1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * rWTM BIU Mailbox driver for Armada 37xx
4  *
5  * Author: Marek Behún <kabel@kernel.org>
6  */
7 
8 #include <linux/device.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/mailbox_controller.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/armada-37xx-rwtm-mailbox.h>
17 
18 #define DRIVER_NAME	"armada-37xx-rwtm-mailbox"
19 
20 /* relative to rWTM BIU Mailbox Registers */
21 #define RWTM_MBOX_PARAM(i)		(0x0 + ((i) << 2))
22 #define RWTM_MBOX_COMMAND		0x40
23 #define RWTM_MBOX_RETURN_STATUS		0x80
24 #define RWTM_MBOX_STATUS(i)		(0x84 + ((i) << 2))
25 #define RWTM_MBOX_FIFO_STATUS		0xc4
26 #define FIFO_STS_RDY			0x100
27 #define FIFO_STS_CNTR_MASK		0x7
28 #define FIFO_STS_CNTR_MAX		4
29 
30 #define RWTM_HOST_INT_RESET		0xc8
31 #define RWTM_HOST_INT_MASK		0xcc
32 #define SP_CMD_COMPLETE			BIT(0)
33 #define SP_CMD_QUEUE_FULL_ACCESS	BIT(17)
34 #define SP_CMD_QUEUE_FULL		BIT(18)
35 
36 struct a37xx_mbox {
37 	struct device *dev;
38 	struct mbox_controller controller;
39 	void __iomem *base;
40 	int irq;
41 };
42 
43 static void a37xx_mbox_receive(struct mbox_chan *chan)
44 {
45 	struct a37xx_mbox *mbox = chan->con_priv;
46 	struct armada_37xx_rwtm_rx_msg rx_msg;
47 	int i;
48 
49 	rx_msg.retval = readl(mbox->base + RWTM_MBOX_RETURN_STATUS);
50 	for (i = 0; i < 16; ++i)
51 		rx_msg.status[i] = readl(mbox->base + RWTM_MBOX_STATUS(i));
52 
53 	mbox_chan_received_data(chan, &rx_msg);
54 }
55 
56 static irqreturn_t a37xx_mbox_irq_handler(int irq, void *data)
57 {
58 	struct mbox_chan *chan = data;
59 	struct a37xx_mbox *mbox = chan->con_priv;
60 	u32 reg;
61 
62 	reg = readl(mbox->base + RWTM_HOST_INT_RESET);
63 
64 	if (reg & SP_CMD_COMPLETE)
65 		a37xx_mbox_receive(chan);
66 
67 	if (reg & (SP_CMD_QUEUE_FULL_ACCESS | SP_CMD_QUEUE_FULL))
68 		dev_err(mbox->dev, "Secure processor command queue full\n");
69 
70 	writel(reg, mbox->base + RWTM_HOST_INT_RESET);
71 	if (reg)
72 		mbox_chan_txdone(chan, 0);
73 
74 	return reg ? IRQ_HANDLED : IRQ_NONE;
75 }
76 
77 static int a37xx_mbox_send_data(struct mbox_chan *chan, void *data)
78 {
79 	struct a37xx_mbox *mbox = chan->con_priv;
80 	struct armada_37xx_rwtm_tx_msg *msg = data;
81 	int i;
82 	u32 reg;
83 
84 	if (!data)
85 		return -EINVAL;
86 
87 	reg = readl(mbox->base + RWTM_MBOX_FIFO_STATUS);
88 	if (!(reg & FIFO_STS_RDY))
89 		dev_warn(mbox->dev, "Secure processor not ready\n");
90 
91 	if ((reg & FIFO_STS_CNTR_MASK) >= FIFO_STS_CNTR_MAX) {
92 		dev_err(mbox->dev, "Secure processor command queue full\n");
93 		return -EBUSY;
94 	}
95 
96 	for (i = 0; i < 16; ++i)
97 		writel(msg->args[i], mbox->base + RWTM_MBOX_PARAM(i));
98 	writel(msg->command, mbox->base + RWTM_MBOX_COMMAND);
99 
100 	return 0;
101 }
102 
103 static int a37xx_mbox_startup(struct mbox_chan *chan)
104 {
105 	struct a37xx_mbox *mbox = chan->con_priv;
106 	u32 reg;
107 	int ret;
