1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
From c3cd26137b3f2031c738ce8be99678aea7d9177f Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Tue, 23 Feb 2016 19:56:04 +0000
Subject: [PATCH 090/782] bcm2835-virtgpio: Virtual GPIO driver
Add a virtual GPIO driver that uses the firmware mailbox interface to
request that the VPU toggles LEDs.
---
drivers/gpio/Kconfig | 6 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-bcm-virt.c | 214 +++++++++++++++++++++++++++++++++++
3 files changed, 221 insertions(+)
create mode 100644 drivers/gpio/gpio-bcm-virt.c
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -151,6 +151,12 @@ config GPIO_BCM_KONA
help
Turn on GPIO support for Broadcom "Kona" chips.
+config GPIO_BCM_VIRT
+ bool "Broadcom Virt GPIO"
+ depends on OF_GPIO && RASPBERRYPI_FIRMWARE && (ARCH_BCM2835 || COMPILE_TEST)
+ help
+ Turn on virtual GPIO support for Broadcom BCM283X chips.
+
config GPIO_BRCMSTB
tristate "BRCMSTB GPIO support"
default y if (ARCH_BRCMSTB || BMIPS_GENERIC)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_GPIO_ASPEED) += gpio-aspeed
obj-$(CONFIG_GPIO_RASPBERRYPI_EXP) += gpio-raspberrypi-exp.o
obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o
obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o
+obj-$(CONFIG_GPIO_BCM_VIRT) += gpio-bcm-virt.o
obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o
obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
obj-$(CONFIG_GPIO_CLPS711X) += gpio-clps711x.o
--- /dev/null
+++ b/drivers/gpio/gpio-bcm-virt.c
@@ -0,0 +1,214 @@
+/*
+ * brcmvirt GPIO driver
+ *
+ * Copyright (C) 2012,2013 Dom Cobley <popcornmix@gmail.com>
+ * Based on gpio-clps711x.c by Alexander Shiyan <shc_work@mail.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MODULE_NAME "brcmvirt-gpio"
+#define NUM_GPIO 2
+
+struct brcmvirt_gpio {
+ struct gpio_chip gc;
+ u32 __iomem *ts_base;
+ /* two packed 16-bit counts of enabled and disables
+ Allows host to detect a brief enable that was missed */
+ u32 enables_disables[NUM_GPIO];
+ dma_addr_t bus_addr;
+};
+
+static int brcmvirt_gpio_dir_in(struct gpio_chip *gc, unsigned off)
+{
+ struct brcmvirt_gpio *gpio;
+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
+ return -EINVAL;
+}
+
+static int brcmvirt_gpio_dir_out(struct gpio_chip *gc, unsigned off, int val)
+{
+ struct brcmvirt_gpio *gpio;
+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
+ return 0;
+}
+
+static int brcmvirt_gpio_get(struct gpio_chip *gc, unsigned off)
+{
+ struct brcmvirt_gpio *gpio;
+ unsigned v;
+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
+ v = readl(gpio->ts_base + off);
+ return (v >> off) & 1;
+}
+
+static void brcmvirt_gpio_set(struct gpio_chip *gc, unsigned off, int val)
+{
+ struct brcmvirt_gpio *gpio;
+ u16 enables, disables;
+ s16 diff;
+ bool lit;
+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
+ enables = gpio->enables_disables[off] >> 16;
+ disables = gpio->enables_disables[off] >> 0;
+ diff = (s16)(enables - disables);
+ lit = diff > 0;
+ if ((val && lit) || (!val && !lit))
+ return;
+ if (val)
+ enables++;
+ else
+ disables++;
+ diff = (s16)(enables - disables);
+ BUG_ON(diff != 0 && diff != 1);
+ gpio->enables_disables[off] = (enables << 16) | (disables << 0);
+ writel(gpio->enables_disables[off], gpio->ts_base + off);
+}
+
