Commit 0bae6af6 authored by Lubomir Rintel's avatar Lubomir Rintel Committed by Jassi Brar
Browse files

mailbox: Enable BCM2835 mailbox support 



This mailbox driver provides a single mailbox channel to write 32-bit
values to the VPU and get a 32-bit response.  The Raspberry Pi
firmware uses this mailbox channel to implement firmware calls, while
Roku 2 (despite being derived from the same firmware tree) doesn't.

The driver was originally submitted by Lubomir, based on the
out-of-tree 2708 mailbox driver.  Eric Anholt fixed it up for
upstreaming, with the major functional change being that it now has no
notion of multiple channels (since that is a firmware-dependent
concept) and instead the raspberrypi-firmware driver will do that
bit-twiddling in its own messages.
[Jassi: made the 'mbox_chan_ops' struct as const and removed a redundant
variable]

Signed-off-by: default avatarLubomir Rintel <lkundrak@v3.sk>
Signed-off-by: default avatarCraig McGeachie <slapdau@yahoo.com.au>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Acked-by: default avatarStephen Warren <swarren@wwwdotorg.org>
Signed-off-by: default avatarJassi Brar <jaswinder.singh@linaro.org>
parent d4b5c782

drivers/mailbox/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -61,4 +61,13 @@ config ALTERA_MBOX 
	  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

+2 −0
Original line number Diff line number Diff line
@@ -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/bcm2835-mailbox.c

0 → 100644
+216 −0
Original line number Diff line number Diff line 
/*

 *  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)



/* 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 + MAIL0_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");

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