Commit 991e5781 authored by Elliot Berman's avatar Elliot Berman Committed by Zhongyuan Zhou
Browse files

mailbox: Allow direct registration to a channel 

mainline inclusion
from mainline-v6.4-rc1
commit 85a95380
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9S5DK
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=85a953806557dbf25d16e8c132b5b9b100d16496



--------------------------------

Support virtual mailbox controllers and clients which are not platform
devices or come from the devicetree by allowing them to match client to
channel via some other mechanism.

Tested-by: Sudeep Holla <sudeep.holla@arm.com> (pcc)
Signed-off-by: default avatarElliot Berman <quic_eberman@quicinc.com>
Signed-off-by: default avatarJassi Brar <jaswinder.singh@linaro.org>
parent ac47fcdd

drivers/mailbox/mailbox.c

+68 −28
Original line number Diff line number Diff line
@@ -317,6 +317,71 @@ int mbox_flush(struct mbox_chan *chan, unsigned long timeout) 
}

EXPORT_SYMBOL_GPL(mbox_flush);



static int __mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)

{

	struct device *dev = cl->dev;

	unsigned long flags;

	int ret;



	if (chan->cl || !try_module_get(chan->mbox->dev->driver->owner)) {

		dev_dbg(dev, "%s: mailbox not free\n", __func__);

		return -EBUSY;

	}



	spin_lock_irqsave(&chan->lock, flags);

	chan->msg_free = 0;

	chan->msg_count = 0;

	chan->active_req = NULL;

	chan->cl = cl;

	init_completion(&chan->tx_complete);



	if (chan->txdone_method	== TXDONE_BY_POLL && cl->knows_txdone)

		chan->txdone_method = TXDONE_BY_ACK;



	spin_unlock_irqrestore(&chan->lock, flags);



	if (chan->mbox->ops->startup) {

		ret = chan->mbox->ops->startup(chan);



		if (ret) {

			dev_err(dev, "Unable to startup the chan (%d)\n", ret);

			mbox_free_channel(chan);

			return ret;

		}

	}



	return 0;

}



/**

 * mbox_bind_client - Request a mailbox channel.

 * @chan: The mailbox channel to bind the client to.

 * @cl: Identity of the client requesting the channel.

 *

 * The Client specifies its requirements and capabilities while asking for

 * a mailbox channel. It can't be called from atomic context.

 * The channel is exclusively allocated and can't be used by another

 * client before the owner calls mbox_free_channel.

 * After assignment, any packet received on this channel will be

 * handed over to the client via the 'rx_callback'.

 * The framework holds reference to the client, so the mbox_client

 * structure shouldn't be modified until the mbox_free_channel returns.

 *

 * Return: 0 if the channel was assigned to the client successfully.

 *         <0 for request failure.

 */

int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)

{

	int ret;



	mutex_lock(&con_mutex);

	ret = __mbox_bind_client(chan, cl);

	mutex_unlock(&con_mutex);



	return ret;

}

EXPORT_SYMBOL_GPL(mbox_bind_client);



/**

 * mbox_request_channel - Request a mailbox channel.

 * @cl: Identity of the client requesting the channel.
@@ -340,7 +405,6 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) 
	struct mbox_controller *mbox;

	struct of_phandle_args spec;

	struct mbox_chan *chan;

	unsigned long flags;

	int ret;



	if (!dev || !dev->of_node) {
@@ -372,33 +436,9 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) 
		return chan;

	}



	if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {

		dev_dbg(dev, "%s: mailbox not free\n", __func__);

		mutex_unlock(&con_mutex);

		return ERR_PTR(-EBUSY);

	}



	spin_lock_irqsave(&chan->lock, flags);

	chan->msg_free = 0;

	chan->msg_count = 0;

	chan->active_req = NULL;

	chan->cl = cl;

	init_completion(&chan->tx_complete);



	if (chan->txdone_method	== TXDONE_BY_POLL && cl->knows_txdone)

		chan->txdone_method = TXDONE_BY_ACK;



	spin_unlock_irqrestore(&chan->lock, flags);



	if (chan->mbox->ops->startup) {

		ret = chan->mbox->ops->startup(chan);



		if (ret) {

			dev_err(dev, "Unable to startup the chan (%d)\n", ret);

			mbox_free_channel(chan);

	ret = __mbox_bind_client(chan, cl);

	if (ret)

		chan = ERR_PTR(ret);

		}

	}



	mutex_unlock(&con_mutex);

	return chan;

include/linux/mailbox_client.h

+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ struct mbox_client { 
	void (*tx_done)(struct mbox_client *cl, void *mssg, int r);

};



int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl);

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);