1/*
2 * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
3 * Copyright (C) 2015 Linaro Ltd.
4 * Author: Jassi Brar <jaswinder.singh@linaro.org>
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 as published by
8 * the Free Software Foundation, version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/interrupt.h>
17#include <linux/spinlock.h>
18#include <linux/mutex.h>
19#include <linux/delay.h>
20#include <linux/slab.h>
21#include <linux/err.h>
22#include <linux/io.h>
23#include <linux/module.h>
24#include <linux/amba/bus.h>
25#include <linux/mailbox_controller.h>
26
27#define INTR_STAT_OFS	0x0
28#define INTR_SET_OFS	0x8
29#define INTR_CLR_OFS	0x10
30
31#define MHU_LP_OFFSET	0x0
32#define MHU_HP_OFFSET	0x20
33#define MHU_SEC_OFFSET	0x200
34#define TX_REG_OFFSET	0x100
35
36#define MHU_CHANS	3
37
38struct mhu_link {
39	unsigned irq;
40	void __iomem *tx_reg;
41	void __iomem *rx_reg;
42};
43
44struct arm_mhu {
45	void __iomem *base;
46	struct mhu_link mlink[MHU_CHANS];
47	struct mbox_chan chan[MHU_CHANS];
48	struct mbox_controller mbox;
49};
50
51static irqreturn_t mhu_rx_interrupt(int irq, void *p)
52{
53	struct mbox_chan *chan = p;
54	struct mhu_link *mlink = chan->con_priv;
55	u32 val;
56
57	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
58	if (!val)
59		return IRQ_NONE;
60
61	mbox_chan_received_data(chan, (void *)&val);
62
63	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
64
65	return IRQ_HANDLED;
66}
67
68static bool mhu_last_tx_done(struct mbox_chan *chan)
69{
70	struct mhu_link *mlink = chan->con_priv;
71	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
72
73	return (val == 0);
74}
75
76static int mhu_send_data(struct mbox_chan *chan, void *data)
77{
78	struct mhu_link *mlink = chan->con_priv;
79	u32 *arg = data;
80
81	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
82
83	return 0;
84}
85
86static int mhu_startup(struct mbox_chan *chan)
87{
88	struct mhu_link *mlink = chan->con_priv;
89	u32 val;
90	int ret;
91
92	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
93	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
94
95	ret = request_irq(mlink->irq, mhu_rx_interrupt,
96			  IRQF_SHARED, "mhu_link", chan);
97	if (ret) {
98		dev_err(chan->mbox->dev,
99			"Unable to acquire IRQ %d\n", mlink->irq);
100		return ret;
101	}
102
103	return 0;
104}
105
106static void mhu_shutdown(struct mbox_chan *chan)
107{
108	struct mhu_link *mlink = chan->con_priv;
109
110	free_irq(mlink->irq, chan);
111}
112
113static const struct mbox_chan_ops mhu_ops = {
114	.send_data = mhu_send_data,
115	.startup = mhu_startup,
116	.shutdown = mhu_shutdown,
117	.last_tx_done = mhu_last_tx_done,
118};
119
120static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
121{
122	int i, err;
123	struct arm_mhu *mhu;
124	struct device *dev = &adev->dev;
125	int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};
126
127	/* Allocate memory for device */
128	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
129	if (!mhu)
130		return -ENOMEM;
131
132	mhu->base = devm_ioremap_resource(dev, &adev->res);
133	if (IS_ERR(mhu->base)) {
134		dev_err(dev, "ioremap failed\n");
135		return PTR_ERR(mhu->base);
136	}
137
138	for (i = 0; i < MHU_CHANS; i++) {
139		mhu->chan[i].con_priv = &mhu->mlink[i];
140		mhu->mlink[i].irq = adev->irq[i];
141		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
142		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
143	}
144
145	mhu->mbox.dev = dev;
146	mhu->mbox.chans = &mhu->chan[0];
147	mhu->mbox.num_chans = MHU_CHANS;
148	mhu->mbox.ops = &mhu_ops;
149	mhu->mbox.txdone_irq = false;
150	mhu->mbox.txdone_poll = true;
151	mhu->mbox.txpoll_period = 1;
152
153	amba_set_drvdata(adev, mhu);
154
155	err = mbox_controller_register(&mhu->mbox);
156	if (err) {
157		dev_err(dev, "Failed to register mailboxes %d\n", err);
158		return err;
159	}
160
161	dev_info(dev, "ARM MHU Mailbox registered\n");
162	return 0;
163}
164
165static int mhu_remove(struct amba_device *adev)
166{
167	struct arm_mhu *mhu = amba_get_drvdata(adev);
168
169	mbox_controller_unregister(&mhu->mbox);
170
171	return 0;
172}
173
174static struct amba_id mhu_ids[] = {
175	{
176		.id	= 0x1bb098,
177		.mask	= 0xffffff,
178	},
179	{ 0, 0 },
180};
181MODULE_DEVICE_TABLE(amba, mhu_ids);
182
183static struct amba_driver arm_mhu_driver = {
184	.drv = {
185		.name	= "mhu",
186	},
187	.id_table	= mhu_ids,
188	.probe		= mhu_probe,
189	.remove		= mhu_remove,
190};
191module_amba_driver(arm_mhu_driver);
192
193MODULE_LICENSE("GPL v2");
194MODULE_DESCRIPTION("ARM MHU Driver");
195MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");
196