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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010,2015 Broadcom
* Copyright (C) 2013-2014 Lubomir Rintel
* Copyright (C) 2013 Craig McGeachie
*
* 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 ERR_PTR(-EINVAL);
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 = devm_mbox_controller_register(dev, &mbox->controller);
if (ret)
return ret;
platform_set_drvdata(pdev, mbox);
dev_info(dev, "mailbox enabled\n");
return ret;
}
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",
.of_match_table = bcm2835_mbox_of_match,
},
.probe = bcm2835_mbox_probe,
};
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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