108 
109 	ret = devm_request_irq(mbox->dev, mbox->irq, a37xx_mbox_irq_handler, 0,
110 			       DRIVER_NAME, chan);
111 	if (ret < 0) {
112 		dev_err(mbox->dev, "Cannot request irq\n");
113 		return ret;
114 	}
115 
116 	/* enable IRQ generation */
117 	reg = readl(mbox->base + RWTM_HOST_INT_MASK);
118 	reg &= ~(SP_CMD_COMPLETE | SP_CMD_QUEUE_FULL_ACCESS | SP_CMD_QUEUE_FULL);
119 	writel(reg, mbox->base + RWTM_HOST_INT_MASK);
120 
121 	return 0;
122 }
123 
124 static void a37xx_mbox_shutdown(struct mbox_chan *chan)
125 {
126 	u32 reg;
127 	struct a37xx_mbox *mbox = chan->con_priv;
128 
129 	/* disable interrupt generation */
130 	reg = readl(mbox->base + RWTM_HOST_INT_MASK);
131 	reg |= SP_CMD_COMPLETE | SP_CMD_QUEUE_FULL_ACCESS | SP_CMD_QUEUE_FULL;
132 	writel(reg, mbox->base + RWTM_HOST_INT_MASK);
133 
134 	devm_free_irq(mbox->dev, mbox->irq, chan);
135 }
136 
137 static const struct mbox_chan_ops a37xx_mbox_ops = {
138 	.send_data	= a37xx_mbox_send_data,
139 	.startup	= a37xx_mbox_startup,
140 	.shutdown	= a37xx_mbox_shutdown,
141 };
142 
143 static int armada_37xx_mbox_probe(struct platform_device *pdev)
144 {
145 	struct a37xx_mbox *mbox;
146 	struct mbox_chan *chans;
147 	int ret;
148 
149 	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
150 	if (!mbox)
151 		return -ENOMEM;
152 
153 	/* Allocated one channel */
154 	chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
155 	if (!chans)
156 		return -ENOMEM;
157 
158 	mbox->base = devm_platform_ioremap_resource(pdev, 0);
159 	if (IS_ERR(mbox->base))
160 		return PTR_ERR(mbox->base);
161 
162 	mbox->irq = platform_get_irq(pdev, 0);
163 	if (mbox->irq < 0)
164 		return mbox->irq;
165 
166 	mbox->dev = &pdev->dev;
167 
168 	/* Hardware supports only one channel. */
169 	chans[0].con_priv = mbox;
170 	mbox->controller.dev = mbox->dev;
171 	mbox->controller.num_chans = 1;
172 	mbox->controller.chans = chans;
173 	mbox->controller.ops = &a37xx_mbox_ops;
174 	mbox->controller.txdone_irq = true;
175 
176 	ret = devm_mbox_controller_register(mbox->dev, &mbox->controller);
177 	if (ret) {
178 		dev_err(&pdev->dev, "Could not register mailbox controller\n");
179 		return ret;
180 	}
181 
182 	platform_set_drvdata(pdev, mbox);
183 	return ret;
184 }
185 
186 
187 static const struct of_device_id armada_37xx_mbox_match[] = {
188 	{ .compatible = "marvell,armada-3700-rwtm-mailbox" },
189 	{ },
190 };
191 
192 MODULE_DEVICE_TABLE(of, armada_37xx_mbox_match);
193 
194 static struct platform_driver armada_37xx_mbox_driver = {
195 	.probe	= armada_37xx_mbox_probe,
196 	.driver	= {
197 		.name		= DRIVER_NAME,
198 		.of_match_table	= armada_37xx_mbox_match,
199 	},
200 };
201 
202 module_platform_driver(armada_37xx_mbox_driver);
203 
204 MODULE_LICENSE("GPL v2");
205 MODULE_DESCRIPTION("rWTM BIU Mailbox driver for Armada 37xx");
206 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
207