The PCC (Platform Communication Channel) is a generic
mailbox to be used by PCC clients such as CPPC, RAS
and MPST as defined in the ACPI 5.0+ spec. This patch
modifies the Mailbox framework to lookup PCC mailbox
controllers and channels such that PCC drivers can work
with or without ACPI support in the kernel.
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
---
drivers/mailbox/mailbox.c | 118 ++++++++++++++++++++++++++++++++++---
include/linux/mailbox_client.h | 6 ++
include/linux/mailbox_controller.h | 1 +
3 files changed, 118 insertions(+), 7 deletions(-)
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 63ecc17..09ad488 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -356,6 +356,14 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
}
EXPORT_SYMBOL_GPL(mbox_request_channel);
+static void inline free_channel(struct mbox_chan *chan)
+{
+ chan->cl = NULL;
+ chan->active_req = NULL;
+ if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+ chan->txdone_method = TXDONE_BY_POLL;
+}
+
/**
* mbox_free_channel - The client relinquishes control of a mailbox
* channel by this call.
@@ -369,14 +377,9 @@ void mbox_free_channel(struct mbox_chan *chan)
return;
chan->mbox->ops->shutdown(chan);
-
/* The queued TX requests are simply aborted, no callbacks are made */
spin_lock_irqsave(&chan->lock, flags);
- chan->cl = NULL;
- chan->active_req = NULL;
- if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
- chan->txdone_method = TXDONE_BY_POLL;
-
+ free_channel(chan);
module_put(chan->mbox->dev->driver->owner);
spin_unlock_irqrestore(&chan->lock, flags);
}
@@ -394,6 +397,97 @@ of_mbox_index_xlate(struct mbox_controller *mbox,
return &mbox->chans[ind];
}
+#ifdef CONFIG_PCC
+/*
+ * The PCC (Platform Communication Channel) is
+ * defined in the ACPI 5.0+ spec. It is a generic
+ * mailbox interface between an OS and a Platform
+ * such as a BMC. The PCCT (Mailbox controller) has
+ * its own ACPI specific way to describe PCC clients
+ * and their subspace ids (Mailbox channels/clients).
+ *
+ * The following API is added such that PCC
+ * drivers continue to work with this Mailbox
+ * framework with or without ACPI.
+ */
+
+static struct mbox_controller *
+mbox_find_pcc_controller(char *name)
+{
+ struct mbox_controller *mbox;
+ list_for_each_entry(mbox, &mbox_cons, node) {
+ if (mbox->name)
+ if (!strcmp(mbox->name, name))
+ return mbox;
+ }
+
+ return NULL;
+}
+
+struct mbox_chan *
+pcc_mbox_request_channel(struct mbox_client *cl,
+ char *name, unsigned chan_id)
+{
+ struct mbox_controller *mbox;
+ struct mbox_chan *pcc_chan;
+ unsigned long flags;
+ int ret;
+
+ mutex_lock(&con_mutex);
+ mbox = mbox_find_pcc_controller(name);
+
+ if (!mbox) {
+ pr_err("PCC mbox %s not found.\n", name);
+ mutex_unlock(&con_mutex);
+ return ERR_PTR(-ENODEV);
+ }
+
+ pcc_chan = &mbox->chans[chan_id];
+
+ spin_lock_irqsave(&pcc_chan->lock, flags);
+ pcc_chan->msg_free = 0;
+ pcc_chan->msg_count = 0;
+ pcc_chan->active_req = NULL;
+ pcc_chan->cl = cl;
+ init_completion(&pcc_chan->tx_complete);
+
+ if (pcc_chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
+ pcc_chan->txdone_method |= TXDONE_BY_ACK;
+
+ spin_unlock_irqrestore(&pcc_chan->lock, flags);
+
+ ret = pcc_chan->mbox->ops->startup(pcc_chan);
+ if (ret) {
+ pr_err("Unable to startup the PCC channel (%d)\n", ret);
+ mbox_free_channel(pcc_chan);
+ mutex_unlock(&con_mutex);
+ return ERR_PTR(-ENODEV);
+ }
+
+ mutex_unlock(&con_mutex);
+
+ return pcc_chan;
+}
+
+EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
+
+void pcc_mbox_free_channel(struct mbox_chan *chan)
+{
+ unsigned long flags;
+
+ if (!chan || !chan->cl)
+ return;
+
+ chan->mbox->ops->shutdown(chan);
+
+ spin_lock_irqsave(&chan->lock, flags);
+ free_channel(chan);
+ spin_unlock_irqrestore(&chan->lock, flags);
+}
+EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
+
+#endif
+
/**
* mbox_controller_register - Register the mailbox controller
* @mbox: Pointer to the mailbox controller.
@@ -405,7 +499,17 @@ int mbox_controller_register(struct mbox_controller *mbox)
int i, txdone;
/* Sanity check */
- if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
+
+ /*
+ * PCC clients and controllers are currently not backed by
+ * platform device structures.
+ */
+#ifndef CONFIG_PCC
+ if (!mbox->dev)
+ return -EINVAL;
+#endif
+
+ if (!mbox || !mbox->ops || !mbox->num_chans)
return -EINVAL;
if (mbox->txdone_irq)
diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h
index 307d9ca..6a78df0 100644
--- a/include/linux/mailbox_client.h
+++ b/include/linux/mailbox_client.h
@@ -37,6 +37,12 @@ struct mbox_client {
void (*tx_done)(struct mbox_client *cl, void *mssg, int r);
};
+#ifdef CONFIG_PCC
+struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *c,
+ char *name, unsigned int chan_id);
+void pcc_mbox_free_channel(struct mbox_chan *chan); /* may sleep */
+#endif
+
struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index);
int mbox_send_message(struct mbox_chan *chan, void *mssg);
void mbox_client_txdone(struct mbox_chan *chan, int r); /* atomic */
diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
index 9ee195b..9f0ae42 100644
--- a/include/linux/mailbox_controller.h
+++ b/include/linux/mailbox_controller.h
@@ -81,6 +81,7 @@ struct mbox_controller {
unsigned txpoll_period;
struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox,
const struct of_phandle_args *sp);
+ char *name;
/* Internal to API */
struct timer_list poll;
unsigned period;
--
1.9.1
--
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