[PATCHv6 0/3] Common Mailbox Framework

[PATCHv6 0/3] Common Mailbox Framework

[Jassi Brar]

Hello,
  Here is the next revision of Mailbox framwork.

Changes since v5:
 o Use standard error types instead of special type mbox_result.
 o Constify client struct in request_channel
 o Use reinit_completion instead of init_completion every time.
 o Improve commentary in bindings and code.

Changes since v4:
 o Common DT binding for Controller and Client drivers
    As a result, discard string based channel matching
 o Provide for an atomic 'peek' api, that a client could
    call to trigger the controller driver push data upwards.
 o OMAP and Highbank conversion to new api is left out, which
    can be converted later by the developers.

Changes since v3:
 o Change name of symbols from ipc to mbox
 o Return real types instead of void *
 o Align structures
 o Change some symbol names
	rxcb -> rx_callback
	txcb -> tx_done
 o Added kernel-doc for exported API
 o Dropped the cl_id and use clients pointer for callbacks.
 o Fixed locking of channel pool
 o Return negative error code for unsuccessful ipc_send_message()
 o Module referencing during mailbox assignment to a client.
 o Made error code symbols specific to mailbox.

Thanks
Jassi

[PATCHv6 1/3] mailbox: rename pl320-ipc specific mailbox.h

[Jassi Brar]

From: Suman Anna <s-anna@ti.com>

The patch 30058677 "ARM / highbank: add support for pl320 IPC"
added a pl320 IPC specific header file as a generic mailbox.h.
This file has been renamed appropriately to allow the
introduction of the generic mailbox API framework.

Acked-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
---
 arch/arm/mach-highbank/highbank.c        | 2 +-
 drivers/cpufreq/highbank-cpufreq.c       | 2 +-
 drivers/mailbox/pl320-ipc.c              | 2 +-
 include/linux/{mailbox.h => pl320-ipc.h} | 0
 4 files changed, 3 insertions(+), 3 deletions(-)
 rename include/linux/{mailbox.h => pl320-ipc.h} (100%)

diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index c7de89b..f295cbb 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -20,7 +20,7 @@
 #include <linux/input.h>
 #include <linux/io.h>
 #include <linux/irqchip.h>
-#include <linux/mailbox.h>
+#include <linux/pl320-ipc.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
diff --git a/drivers/cpufreq/highbank-cpufreq.c b/drivers/cpufreq/highbank-cpufreq.c
index bf8902a..b464f29 100644
--- a/drivers/cpufreq/highbank-cpufreq.c
+++ b/drivers/cpufreq/highbank-cpufreq.c
@@ -19,7 +19,7 @@
 #include <linux/cpu.h>
 #include <linux/err.h>
 #include <linux/of.h>
-#include <linux/mailbox.h>
+#include <linux/pl320-ipc.h>
 #include <linux/platform_device.h>
 
 #define HB_CPUFREQ_CHANGE_NOTE	0x80000001
diff --git a/drivers/mailbox/pl320-ipc.c b/drivers/mailbox/pl320-ipc.c
index d873cba..f3755e0 100644
--- a/drivers/mailbox/pl320-ipc.c
+++ b/drivers/mailbox/pl320-ipc.c
@@ -26,7 +26,7 @@
 #include <linux/device.h>
 #include <linux/amba/bus.h>
 
-#include <linux/mailbox.h>
+#include <linux/pl320-ipc.h>
 
 #define IPCMxSOURCE(m)		((m) * 0x40)
 #define IPCMxDSET(m)		(((m) * 0x40) + 0x004)
diff --git a/include/linux/mailbox.h b/include/linux/pl320-ipc.h
similarity index 100%
rename from include/linux/mailbox.h
rename to include/linux/pl320-ipc.h
-- 
1.8.1.2

[PATCHv6 2/3] mailbox: Introduce framework for mailbox

[Jassi Brar]

Introduce common framework for client/protocol drivers and
controller drivers of Inter-Processor-Communication (IPC).

