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mailbox: Allow direct registration to a channel

Browse source 
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: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
This commit is contained in:
Elliot Berman 2023-04-10 09:16:52 -07:00 committed by Jassi Brar
parent 6a8f57ae2e
commit 85a9538065
2 changed files with 69 additions and 28 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

96
drivers/mailbox/mailbox.c
View file

@ -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);
chan = ERR_PTR(ret);
}
}
ret = __mbox_bind_client(chan, cl);
if (ret)
chan = ERR_PTR(ret);
mutex_unlock(&con_mutex);
return chan;

1
include/linux/mailbox_client.h
View file

@ -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);