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

Pull mailbox updates from Jassi Brar.

* 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox/bcm2835: Fix mailbox full detection.
  dt: mailbox: Remove 'mbox-names property is discouraged' message from binding
  mailbox: Add ability for clients to request channels by name
  mailbox: Enable BCM2835 mailbox support
  dt/bindings: Add binding for the BCM2835 mailbox driver
  mailbox: Fix up error handling in mbox_request_channel()
  mailbox: Make mbox_chan_ops const
  mailbox: altera: Add dependency on HAS_IOMEM

Documentation/devicetree/bindings/mailbox/brcm,bcm2835-mbox.txt

+Broadcom BCM2835 VideoCore mailbox IPC
+
+Required properties:
+
+- compatible:	Should be "brcm,bcm2835-mbox"
+- reg:		Specifies base physical address and size of the registers
+- interrupts:	The interrupt number
+		  See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
+- #mbox-cells:	Specifies the number of cells needed to encode a mailbox
+		  channel. The value shall be 0, since there is only one
+		  mailbox channel implemented by the device.
+
+Example:
+
+mailbox: mailbox@7e00b800 {
+	compatible = "brcm,bcm2835-mbox";
+	reg = <0x7e00b880 0x40>;
+	interrupts = <0 1>;
+	#mbox-cells = <0>;
+};
+
+firmware: firmware {
+	compatible = "raspberrypi,firmware";
+	mboxes = <&mailbox>;
+	#power-domain-cells = <1>;
+};

Documentation/devicetree/bindings/mailbox/mailbox.txt

@@ -22,17 +22,11 @@ Required property:
 - mboxes: List of phandle and mailbox channel specifiers.
 
 Optional property:
-- mbox-names: List of identifier strings for each mailbox channel
-		required by the client. The use of this property
-		is discouraged in favor of using index in list of
-		'mboxes' while requesting a mailbox. Instead the
-		platforms may define channel indices, in DT headers,
-		to something legible.
+- mbox-names: List of identifier strings for each mailbox channel.
 
 Example:
 	pwr_cntrl: power {
 		...
 		mbox-names = "pwr-ctrl", "rpc";
-		mboxes = <&mailbox 0
-			&mailbox 1>;
+		mboxes = <&mailbox 0 &mailbox 1>;
 	};

drivers/mailbox/Kconfig

@@ -56,8 +56,18 @@ config PCC
 
 config ALTERA_MBOX
 	tristate "Altera Mailbox"
+	depends on HAS_IOMEM
 	help
 	  An implementation of the Altera Mailbox soft core. It is used
 	  to send message between processors. Say Y here if you want to use the
 	  Altera mailbox support.
+
+config BCM2835_MBOX
+	tristate "BCM2835 Mailbox"
+	depends on ARCH_BCM2835
+	help
+	  An implementation of the BCM2385 Mailbox.  It is used to invoke
+	  the services of the Videocore. Say Y here if you want to use the
+	  BCM2835 Mailbox.
+
 endif

drivers/mailbox/Makefile

@@ -11,3 +11,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 obj-$(CONFIG_PCC)		+= pcc.o
 
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
+
+obj-$(CONFIG_BCM2835_MBOX)	+= bcm2835-mailbox.o

drivers/mailbox/arm_mhu.c

@@ -110,7 +110,7 @@ static void mhu_shutdown(struct mbox_chan *chan)
 	free_irq(mlink->irq, chan);
 }
 
-static struct mbox_chan_ops mhu_ops = {
+static const struct mbox_chan_ops mhu_ops = {
 	.send_data = mhu_send_data,
 	.startup = mhu_startup,
 	.shutdown = mhu_shutdown,