+static int brcmvirt_gpio_probe(struct platform_device *pdev)
+{
+ int err = 0;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct device_node *fw_node;
+ struct rpi_firmware *fw;
+ struct brcmvirt_gpio *ucb;
+ u32 gpiovirtbuf;
+
+ fw_node = of_parse_phandle(np, "firmware", 0);
+ if (!fw_node) {
+ dev_err(dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ fw = rpi_firmware_get(fw_node);
+ if (!fw)
+ return -EPROBE_DEFER;
+
+ ucb = devm_kzalloc(dev, sizeof *ucb, GFP_KERNEL);
+ if (!ucb) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ ucb->ts_base = dma_zalloc_coherent(dev, PAGE_SIZE, &ucb->bus_addr, GFP_KERNEL);
+ if (!ucb->ts_base) {
+ pr_err("[%s]: failed to dma_alloc_coherent(%ld)\n",
+ __func__, PAGE_SIZE);
+ err = -ENOMEM;
+ goto out;
+ }
+
+ gpiovirtbuf = (u32)ucb->bus_addr;
+ err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_GPIOVIRTBUF,
+ &gpiovirtbuf, sizeof(gpiovirtbuf));
+
+ if (err || gpiovirtbuf != 0) {
+ dev_warn(dev, "Failed to set gpiovirtbuf, trying to get err:%x\n", err);
+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
+ ucb->ts_base = 0;
+ ucb->bus_addr = 0;
+ }
+
+ if (!ucb->ts_base) {
+ err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_GET_GPIOVIRTBUF,
+ &gpiovirtbuf, sizeof(gpiovirtbuf));
+
+ if (err) {
+ dev_err(dev, "Failed to get gpiovirtbuf\n");
+ goto out;
+ }
+
+ if (!gpiovirtbuf) {
+ dev_err(dev, "No virtgpio buffer\n");
+ err = -ENOENT;
+ goto out;
+ }
+
+ // mmap the physical memory
+ gpiovirtbuf &= ~0xc0000000;
+ ucb->ts_base = ioremap(gpiovirtbuf, 4096);
+ if (ucb->ts_base == NULL) {
+ dev_err(dev, "Failed to map physical address\n");
+ err = -ENOENT;
+ goto out;
+ }
+ ucb->bus_addr = 0;
+ }
+ ucb->gc.label = MODULE_NAME;
+ ucb->gc.owner = THIS_MODULE;
+ //ucb->gc.dev = dev;
+ ucb->gc.of_node = np;
+ ucb->gc.base = 100;
+ ucb->gc.ngpio = NUM_GPIO;
+
+ ucb->gc.direction_input = brcmvirt_gpio_dir_in;
+ ucb->gc.direction_output = brcmvirt_gpio_dir_out;
+ ucb->gc.get = brcmvirt_gpio_get;
+ ucb->gc.set = brcmvirt_gpio_set;
+ ucb->gc.can_sleep = true;
+
+ err = gpiochip_add(&ucb->gc);
+ if (err)
+ goto out;
+
+ platform_set_drvdata(pdev, ucb);
+
+ return 0;
+out:
+ if (ucb->bus_addr) {
+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
+ ucb->bus_addr = 0;
+ ucb->ts_base = NULL;
+ } else if (ucb->ts_base) {
+ iounmap(ucb->ts_base);
+ ucb->ts_base = NULL;
+ }
+ return err;
+}
+
+static int brcmvirt_gpio_remove(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int err = 0;
+ struct brcmvirt_gpio *ucb = platform_get_drvdata(pdev);
+
+ gpiochip_remove(&ucb->gc);
+ if (ucb->bus_addr)
+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
+ else if (ucb->ts_base)
+ iounmap(ucb->ts_base);
+ return err;
+}
+
+static const struct of_device_id __maybe_unused brcmvirt_gpio_ids[] = {
+ { .compatible = "brcm,bcm2835-virtgpio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, brcmvirt_gpio_ids);
+
+static struct platform_driver brcmvirt_gpio_driver = {
+ .driver = {
+ .name = MODULE_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(brcmvirt_gpio_ids),
+ },
+ .probe = brcmvirt_gpio_probe,
+ .remove = brcmvirt_gpio_remove,
+};
+module_platform_driver(brcmvirt_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dom Cobley <popcornmix@gmail.com>");
+MODULE_DESCRIPTION("brcmvirt GPIO driver");
+MODULE_ALIAS("platform:brcmvirt-gpio");
|
