1 /*
2  * Copyright (C) 2016 BayLibre SAS.
3  * Author: Neil Armstrong <narmstrong@baylibre.com>
4  * Synchronised with arm_mhu.c from :
5  * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
6  * Copyright (C) 2015 Linaro Ltd.
7  * Author: Jassi Brar <jaswinder.singh@linaro.org>
8  *
9  * This program is free software: you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation, version 2 of the License.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  */
18 
19 #include <linux/interrupt.h>
20 #include <linux/spinlock.h>
21 #include <linux/mutex.h>
22 #include <linux/delay.h>
23 #include <linux/slab.h>
24 #include <linux/err.h>
25 #include <linux/io.h>
26 #include <linux/module.h>
27 #include <linux/platform_device.h>
28 #include <linux/mailbox_controller.h>
29 
30 #define INTR_SET_OFS	0x0
31 #define INTR_STAT_OFS	0x4
32 #define INTR_CLR_OFS	0x8
33 
34 #define MHU_SEC_OFFSET	0x0
35 #define MHU_LP_OFFSET	0xc
36 #define MHU_HP_OFFSET	0x18
37 #define TX_REG_OFFSET	0x24
38 
39 #define MHU_CHANS	3
40 
41 struct platform_mhu_link {
42 	int irq;
43 	void __iomem *tx_reg;
44 	void __iomem *rx_reg;
45 };
46 
47 struct platform_mhu {
48 	void __iomem *base;
49 	struct platform_mhu_link mlink[MHU_CHANS];
50 	struct mbox_chan chan[MHU_CHANS];
51 	struct mbox_controller mbox;
52 };
53 
54 static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)
55 {
56 	struct mbox_chan *chan = p;
57 	struct platform_mhu_link *mlink = chan->con_priv;
58 	u32 val;
59 
60 	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
61 	if (!val)
62 		return IRQ_NONE;
63 
64 	mbox_chan_received_data(chan, (void *)&val);
65 
66 	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
67 
68 	return IRQ_HANDLED;
69 }
70 
71 static bool platform_mhu_last_tx_done(struct mbox_chan *chan)
72 {
73 	struct platform_mhu_link *mlink = chan->con_priv;
74 	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
75 
76 	return (val == 0);
77 }
78 
79 static int platform_mhu_send_data(struct mbox_chan *chan, void *data)
80 {
81 	struct platform_mhu_link *mlink = chan->con_priv;
82 	u32 *arg = data;
83 
84 	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
85 
86 	return 0;
87 }
88 
89 static int platform_mhu_startup(struct mbox_chan *chan)
90 {
91 	struct platform_mhu_link *mlink = chan->con_priv;
92 	u32 val;
93 	int ret;
94 
95 	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
96 	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
97 
98 	ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,
99 			  IRQF_SHARED, "platform_mhu_link", chan);
100 	if (ret) {
101 		dev_err(chan->mbox->dev,
102 			"Unable to acquire IRQ %d\n", mlink->irq);
103 		return ret;
104 	}
105 
106 	return 0;
107 }
108 
109 static void platform_mhu_shutdown(struct mbox_chan *chan)
110 {
111 	struct platform_mhu_link *mlink = chan->con_priv;
112 
113 	free_irq(mlink->irq, chan);
114 }
115 
116 static const struct mbox_chan_ops platform_mhu_ops = {
117 	.send_data = platform_mhu_send_data,
118 	.startup = platform_mhu_startup,
119 	.shutdown = platform_mhu_shutdown,
120 	.last_tx_done = platform_mhu_last_tx_done,
121 };
122 
123 static int platform_mhu_probe(struct platform_device *pdev)
124 {
125 	int i, err;
126 	struct platform_mhu *mhu;
127 	struct device *dev = &pdev->dev;
128 	struct resource *res;
129 	int platform_mhu_reg[MHU_CHANS] = {
130 		MHU_SEC_OFFSET, MHU_LP_OFFSET, MHU_HP_OFFSET
131 	};
132 
133 	/* Allocate memory for device */
134 	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
135 	if (!mhu)
136 		return -ENOMEM;
137 
138 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
139 	mhu->base = devm_ioremap_resource(dev, res);
140 	if (IS_ERR(mhu->base)) {
141 		dev_err(dev, "ioremap failed\n");
142 		return PTR_ERR(mhu->base);
143 	}
144 
145 	for (i = 0; i < MHU_CHANS; i++) {
146 		mhu->chan[i].con_priv = &mhu->mlink[i];
147 		mhu->mlink[i].irq = platform_get_irq(pdev, i);
148 		if (mhu->mlink[i].irq < 0) {
149 			dev_err(dev, "failed to get irq%d\n", i);
150 			return mhu->mlink[i].irq;
151 		}
152 		mhu->mlink[i].rx_reg = mhu->base + platform_mhu_reg[i];
153 		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
154 	}
155 
156 	mhu->mbox.dev = dev;
157 	mhu->mbox.chans = &mhu->chan[0];
158 	mhu->mbox.num_chans = MHU_CHANS;
159 	mhu->mbox.ops = &platform_mhu_ops;
160 	mhu->mbox.txdone_irq = false;
161 	mhu->mbox.txdone_poll = true;
162 	mhu->mbox.txpoll_period = 1;
163 
164 	platform_set_drvdata(pdev, mhu);
165 
166 	err = mbox_controller_register(&mhu->mbox);
167 	if (err) {
168 		dev_err(dev, "Failed to register mailboxes %d\n", err);
169 		return err;
170 	}
171 
172 	dev_info(dev, "Platform MHU Mailbox registered\n");
173 	return 0;
174 }
175 
176 static int platform_mhu_remove(struct platform_device *pdev)
177 {
178 	struct platform_mhu *mhu = platform_get_drvdata(pdev);
179 
180 	mbox_controller_unregister(&mhu->mbox);
181 
182 	return 0;
183 }
184 
185 static const struct of_device_id platform_mhu_dt_ids[] = {
186 	{ .compatible = "amlogic,meson-gxbb-mhu", },
187 	{ /* sentinel */ },
188 };
189 MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);
190 
191 static struct platform_driver platform_mhu_driver = {
192 	.probe	= platform_mhu_probe,
193 	.remove	= platform_mhu_remove,
194 	.driver = {
195 		.name = "platform-mhu",
196 		.of_match_table	= platform_mhu_dt_ids,
197 	},
198 };
199 
200 module_platform_driver(platform_mhu_driver);
201 
202 MODULE_LICENSE("GPL v2");
203 MODULE_ALIAS("platform:platform-mhu");
204 MODULE_DESCRIPTION("Platform MHU Driver");
205 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
206