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616 lines
16 KiB
616 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Mailbox: Common code for Mailbox controllers and users |
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* |
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* Copyright (C) 2013-2014 Linaro Ltd. |
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* Author: Jassi Brar <[email protected]> |
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*/ |
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#include <linux/interrupt.h> |
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#include <linux/spinlock.h> |
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#include <linux/mutex.h> |
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#include <linux/delay.h> |
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#include <linux/slab.h> |
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#include <linux/err.h> |
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#include <linux/module.h> |
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#include <linux/device.h> |
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#include <linux/bitops.h> |
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#include <linux/mailbox_client.h> |
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#include <linux/mailbox_controller.h> |
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#include "mailbox.h" |
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static LIST_HEAD(mbox_cons); |
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static DEFINE_MUTEX(con_mutex); |
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static int add_to_rbuf(struct mbox_chan *chan, void *mssg) |
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{ |
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int idx; |
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unsigned long flags; |
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spin_lock_irqsave(&chan->lock, flags); |
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/* See if there is any space left */ |
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if (chan->msg_count == MBOX_TX_QUEUE_LEN) { |
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spin_unlock_irqrestore(&chan->lock, flags); |
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return -ENOBUFS; |
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} |
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idx = chan->msg_free; |
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chan->msg_data[idx] = mssg; |
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chan->msg_count++; |
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if (idx == MBOX_TX_QUEUE_LEN - 1) |
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chan->msg_free = 0; |
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else |
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chan->msg_free++; |
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spin_unlock_irqrestore(&chan->lock, flags); |
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return idx; |
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} |
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static void msg_submit(struct mbox_chan *chan) |
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{ |
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unsigned count, idx; |
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unsigned long flags; |
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void *data; |
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int err = -EBUSY; |
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spin_lock_irqsave(&chan->lock, flags); |
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if (!chan->msg_count || chan->active_req) |
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goto exit; |
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count = chan->msg_count; |
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idx = chan->msg_free; |
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if (idx >= count) |
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idx -= count; |
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else |
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idx += MBOX_TX_QUEUE_LEN - count; |
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data = chan->msg_data[idx]; |
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if (chan->cl->tx_prepare) |
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chan->cl->tx_prepare(chan->cl, data); |
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/* Try to submit a message to the MBOX controller */ |
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err = chan->mbox->ops->send_data(chan, data); |
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if (!err) { |
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chan->active_req = data; |
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chan->msg_count--; |
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} |
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exit: |
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spin_unlock_irqrestore(&chan->lock, flags); |
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if (!err && (chan->txdone_method & TXDONE_BY_POLL)) |
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/* kick start the timer immediately to avoid delays */ |
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hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); |
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} |
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static void tx_tick(struct mbox_chan *chan, int r) |
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{ |
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unsigned long flags; |
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void *mssg; |
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spin_lock_irqsave(&chan->lock, flags); |
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mssg = chan->active_req; |
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chan->active_req = NULL; |
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spin_unlock_irqrestore(&chan->lock, flags); |
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/* Submit next message */ |
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msg_submit(chan); |
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if (!mssg) |
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return; |
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/* Notify the client */ |
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if (chan->cl->tx_done) |
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chan->cl->tx_done(chan->cl, mssg, r); |
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if (r != -ETIME && chan->cl->tx_block) |
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complete(&chan->tx_complete); |
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} |
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static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer) |
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{ |
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struct mbox_controller *mbox = |
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container_of(hrtimer, struct mbox_controller, poll_hrt); |
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bool txdone, resched = false; |
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int i; |
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for (i = 0; i < mbox->num_chans; i++) { |
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struct mbox_chan *chan = &mbox->chans[i]; |
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if (chan->active_req && chan->cl) { |
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txdone = chan->mbox->ops->last_tx_done(chan); |
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if (txdone) |
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tx_tick(chan, 0); |
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else |
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resched = true; |
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} |
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} |
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if (resched) { |
