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