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