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mailbox: Allow direct registration to a channel 

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);