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hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period)); |
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return HRTIMER_RESTART; |
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} |
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return HRTIMER_NORESTART; |
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} |
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/** |
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* mbox_chan_received_data - A way for controller driver to push data |
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* received from remote to the upper layer. |
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* @chan: Pointer to the mailbox channel on which RX happened. |
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* @mssg: Client specific message typecasted as void * |
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* |
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* After startup and before shutdown any data received on the chan |
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* is passed on to the API via atomic mbox_chan_received_data(). |
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* The controller should ACK the RX only after this call returns. |
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*/ |
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void mbox_chan_received_data(struct mbox_chan *chan, void *mssg) |
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{ |
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/* No buffering the received data */ |
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if (chan->cl->rx_callback) |
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chan->cl->rx_callback(chan->cl, mssg); |
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} |
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EXPORT_SYMBOL_GPL(mbox_chan_received_data); |
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/** |
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* mbox_chan_txdone - A way for controller driver to notify the |
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* framework that the last TX has completed. |
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* @chan: Pointer to the mailbox chan on which TX happened. |
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* @r: Status of last TX - OK or ERROR |
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* |
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* The controller that has IRQ for TX ACK calls this atomic API |
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* to tick the TX state machine. It works only if txdone_irq |
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* is set by the controller. |
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*/ |
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void mbox_chan_txdone(struct mbox_chan *chan, int r) |
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{ |
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if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) { |
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dev_err(chan->mbox->dev, |
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"Controller can't run the TX ticker\n"); |
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return; |
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} |
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tx_tick(chan, r); |
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} |
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EXPORT_SYMBOL_GPL(mbox_chan_txdone); |
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/** |
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* mbox_client_txdone - The way for a client to run the TX state machine. |
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* @chan: Mailbox channel assigned to this client. |
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* @r: Success status of last transmission. |
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* |
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* The client/protocol had received some 'ACK' packet and it notifies |
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* the API that the last packet was sent successfully. This only works |
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* if the controller can't sense TX-Done. |
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*/ |
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void mbox_client_txdone(struct mbox_chan *chan, int r) |
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{ |
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if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) { |
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dev_err(chan->mbox->dev, "Client can't run the TX ticker\n"); |
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return; |
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} |
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tx_tick(chan, r); |
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} |
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EXPORT_SYMBOL_GPL(mbox_client_txdone); |
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/** |
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* mbox_client_peek_data - A way for client driver to pull data |
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* received from remote by the controller. |
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* @chan: Mailbox channel assigned to this client. |
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* |
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* A poke to controller driver for any received data. |
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* The data is actually passed onto client via the |
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* mbox_chan_received_data() |
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* The call can be made from atomic context, so the controller's |
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* implementation of peek_data() must not sleep. |
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* |
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* Return: True, if controller has, and is going to push after this, |
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* some data. |
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* False, if controller doesn't have any data to be read. |
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*/ |
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bool mbox_client_peek_data(struct mbox_chan *chan) |
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{ |
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if (chan->mbox->ops->peek_data) |
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return chan->mbox->ops->peek_data(chan); |
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return false; |
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} |
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EXPORT_SYMBOL_GPL(mbox_client_peek_data); |
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/** |
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* mbox_send_message - For client to submit a message to be |
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* sent to the remote. |
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* @chan: Mailbox channel assigned to this client. |
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* @mssg: Client specific message typecasted. |
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* |
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* For client to submit data to the controller destined for a remote |
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* processor. If the client had set 'tx_block', the call will return |
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* either when the remote receives the data or when 'tx_tout' millisecs |
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* run out. |
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* In non-blocking mode, the requests are buffered by the API and a |
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* non-negative token is returned for each queued request. If the request |
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* is not queued, a negative token is returned. Upon failure or successful |
