_free: Index of next available mssg slot |
| * @msg_data: Hook for data packet |
| * @lock: Serialise access to the channel |
| * @con_priv: Hook for controller driver to attach private data |
| */ |
| struct mbox_chan { |
| struct mbox_controller *mbox; |
| unsigned txdone_method; |
| struct mbox_client *cl; |
| struct completion tx_complete; |
| void *active_req; |
| unsigned msg_count, msg_free; |
| void *msg_data[MBOX_TX_QUEUE_LEN]; |
| spinlock_t lock; /* Serialise access to the channel */ |
| void *con_priv; |
| }; |
| |
| int mbox_controller_register(struct mbox_controller *mbox); /* can sleep */ |
| void mbox_controller_unregister(struct mbox_controller *mbox); /* can sleep */ |
| void mbox_chan_received_data(struct mbox_chan *chan, void *data); /* atomic */ |
| void mbox_chan_txdone(struct mbox_chan *chan, int r); /* atomic */ |
| |
| int devm_mbox_controller_register(struct device *dev, |
| struct mbox_controller *mbox); |
| void devm_mbox_controller_unregister(struct device *dev, |
| struct mbox_controller *mbox); |
| |
| #endif /* __MAILBOX_CONTROLLER_H */ |