Client driver developers should have a look at
 include/linux/mailbox_client.h to understand the part of
the API exposed to client drivers.
Similarly controller driver developers should have a look
at include/linux/mailbox_controller.h

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 .../devicetree/bindings/mailbox/mailbox.txt        |  33 ++
 drivers/mailbox/Makefile                           |   4 +
 drivers/mailbox/mailbox.c                          | 487 +++++++++++++++++++++
 include/linux/mailbox_client.h                     |  45 ++
 include/linux/mailbox_controller.h                 | 121 +++++
 5 files changed, 690 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/mailbox.txt
 create mode 100644 drivers/mailbox/mailbox.c
 create mode 100644 include/linux/mailbox_client.h
 create mode 100644 include/linux/mailbox_controller.h

diff --git a/Documentation/devicetree/bindings/mailbox/mailbox.txt b/Documentation/devicetree/bindings/mailbox/mailbox.txt
new file mode 100644
index 0000000..3f00955
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/mailbox.txt
@@ -0,0 +1,33 @@
+* Generic Mailbox Controller and client driver bindings
+
+Generic binding to provide a way for Mailbox controller drivers to
+assign appropriate mailbox channel to client drivers.
+
+* Mailbox Controller
+
+Required property:
+- #mbox-cells: Must be at least 1. Number of cells in a mailbox
+		specifier.
+
+Example:
+	mailbox: mailbox {
+		...
+		#mbox-cells = <1>;
+	};
+
+
+* Mailbox Client
+
+Required property:
+- mbox: List of phandle and mailbox channel specifier.
+
+- mbox-names: List of identifier strings for each mailbox channel
+		required by the client.
+
+Example:
+	pwr_cntrl: power {
+		...
+		mbox-names = "pwr-ctrl", "rpc";
+		mbox = <&mailbox 0
+			&mailbox 1>;
+	};
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index e0facb3..2fa343a 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -1,3 +1,7 @@
+# Generic MAILBOX API
+
+obj-$(CONFIG_MAILBOX)		+= mailbox.o
+
 obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
 
