The current Mailbox framework expects the Mailbox controller and clients to be backed by Struct devices and uses a DT specific matching method for clients to lookup channels in a controller.
The helper functions introduced here allow the PCC Mailbox as defined in the ACPI 5.0+ specification to workaround these expectations and continue to work with the rest of the Mailbox framework even in the case where PCC is defined using DT bindings.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org --- drivers/mailbox/Kconfig | 8 +++ drivers/mailbox/Makefile | 2 + drivers/mailbox/pcc_mailbox.c | 136 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 146 insertions(+) create mode 100644 drivers/mailbox/pcc_mailbox.c
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index c8b5c13..0e7be60 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -50,4 +50,12 @@ config OMAP_MBOX_KFIFO_SIZE Specify the default size of mailbox's kfifo buffers (bytes). This can also be changed at runtime (via the mbox_kfifo_size module parameter). + +config PCC_MAILBOX_API + bool "Platform Communication Channel Mailbox API" + help + This contains helper functions for registering a PCC mailbox + with the generic Mailbox framework and for looking up a PCC + channel. + endif diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index 2fa343a..3a4f94d 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -9,3 +9,5 @@ obj-$(CONFIG_OMAP1_MBOX) += mailbox_omap1.o mailbox_omap1-objs := mailbox-omap1.o obj-$(CONFIG_OMAP2PLUS_MBOX) += mailbox_omap2.o mailbox_omap2-objs := mailbox-omap2.o + +obj-$(CONFIG_PCC_MAILBOX_API) += pcc_mailbox.o diff --git a/drivers/mailbox/pcc_mailbox.c b/drivers/mailbox/pcc_mailbox.c new file mode 100644 index 0000000..1454b67 --- /dev/null +++ b/drivers/mailbox/pcc_mailbox.c @@ -0,0 +1,136 @@ +/* + * Copyright (C) 2014 Linaro Ltd. + * Author: Ashwin Chaugule ashwin.chaugule@linaro.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/mailbox_controller.h> +#include <linux/mailbox_client.h> + +extern struct list_head mbox_cons; +extern struct mutex con_mutex; +extern void mbox_free_channel(struct mbox_chan *chan); +extern void poll_txdone(unsigned long data); + +static struct mbox_controller *pcc_mbox; + +struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl, int index) +{ + struct mbox_chan *chan; + unsigned long flags; + int ret; + + if (!pcc_mbox) { + pr_err("PCC Mailbox not found.\n"); + return ERR_PTR(-ENODEV); + } + + mutex_lock(&con_mutex); + /* + * Each PCC Subspace is a Mailbox Channel. + * The PCC Clients get their PCC Subspace ID + * from their own tables and pass it here. + * This returns a pointer to the PCC subspace + * for the Client to operate on. + */ + chan = &pcc_mbox->chans[index]; + + if (!chan || chan->cl || !try_module_get(pcc_mbox->dev->driver->owner)) { + pr_err("%s: PCC 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); + + mutex_unlock(&con_mutex); + return 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; + + 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; + + module_put(chan->mbox->dev->driver->owner); + spin_unlock_irqrestore(&chan->lock, flags); +} +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); + +int pcc_mbox_controller_register(struct mbox_controller *mbox) +{ + int i, txdone; + + /* Sanity check */ + if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans) + return -EINVAL; + + if (mbox->txdone_irq) + txdone = TXDONE_BY_IRQ; + else if (mbox->txdone_poll) + txdone = TXDONE_BY_POLL; + else /* It has to be ACK then */ + txdone = TXDONE_BY_ACK; + + if (txdone == TXDONE_BY_POLL) { + mbox->poll.function = &poll_txdone; + mbox->poll.data = (unsigned long)mbox; + init_timer(&mbox->poll); + } + + for (i = 0; i < mbox->num_chans; i++) { + struct mbox_chan *chan = &mbox->chans[i]; + + chan->cl = NULL; + chan->mbox = mbox; + chan->txdone_method = txdone; + spin_lock_init(&chan->lock); + } + + mutex_lock(&con_mutex); + list_add_tail(&mbox->node, &mbox_cons); + /* + * Store this so we avoid digging for a PCC mbox in + * the Channel lookup. + */ + pcc_mbox = mbox; + mutex_unlock(&con_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(pcc_mbox_controller_register); +