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* TX, the API calls 'tx_done' from atomic context, from which the client |
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* could submit yet another request. |
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* The pointer to message should be preserved until it is sent |
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* over the chan, i.e, tx_done() is made. |
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* This function could be called from atomic context as it simply |
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* queues the data and returns a token against the request. |
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* |
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* Return: Non-negative integer for successful submission (non-blocking mode) |
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* or transmission over chan (blocking mode). |
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* Negative value denotes failure. |
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*/ |
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int mbox_send_message(struct mbox_chan *chan, void *mssg) |
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{ |
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int t; |
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if (!chan || !chan->cl) |
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return -EINVAL; |
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t = add_to_rbuf(chan, mssg); |
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if (t < 0) { |
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dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n"); |
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return t; |
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} |
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msg_submit(chan); |
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if (chan->cl->tx_block) { |
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unsigned long wait; |
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int ret; |
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if (!chan->cl->tx_tout) /* wait forever */ |
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wait = msecs_to_jiffies(3600000); |
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else |
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wait = msecs_to_jiffies(chan->cl->tx_tout); |
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ret = wait_for_completion_timeout(&chan->tx_complete, wait); |
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if (ret == 0) { |
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t = -ETIME; |
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tx_tick(chan, t); |
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} |
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} |
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return t; |
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} |
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EXPORT_SYMBOL_GPL(mbox_send_message); |
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/** |
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* mbox_flush - flush a mailbox channel |
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* @chan: mailbox channel to flush |
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* @timeout: time, in milliseconds, to allow the flush operation to succeed |
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* |
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* Mailbox controllers that need to work in atomic context can implement the |
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* ->flush() callback to busy loop until a transmission has been completed. |
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* The implementation must call mbox_chan_txdone() upon success. Clients can |
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* call the mbox_flush() function at any time after mbox_send_message() to |
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* flush the transmission. After the function returns success, the mailbox |
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* transmission is guaranteed to have completed. |
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* |
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* Returns: 0 on success or a negative error code on failure. |
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*/ |
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int mbox_flush(struct mbox_chan *chan, unsigned long timeout) |
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{ |
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int ret; |
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if (!chan->mbox->ops->flush) |
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return -ENOTSUPP; |
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ret = chan->mbox->ops->flush(chan, timeout); |
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if (ret < 0) |
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tx_tick(chan, ret); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(mbox_flush); |
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/** |
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* mbox_request_channel - Request a mailbox channel. |
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* @cl: Identity of the client requesting the channel. |
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* @index: Index of mailbox specifier in 'mboxes' property. |
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* |
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* The Client specifies its requirements and capabilities while asking for |
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* a mailbox channel. It can't be called from atomic context. |
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* The channel is exclusively allocated and can't be used by another |
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* client before the owner calls mbox_free_channel. |
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* After assignment, any packet received on this channel will be |
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* handed over to the client via the 'rx_callback'. |
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* The framework holds reference to the client, so the mbox_client |
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* structure shouldn't be modified until the mbox_free_channel returns. |
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* |
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* Return: Pointer to the channel assigned to the client if successful. |
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* ERR_PTR for request failure. |
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*/ |
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struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) |
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{ |
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struct device *dev = cl->dev; |
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struct mbox_controller *mbox; |
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struct of_phandle_args spec; |
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struct mbox_chan *chan; |
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unsigned long flags; |
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int ret; |
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if (!dev || !dev->of_node) { |
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pr_debug("%s: No owner device node\n", __func__); |
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return ERR_PTR(-ENODEV); |
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} |
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mutex_lock(&con_mutex); |
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if (of_parse_phandle_with_args(dev->of_node, "mboxes", |
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"#mbox-cells", index, &spec)) { |
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dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__); |
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mutex_unlock(&con_mutex); |
