Merge branch 'mailbox-for-linus' of git://git.linaro.org/landing-teams/working/fujitsu/integration

Pull mailbox framework from Jassi Brar:
 "A framework for Mailbox controllers and clients have been cooking for
  more than a year now.

  Everybody in the CC list had been copied on patchset revisions and
  most of them have made sounds of approval, though just one concrete
  Reviewed-by.  The patchset has also been in linux-next for a couple of
  weeks now and no conflict has been reported.  The framework has the
  backing of at least 5 platforms, though I can't say if/when they
  upstream their drivers (some businesses have 'changed')"

(Further acked-by by Arnd Bergmann and Suman Anna in the pull request
thread)

* 'mailbox-for-linus' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  dt: mailbox: add generic bindings
  doc: add documentation for mailbox framework
  mailbox: Introduce framework for mailbox
  mailbox: rename pl320-ipc specific mailbox.h

3 files changed, 179 insertions, 0 deletions

diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h
new file mode 100644
index 000000000000..307d9cab2026
--- /dev/null
+++ b/include/linux/mailbox_client.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2013-2014 Linaro Ltd.
+ * Author: Jassi Brar <jassisinghbrar@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MAILBOX_CLIENT_H
+#define __MAILBOX_CLIENT_H
+
+#include <linux/of.h>
+#include <linux/device.h>
+
+struct mbox_chan;
+
+/**
+ * struct mbox_client - User of a mailbox
+ * @dev:                The client device
+ * @tx_block:           If the mbox_send_message should block until data is
+ *                      transmitted.
+ * @tx_tout:            Max block period in ms before TX is assumed failure
+ * @knows_txdone:       If the client could run the TX state machine. Usually
+ *                      if the client receives some ACK packet for transmission.
+ *                      Unused if the controller already has TX_Done/RTR IRQ.
+ * @rx_callback:        Atomic callback to provide client the data received
+ * @tx_done:            Atomic callback to tell client of data transmission
+ */
+struct mbox_client {
+        struct device *dev;
+        bool tx_block;
+        unsigned long tx_tout;
+        bool knows_txdone;
+
+        void (*rx_callback)(struct mbox_client *cl, void *mssg);
+        void (*tx_done)(struct mbox_client *cl, void *mssg, int r);
+};
+
+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 */
+bool mbox_client_peek_data(struct mbox_chan *chan); /* atomic */
+void mbox_free_channel(struct mbox_chan *chan); /* may sleep */
+
+#endif /* __MAILBOX_CLIENT_H */
diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
new file mode 100644
index 000000000000..d4cf96f07cfc
--- /dev/null
+++ b/include/linux/mailbox_controller.h
@@ -0,0 +1,133 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MAILBOX_CONTROLLER_H
+#define __MAILBOX_CONTROLLER_H
+
+#include <linux/of.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/device.h>
+#include <linux/completion.h>
+
+struct mbox_chan;
+
+/**
+ * struct mbox_chan_ops - methods to control mailbox channels
+ * @send_data:  The API asks the MBOX controller driver, in atomic
+ *              context try to transmit a message on the bus. Returns 0 if
+ *              data is accepted for transmission, -EBUSY while rejecting
+ *              if the remote hasn't yet read the last data sent. Actual
+ *              transmission of data is reported by the controller via
+ *              mbox_chan_txdone (if it has some TX ACK irq). It must not
+ *              sleep.
+ * @startup:    Called when a client requests the chan. The controller
+ *              could ask clients for additional parameters of communication
+ *              to be provided via client's chan_data. This call may
+ *              block. After this call the Controller must forward any
+ *              data received on the chan by calling mbox_chan_received_data.
+ *              The controller may do stuff that need to sleep.
+ * @shutdown:   Called when a client relinquishes control of a chan.
+ *              This call may block too. The controller must not forward
+ *              any received data anymore.
+ *              The controller may do stuff that need to sleep.
+ * @last_tx_done: If the controller sets 'txdone_poll', the API calls
+ *                this to poll status of last TX. The controller must
+ *                give priority to IRQ method over polling and never
+ *                set both txdone_poll and txdone_irq. Only in polling
