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@linaro.org --- 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;