1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
4 * Copyright (C) 2015 Linaro Ltd.
5 * Author: Jassi Brar <jaswinder.singh@linaro.org>
6 */
7
8 #include <linux/amba/bus.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/mailbox_controller.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16
17 #define INTR_STAT_OFS 0x0
18 #define INTR_SET_OFS 0x8
19 #define INTR_CLR_OFS 0x10
20
21 #define MHU_LP_OFFSET 0x0
22 #define MHU_HP_OFFSET 0x20
23 #define MHU_SEC_OFFSET 0x200
24 #define TX_REG_OFFSET 0x100
25
26 #define MHU_CHANS 3
27
28 struct mhu_link {
29 unsigned irq;
30 void __iomem *tx_reg;
31 void __iomem *rx_reg;
32 };
33
34 struct arm_mhu {
35 void __iomem *base;
36 struct mhu_link mlink[MHU_CHANS];
37 struct mbox_chan chan[MHU_CHANS];
38 struct mbox_controller mbox;
39 };
40
mhu_rx_interrupt(int irq,void * p)41 static irqreturn_t mhu_rx_interrupt(int irq, void *p)
42 {
43 struct mbox_chan *chan = p;
44 struct mhu_link *mlink = chan->con_priv;
45 u32 val;
46
47 val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
48 if (!val)
49 return IRQ_NONE;
50
51 mbox_chan_received_data(chan, (void *)&val);
52
53 writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);
54
55 return IRQ_HANDLED;
56 }
57
mhu_last_tx_done(struct mbox_chan * chan)58 static bool mhu_last_tx_done(struct mbox_chan *chan)
59 {
60 struct mhu_link *mlink = chan->con_priv;
61 u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
62
63 return (val == 0);
64 }
65
mhu_send_data(struct mbox_chan * chan,void * data)66 static int mhu_send_data(struct mbox_chan *chan, void *data)
67 {
68 struct mhu_link *mlink = chan->con_priv;
69 u32 *arg = data;
70
71 writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);
72
73 return 0;
74 }
75
mhu_startup(struct mbox_chan * chan)76 static int mhu_startup(struct mbox_chan *chan)
77 {
78 struct mhu_link *mlink = chan->con_priv;
79 u32 val;
80 int ret;
81
82 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
83 writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
84
85 ret = request_irq(mlink->irq, mhu_rx_interrupt,
86 IRQF_SHARED, "mhu_link", chan);
87 if (ret) {
88 dev_err(chan->mbox->dev,
89 "Unable to acquire IRQ %d\n", mlink->irq);
90 return ret;
91 }
92
93 return 0;
94 }
95
mhu_shutdown(struct mbox_chan * chan)96 static void mhu_shutdown(struct mbox_chan *chan)
97 {
98 struct mhu_link *mlink = chan->con_priv;
99
100 free_irq(mlink->irq, chan);
101 }
102
103 static const struct mbox_chan_ops mhu_ops = {
104 .send_data = mhu_send_data,
105 .startup = mhu_startup,
106 .shutdown = mhu_shutdown,
107 .last_tx_done = mhu_last_tx_done,
108 };
109
mhu_probe(struct amba_device * adev,const struct amba_id * id)110 static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
111 {
112 int i, err;
113 struct arm_mhu *mhu;
114 struct device *dev = &adev->dev;
115 int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};
116
117 if (!of_device_is_compatible(dev->of_node, "arm,mhu"))
118 return -ENODEV;
119
120 /* Allocate memory for device */
121 mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
122 if (!mhu)
123 return -ENOMEM;
124
125 mhu->base = devm_ioremap_resource(dev, &adev->res);
126 if (IS_ERR(mhu->base))
127 return PTR_ERR(mhu->base);
128
129 for (i = 0; i < MHU_CHANS; i++) {
130 mhu->chan[i].con_priv = &mhu->mlink[i];
131 mhu->mlink[i].irq = adev->irq[i];
132 mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
133 mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
134 }
135
136 mhu->mbox.dev = dev;
137 mhu->mbox.chans = &mhu->chan[0];
138 mhu->mbox.num_chans = MHU_CHANS;
139 mhu->mbox.ops = &mhu_ops;
140 mhu->mbox.txdone_irq = false;
141 mhu->mbox.txdone_poll = true;
142 mhu->mbox.txpoll_period = 1;
143
144 amba_set_drvdata(adev, mhu);
145
146 err = devm_mbox_controller_register(dev, &mhu->mbox);
147 if (err) {
148 dev_err(dev, "Failed to register mailboxes %d\n", err);
149 return err;
150 }
151
152 dev_info(dev, "ARM MHU Mailbox registered\n");
153 return 0;
154 }
155
156 static struct amba_id mhu_ids[] = {
157 {
158 .id = 0x1bb098,
159 .mask = 0xffffff,
160 },
161 { 0, 0 },
162 };
163 MODULE_DEVICE_TABLE(amba, mhu_ids);
164
165 static struct amba_driver arm_mhu_driver = {
166 .drv = {
167 .name = "mhu",
168 },
169 .id_table = mhu_ids,
170 .probe = mhu_probe,
171 };
172 module_amba_driver(arm_mhu_driver);
173
174 MODULE_LICENSE("GPL v2");
175 MODULE_DESCRIPTION("ARM MHU Driver");
176 MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");
177