+ *                mode 'send_data' is expected to return -EBUSY.
+ *                The controller may do stuff that need to sleep/block.
+ *                Used only if txdone_poll:=true && txdone_irq:=false
+ * @peek_data: Atomic check for any received data. Return true if controller
+ *                has some data to push to the client. False otherwise.
+ */
+struct mbox_chan_ops {
+        int (*send_data)(struct mbox_chan *chan, void *data);
+        int (*startup)(struct mbox_chan *chan);
+        void (*shutdown)(struct mbox_chan *chan);
+        bool (*last_tx_done)(struct mbox_chan *chan);
+        bool (*peek_data)(struct mbox_chan *chan);
+};
+
+/**
+ * struct mbox_controller - Controller of a class of communication channels
+ * @dev:                Device backing this controller
+ * @ops:                Operators that work on each communication chan
+ * @chans:              Array of channels
+ * @num_chans:          Number of channels in the 'chans' array.
+ * @txdone_irq:         Indicates if the controller can report to API when
+ *                      the last transmitted data was read by the remote.
+ *                      Eg, if it has some TX ACK irq.
+ * @txdone_poll:        If the controller can read but not report the TX
+ *                      done. Ex, some register shows the TX status but
+ *                      no interrupt rises. Ignored if 'txdone_irq' is set.
+ * @txpoll_period:      If 'txdone_poll' is in effect, the API polls for
+ *                      last TX's status after these many millisecs
+ * @of_xlate:           Controller driver specific mapping of channel via DT
+ * @poll:               API private. Used to poll for TXDONE on all channels.
+ * @node:               API private. To hook into list of controllers.
+ */
+struct mbox_controller {
+        struct device *dev;
+        struct mbox_chan_ops *ops;
+        struct mbox_chan *chans;
+        int num_chans;
+        bool txdone_irq;
+        bool txdone_poll;
+        unsigned txpoll_period;
+        struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox,
+                                      const struct of_phandle_args *sp);
+        /* Internal to API */
+        struct timer_list poll;
+        struct list_head node;
+};
+
+/*
+ * The length of circular buffer for queuing messages from a client.
+ * 'msg_count' tracks the number of buffered messages while 'msg_free'
+ * is the index where the next message would be buffered.
+ * We shouldn't need it too big because every transfer is interrupt
+ * triggered and if we have lots of data to transfer, the interrupt
+ * latencies are going to be the bottleneck, not the buffer length.
+ * Besides, mbox_send_message could be called from atomic context and
+ * the client could also queue another message from the notifier 'tx_done'
+ * of the last transfer done.
+ * REVISIT: If too many platforms see the "Try increasing MBOX_TX_QUEUE_LEN"
+ * print, it needs to be taken from config option or somesuch.
+ */
+#define MBOX_TX_QUEUE_LEN       20
+
+/**
+ * struct mbox_chan - s/w representation of a communication chan
+ * @mbox:               Pointer to the parent/provider of this channel
+ * @txdone_method:      Way to detect TXDone chosen by the API
+ * @cl:                 Pointer to the current owner of this channel
+ * @tx_complete:        Transmission completion
+ * @active_req:         Currently active request hook
+ * @msg_count:          No. of mssg currently queued
+ * @msg_free:           Index of next available mssg slot
+ * @msg_data:           Hook for data packet
+ * @lock:               Serialise access to the channel
+ * @con_priv:           Hook for controller driver to attach private data
+ */
+struct mbox_chan {
+        struct mbox_controller *mbox;
+        unsigned txdone_method;
+        struct mbox_client *cl;
+        struct completion tx_complete;
+        void *active_req;
+        unsigned msg_count, msg_free;
+        void *msg_data[MBOX_TX_QUEUE_LEN];
+        spinlock_t lock; /* Serialise access to the channel */
+        void *con_priv;
+};
+
+int mbox_controller_register(struct mbox_controller *mbox); /* can sleep */
+void mbox_controller_unregister(struct mbox_controller *mbox); /* can sleep */
+void mbox_chan_received_data(struct mbox_chan *chan, void *data); /* atomic */
+void mbox_chan_txdone(struct mbox_chan *chan, int r); /* atomic */
+
+#endif /* __MAILBOX_CONTROLLER_H */
diff --git a/include/linux/mailbox.h b/include/linux/pl320-ipc.h
index 5161f63ec1c8..5161f63ec1c8 100644
--- a/include/linux/mailbox.h
+++ b/include/linux/pl320-ipc.h