 obj-$(CONFIG_OMAP_MBOX)		+= omap-mailbox.o
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
new file mode 100644
index 0000000..336fa10
--- /dev/null
+++ b/drivers/mailbox/mailbox.c
@@ -0,0 +1,487 @@
+/*
+ * Mailbox: Common code for Mailbox controllers and users
+ *
+ * Copyright (C) 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.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox_controller.h>
+
+#define TXDONE_BY_IRQ	(1 << 0) /* controller has remote RTR irq */
+#define TXDONE_BY_POLL	(1 << 1) /* controller can read status of last TX */
+#define TXDONE_BY_ACK	(1 << 2) /* S/W ACK recevied by Client ticks the TX */
+
+static LIST_HEAD(mbox_cons);
+static DEFINE_MUTEX(con_mutex);
+
+static int _add_to_rbuf(struct mbox_chan *chan, void *mssg)
+{
+	int idx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	/* See if there is any space left */
+	if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
+		spin_unlock_irqrestore(&chan->lock, flags);
+		return -ENOMEM;
+	}
+
+	idx = chan->msg_free;
+	chan->msg_data[idx] = mssg;
+	chan->msg_count++;
+
+	if (idx == MBOX_TX_QUEUE_LEN - 1)
+		chan->msg_free = 0;
+	else
+		chan->msg_free++;
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return idx;
+}
+
+static void _msg_submit(struct mbox_chan *chan)
+{
+	unsigned count, idx;
+	unsigned long flags;
+	void *data;
+	int err;
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	if (!chan->msg_count || chan->active_req) {
+		spin_unlock_irqrestore(&chan->lock, flags);
+		return;
+	}
+
+	count = chan->msg_count;
+	idx = chan->msg_free;
+	if (idx >= count)
+		idx -= count;
+	else
+		idx += MBOX_TX_QUEUE_LEN - count;
+
+	data = chan->msg_data[idx];
+
+	/* Try to submit a message to the MBOX controller */
+	err = chan->mbox->ops->send_data(chan, data);
+	if (!err) {
+		chan->active_req = data;
+		chan->msg_count--;
+	}
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static void tx_tick(struct mbox_chan *chan, int r)
+{
+	unsigned long flags;
+	void *mssg;
+
+	spin_lock_irqsave(&chan->lock, flags);
+	mssg = chan->active_req;
+	chan->active_req = NULL;
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	/* Submit next message */
+	_msg_submit(chan);
+
+	/* Notify the client */
+	if (chan->cl->tx_block)
+		complete(&chan->tx_complete);
+	else if (mssg && chan->cl->tx_done)
+		chan->cl->tx_done(chan->cl, mssg, r);
+}
+
+static void poll_txdone(unsigned long data)
+{
+	struct mbox_controller *mbox = (struct mbox_controller *)data;
+	bool txdone, resched = false;
+	int i;
+
+	for (i = 0; i < mbox->num_chans; i++) {
+		struct mbox_chan *chan = &mbox->chans[i];
+
+		if (chan->active_req && chan->cl) {
+			resched = true;
+			txdone = chan->mbox->ops->last_tx_done(chan);
+			if (txdone)
+				tx_tick(chan, 0);
+		}
+	}
+
+	if (resched)
+		mod_timer(&mbox->poll,
+			jiffies + msecs_to_jiffies(mbox->period));
+}
+
+/**
+ * mbox_chan_received_data - A way for controller driver to push data
+ *				received from remote to the upper layer.
+ * @chan: Pointer to the mailbox channel on which RX happened.
+ * @data: Client specific message typecasted as void *
+ *
+ * After startup and before shutdown any data received on the chan
+ * is passed on to the API via atomic mbox_chan_received_data().
+ * The controller should ACK the RX only after this call returns.
+ */
+void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
+{
+	/* No buffering the received data */
+	if (chan->cl->rx_callback)
+		chan->cl->rx_callback(chan->cl, mssg);
+}
+EXPORT_SYMBOL_GPL(mbox_chan_received_data);
+
+/**
+ * mbox_chan_txdone - A way for controller driver to notify the
+ *			framework that the last TX has completed.
+ * @chan: Pointer to the mailbox chan on which TX happened.
+ * @r: Status of last TX - OK or ERROR
+ *
+ * The controller that has IRQ for TX ACK calls this atomic API
+ * to tick the TX state machine. It works only if txdone_irq
+ * is set by the controller.
+ */
+void mbox_chan_txdone(struct mbox_chan *chan, int r)
+{
+	if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
+		pr_err("Controller can't run the TX ticker\n");
+		return;
+	}
+
+	tx_tick(chan, r);
+}
+EXPORT_SYMBOL_GPL(mbox_chan_txdone);
+
+/**
+ * mbox_client_txdone - The way for a client to run the TX state machine.
+ * @chan: Mailbox channel assigned to this client.
+ * @r: Success status of last transmission.
+ *
+ * The client/protocol had received some 'ACK' packet and it notifies
+ * the API that the last packet was sent successfully. This only works
+ * if the controller can't sense TX-Done.
+ */
+void mbox_client_txdone(struct mbox_chan *chan, int r)
+{
+	if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
+		pr_err("Client can't run the TX ticker\n");
+		return;
+	}
+
+	tx_tick(chan, r);
+}
+EXPORT_SYMBOL_GPL(mbox_client_txdone);
+
+/**
