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Lubomir Rintel0bae6af2015-05-05 13:27:45 -07001/*
2 * Copyright (C) 2010,2015 Broadcom
3 * Copyright (C) 2013-2014 Lubomir Rintel
4 * Copyright (C) 2013 Craig McGeachie
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This device provides a mechanism for writing to the mailboxes,
11 * that are shared between the ARM and the VideoCore processor
12 *
13 * Parts of the driver are based on:
14 * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was
15 * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/
16 * linux.git
17 * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at
18 * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/
19 * mailbox/bcm2835-ipc.c
20 * - documentation available on the following web site:
21 * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
22 */
23
24#include <linux/device.h>
25#include <linux/dma-mapping.h>
26#include <linux/err.h>
27#include <linux/interrupt.h>
28#include <linux/irq.h>
29#include <linux/kernel.h>
30#include <linux/mailbox_controller.h>
31#include <linux/module.h>
32#include <linux/of_address.h>
33#include <linux/of_irq.h>
34#include <linux/platform_device.h>
35#include <linux/spinlock.h>
36
37/* Mailboxes */
38#define ARM_0_MAIL0 0x00
39#define ARM_0_MAIL1 0x20
40
41/*
42 * Mailbox registers. We basically only support mailbox 0 & 1. We
43 * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See
44 * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about
45 * the placement of memory barriers.
46 */
47#define MAIL0_RD (ARM_0_MAIL0 + 0x00)
48#define MAIL0_POL (ARM_0_MAIL0 + 0x10)
49#define MAIL0_STA (ARM_0_MAIL0 + 0x18)
50#define MAIL0_CNF (ARM_0_MAIL0 + 0x1C)
51#define MAIL1_WRT (ARM_0_MAIL1 + 0x00)
Eric Anholt7d641932015-05-13 13:10:32 -070052#define MAIL1_STA (ARM_0_MAIL1 + 0x18)
Lubomir Rintel0bae6af2015-05-05 13:27:45 -070053
54/* Status register: FIFO state. */
55#define ARM_MS_FULL BIT(31)
56#define ARM_MS_EMPTY BIT(30)
57
58/* Configuration register: Enable interrupts. */
59#define ARM_MC_IHAVEDATAIRQEN BIT(0)
60
61struct bcm2835_mbox {
62 void __iomem *regs;
63 spinlock_t lock;
64 struct mbox_controller controller;
65};
66
67static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link)
68{
69 return container_of(link->mbox, struct bcm2835_mbox, controller);
70}
71
72static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id)
73{
74 struct bcm2835_mbox *mbox = dev_id;
75 struct device *dev = mbox->controller.dev;
76 struct mbox_chan *link = &mbox->controller.chans[0];
77
78 while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) {
79 u32 msg = readl(mbox->regs + MAIL0_RD);
80 dev_dbg(dev, "Reply 0x%08X\n", msg);
81 mbox_chan_received_data(link, &msg);
82 }
83 return IRQ_HANDLED;
84}
85
86static int bcm2835_send_data(struct mbox_chan *link, void *data)
87{
88 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
89 u32 msg = *(u32 *)data;
90
91 spin_lock(&mbox->lock);
92 writel(msg, mbox->regs + MAIL1_WRT);
93 dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg);
94 spin_unlock(&mbox->lock);
95 return 0;
96}
97
98static int bcm2835_startup(struct mbox_chan *link)
99{
100 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
101
102 /* Enable the interrupt on data reception */
103 writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF);
104
105 return 0;
106}
107
108static void bcm2835_shutdown(struct mbox_chan *link)
109{
110 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
111
112 writel(0, mbox->regs + MAIL0_CNF);
113}
114
115static bool bcm2835_last_tx_done(struct mbox_chan *link)
116{
117 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
118 bool ret;
119
120 spin_lock(&mbox->lock);
Eric Anholt7d641932015-05-13 13:10:32 -0700121 ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
Lubomir Rintel0bae6af2015-05-05 13:27:45 -0700122 spin_unlock(&mbox->lock);
123 return ret;
124}
125
126static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
127 .send_data = bcm2835_send_data,
128 .startup = bcm2835_startup,
129 .shutdown = bcm2835_shutdown,
130 .last_tx_done = bcm2835_last_tx_done
131};
132
133static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox,
134 const struct of_phandle_args *sp)
135{
136 if (sp->args_count != 0)
137 return NULL;
138
139 return &mbox->chans[0];
140}
141
142static int bcm2835_mbox_probe(struct platform_device *pdev)
143{
144 struct device *dev = &pdev->dev;
145 int ret = 0;
146 struct resource *iomem;
147 struct bcm2835_mbox *mbox;
148
149 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
150 if (mbox == NULL)
151 return -ENOMEM;
152 spin_lock_init(&mbox->lock);
153
154 ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0),
155 bcm2835_mbox_irq, 0, dev_name(dev), mbox);
156 if (ret) {
157 dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
158 ret);
159 return -ENODEV;
160 }
161
162 iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
163 mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
164 if (IS_ERR(mbox->regs)) {
165 ret = PTR_ERR(mbox->regs);
166 dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
167 return ret;
168 }
169
170 mbox->controller.txdone_poll = true;
171 mbox->controller.txpoll_period = 5;
172 mbox->controller.ops = &bcm2835_mbox_chan_ops;
173 mbox->controller.of_xlate = &bcm2835_mbox_index_xlate;
174 mbox->controller.dev = dev;
175 mbox->controller.num_chans = 1;
176 mbox->controller.chans = devm_kzalloc(dev,
177 sizeof(*mbox->controller.chans), GFP_KERNEL);
178 if (!mbox->controller.chans)
179 return -ENOMEM;
180
181 ret = mbox_controller_register(&mbox->controller);
182 if (ret)
183 return ret;
184
185 platform_set_drvdata(pdev, mbox);
186 dev_info(dev, "mailbox enabled\n");
187
188 return ret;
189}
190
191static int bcm2835_mbox_remove(struct platform_device *pdev)
192{
193 struct bcm2835_mbox *mbox = platform_get_drvdata(pdev);
194 mbox_controller_unregister(&mbox->controller);
195 return 0;
196}
197
198static const struct of_device_id bcm2835_mbox_of_match[] = {
199 { .compatible = "brcm,bcm2835-mbox", },
200 {},
201};
202MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match);
203
204static struct platform_driver bcm2835_mbox_driver = {
205 .driver = {
206 .name = "bcm2835-mbox",
207 .owner = THIS_MODULE,
208 .of_match_table = bcm2835_mbox_of_match,
209 },
210 .probe = bcm2835_mbox_probe,
211 .remove = bcm2835_mbox_remove,
212};
213module_platform_driver(bcm2835_mbox_driver);
214
215MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
216MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
217MODULE_LICENSE("GPL v2");