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 
27 struct mhu_link {
28 	unsigned irq;
29 	void __iomem *tx_reg;
30 	void __iomem *rx_reg;
31 };
32 
33 struct 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 
mhu_rx_interrupt(int irq,void * p)40 static 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 
mhu_last_tx_done(struct mbox_chan * chan)57 static 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 
mhu_send_data(struct mbox_chan * chan,void * data)65 static 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 
mhu_startup(struct mbox_chan * chan)75 static 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 
mhu_shutdown(struct mbox_chan * chan)95 static 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 
102 static 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 
mhu_probe(struct amba_device * adev,const struct amba_id * id)109 static 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 		return PTR_ERR(mhu->base);
127 
128 	for (i = 0; i < MHU_CHANS; i++) {
129 		mhu->chan[i].con_priv = &mhu->mlink[i];
130 		mhu->mlink[i].irq = adev->irq[i];
131 		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
132 		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
133 	}
134 
135 	mhu->mbox.dev = dev;
136 	mhu->mbox.chans = &mhu->chan[0];
137 	mhu->mbox.num_chans = MHU_CHANS;
138 	mhu->mbox.ops = &mhu_ops;
139 	mhu->mbox.txdone_irq = false;
140 	mhu->mbox.txdone_poll = true;
141 	mhu->mbox.txpoll_period = 1;
142 
143 	amba_set_drvdata(adev, mhu);
144 
145 	err = devm_mbox_controller_register(dev, &mhu->mbox);
146 	if (err) {
147 		dev_err(dev, "Failed to register mailboxes %d\n", err);
148 		return err;
149 	}
150 
151 	dev_info(dev, "ARM MHU Mailbox registered\n");
152 	return 0;
153 }
154 
155 static struct amba_id mhu_ids[] = {
156 	{
157 		.id	= 0x1bb098,
158 		.mask	= 0xffffff,
159 	},
160 	{ 0, 0 },
161 };
162 MODULE_DEVICE_TABLE(amba, mhu_ids);
163 
164 static struct amba_driver arm_mhu_driver = {
165 	.drv = {
166 		.name	= "mhu",
167 	},
168 	.id_table	= mhu_ids,
169 	.probe		= mhu_probe,
170 };
171 module_amba_driver(arm_mhu_driver);
172 
173 MODULE_LICENSE("GPL v2");
174 MODULE_DESCRIPTION("ARM MHU Driver");
175 MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");
176