1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2010,2015 Broadcom |
4 | * Copyright (C) 2013-2014 Lubomir Rintel |
5 | * Copyright (C) 2013 Craig McGeachie |
6 | * |
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) |
46 | #define MAIL1_STA (ARM_0_MAIL1 + 0x18) |
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(addr: mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) { |
73 | u32 msg = readl(addr: mbox->regs + MAIL0_RD); |
74 | dev_dbg(dev, "Reply 0x%08X\n" , msg); |
75 | mbox_chan_received_data(chan: link, data: &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(lock: &mbox->lock); |
86 | writel(val: msg, addr: mbox->regs + MAIL1_WRT); |
87 | dev_dbg(mbox->controller.dev, "Request 0x%08X\n" , msg); |
88 | spin_unlock(lock: &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, addr: 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(val: 0, addr: 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(lock: &mbox->lock); |
115 | ret = !(readl(addr: mbox->regs + MAIL1_STA) & ARM_MS_FULL); |
116 | spin_unlock(lock: &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) |
131 | return ERR_PTR(error: -EINVAL); |
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 bcm2835_mbox *mbox; |
141 | |
142 | mbox = devm_kzalloc(dev, size: sizeof(*mbox), GFP_KERNEL); |
143 | if (mbox == NULL) |
144 | return -ENOMEM; |
145 | spin_lock_init(&mbox->lock); |
146 | |
147 | ret = devm_request_irq(dev, irq: irq_of_parse_and_map(node: dev->of_node, index: 0), |
148 | handler: bcm2835_mbox_irq, irqflags: 0, devname: dev_name(dev), dev_id: mbox); |
149 | if (ret) { |
150 | dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n" , |
151 | ret); |
152 | return -ENODEV; |
153 | } |
154 | |
155 | mbox->regs = devm_platform_ioremap_resource(pdev, index: 0); |
156 | if (IS_ERR(ptr: mbox->regs)) { |
157 | ret = PTR_ERR(ptr: mbox->regs); |
158 | return ret; |
159 | } |
160 | |
161 | mbox->controller.txdone_poll = true; |
162 | mbox->controller.txpoll_period = 5; |
163 | mbox->controller.ops = &bcm2835_mbox_chan_ops; |
164 | mbox->controller.of_xlate = &bcm2835_mbox_index_xlate; |
165 | mbox->controller.dev = dev; |
166 | mbox->controller.num_chans = 1; |
167 | mbox->controller.chans = devm_kzalloc(dev, |
168 | size: sizeof(*mbox->controller.chans), GFP_KERNEL); |
169 | if (!mbox->controller.chans) |
170 | return -ENOMEM; |
171 | |
172 | ret = devm_mbox_controller_register(dev, mbox: &mbox->controller); |
173 | if (ret) |
174 | return ret; |
175 | |
176 | platform_set_drvdata(pdev, data: mbox); |
177 | dev_info(dev, "mailbox enabled\n" ); |
178 | |
179 | return ret; |
180 | } |
181 | |
182 | static const struct of_device_id bcm2835_mbox_of_match[] = { |
183 | { .compatible = "brcm,bcm2835-mbox" , }, |
184 | {}, |
185 | }; |
186 | MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match); |
187 | |
188 | static struct platform_driver bcm2835_mbox_driver = { |
189 | .driver = { |
190 | .name = "bcm2835-mbox" , |
191 | .of_match_table = bcm2835_mbox_of_match, |
192 | }, |
193 | .probe = bcm2835_mbox_probe, |
194 | }; |
195 | module_platform_driver(bcm2835_mbox_driver); |
196 | |
197 | MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>" ); |
198 | MODULE_DESCRIPTION("BCM2835 mailbox IPC driver" ); |
199 | MODULE_LICENSE("GPL v2" ); |
200 | |