1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2015, Fuzhou Rockchip Electronics Co., Ltd
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/mailbox_controller.h>
11 #include <linux/of.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 
15 #define MAILBOX_A2B_INTEN		0x00
16 #define MAILBOX_A2B_STATUS		0x04
17 #define MAILBOX_A2B_CMD(x)		(0x08 + (x) * 8)
18 #define MAILBOX_A2B_DAT(x)		(0x0c + (x) * 8)
19 
20 #define MAILBOX_B2A_INTEN		0x28
21 #define MAILBOX_B2A_STATUS		0x2C
22 #define MAILBOX_B2A_CMD(x)		(0x30 + (x) * 8)
23 #define MAILBOX_B2A_DAT(x)		(0x34 + (x) * 8)
24 
25 struct rockchip_mbox_msg {
26 	u32 cmd;
27 	int rx_size;
28 };
29 
30 struct rockchip_mbox_data {
31 	int num_chans;
32 };
33 
34 struct rockchip_mbox_chan {
35 	int idx;
36 	int irq;
37 	struct rockchip_mbox_msg *msg;
38 	struct rockchip_mbox *mb;
39 };
40 
41 struct rockchip_mbox {
42 	struct mbox_controller mbox;
43 	struct clk *pclk;
44 	void __iomem *mbox_base;
45 
46 	/* The maximum size of buf for each channel */
47 	u32 buf_size;
48 
49 	struct rockchip_mbox_chan *chans;
50 };
51 
52 static int rockchip_mbox_send_data(struct mbox_chan *chan, void *data)
53 {
54 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
55 	struct rockchip_mbox_msg *msg = data;
56 	struct rockchip_mbox_chan *chans = mb->chans;
57 
58 	if (!msg)
59 		return -EINVAL;
60 
61 	if (msg->rx_size > mb->buf_size) {
62 		dev_err(mb->mbox.dev, "Transmit size over buf size(%d)\n",
63 			mb->buf_size);
64 		return -EINVAL;
65 	}
66 
67 	dev_dbg(mb->mbox.dev, "Chan[%d]: A2B message, cmd 0x%08x\n",
68 		chans->idx, msg->cmd);
69 
70 	mb->chans[chans->idx].msg = msg;
71 
72 	writel_relaxed(msg->cmd, mb->mbox_base + MAILBOX_A2B_CMD(chans->idx));
73 	writel_relaxed(msg->rx_size, mb->mbox_base +
74 		       MAILBOX_A2B_DAT(chans->idx));
75 
76 	return 0;
77 }
78 
79 static int rockchip_mbox_startup(struct mbox_chan *chan)
80 {
81 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
82 
83 	/* Enable all B2A interrupts */
84 	writel_relaxed((1 << mb->mbox.num_chans) - 1,
85 		       mb->mbox_base + MAILBOX_B2A_INTEN);
86 
87 	return 0;
88 }
89 
90 static void rockchip_mbox_shutdown(struct mbox_chan *chan)
91 {
92 	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
93 	struct rockchip_mbox_chan *chans = mb->chans;
94 
95 	/* Disable all B2A interrupts */
96 	writel_relaxed(0, mb->mbox_base + MAILBOX_B2A_INTEN);
97 
98 	mb->chans[chans->idx].msg = NULL;
99 }
100 
101 static const struct mbox_chan_ops rockchip_mbox_chan_ops = {
102 	.send_data	= rockchip_mbox_send_data,
103 	.startup	= rockchip_mbox_startup,
104 	.shutdown	= rockchip_mbox_shutdown,
105 };
106 
107 static irqreturn_t rockchip_mbox_irq(int irq, void *dev_id)
108 {
109 	int idx;
110 	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
111 	u32 status = readl_relaxed(mb->mbox_base + MAILBOX_B2A_STATUS);
112 
113 	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
114 		if ((status & (1 << idx)) && (irq == mb->chans[idx].irq)) {
115 			/* Clear mbox interrupt */
116 			writel_relaxed(1 << idx,
117 				       mb->mbox_base + MAILBOX_B2A_STATUS);
118 			return IRQ_WAKE_THREAD;
119 		}
120 	}
121 
122 	return IRQ_NONE;
123 }
124 
125 static irqreturn_t rockchip_mbox_isr(int irq, void *dev_id)
126 {
127 	int idx;
128 	struct rockchip_mbox_msg *msg = NULL;
129 	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
130 
131 	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
132 		if (irq != mb->chans[idx].irq)
133 			continue;
