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Subject[PATCH v7 07/20] mailbox: Allow direct registration to a channel
Date
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.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
drivers/mailbox/mailbox.c | 96 ++++++++++++++++++++++++----------
drivers/mailbox/omap-mailbox.c | 18 ++-----
drivers/mailbox/pcc.c | 17 ++----
include/linux/mailbox_client.h | 1 +
4 files changed, 76 insertions(+), 56 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 4229b9b5da98..adf36c05fa43 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -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;
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 098c82d87137..711a56ec8592 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -441,21 +441,9 @@ struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
if (!mbox || !mbox->chan)
return ERR_PTR(-ENOENT);

- chan = mbox->chan;
- 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);
- spin_unlock_irqrestore(&chan->lock, flags);
-
- ret = chan->mbox->ops->startup(chan);
- if (ret) {
- pr_err("Unable to startup the chan (%d)\n", ret);
- mbox_free_channel(chan);
- chan = ERR_PTR(ret);
- }
+ ret = mbox_bind_client(mbox->chan, cl);
+ if (ret)
+ return ERR_PTR(ret);

return chan;
}
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 3c2bc0ca454c..b93fd95559c0 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -284,6 +284,7 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
struct mbox_chan *chan;
struct device *dev;
unsigned long flags;
+ int rc;

if (subspace_id < 0 || subspace_id >= pcc_chan_count)
return ERR_PTR(-ENOENT);
@@ -296,21 +297,11 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
}
dev = chan->mbox->dev;

- 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);
+ rc = mbox_bind_client(chan, cl);
+ if (rc)
+ return ERR_PTR(rc);

if (pchan->plat_irq > 0) {
- int rc;
-
rc = devm_request_irq(dev, pchan->plat_irq, pcc_mbox_irq, 0,
MBOX_IRQ_NAME, chan);
if (unlikely(rc)) {
diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h
index 65229a45590f..734694912ef7 100644
--- a/include/linux/mailbox_client.h
+++ b/include/linux/mailbox_client.h
@@ -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);
--
2.25.1
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