1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2010,2015 Broadcom
4 * Copyright (C) 2013-2014 Lubomir Rintel
5 * Copyright (C) 2013 Craig McGeachie
7 * Parts of the driver are based on:
8 * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was
9 * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/
11 * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at
12 * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/
13 * mailbox/bcm2835-ipc.c
14 * - documentation available on the following web site:
15 * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
18 #include <linux/device.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/err.h>
21 #include <linux/interrupt.h>
22 #include <linux/irq.h>
23 #include <linux/kernel.h>
24 #include <linux/mailbox_controller.h>
25 #include <linux/module.h>
26 #include <linux/of_address.h>
27 #include <linux/of_irq.h>
28 #include <linux/platform_device.h>
29 #include <linux/spinlock.h>
32 #define ARM_0_MAIL0 0x00
33 #define ARM_0_MAIL1 0x20
36 * Mailbox registers. We basically only support mailbox 0 & 1. We
37 * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See
38 * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about
39 * the placement of memory barriers.
41 #define MAIL0_RD (ARM_0_MAIL0 + 0x00)
42 #define MAIL0_POL (ARM_0_MAIL0 + 0x10)
43 #define MAIL0_STA (ARM_0_MAIL0 + 0x18)
44 #define MAIL0_CNF (ARM_0_MAIL0 + 0x1C)
45 #define MAIL1_WRT (ARM_0_MAIL1 + 0x00)
46 #define MAIL1_STA (ARM_0_MAIL1 + 0x18)
48 /* On ARCH_BCM270x these come through <linux/interrupt.h> (arm_control.h ) */
50 /* Status register: FIFO state. */
51 #define ARM_MS_FULL BIT(31)
52 #define ARM_MS_EMPTY BIT(30)
54 /* Configuration register: Enable interrupts. */
55 #define ARM_MC_IHAVEDATAIRQEN BIT(0)
61 struct mbox_controller controller;
64 static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link)
66 return container_of(link->mbox, struct bcm2835_mbox, controller);
69 static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id)
71 struct bcm2835_mbox *mbox = dev_id;
72 struct device *dev = mbox->controller.dev;
73 struct mbox_chan *link = &mbox->controller.chans[0];
75 while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) {
76 u32 msg = readl(mbox->regs + MAIL0_RD);
77 dev_dbg(dev, "Reply 0x%08X\n", msg);
78 mbox_chan_received_data(link, &msg);
83 static int bcm2835_send_data(struct mbox_chan *link, void *data)
85 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
86 u32 msg = *(u32 *)data;
88 spin_lock(&mbox->lock);
89 writel(msg, mbox->regs + MAIL1_WRT);
90 dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg);
91 spin_unlock(&mbox->lock);
95 static int bcm2835_startup(struct mbox_chan *link)
97 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
99 /* Enable the interrupt on data reception */
100 writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF);
105 static void bcm2835_shutdown(struct mbox_chan *link)
107 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
109 writel(0, mbox->regs + MAIL0_CNF);
112 static bool bcm2835_last_tx_done(struct mbox_chan *link)
114 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
117 spin_lock(&mbox->lock);
118 ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
119 spin_unlock(&mbox->lock);
123 static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
124 .send_data = bcm2835_send_data,
125 .startup = bcm2835_startup,
126 .shutdown = bcm2835_shutdown,
127 .last_tx_done = bcm2835_last_tx_done
130 static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox,
131 const struct of_phandle_args *sp)
133 if (sp->args_count != 0)
134 return ERR_PTR(-EINVAL);
136 return &mbox->chans[0];
139 static int bcm2835_mbox_probe(struct platform_device *pdev)
141 struct device *dev = &pdev->dev;
143 struct resource *iomem;
144 struct bcm2835_mbox *mbox;
146 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
149 spin_lock_init(&mbox->lock);
151 ret = devm_request_irq(dev, platform_get_irq(pdev, 0),
152 bcm2835_mbox_irq, 0, dev_name(dev), mbox);
154 dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
159 iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
160 mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
161 if (IS_ERR(mbox->regs)) {
162 ret = PTR_ERR(mbox->regs);
166 mbox->controller.txdone_poll = true;
167 mbox->controller.txpoll_period = 5;
168 mbox->controller.ops = &bcm2835_mbox_chan_ops;
169 mbox->controller.of_xlate = &bcm2835_mbox_index_xlate;
170 mbox->controller.dev = dev;
171 mbox->controller.num_chans = 1;
172 mbox->controller.chans = devm_kzalloc(dev,
173 sizeof(*mbox->controller.chans), GFP_KERNEL);
174 if (!mbox->controller.chans)
177 ret = devm_mbox_controller_register(dev, &mbox->controller);
181 platform_set_drvdata(pdev, mbox);
182 dev_info(dev, "mailbox enabled\n");
187 static const struct of_device_id bcm2835_mbox_of_match[] = {
188 { .compatible = "brcm,bcm2835-mbox", },
191 MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match);
193 static struct platform_driver bcm2835_mbox_driver = {
195 .name = "bcm2835-mbox",
196 .of_match_table = bcm2835_mbox_of_match,
198 .probe = bcm2835_mbox_probe,
201 static int __init bcm2835_mbox_init(void)
203 return platform_driver_register(&bcm2835_mbox_driver);
205 arch_initcall(bcm2835_mbox_init);
207 static void __init bcm2835_mbox_exit(void)
209 platform_driver_unregister(&bcm2835_mbox_driver);
211 module_exit(bcm2835_mbox_exit);
213 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
214 MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
215 MODULE_LICENSE("GPL v2");