+ * mbox_client_peek_data - A way for client driver to pull data
+ *			received from remote by the controller.
+ * @chan: Mailbox channel assigned to this client.
+ *
+ * A poke to controller driver for any received data.
+ * The data is actually passed onto client via the
+ * mbox_chan_received_data()
+ * The call can be made from atomic context, so the controller's
+ * implementation of peek_data() must not sleep.
+ *
+ * Return: True, if controller has, and is going to push after this,
+ *          some data.
+ *         False, if controller doesn't have any data to be read.
+ */
+bool mbox_client_peek_data(struct mbox_chan *chan)
+{
+	if (chan->mbox->ops->peek_data)
+		return chan->mbox->ops->peek_data(chan);
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(mbox_client_peek_data);
+
+/**
+ * mbox_send_message -	For client to submit a message to be
+ *				sent to the remote.
+ * @chan: Mailbox channel assigned to this client.
+ * @mssg: Client specific message typecasted.
+ *
+ * For client to submit data to the controller destined for a remote
+ * processor. If the client had set 'tx_block', the call will return
+ * either when the remote receives the data or when 'tx_tout' millisecs
+ * run out.
+ *  In non-blocking mode, the requests are buffered by the API and a
+ * non-negative token is returned for each queued request. If the request
+ * is not queued, a negative token is returned. Upon failure or successful
+ * TX, the API calls 'tx_done' from atomic context, from which the client
+ * could submit yet another request.
+ *  In blocking mode, 'tx_done' is not called, effectively making the
+ * queue length 1.
+ * The pointer to message should be preserved until it is sent
+ * over the chan, i.e, tx_done() is made.
+ * This function could be called from atomic context as it simply
+ * queues the data and returns a token against the request.
+ *
+ * Return: Non-negative integer for successful submission (non-blocking mode)
+ *	or transmission over chan (blocking mode).
+ *	Negative value denotes failure.
+ */
+int mbox_send_message(struct mbox_chan *chan, void *mssg)
+{
+	int t;
+
+	if (!chan || !chan->cl)
+		return -EINVAL;
+
+	t = _add_to_rbuf(chan, mssg);
+	if (t < 0) {
+		pr_err("Try increasing MBOX_TX_QUEUE_LEN\n");
+		return t;
+	}
+
+	_msg_submit(chan);
+
+	reinit_completion(&chan->tx_complete);
+
+	if (chan->txdone_method	== TXDONE_BY_POLL)
+		poll_txdone((unsigned long)chan->mbox);
+
+	if (chan->cl->tx_block && chan->active_req) {
+		unsigned long wait;
+		int ret;
+
+		if (!chan->cl->tx_tout) /* wait for ever */
+			wait = msecs_to_jiffies(3600000);
+		else
+			wait = msecs_to_jiffies(chan->cl->tx_tout);
+
+		ret = wait_for_completion_timeout(&chan->tx_complete, wait);
+		if (ret == 0) {
+			t = -EIO;
+			tx_tick(chan, -EIO);
+		}
+	}
+
+	return t;
+}
+EXPORT_SYMBOL_GPL(mbox_send_message);
+
+/**
+ * mbox_request_channel - Request a mailbox channel.
+ * @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: Pointer to the channel assigned to the client if successful.
+ *		ERR_PTR for request failure.
+ */
+struct mbox_chan *mbox_request_channel(const struct mbox_client *cl)
+{
+	struct device *dev = cl->dev;
+	struct mbox_controller *mbox;
+	struct of_phandle_args spec;
+	struct mbox_chan *chan;
+	unsigned long flags;
+	int count, i, ret;
+
+	if (!dev || !dev->of_node) {
+		pr_err("%s: No owner device node\n", __func__);
+		return ERR_PTR(-ENODEV);
+	}
+
+	count = of_property_count_strings(dev->of_node, "mbox-names");
+	if (count < 0) {
+		pr_err("%s: mbox-names property of node '%s' missing\n",
+			__func__, dev->of_node->full_name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	mutex_lock(&con_mutex);
+
+	ret = -ENODEV;
+	for (i = 0; i < count; i++) {
+		const char *s;
+
+		if (of_property_read_string_index(dev->of_node,
+						"mbox-names", i, &s))
+			continue;
+
+		if (strcmp(cl->chan_name, s))
+			continue;
+
+		if (of_parse_phandle_with_args(dev->of_node,
+					 "mbox", "#mbox-cells",	i, &spec))
+			continue;
+
+		chan = NULL;
+		list_for_each_entry(mbox, &mbox_cons, node)
+			if (mbox->dev->of_node == spec.np) {
+				chan = mbox->of_xlate(mbox, &spec);
+				break;
+			}
+
+		of_node_put(spec.np);
+
+		if (!chan)
+			continue;
+
+		ret = -EBUSY;
+		if (!chan->cl && try_module_get(mbox->dev->driver->owner))
+			break;
+	}
+
+	if (i == count) {
+		mutex_unlock(&con_mutex);
+		return ERR_PTR(ret);
+	}
+
+	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);
+
+	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);
+	}
+
+	mutex_unlock(&con_mutex);
+	return chan;
+}
+EXPORT_SYMBOL_GPL(mbox_request_channel);
+
+/**
+ * mbox_free_channel - The client relinquishes control of a mailbox
+ *			channel by this call.
+ * @chan: The mailbox channel to be freed.
+ */
