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e2affdbe | 1 | // SPDX-License-Identifier: GPL-2.0 |
0bae6af6 LR |
2 | /* |
3 | * Copyright (C) 2010,2015 Broadcom | |
4 | * Copyright (C) 2013-2014 Lubomir Rintel | |
5 | * Copyright (C) 2013 Craig McGeachie | |
6 | * | |
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7 | * Parts of the driver are based on: |
8 | * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was | |
9 | * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/ | |
10 | * linux.git | |
11 | * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at | |
12 | * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/ | |
13 | * mailbox/bcm2835-ipc.c | |
14 | * - documentation available on the following web site: | |
15 | * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface | |
16 | */ | |
17 | ||
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 | /* Mailboxes */ | |
32 | #define ARM_0_MAIL0 0x00 | |
33 | #define ARM_0_MAIL1 0x20 | |
34 | ||
35 | /* | |
36 | * Mailbox registers. We basically only support mailbox 0 & 1. We | |
37 | * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See | |
38 | * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about | |
39 | * the placement of memory barriers. | |
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) | |
7d641938 | 46 | #define MAIL1_STA (ARM_0_MAIL1 + 0x18) |
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47 | |
48 | /* Status register: FIFO state. */ | |
49 | #define ARM_MS_FULL BIT(31) | |
50 | #define ARM_MS_EMPTY BIT(30) | |
51 | ||
52 | /* Configuration register: Enable interrupts. */ | |
53 | #define ARM_MC_IHAVEDATAIRQEN BIT(0) | |
54 | ||
55 | struct bcm2835_mbox { | |
56 | void __iomem *regs; | |
57 | spinlock_t lock; | |
58 | struct mbox_controller controller; | |
59 | }; | |
60 | ||
61 | static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link) | |
62 | { | |
63 | return container_of(link->mbox, struct bcm2835_mbox, controller); | |
64 | } | |
65 | ||
66 | static 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 | ||
80 | static 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 | ||
92 | static int bcm2835_startup(struct mbox_chan *link) | |
93 | { | |
94 | struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); | |
95 | ||
96 | /* Enable the interrupt on data reception */ | |
97 | writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF); | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | static 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 | ||
109 | static 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); | |
7d641938 | 115 | ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL); |
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116 | spin_unlock(&mbox->lock); |
117 | return ret; | |
118 | } | |
119 | ||
120 | static 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 | ||
127 | static 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) | |
00ee3a13 | 131 | return ERR_PTR(-EINVAL); |
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132 | |
133 | return &mbox->chans[0]; | |
134 | } | |
135 | ||
136 | static 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 | ||
709cbeea | 175 | ret = devm_mbox_controller_register(dev, &mbox->controller); |
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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 | ||
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185 | static const struct of_device_id bcm2835_mbox_of_match[] = { |
186 | { .compatible = "brcm,bcm2835-mbox", }, | |
187 | {}, | |
188 | }; | |
189 | MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match); | |
190 | ||
191 | static struct platform_driver bcm2835_mbox_driver = { | |
192 | .driver = { | |
193 | .name = "bcm2835-mbox", | |
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194 | .of_match_table = bcm2835_mbox_of_match, |
195 | }, | |
196 | .probe = bcm2835_mbox_probe, | |
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197 | }; |
198 | module_platform_driver(bcm2835_mbox_driver); | |
199 | ||
200 | MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); | |
201 | MODULE_DESCRIPTION("BCM2835 mailbox IPC driver"); | |
202 | MODULE_LICENSE("GPL v2"); |