1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2016 BayLibre SAS.
4  * Author: Neil Armstrong <narmstrong@baylibre.com>
5  * Synchronised with arm_mhu.c from :
6  * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
7  * Copyright (C) 2015 Linaro Ltd.
8  * Author: Jassi Brar <jaswinder.singh@linaro.org>
9  */
10 
11 #include <linux/interrupt.h>
12 #include <linux/spinlock.h>
13 #include <linux/mutex.h>
14 #include <linux/delay.h>
15 #include <linux/slab.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/mailbox_controller.h>
21 
22 #define INTR_SET_OFS	0x0
23 #define INTR_STAT_OFS	0x4
24 #define INTR_CLR_OFS	0x8
25 
26 #define MHU_SEC_OFFSET	0x0
27 #define MHU_LP_OFFSET	0xc
28 #define MHU_HP_OFFSET	0x18
29 #define TX_REG_OFFSET	0x24
30 
31 #define MHU_CHANS	3
32 
33 struct platform_mhu_link {
34 	int irq;
35 	void __iomem *tx_reg;
36 	void __iomem *rx_reg;
37 };
38 
39 struct platform_mhu {
40 	void __iomem *base;
41 	struct platform_mhu_link mlink[MHU_CHANS];
42 	struct mbox_chan chan[MHU_CHANS];
43 	struct mbox_controller mbox;
44 };
45 
46 static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)
47 {
48 	struct mbox_chan *chan = p;
49 	struct platform_mhu_link *mlink = chan->con_priv;
50 	u32 val;
51 
52 	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
53 	if (!val)
54 		return IRQ_NONE;
55 
56 	mbox_chan_received_data(chan, (void *)&val);
57 
58 	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
59 
60 	return IRQ_HANDLED;
61 }
62 
63 static bool platform_mhu_last_tx_done(struct mbox_chan *chan)
64 {
65 	struct platform_mhu_link *mlink = chan->con_priv;
66 	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
67 
68 	return (val == 0);
69 }
70 
71 static int platform_mhu_send_data(struct mbox_chan *chan, void *data)
72 {
73 	struct platform_mhu_link *mlink = chan->con_priv;
74 	u32 *arg = data;
75 
76 	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
77 
78 	return 0;
79 }
80 
81 static int platform_mhu_startup(struct mbox_chan *chan)
82 {
83 	struct platform_mhu_link *mlink = chan->con_priv;
84 	u32 val;
85 	int ret;
86 
87 	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
88 	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
89 
90 	ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,
91 			  IRQF_SHARED, "platform_mhu_link", chan);
92 	if (ret) {
93 		dev_err(chan->mbox->dev,
94 			"Unable to acquire IRQ %d\n", mlink->irq);
95 		return ret;
96 	}
97 
98 	return 0;
99 }
100 
101 static void platform_mhu_shutdown(struct mbox_chan *chan)
102 {
103 	struct platform_mhu_link *mlink = chan->con_priv;
104 
105 	free_irq(mlink->irq, chan);
106 }
107 
108 static const struct mbox_chan_ops platform_mhu_ops = {
109 	.send_data = platform_mhu_send_data,
110 	.startup = platform_mhu_startup,
111 	.shutdown = platform_mhu_shutdown,
112 	.last_tx_done = platform_mhu_last_tx_done,
113 };
114 
115 static int platform_mhu_probe(struct platform_device *pdev)
116 {
117 	int i, err;
118 	struct platform_mhu *mhu;
119 	struct device *dev = &pdev->dev;
120 	int platform_mhu_reg[MHU_CHANS] = {
121 		MHU_SEC_OFFSET, MHU_LP_OFFSET, MHU_HP_OFFSET
122 	};
123 
124 	/* Allocate memory for device */
125 	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
126 	if (!mhu)
127 		return -ENOMEM;
128 
129 	mhu->base = devm_platform_ioremap_resource(pdev, 0);
130 	if (IS_ERR(mhu->base)) {
131 		dev_err(dev, "ioremap failed\n");
132 		return PTR_ERR(mhu->base);
133 	}
134 
135 	for (i = 0; i < MHU_CHANS; i++) {
136 		mhu->chan[i].con_priv = &mhu->mlink[i];
137 		mhu->mlink[i].irq = platform_get_irq(pdev, i);
138 		if (mhu->mlink[i].irq < 0) {
139 			dev_err(dev, "failed to get irq%d\n", i);
140 			return mhu->mlink[i].irq;
141 		}
142 		mhu->mlink[i].rx_reg = mhu->base + platform_mhu_reg[i];
143 		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
144 	}
145 
146 	mhu->mbox.dev = dev;
147 	mhu->mbox.chans = &mhu->chan[0];
148 	mhu->mbox.num_chans = MHU_CHANS;
149 	mhu->mbox.ops = &platform_mhu_ops;
150 	mhu->mbox.txdone_irq = false;
151 	mhu->mbox.txdone_poll = true;
152 	mhu->mbox.txpoll_period = 1;
153 
154 	platform_set_drvdata(pdev, mhu);
155 
156 	err = devm_mbox_controller_register(dev, &mhu->mbox);
157 	if (err) {
158 		dev_err(dev, "Failed to register mailboxes %d\n", err);
159 		return err;
160 	}
161 
162 	dev_info(dev, "Platform MHU Mailbox registered\n");
163 	return 0;
164 }
165 
166 static const struct of_device_id platform_mhu_dt_ids[] = {
167 	{ .compatible = "amlogic,meson-gxbb-mhu", },
168 	{ /* sentinel */ },
169 };
170 MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);
171 
172 static struct platform_driver platform_mhu_driver = {
173 	.probe	= platform_mhu_probe,
174 	.driver = {
175 		.name = "platform-mhu",
176 		.of_match_table	= platform_mhu_dt_ids,
177 	},
178 };
179 
180 module_platform_driver(platform_mhu_driver);
181 
182 MODULE_LICENSE("GPL v2");
183 MODULE_ALIAS("platform:platform-mhu");
184 MODULE_DESCRIPTION("Platform MHU Driver");
185 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
186