+void mbox_free_channel(struct mbox_chan *chan)
+{
+	unsigned long flags;
+
+	if (!chan || !chan->cl)
+		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;
+
+	module_put(chan->mbox->dev->driver->owner);
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mbox_free_channel);
+
+static struct mbox_chan *
+of_mbox_index_xlate(struct mbox_controller *mbox,
+				const struct of_phandle_args *sp)
+{
+	int ind = sp->args[0];
+
+	if (ind >= mbox->num_chans)
+		return NULL;
+
+	return &mbox->chans[ind];
+}
+
+/**
+ * mbox_controller_register - Register the mailbox controller
+ * @mbox:	Pointer to the mailbox controller.
+ *
+ * The controller driver registers its communication chans
+ */
+int 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);
+	}
+
+	if (!mbox->of_xlate)
+		mbox->of_xlate = of_mbox_index_xlate;
+
+	mutex_lock(&con_mutex);
+	list_add_tail(&mbox->node, &mbox_cons);
+	mutex_unlock(&con_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mbox_controller_register);
+
+/**
+ * mbox_controller_unregister - UnRegister the mailbox controller
+ * @mbox:	Pointer to the mailbox controller.
+ */
+void mbox_controller_unregister(struct mbox_controller *mbox)
+{
+	int i;
+
+	if (!mbox)
+		return;
+
+	mutex_lock(&con_mutex);
+
+	list_del(&mbox->node);
+
+	for (i = 0; i < mbox->num_chans; i++)
+		mbox_free_channel(&mbox->chans[i]);
+
+	del_timer_sync(&mbox->poll);
+
+	mutex_unlock(&con_mutex);
+}
+EXPORT_SYMBOL_GPL(mbox_controller_unregister);
diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h
new file mode 100644
index 0000000..53eb078
--- /dev/null
+++ b/include/linux/mailbox_client.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 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>
+
+struct mbox_chan;
+
+/**
+ * struct mbox_client - User of a mailbox
+ * @dev:		The client device
+ * @chan_name:		The "controller:channel" this client wants
+ * @rx_callback:	Atomic callback to provide client the data received
+ * @tx_done:		Atomic callback to tell client of data transmission
+ * @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.
+ */
+struct mbox_client {
+	struct device *dev;
+	const char *chan_name;
+	void (*rx_callback)(struct mbox_client *cl, void *mssg);
+	void (*tx_done)(struct mbox_client *cl, void *mssg, int r);
+	bool tx_block;
+	unsigned long tx_tout;
+	bool knows_txdone;
+};
+
+struct mbox_chan *mbox_request_channel(const struct mbox_client *cl);
+int mbox_send_message(struct mbox_chan *chan, void *mssg);
+void mbox_client_txdone(struct mbox_chan *chan, int r);
+void mbox_free_channel(struct mbox_chan *chan);
+
+#endif /* __MAILBOX_CLIENT_H */
diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
new file mode 100644
index 0000000..49bd64e
--- /dev/null
+++ b/include/linux/mailbox_controller.h
@@ -0,0 +1,121 @@
+/*
+ * 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>
+
+struct mbox_chan;
+
+/**
+ * struct mbox_chan_ops - s/w representation of a communication chan
+ * @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
+ *		block.
+ * @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.
+ * @shutdown:	Called when a client relinquishes control of a chan.
+ *		This call may block too. The controller must not forwared
+ *		any received data anymore.
+ * @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.
+ *		  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 chans
+ * @dev:		Device backing this controller
+ * @controller_name:	Literal name of the controller.
+ * @ops:		Operators that work on each communication chan
+ * @chans:		Null terminated array of chans.
+ * @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
+ */
+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);
+	/*
+	 * If the controller supports only TXDONE_BY_POLL,
+	 * this timer polls all the links for txdone.
+	 */
+	struct timer_list poll;
+	unsigned period;
+	/* Hook to add to the global controller list */
+	struct list_head node;
+} __aligned(32);
+
+/*
+ * 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 transferr 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.
+ * REVIST: 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 {
+	struct mbox_controller *mbox; /* Parent Controller */
+	unsigned txdone_method;
+
+	/* client */
+	struct mbox_client *cl;
+	struct completion tx_complete;
+
+	void *active_req;
+	unsigned msg_count, msg_free;
+	void *msg_data[MBOX_TX_QUEUE_LEN];
+	/* Access to the channel */
+	spinlock_t lock;
+
+	/* Private data for controller */
+	void *con_priv;
+} __aligned(32);
+
+int mbox_controller_register(struct mbox_controller *mbox);
+void mbox_chan_received_data(struct mbox_chan *chan, void *data);
+void mbox_chan_txdone(struct mbox_chan *chan, int r);
+void mbox_controller_unregister(struct mbox_controller *mbox);
+
+#endif /* __MAILBOX_CONTROLLER_H */
-- 
1.8.1.2

