1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
4 * Copyright (C) 2015 Linaro Ltd.
5 * Author: Jassi Brar <jaswinder.singh@linaro.org>
6 */
7
8#include <linux/amba/bus.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/mailbox_controller.h>
14#include <linux/module.h>
15
16#define INTR_STAT_OFS	0x0
17#define INTR_SET_OFS	0x8
18#define INTR_CLR_OFS	0x10
19
20#define MHU_LP_OFFSET	0x0
21#define MHU_HP_OFFSET	0x20
22#define MHU_SEC_OFFSET	0x200
23#define TX_REG_OFFSET	0x100
24
25#define MHU_CHANS	3
26
27struct mhu_link {
28	unsigned irq;
29	void __iomem *tx_reg;
30	void __iomem *rx_reg;
31};
32
33struct arm_mhu {
34	void __iomem *base;
35	struct mhu_link mlink[MHU_CHANS];
36	struct mbox_chan chan[MHU_CHANS];
37	struct mbox_controller mbox;
38};
39
40static irqreturn_t mhu_rx_interrupt(int irq, void *p)
41{
42	struct mbox_chan *chan = p;
43	struct mhu_link *mlink = chan->con_priv;
44	u32 val;
45
46	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
47	if (!val)
48		return IRQ_NONE;
49
50	mbox_chan_received_data(chan, (void *)&val);
51
52	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
53
54	return IRQ_HANDLED;
55}
56
57static bool mhu_last_tx_done(struct mbox_chan *chan)
58{
59	struct mhu_link *mlink = chan->con_priv;
60	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
61
62	return (val == 0);
63}
64
65static int mhu_send_data(struct mbox_chan *chan, void *data)
66{
67	struct mhu_link *mlink = chan->con_priv;
68	u32 *arg = data;
69
70	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
71
72	return 0;
73}
74
75static int mhu_startup(struct mbox_chan *chan)
76{
77	struct mhu_link *mlink = chan->con_priv;
78	u32 val;
79	int ret;
80
81	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
82	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
83
84	ret = request_irq(mlink->irq, mhu_rx_interrupt,
85			  IRQF_SHARED, "mhu_link", chan);
86	if (ret) {
87		dev_err(chan->mbox->dev,
88			"Unable to acquire IRQ %d\n", mlink->irq);
89		return ret;
90	}
91
92	return 0;
93}
94
95static void mhu_shutdown(struct mbox_chan *chan)
96{
97	struct mhu_link *mlink = chan->con_priv;
98
99	free_irq(mlink->irq, chan);
100}
101
102static const struct mbox_chan_ops mhu_ops = {
103	.send_data = mhu_send_data,
104	.startup = mhu_startup,
105	.shutdown = mhu_shutdown,
106	.last_tx_done = mhu_last_tx_done,
107};
108
109static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
110{
111	int i, err;
112	struct arm_mhu *mhu;
113	struct device *dev = &adev->dev;
114	int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};
115
116	if (!of_device_is_compatible(dev->of_node, "arm,mhu"))
117		return -ENODEV;
118
119	/* Allocate memory for device */
120	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
121	if (!mhu)
122		return -ENOMEM;
123
124	mhu->base = devm_ioremap_resource(dev, &adev->res);
125	if (IS_ERR(mhu->base)) {
126		dev_err(dev, "ioremap failed\n");
127		return PTR_ERR(mhu->base);
128	}
129
130	for (i = 0; i < MHU_CHANS; i++) {
131		mhu->chan[i].con_priv = &mhu->mlink[i];
132		mhu->mlink[i].irq = adev->irq[i];
133		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
134		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
135	}
136
137	mhu->mbox.dev = dev;
138	mhu->mbox.chans = &mhu->chan[0];
139	mhu->mbox.num_chans = MHU_CHANS;
140	mhu->mbox.ops = &mhu_ops;
141	mhu->mbox.txdone_irq = false;
142	mhu->mbox.txdone_poll = true;
143	mhu->mbox.txpoll_period = 1;
144
145	amba_set_drvdata(adev, mhu);
146
147	err = devm_mbox_controller_register(dev, &mhu->mbox);
148	if (err) {
149		dev_err(dev, "Failed to register mailboxes %d\n", err);
150		return err;
151	}
152
153	dev_info(dev, "ARM MHU Mailbox registered\n");
154	return 0;
155}
156
157static struct amba_id mhu_ids[] = {
158	{
159		.id	= 0x1bb098,
160		.mask	= 0xffffff,
161	},
162	{ 0, 0 },
163};
164MODULE_DEVICE_TABLE(amba, mhu_ids);
165
166static struct amba_driver arm_mhu_driver = {
167	.drv = {
168		.name	= "mhu",
169	},
170	.id_table	= mhu_ids,
171	.probe		= mhu_probe,
172};
173module_amba_driver(arm_mhu_driver);
174
175MODULE_LICENSE("GPL v2");
176MODULE_DESCRIPTION("ARM MHU Driver");
177MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");
178