/* 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 { … }; /** * 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 { … }; /* * 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 … /** * 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 { … }; 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 */
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