[PATCHv6 3/3] mailbox: Fix deleteing poll timer

[Jassi Brar]

From: LeyFoon Tan <lftan.linux@gmail.com>

Try to delete the timer only if it was init/used.

Signed-off-by: LeyFoon Tan <lftan.linux@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 drivers/mailbox/mailbox.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 336fa10..ae4abd9 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -480,7 +480,8 @@ void mbox_controller_unregister(struct mbox_controller *mbox)
 	for (i = 0; i < mbox->num_chans; i++)
 		mbox_free_channel(&mbox->chans[i]);
 
-	del_timer_sync(&mbox->poll);
+	if (mbox->txdone_poll)
+		del_timer_sync(&mbox->poll);
 
 	mutex_unlock(&con_mutex);
 }
-- 
1.8.1.2

Re: [PATCHv6 2/3] mailbox: Introduce framework for mailbox

[Jassi Brar]

On 3 June 2014 00:01, Jassi Brar <jaswinder.singh@linaro.org> wrote:

> diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
> new file mode 100644
> index 0000000..49bd64e
> --- /dev/null
> +++ b/include/linux/mailbox_controller.h
> @@ -0,0 +1,121 @@
> +/*
> + * 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>
> +
> +struct mbox_chan;
> +
> +/**
> + * struct mbox_chan_ops - s/w representation of a communication chan
> + * @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
> + *             block.
> + * @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.
> + * @shutdown:  Called when a client relinquishes control of a chan.
> + *             This call may block too. The controller must not forwared
> + *             any received data anymore.
> + * @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.
> + *               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 chans
> + * @dev:               Device backing this controller
> + * @controller_name:   Literal name of the controller.
> + * @ops:               Operators that work on each communication chan
> + * @chans:             Null terminated array of chans.
> + * @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
> + */
> +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);
> +       /*
> +        * If the controller supports only TXDONE_BY_POLL,
> +        * this timer polls all the links for txdone.
> +        */
> +       struct timer_list poll;
> +       unsigned period;
> +       /* Hook to add to the global controller list */
> +       struct list_head node;
> +} __aligned(32);
> +
> +/*
> + * 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 transferr 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.
> + * REVIST: 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 {
> +       struct mbox_controller *mbox; /* Parent Controller */
> +       unsigned txdone_method;
> +
> +       /* client */
> +       struct mbox_client *cl;
> +       struct completion tx_complete;
> +
> +       void *active_req;
> +       unsigned msg_count, msg_free;
> +       void *msg_data[MBOX_TX_QUEUE_LEN];
> +       /* Access to the channel */
> +       spinlock_t lock;
> +
> +       /* Private data for controller */
> +       void *con_priv;
> +} __aligned(32);
> +
I forgot to drop the unneeded __aligned attribute. Other than this, I
am keen on knowing what else.

Thanks
Jassi

Re: [PATCHv6 2/3] mailbox: Introduce framework for mailbox

[Matt Porter]

On Tue, Jun 03, 2014 at 12:01:24AM +0530, Jassi Brar wrote:
> Introduce common framework for client/protocol drivers and
> controller drivers of Inter-Processor-Communication (IPC).
> 
> Client driver developers should have a look at
>  include/linux/mailbox_client.h to understand the part of
> the API exposed to client drivers.
> Similarly controller driver developers should have a look
> at include/linux/mailbox_controller.h
> 
> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
> ---
>  .../devicetree/bindings/mailbox/mailbox.txt        |  33 ++
>  drivers/mailbox/Makefile                           |   4 +
>  drivers/mailbox/mailbox.c                          | 487 +++++++++++++++++++++
>  include/linux/mailbox_client.h                     |  45 ++
>  include/linux/mailbox_controller.h                 | 121 +++++

Could you please include all the DT maintainers here? It's a generic
binding that needs wider review and an ack. The binding should be
separated as noted below.

