1 /*
2  * Copyright (c) 2015, Fuzhou Rockchip Electronics Co., Ltd
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  */
13 
14 #include <linux/clk.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/mailbox_controller.h>
19 #include <linux/module.h>
20 #include <linux/of_device.h>
21 #include <linux/platform_device.h>
22 
23 #define MAILBOX_A2B_INTEN		0x00
24 #define MAILBOX_A2B_STATUS		0x04
25 #define MAILBOX_A2B_CMD(x)		(0x08 + (x) * 8)
26 #define MAILBOX_A2B_DAT(x)		(0x0c + (x) * 8)
27 
28 #define MAILBOX_B2A_INTEN		0x28
29 #define MAILBOX_B2A_STATUS		0x2C
30 #define MAILBOX_B2A_CMD(x)		(0x30 + (x) * 8)
31 #define MAILBOX_B2A_DAT(x)		(0x34 + (x) * 8)
32 
33 struct rockchip_mbox_msg {
34 	u32 cmd;
35 	int rx_size;
36 };
37 
38 struct rockchip_mbox_data {
39 	int num_chans;
40 };
41 
42 struct rockchip_mbox_chan {
43 	int idx;
44 	int irq;
45 	struct rockchip_mbox_msg *msg;
46 	struct rockchip_mbox *mb;
47 };
48 
49 struct rockchip_mbox {
50 	struct mbox_controller mbox;
51 	struct clk *pclk;
52 	void __iomem *mbox_base;
53 
54 	/* The maximum size of buf for each channel */
55 	u32 buf_size;
56 
57 	struct rockchip_mbox_chan *chans;
58 };
59 
60 static int rockchip_mbox_send_data(struct mbox_chan *chan, void *data)
61 {
62 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
63 	struct rockchip_mbox_msg *msg = data;
64 	struct rockchip_mbox_chan *chans = mb->chans;
65 
66 	if (!msg)
67 		return -EINVAL;
68 
69 	if (msg->rx_size > mb->buf_size) {
70 		dev_err(mb->mbox.dev, "Transmit size over buf size(%d)\n",
71 			mb->buf_size);
72 		return -EINVAL;
73 	}
74 
75 	dev_dbg(mb->mbox.dev, "Chan[%d]: A2B message, cmd 0x%08x\n",
76 		chans->idx, msg->cmd);
77 
78 	mb->chans[chans->idx].msg = msg;
79 
80 	writel_relaxed(msg->cmd, mb->mbox_base + MAILBOX_A2B_CMD(chans->idx));
81 	writel_relaxed(msg->rx_size, mb->mbox_base +
82 		       MAILBOX_A2B_DAT(chans->idx));
83 
84 	return 0;
85 }
86 
87 static int rockchip_mbox_startup(struct mbox_chan *chan)
88 {
89 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
90 
91 	/* Enable all B2A interrupts */
92 	writel_relaxed((1 << mb->mbox.num_chans) - 1,
93 		       mb->mbox_base + MAILBOX_B2A_INTEN);
94 
95 	return 0;
96 }
97 
98 static void rockchip_mbox_shutdown(struct mbox_chan *chan)
99 {
100 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
101 	struct rockchip_mbox_chan *chans = mb->chans;
102 
103 	/* Disable all B2A interrupts */
104 	writel_relaxed(0, mb->mbox_base + MAILBOX_B2A_INTEN);
105 
106 	mb->chans[chans->idx].msg = NULL;
107 }
108 
109 static const struct mbox_chan_ops rockchip_mbox_chan_ops = {
110 	.send_data	= rockchip_mbox_send_data,
111 	.startup	= rockchip_mbox_startup,
112 	.shutdown	= rockchip_mbox_shutdown,
113 };
114 
115 static irqreturn_t rockchip_mbox_irq(int irq, void *dev_id)
116 {
117 	int idx;
118 	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
119 	u32 status = readl_relaxed(mb->mbox_base + MAILBOX_B2A_STATUS);
120 
121 	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
122 		if ((status & (1 << idx)) && (irq == mb->chans[idx].irq)) {
123 			/* Clear mbox interrupt */
124 			writel_relaxed(1 << idx,
125 				       mb->mbox_base + MAILBOX_B2A_STATUS);
126 			return IRQ_WAKE_THREAD;
127 		}
128 	}
129 
130 	return IRQ_NONE;
131 }
132 
133 static irqreturn_t rockchip_mbox_isr(int irq, void *dev_id)
134 {
135 	int idx;
136 	struct rockchip_mbox_msg *msg = NULL;
137 	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
138 
139 	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
140 		if (irq != mb->chans[idx].irq)
141 			continue;
142 
143 		msg = mb->chans[idx].msg;
144 		if (!msg) {
