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18#include <linux/device.h>
19#include <linux/dma-mapping.h>
20#include <linux/err.h>
21#include <linux/interrupt.h>
22#include <linux/irq.h>
23#include <linux/kernel.h>
24#include <linux/mailbox_controller.h>
25#include <linux/module.h>
26#include <linux/of_address.h>
27#include <linux/of_irq.h>
28#include <linux/platform_device.h>
29#include <linux/spinlock.h>
30
31
32#define ARM_0_MAIL0 0x00
33#define ARM_0_MAIL1 0x20
34
35
36
37
38
39
40
41#define MAIL0_RD (ARM_0_MAIL0 + 0x00)
42#define MAIL0_POL (ARM_0_MAIL0 + 0x10)
43#define MAIL0_STA (ARM_0_MAIL0 + 0x18)
44#define MAIL0_CNF (ARM_0_MAIL0 + 0x1C)
45#define MAIL1_WRT (ARM_0_MAIL1 + 0x00)
46#define MAIL1_STA (ARM_0_MAIL1 + 0x18)
47
48
49#define ARM_MS_FULL BIT(31)
50#define ARM_MS_EMPTY BIT(30)
51
52
53#define ARM_MC_IHAVEDATAIRQEN BIT(0)
54
55struct bcm2835_mbox {
56 void __iomem *regs;
57 spinlock_t lock;
58 struct mbox_controller controller;
59};
60
61static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link)
62{
63 return container_of(link->mbox, struct bcm2835_mbox, controller);
64}
65
66static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id)
67{
68 struct bcm2835_mbox *mbox = dev_id;
69 struct device *dev = mbox->controller.dev;
70 struct mbox_chan *link = &mbox->controller.chans[0];
71
72 while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) {
73 u32 msg = readl(mbox->regs + MAIL0_RD);
74 dev_dbg(dev, "Reply 0x%08X\n", msg);
75 mbox_chan_received_data(link, &msg);
76 }
77 return IRQ_HANDLED;
78}
79
80static int bcm2835_send_data(struct mbox_chan *link, void *data)
81{
82 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
83 u32 msg = *(u32 *)data;
84
85 spin_lock(&mbox->lock);
86 writel(msg, mbox->regs + MAIL1_WRT);
87 dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg);
88 spin_unlock(&mbox->lock);
89 return 0;
90}
91
92static int bcm2835_startup(struct mbox_chan *link)
93{
94 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
95
96
97 writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF);
98
99 return 0;
100}
101
102static void bcm2835_shutdown(struct mbox_chan *link)
103{
104 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
105
106 writel(0, mbox->regs + MAIL0_CNF);
107}
108
109static bool bcm2835_last_tx_done(struct mbox_chan *link)
110{
111 struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
112 bool ret;
113
114 spin_lock(&mbox->lock);
115 ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
116 spin_unlock(&mbox->lock);
117 return ret;
118}
119
120static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
121 .send_data = bcm2835_send_data,
122 .startup = bcm2835_startup,
123 .shutdown = bcm2835_shutdown,
124 .last_tx_done = bcm2835_last_tx_done
125};
126
127static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox,
128 const struct of_phandle_args *sp)
129{
130 if (sp->args_count != 0)
131 return ERR_PTR(-EINVAL);
132
133 return &mbox->chans[0];
134}
135
136static int bcm2835_mbox_probe(struct platform_device *pdev)
137{
138 struct device *dev = &pdev->dev;
139 int ret = 0;
140 struct resource *iomem;
141 struct bcm2835_mbox *mbox;
142
143 mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
144 if (mbox == NULL)
145 return -ENOMEM;
146 spin_lock_init(&mbox->lock);
147
148 ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0),
149 bcm2835_mbox_irq, 0, dev_name(dev), mbox);
150 if (ret) {
151 dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
152 ret);
153 return -ENODEV;
154 }
155
156 iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
157 mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
158 if (IS_ERR(mbox->regs)) {
159 ret = PTR_ERR(mbox->regs);
160 dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
161 return ret;
162 }
163
164 mbox->controller.txdone_poll = true;
165 mbox->controller.txpoll_period = 5;
166 mbox->controller.ops = &bcm2835_mbox_chan_ops;
167 mbox->controller.of_xlate = &bcm2835_mbox_index_xlate;
168 mbox->controller.dev = dev;
169 mbox->controller.num_chans = 1;
170 mbox->controller.chans = devm_kzalloc(dev,
171 sizeof(*mbox->controller.chans), GFP_KERNEL);
172 if (!mbox->controller.chans)
173 return -ENOMEM;
174
175 ret = devm_mbox_controller_register(dev, &mbox->controller);
176 if (ret)
177 return ret;
178
179 platform_set_drvdata(pdev, mbox);
180 dev_info(dev, "mailbox enabled\n");
181
182 return ret;
183}
184
185static const struct of_device_id bcm2835_mbox_of_match[] = {
186 { .compatible = "brcm,bcm2835-mbox", },
187 {},
188};
189MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match);
190
191static struct platform_driver bcm2835_mbox_driver = {
192 .driver = {
193 .name = "bcm2835-mbox",
194 .of_match_table = bcm2835_mbox_of_match,
195 },
196 .probe = bcm2835_mbox_probe,
197};
198module_platform_driver(bcm2835_mbox_driver);
199
200MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
201MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
202MODULE_LICENSE("GPL v2");
203