>From Documentations/devicetree/bindings/submitting-patches.txt:

I. For patch submitters

  0) Normal patch submission rules from Documentation/SubmittingPatches
     applies.

  1) The Documentation/ portion of the patch should be a separate patch.

  2) Submit the entire series to the devicetree mailinglist at

       devicetree@vger.kernel.org

-Matt

Re: [PATCHv6 2/3] mailbox: Introduce framework for mailbox

[Jassi Brar]

On 5 June 2014 16:21, Matt Porter <mporter@linaro.org> wrote:
> On Tue, Jun 03, 2014 at 12:01:24AM +0530, Jassi Brar wrote:
>> Introduce common framework for client/protocol drivers and
>> controller drivers of Inter-Processor-Communication (IPC).
>>
>> Client driver developers should have a look at
>>  include/linux/mailbox_client.h to understand the part of
>> the API exposed to client drivers.
>> Similarly controller driver developers should have a look
>> at include/linux/mailbox_controller.h
>>
>> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
>> ---
>>  .../devicetree/bindings/mailbox/mailbox.txt        |  33 ++
>>  drivers/mailbox/Makefile                           |   4 +
>>  drivers/mailbox/mailbox.c                          | 487 +++++++++++++++++++++
>>  include/linux/mailbox_client.h                     |  45 ++
>>  include/linux/mailbox_controller.h                 | 121 +++++
>
> Could you please include all the DT maintainers here? It's a generic
> binding that needs wider review and an ack. The binding should be
> separated as noted below.
>
> From Documentations/devicetree/bindings/submitting-patches.txt:
>
> I. For patch submitters
>
>   0) Normal patch submission rules from Documentation/SubmittingPatches
>      applies.
>
>   1) The Documentation/ portion of the patch should be a separate patch.
>
>   2) Submit the entire series to the devicetree mailinglist at
>
>        devicetree@vger.kernel.org
>
Thanks. I missed CC'ing DT ML.  I remember patches with DT bindings
and parser code getting upstream... and actually see better sense in
that. But I guess I have to separate out the bindings.

Thanks
Jassi

Re: [PATCHv6 2/3] mailbox: Introduce framework for mailbox

[Jassi Brar]

On 5 June 2014 16:21, Matt Porter <mporter-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Tue, Jun 03, 2014 at 12:01:24AM +0530, Jassi Brar wrote:
>> Introduce common framework for client/protocol drivers and
>> controller drivers of Inter-Processor-Communication (IPC).
>>
>> Client driver developers should have a look at
>>  include/linux/mailbox_client.h to understand the part of
>> the API exposed to client drivers.
>> Similarly controller driver developers should have a look
>> at include/linux/mailbox_controller.h
>>
>> Signed-off-by: Jassi Brar <jaswinder.singh-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> ---
>>  .../devicetree/bindings/mailbox/mailbox.txt        |  33 ++
>>  drivers/mailbox/Makefile                           |   4 +
>>  drivers/mailbox/mailbox.c                          | 487 +++++++++++++++++++++
>>  include/linux/mailbox_client.h                     |  45 ++
>>  include/linux/mailbox_controller.h                 | 121 +++++
>
> Could you please include all the DT maintainers here? It's a generic
> binding that needs wider review and an ack. The binding should be
> separated as noted below.
>
> From Documentations/devicetree/bindings/submitting-patches.txt:
>
> I. For patch submitters
>
>   0) Normal patch submission rules from Documentation/SubmittingPatches
>      applies.
>
>   1) The Documentation/ portion of the patch should be a separate patch.
>
>   2) Submit the entire series to the devicetree mailinglist at
>
>        devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>
Thanks. I missed CC'ing DT ML.  I remember patches with DT bindings
and parser code getting upstream... and actually see better sense in
that. But I guess I have to separate out the bindings.

Thanks
Jassi
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