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![Jassi Brar](/assets/img/avatar_default.png)
Before polling we just need to see if the TXDONE_BY_POLL bit is set in txdone_method. There may be another bit (method) specified as well, like TXDONE_BY_ACK. Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
468 lines
12 KiB
C
468 lines
12 KiB
C
/*
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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 <jassisinghbrar@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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 void poll_txdone(unsigned long data);
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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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poll_txdone((unsigned long)chan->mbox);
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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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/* Notify the client */
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if (mssg && chan->cl->tx_done)
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chan->cl->tx_done(chan->cl, mssg, r);
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if (chan->cl->tx_block)
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complete(&chan->tx_complete);
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}
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static void poll_txdone(unsigned long data)
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{
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struct mbox_controller *mbox = (struct mbox_controller *)data;
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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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mod_timer(&mbox->poll, jiffies +
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msecs_to_jiffies(mbox->txpoll_period));
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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 && chan->active_req) {
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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 = -EIO;
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tx_tick(chan, -EIO);
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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_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 = NULL;
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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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break;
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}
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of_node_put(spec.np);
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if (!chan || 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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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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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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/**
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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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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_POLL | 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 NULL;
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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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mbox->poll.function = &poll_txdone;
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mbox->poll.data = (unsigned long)mbox;
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init_timer(&mbox->poll);
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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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* 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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del_timer_sync(&mbox->poll);
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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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