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return ERR_PTR(-ENODEV); |
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} |
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chan = ERR_PTR(-EPROBE_DEFER); |
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list_for_each_entry(mbox, &mbox_cons, node) |
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if (mbox->dev->of_node == spec.np) { |
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chan = mbox->of_xlate(mbox, &spec); |
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if (!IS_ERR(chan)) |
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break; |
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} |
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of_node_put(spec.np); |
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if (IS_ERR(chan)) { |
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mutex_unlock(&con_mutex); |
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return chan; |
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} |
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if (chan->cl || !try_module_get(mbox->dev->driver->owner)) { |
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dev_dbg(dev, "%s: mailbox not free\n", __func__); |
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mutex_unlock(&con_mutex); |
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return ERR_PTR(-EBUSY); |
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} |
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spin_lock_irqsave(&chan->lock, flags); |
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chan->msg_free = 0; |
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chan->msg_count = 0; |
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chan->active_req = NULL; |
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chan->cl = cl; |
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init_completion(&chan->tx_complete); |
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if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone) |
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chan->txdone_method = TXDONE_BY_ACK; |
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spin_unlock_irqrestore(&chan->lock, flags); |
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if (chan->mbox->ops->startup) { |
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ret = chan->mbox->ops->startup(chan); |
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if (ret) { |
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dev_err(dev, "Unable to startup the chan (%d)\n", ret); |
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mbox_free_channel(chan); |
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chan = ERR_PTR(ret); |
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} |
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} |
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mutex_unlock(&con_mutex); |
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return chan; |
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} |
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EXPORT_SYMBOL_GPL(mbox_request_channel); |
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struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl, |
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const char *name) |
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{ |
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struct device_node *np = cl->dev->of_node; |
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struct property *prop; |
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const char *mbox_name; |
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int index = 0; |
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if (!np) { |
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dev_err(cl->dev, "%s() currently only supports DT\n", __func__); |
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return ERR_PTR(-EINVAL); |
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} |
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if (!of_get_property(np, "mbox-names", NULL)) { |
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dev_err(cl->dev, |
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"%s() requires an \"mbox-names\" property\n", __func__); |
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return ERR_PTR(-EINVAL); |
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} |
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of_property_for_each_string(np, "mbox-names", prop, mbox_name) { |
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if (!strncmp(name, mbox_name, strlen(name))) |
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return mbox_request_channel(cl, index); |
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index++; |
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} |
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dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n", |
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__func__, name); |
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return ERR_PTR(-EINVAL); |
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} |
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EXPORT_SYMBOL_GPL(mbox_request_channel_byname); |
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/** |
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* mbox_free_channel - The client relinquishes control of a mailbox |
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* channel by this call. |
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* @chan: The mailbox channel to be freed. |
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*/ |
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void mbox_free_channel(struct mbox_chan *chan) |
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{ |
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unsigned long flags; |
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if (!chan || !chan->cl) |
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return; |
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if (chan->mbox->ops->shutdown) |
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chan->mbox->ops->shutdown(chan); |
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/* The queued TX requests are simply aborted, no callbacks are made */ |
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spin_lock_irqsave(&chan->lock, flags); |
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chan->cl = NULL; |
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chan->active_req = NULL; |
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if (chan->txdone_method == TXDONE_BY_ACK) |
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chan->txdone_method = TXDONE_BY_POLL; |
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module_put(chan->mbox->dev->driver->owner); |
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spin_unlock_irqrestore(&chan->lock, flags); |
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} |
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EXPORT_SYMBOL_GPL(mbox_free_channel); |
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static struct mbox_chan * |
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of_mbox_index_xlate(struct mbox_controller *mbox, |
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const struct of_phandle_args *sp) |
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{ |
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int ind = sp->args[0]; |
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if (ind >= mbox->num_chans) |
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return ERR_PTR(-EINVAL); |
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return &mbox->chans[ind]; |
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} |
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/** |
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* mbox_controller_register - Register the mailbox controller |
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* @mbox: Pointer to the mailbox controller. |
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* |
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* The controller driver registers its communication channels |
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*/ |