134 
135 		msg = mb->chans[idx].msg;
136 		if (!msg) {
137 			dev_err(mb->mbox.dev,
138 				"Chan[%d]: B2A message is NULL\n", idx);
139 			break; /* spurious */
140 		}
141 
142 		mbox_chan_received_data(&mb->mbox.chans[idx], msg);
143 		mb->chans[idx].msg = NULL;
144 
145 		dev_dbg(mb->mbox.dev, "Chan[%d]: B2A message, cmd 0x%08x\n",
146 			idx, msg->cmd);
147 
148 		break;
149 	}
150 
151 	return IRQ_HANDLED;
152 }
153 
154 static const struct rockchip_mbox_data rk3368_drv_data = {
155 	.num_chans = 4,
156 };
157 
158 static const struct of_device_id rockchip_mbox_of_match[] = {
159 	{ .compatible = "rockchip,rk3368-mailbox", .data = &rk3368_drv_data},
160 	{ },
161 };
162 MODULE_DEVICE_TABLE(of, rockchp_mbox_of_match);
163 
164 static int rockchip_mbox_probe(struct platform_device *pdev)
165 {
166 	struct rockchip_mbox *mb;
167 	const struct rockchip_mbox_data *drv_data;
168 	struct resource *res;
169 	int ret, irq, i;
170 
171 	if (!pdev->dev.of_node)
172 		return -ENODEV;
173 
174 	drv_data = (const struct rockchip_mbox_data *) device_get_match_data(&pdev->dev);
175 
176 	mb = devm_kzalloc(&pdev->dev, sizeof(*mb), GFP_KERNEL);
177 	if (!mb)
178 		return -ENOMEM;
179 
180 	mb->chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
181 				 sizeof(*mb->chans), GFP_KERNEL);
182 	if (!mb->chans)
183 		return -ENOMEM;
184 
185 	mb->mbox.chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
186 				      sizeof(*mb->mbox.chans), GFP_KERNEL);
187 	if (!mb->mbox.chans)
188 		return -ENOMEM;
189 
190 	platform_set_drvdata(pdev, mb);
191 
192 	mb->mbox.dev = &pdev->dev;
193 	mb->mbox.num_chans = drv_data->num_chans;
194 	mb->mbox.ops = &rockchip_mbox_chan_ops;
195 	mb->mbox.txdone_irq = true;
196 
197 	mb->mbox_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
198 	if (IS_ERR(mb->mbox_base))
199 		return PTR_ERR(mb->mbox_base);
200 
201 	/* Each channel has two buffers for A2B and B2A */
202 	mb->buf_size = (size_t)resource_size(res) / (drv_data->num_chans * 2);
203 
204 	mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
205 	if (IS_ERR(mb->pclk)) {
206 		ret = PTR_ERR(mb->pclk);
207 		dev_err(&pdev->dev, "failed to get pclk_mailbox clock: %d\n",
208 			ret);
209 		return ret;
210 	}
211 
212 	ret = clk_prepare_enable(mb->pclk);
213 	if (ret) {
214 		dev_err(&pdev->dev, "failed to enable pclk: %d\n", ret);
215 		return ret;
216 	}
217 
218 	for (i = 0; i < mb->mbox.num_chans; i++) {
219 		irq = platform_get_irq(pdev, i);
220 		if (irq < 0)
221 			return irq;
222 
223 		ret = devm_request_threaded_irq(&pdev->dev, irq,
224 						rockchip_mbox_irq,
225 						rockchip_mbox_isr, IRQF_ONESHOT,
226 						dev_name(&pdev->dev), mb);
227 		if (ret < 0)
228 			return ret;
229 
230 		mb->chans[i].idx = i;
231 		mb->chans[i].irq = irq;
232 		mb->chans[i].mb = mb;
233 		mb->chans[i].msg = NULL;
234 	}
235 
236 	ret = devm_mbox_controller_register(&pdev->dev, &mb->mbox);
237 	if (ret < 0)
238 		dev_err(&pdev->dev, "Failed to register mailbox: %d\n", ret);
239 
240 	return ret;
241 }
242 
243 static struct platform_driver rockchip_mbox_driver = {
244 	.probe	= rockchip_mbox_probe,
245 	.driver = {
246 		.name = "rockchip-mailbox",
247 		.of_match_table = rockchip_mbox_of_match,
248 	},
249 };
250 
251 module_platform_driver(rockchip_mbox_driver);
252 
253 MODULE_DESCRIPTION("Rockchip mailbox: communicate between CPU cores and MCU");
254 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
255 MODULE_AUTHOR("Caesar Wang <wxt@rock-chips.com>");
256