drivers/mailbox/bcm2835-mailbox.c

+/*
+ *  Copyright (C) 2010,2015 Broadcom
+ *  Copyright (C) 2013-2014 Lubomir Rintel
+ *  Copyright (C) 2013 Craig McGeachie
+ *
+ * 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.
+ *
+ * This device provides a mechanism for writing to the mailboxes,
+ * that are shared between the ARM and the VideoCore processor
+ *
+ * Parts of the driver are based on:
+ *  - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was
+ *    obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/
+ *    linux.git
+ *  - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at
+ *    https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/
+ *    mailbox/bcm2835-ipc.c
+ *  - documentation available on the following web site:
+ *    https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* Mailboxes */
+#define ARM_0_MAIL0	0x00
+#define ARM_0_MAIL1	0x20
+
+/*
+ * Mailbox registers. We basically only support mailbox 0 & 1. We
+ * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See
+ * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about
+ * the placement of memory barriers.
+ */
+#define MAIL0_RD	(ARM_0_MAIL0 + 0x00)
+#define MAIL0_POL	(ARM_0_MAIL0 + 0x10)
+#define MAIL0_STA	(ARM_0_MAIL0 + 0x18)
+#define MAIL0_CNF	(ARM_0_MAIL0 + 0x1C)
+#define MAIL1_WRT	(ARM_0_MAIL1 + 0x00)
+#define MAIL1_STA	(ARM_0_MAIL1 + 0x18)
+
+/* Status register: FIFO state. */
+#define ARM_MS_FULL		BIT(31)
+#define ARM_MS_EMPTY		BIT(30)
+
+/* Configuration register: Enable interrupts. */
+#define ARM_MC_IHAVEDATAIRQEN	BIT(0)
+
+struct bcm2835_mbox {
+	void __iomem *regs;
+	spinlock_t lock;
+	struct mbox_controller controller;
+};
+
+static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link)
+{
+	return container_of(link->mbox, struct bcm2835_mbox, controller);
+}
+
+static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id)
+{
+	struct bcm2835_mbox *mbox = dev_id;
+	struct device *dev = mbox->controller.dev;
+	struct mbox_chan *link = &mbox->controller.chans[0];
+
+	while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) {
+		u32 msg = readl(mbox->regs + MAIL0_RD);
+		dev_dbg(dev, "Reply 0x%08X\n", msg);
+		mbox_chan_received_data(link, &msg);
+	}
+	return IRQ_HANDLED;
+}
+
+static int bcm2835_send_data(struct mbox_chan *link, void *data)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+	u32 msg = *(u32 *)data;
+
+	spin_lock(&mbox->lock);
+	writel(msg, mbox->regs + MAIL1_WRT);
+	dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg);
+	spin_unlock(&mbox->lock);
+	return 0;
+}
+
+static int bcm2835_startup(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+
+	/* Enable the interrupt on data reception */
+	writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF);
+
+	return 0;
+}
+
+static void bcm2835_shutdown(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+
+	writel(0, mbox->regs + MAIL0_CNF);
+}
+
+static bool bcm2835_last_tx_done(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+	bool ret;
+
+	spin_lock(&mbox->lock);
+	ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
+	spin_unlock(&mbox->lock);
+	return ret;
+}
+
+static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
+	.send_data	= bcm2835_send_data,
+	.startup	= bcm2835_startup,
+	.shutdown	= bcm2835_shutdown,
+	.last_tx_done	= bcm2835_last_tx_done
+};
+
+static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox,
+		    const struct of_phandle_args *sp)
+{
+	if (sp->args_count != 0)
+		return NULL;
+
+	return &mbox->chans[0];
+}
+
+static int bcm2835_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ret = 0;
+	struct resource *iomem;
+	struct bcm2835_mbox *mbox;
+
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (mbox == NULL)
+		return -ENOMEM;
+	spin_lock_init(&mbox->lock);
+
+	ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0),
+			       bcm2835_mbox_irq, 0, dev_name(dev), mbox);
+	if (ret) {
+		dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
+			ret);
+		return -ENODEV;
+	}
+
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
+	if (IS_ERR(mbox->regs)) {
+		ret = PTR_ERR(mbox->regs);
+		dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
+		return ret;
+	}
+
+	mbox->controller.txdone_poll = true;
+	mbox->controller.txpoll_period = 5;
+	mbox->controller.ops = &bcm2835_mbox_chan_ops;
+	mbox->controller.of_xlate = &bcm2835_mbox_index_xlate;
+	mbox->controller.dev = dev;
+	mbox->controller.num_chans = 1;
+	mbox->controller.chans = devm_kzalloc(dev,
+		sizeof(*mbox->controller.chans), GFP_KERNEL);
+	if (!mbox->controller.chans)
+		return -ENOMEM;
+
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, mbox);
+	dev_info(dev, "mailbox enabled\n");
+
+	return ret;
+}
+
+static int bcm2835_mbox_remove(struct platform_device *pdev)
+{
+	struct bcm2835_mbox *mbox = platform_get_drvdata(pdev);
+	mbox_controller_unregister(&mbox->controller);
+	return 0;
+}
+
+static const struct of_device_id bcm2835_mbox_of_match[] = {
+	{ .compatible = "brcm,bcm2835-mbox", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match);
+
+static struct platform_driver bcm2835_mbox_driver = {
+	.driver = {
+		.name = "bcm2835-mbox",
+		.owner = THIS_MODULE,
+		.of_match_table = bcm2835_mbox_of_match,
+	},
+	.probe		= bcm2835_mbox_probe,
+	.remove		= bcm2835_mbox_remove,
+};
+module_platform_driver(bcm2835_mbox_driver);
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
+MODULE_LICENSE("GPL v2");

drivers/mailbox/mailbox-altera.c

@@ -285,7 +285,7 @@ static void altera_mbox_shutdown(struct mbox_chan *chan)
 	}
 }
 