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int mbox_controller_register(struct mbox_controller *mbox) |
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{ |
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int i, txdone; |
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/* Sanity check */ |
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if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans) |
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return -EINVAL; |
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if (mbox->txdone_irq) |
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txdone = TXDONE_BY_IRQ; |
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else if (mbox->txdone_poll) |
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txdone = TXDONE_BY_POLL; |
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else /* It has to be ACK then */ |
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txdone = TXDONE_BY_ACK; |
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if (txdone == TXDONE_BY_POLL) { |
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if (!mbox->ops->last_tx_done) { |
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dev_err(mbox->dev, "last_tx_done method is absent\n"); |
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return -EINVAL; |
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} |
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hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC, |
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HRTIMER_MODE_REL); |
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mbox->poll_hrt.function = txdone_hrtimer; |
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} |
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for (i = 0; i < mbox->num_chans; i++) { |
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struct mbox_chan *chan = &mbox->chans[i]; |
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chan->cl = NULL; |
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chan->mbox = mbox; |
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chan->txdone_method = txdone; |
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spin_lock_init(&chan->lock); |
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} |
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if (!mbox->of_xlate) |
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mbox->of_xlate = of_mbox_index_xlate; |
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mutex_lock(&con_mutex); |
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list_add_tail(&mbox->node, &mbox_cons); |
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mutex_unlock(&con_mutex); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(mbox_controller_register); |
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|
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/** |
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* mbox_controller_unregister - Unregister the mailbox controller |
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* @mbox: Pointer to the mailbox controller. |
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*/ |
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void mbox_controller_unregister(struct mbox_controller *mbox) |
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{ |
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int i; |
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if (!mbox) |
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return; |
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mutex_lock(&con_mutex); |
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list_del(&mbox->node); |
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for (i = 0; i < mbox->num_chans; i++) |
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mbox_free_channel(&mbox->chans[i]); |
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if (mbox->txdone_poll) |
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hrtimer_cancel(&mbox->poll_hrt); |
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mutex_unlock(&con_mutex); |
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} |
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EXPORT_SYMBOL_GPL(mbox_controller_unregister); |
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static void __devm_mbox_controller_unregister(struct device *dev, void *res) |
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{ |
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struct mbox_controller **mbox = res; |
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mbox_controller_unregister(*mbox); |
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} |
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static int devm_mbox_controller_match(struct device *dev, void *res, void *data) |
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{ |
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struct mbox_controller **mbox = res; |
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if (WARN_ON(!mbox || !*mbox)) |
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return 0; |
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return *mbox == data; |
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} |
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/** |
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* devm_mbox_controller_register() - managed mbox_controller_register() |
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* @dev: device owning the mailbox controller being registered |
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* @mbox: mailbox controller being registered |
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* |
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* This function adds a device-managed resource that will make sure that the |
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* mailbox controller, which is registered using mbox_controller_register() |
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* as part of this function, will be unregistered along with the rest of |
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* device-managed resources upon driver probe failure or driver removal. |
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* |
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* Returns 0 on success or a negative error code on failure. |
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*/ |
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int devm_mbox_controller_register(struct device *dev, |
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struct mbox_controller *mbox) |
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{ |
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struct mbox_controller **ptr; |
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int err; |
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ptr = devres_alloc(__devm_mbox_controller_unregister, sizeof(*ptr), |
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GFP_KERNEL); |
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if (!ptr) |
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return -ENOMEM; |
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err = mbox_controller_register(mbox); |
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if (err < 0) { |
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devres_free(ptr); |
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return err; |
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} |
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devres_add(dev, ptr); |
|
*ptr = mbox; |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(devm_mbox_controller_register); |
|
|
|
/** |
|
* devm_mbox_controller_unregister() - managed mbox_controller_unregister() |
|
* @dev: device owning the mailbox controller being unregistered |
|
* @mbox: mailbox controller being unregistered |
|
* |
|
* This function unregisters the mailbox controller and removes the device- |
|
* managed resource that was set up to automatically unregister the mailbox |
|
* controller on driver probe failure or driver removal. It's typically not |
|
* necessary to call this function. |
|
*/ |
|
void devm_mbox_controller_unregister(struct device *dev, struct mbox_controller *mbox) |
|
{ |
|
WARN_ON(devres_release(dev, __devm_mbox_controller_unregister, |
|
devm_mbox_controller_match, mbox)); |
|
} |
|
EXPORT_SYMBOL_GPL(devm_mbox_controller_unregister);
|
|
|