145 			dev_err(mb->mbox.dev,
146 				"Chan[%d]: B2A message is NULL\n", idx);
147 			break; /* spurious */
148 		}
149 
150 		mbox_chan_received_data(&mb->mbox.chans[idx], msg);
151 		mb->chans[idx].msg = NULL;
152 
153 		dev_dbg(mb->mbox.dev, "Chan[%d]: B2A message, cmd 0x%08x\n",
154 			idx, msg->cmd);
155 
156 		break;
157 	}
158 
159 	return IRQ_HANDLED;
160 }
161 
162 static const struct rockchip_mbox_data rk3368_drv_data = {
163 	.num_chans = 4,
164 };
165 
166 static const struct of_device_id rockchip_mbox_of_match[] = {
167 	{ .compatible = "rockchip,rk3368-mailbox", .data = &rk3368_drv_data},
168 	{ },
169 };
170 MODULE_DEVICE_TABLE(of, rockchp_mbox_of_match);
171 
172 static int rockchip_mbox_probe(struct platform_device *pdev)
173 {
174 	struct rockchip_mbox *mb;
175 	const struct of_device_id *match;
176 	const struct rockchip_mbox_data *drv_data;
177 	struct resource *res;
178 	int ret, irq, i;
179 
180 	if (!pdev->dev.of_node)
181 		return -ENODEV;
182 
183 	match = of_match_node(rockchip_mbox_of_match, pdev->dev.of_node);
184 	drv_data = (const struct rockchip_mbox_data *)match->data;
185 
186 	mb = devm_kzalloc(&pdev->dev, sizeof(*mb), GFP_KERNEL);
187 	if (!mb)
188 		return -ENOMEM;
189 
190 	mb->chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
191 				 sizeof(*mb->chans), GFP_KERNEL);
192 	if (!mb->chans)
193 		return -ENOMEM;
194 
195 	mb->mbox.chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
196 				      sizeof(*mb->mbox.chans), GFP_KERNEL);
197 	if (!mb->mbox.chans)
198 		return -ENOMEM;
199 
200 	platform_set_drvdata(pdev, mb);
201 
202 	mb->mbox.dev = &pdev->dev;
203 	mb->mbox.num_chans = drv_data->num_chans;
204 	mb->mbox.ops = &rockchip_mbox_chan_ops;
205 	mb->mbox.txdone_irq = true;
206 
207 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
208 	if (!res)
209 		return -ENODEV;
210 
211 	mb->mbox_base = devm_ioremap_resource(&pdev->dev, res);
212 	if (IS_ERR(mb->mbox_base))
213 		return PTR_ERR(mb->mbox_base);
214 
215 	/* Each channel has two buffers for A2B and B2A */
216 	mb->buf_size = (size_t)resource_size(res) / (drv_data->num_chans * 2);
217 
218 	mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
219 	if (IS_ERR(mb->pclk)) {
220 		ret = PTR_ERR(mb->pclk);
221 		dev_err(&pdev->dev, "failed to get pclk_mailbox clock: %d\n",
222 			ret);
223 		return ret;
224 	}
225 
226 	ret = clk_prepare_enable(mb->pclk);
227 	if (ret) {
228 		dev_err(&pdev->dev, "failed to enable pclk: %d\n", ret);
229 		return ret;
230 	}
231 
232 	for (i = 0; i < mb->mbox.num_chans; i++) {
233 		irq = platform_get_irq(pdev, i);
234 		if (irq < 0)
235 			return irq;
236 
237 		ret = devm_request_threaded_irq(&pdev->dev, irq,
238 						rockchip_mbox_irq,
239 						rockchip_mbox_isr, IRQF_ONESHOT,
240 						dev_name(&pdev->dev), mb);
241 		if (ret < 0)
242 			return ret;
243 
244 		mb->chans[i].idx = i;
245 		mb->chans[i].irq = irq;
246 		mb->chans[i].mb = mb;
247 		mb->chans[i].msg = NULL;
248 	}
249 
250 	ret = devm_mbox_controller_register(&pdev->dev, &mb->mbox);
251 	if (ret < 0)
252 		dev_err(&pdev->dev, "Failed to register mailbox: %d\n", ret);
253 
254 	return ret;
255 }
256 
257 static struct platform_driver rockchip_mbox_driver = {
258 	.probe	= rockchip_mbox_probe,
259 	.driver = {
260 		.name = "rockchip-mailbox",
261 		.of_match_table = of_match_ptr(rockchip_mbox_of_match),
262 	},
263 };
264 
265 module_platform_driver(rockchip_mbox_driver);
266 
267 MODULE_LICENSE("GPL v2");
268 MODULE_DESCRIPTION("Rockchip mailbox: communicate between CPU cores and MCU");
269 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
270 MODULE_AUTHOR("Caesar Wang <wxt@rock-chips.com>");
271