-static struct mbox_chan_ops altera_mbox_ops = {
+static const struct mbox_chan_ops altera_mbox_ops = {
 	.send_data = altera_mbox_send_data,
 	.startup = altera_mbox_startup,
 	.shutdown = altera_mbox_shutdown,

drivers/mailbox/mailbox.c

@@ -318,7 +318,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 		return ERR_PTR(-ENODEV);
 	}
 
-	chan = NULL;
+	chan = ERR_PTR(-EPROBE_DEFER);
 	list_for_each_entry(mbox, &mbox_cons, node)
 		if (mbox->dev->of_node == spec.np) {
 			chan = mbox->of_xlate(mbox, &spec);
@@ -327,7 +327,12 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 
 	of_node_put(spec.np);
 
-	if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
+	if (IS_ERR(chan)) {
+		mutex_unlock(&con_mutex);
+		return chan;
+	}
+
+	if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
 		dev_dbg(dev, "%s: mailbox not free\n", __func__);
 		mutex_unlock(&con_mutex);
 		return ERR_PTR(-EBUSY);
@@ -357,6 +362,35 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 }
 EXPORT_SYMBOL_GPL(mbox_request_channel);
 
+struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
+					      const char *name)
+{
+	struct device_node *np = cl->dev->of_node;
+	struct property *prop;
+	const char *mbox_name;
+	int index = 0;
+
+	if (!np) {
+		dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
+		return ERR_PTR(-ENOSYS);
+	}
+
+	if (!of_get_property(np, "mbox-names", NULL)) {
+		dev_err(cl->dev,
+			"%s() requires an \"mbox-names\" property\n", __func__);
+		return ERR_PTR(-ENOSYS);
+	}
+
+	of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
+		if (!strncmp(name, mbox_name, strlen(name)))
+			break;
+		index++;
+	}
+
+	return mbox_request_channel(cl, index);
+}
+EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
+
 /**
  * mbox_free_channel - The client relinquishes control of a mailbox
  *			channel by this call.
@@ -390,7 +424,7 @@ of_mbox_index_xlate(struct mbox_controller *mbox,
 	int ind = sp->args[0];
 
 	if (ind >= mbox->num_chans)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	return &mbox->chans[ind];
 }

drivers/mailbox/omap-mailbox.c

@@ -604,7 +604,7 @@ static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
 	return ret;
 }
 
-static struct mbox_chan_ops omap_mbox_chan_ops = {
+static const struct mbox_chan_ops omap_mbox_chan_ops = {
 	.startup        = omap_mbox_chan_startup,
 	.send_data      = omap_mbox_chan_send_data,
 	.shutdown       = omap_mbox_chan_shutdown,
@@ -639,18 +639,18 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
 
 	mdev = container_of(controller, struct omap_mbox_device, controller);
 	if (WARN_ON(!mdev))
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	node = of_find_node_by_phandle(phandle);
 	if (!node) {
 		pr_err("%s: could not find node phandle 0x%x\n",
 		       __func__, phandle);
-		return NULL;
+		return ERR_PTR(-ENODEV);
 	}
 
 	mbox = omap_mbox_device_find(mdev, node->name);
 	of_node_put(node);
-	return mbox ? mbox->chan : NULL;
+	return mbox ? mbox->chan : ERR_PTR(-ENOENT);
 }
 
 static int omap_mbox_probe(struct platform_device *pdev)

drivers/mailbox/pcc.c

@@ -198,7 +198,7 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
 	return 0;
 }
 
-static struct mbox_chan_ops pcc_chan_ops = {
+static const struct mbox_chan_ops pcc_chan_ops = {
 	.send_data = pcc_send_data,
 };
 

include/linux/mailbox_client.h

@@ -40,6 +40,8 @@ struct mbox_client {
 	void (*tx_done)(struct mbox_client *cl, void *mssg, int r);
 };
 
+struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
+					      const char *name);
 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 */

include/linux/mailbox_controller.h

@@ -72,7 +72,7 @@ struct mbox_chan_ops {
  */
 struct mbox_controller {
 	struct device *dev;
-	struct mbox_chan_ops *ops;
+	const struct mbox_chan_ops *ops;
 	struct mbox_chan *chans;
 	int num_chans;
 	bool txdone_irq;