1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Raspberry Pi 4 firmware reset driver
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun #include <linux/delay.h>
8*4882a593Smuzhiyun #include <linux/device.h>
9*4882a593Smuzhiyun #include <linux/module.h>
10*4882a593Smuzhiyun #include <linux/of.h>
11*4882a593Smuzhiyun #include <linux/platform_device.h>
12*4882a593Smuzhiyun #include <linux/reset-controller.h>
13*4882a593Smuzhiyun #include <soc/bcm2835/raspberrypi-firmware.h>
14*4882a593Smuzhiyun #include <dt-bindings/reset/raspberrypi,firmware-reset.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun struct rpi_reset {
17*4882a593Smuzhiyun struct reset_controller_dev rcdev;
18*4882a593Smuzhiyun struct rpi_firmware *fw;
19*4882a593Smuzhiyun };
20*4882a593Smuzhiyun
to_rpi(struct reset_controller_dev * rcdev)21*4882a593Smuzhiyun static inline struct rpi_reset *to_rpi(struct reset_controller_dev *rcdev)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun return container_of(rcdev, struct rpi_reset, rcdev);
24*4882a593Smuzhiyun }
25*4882a593Smuzhiyun
rpi_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)26*4882a593Smuzhiyun static int rpi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun struct rpi_reset *priv = to_rpi(rcdev);
29*4882a593Smuzhiyun u32 dev_addr;
30*4882a593Smuzhiyun int ret;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun switch (id) {
33*4882a593Smuzhiyun case RASPBERRYPI_FIRMWARE_RESET_ID_USB:
34*4882a593Smuzhiyun /*
35*4882a593Smuzhiyun * The Raspberry Pi 4 gets its USB functionality from VL805, a
36*4882a593Smuzhiyun * PCIe chip that implements xHCI. After a PCI reset, VL805's
37*4882a593Smuzhiyun * firmware may either be loaded directly from an EEPROM or, if
38*4882a593Smuzhiyun * not present, by the SoC's co-processor, VideoCore. rpi's
39*4882a593Smuzhiyun * VideoCore OS contains both the non public firmware load
40*4882a593Smuzhiyun * logic and the VL805 firmware blob. This triggers the
41*4882a593Smuzhiyun * aforementioned process.
42*4882a593Smuzhiyun *
43*4882a593Smuzhiyun * The pci device address is expected is expected by the
44*4882a593Smuzhiyun * firmware encoded like this:
45*4882a593Smuzhiyun *
46*4882a593Smuzhiyun * PCI_BUS << 20 | PCI_SLOT << 15 | PCI_FUNC << 12
47*4882a593Smuzhiyun *
48*4882a593Smuzhiyun * But since rpi's PCIe is hardwired, we know the address in
49*4882a593Smuzhiyun * advance.
50*4882a593Smuzhiyun */
51*4882a593Smuzhiyun dev_addr = 0x100000;
52*4882a593Smuzhiyun ret = rpi_firmware_property(priv->fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
53*4882a593Smuzhiyun &dev_addr, sizeof(dev_addr));
54*4882a593Smuzhiyun if (ret)
55*4882a593Smuzhiyun return ret;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /* Wait for vl805 to startup */
58*4882a593Smuzhiyun usleep_range(200, 1000);
59*4882a593Smuzhiyun break;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun default:
62*4882a593Smuzhiyun return -EINVAL;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun return 0;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun static const struct reset_control_ops rpi_reset_ops = {
69*4882a593Smuzhiyun .reset = rpi_reset_reset,
70*4882a593Smuzhiyun };
71*4882a593Smuzhiyun
rpi_reset_probe(struct platform_device * pdev)72*4882a593Smuzhiyun static int rpi_reset_probe(struct platform_device *pdev)
73*4882a593Smuzhiyun {
74*4882a593Smuzhiyun struct device *dev = &pdev->dev;
75*4882a593Smuzhiyun struct rpi_firmware *fw;
76*4882a593Smuzhiyun struct device_node *np;
77*4882a593Smuzhiyun struct rpi_reset *priv;
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun np = of_get_parent(dev->of_node);
80*4882a593Smuzhiyun if (!np) {
81*4882a593Smuzhiyun dev_err(dev, "Missing firmware node\n");
82*4882a593Smuzhiyun return -ENOENT;
83*4882a593Smuzhiyun }
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun fw = rpi_firmware_get(np);
86*4882a593Smuzhiyun of_node_put(np);
87*4882a593Smuzhiyun if (!fw)
88*4882a593Smuzhiyun return -EPROBE_DEFER;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
91*4882a593Smuzhiyun if (!priv)
92*4882a593Smuzhiyun return -ENOMEM;
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun dev_set_drvdata(dev, priv);
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun priv->fw = fw;
97*4882a593Smuzhiyun priv->rcdev.owner = THIS_MODULE;
98*4882a593Smuzhiyun priv->rcdev.nr_resets = RASPBERRYPI_FIRMWARE_RESET_NUM_IDS;
99*4882a593Smuzhiyun priv->rcdev.ops = &rpi_reset_ops;
100*4882a593Smuzhiyun priv->rcdev.of_node = dev->of_node;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun return devm_reset_controller_register(dev, &priv->rcdev);
103*4882a593Smuzhiyun }
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun static const struct of_device_id rpi_reset_of_match[] = {
106*4882a593Smuzhiyun { .compatible = "raspberrypi,firmware-reset" },
107*4882a593Smuzhiyun { /* sentinel */ }
108*4882a593Smuzhiyun };
109*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, rpi_reset_of_match);
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun static struct platform_driver rpi_reset_driver = {
112*4882a593Smuzhiyun .probe = rpi_reset_probe,
113*4882a593Smuzhiyun .driver = {
114*4882a593Smuzhiyun .name = "raspberrypi-reset",
115*4882a593Smuzhiyun .of_match_table = rpi_reset_of_match,
116*4882a593Smuzhiyun },
117*4882a593Smuzhiyun };
118*4882a593Smuzhiyun module_platform_driver(rpi_reset_driver);
119*4882a593Smuzhiyun
120*4882a593Smuzhiyun MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
121*4882a593Smuzhiyun MODULE_DESCRIPTION("Raspberry Pi 4 firmware reset driver");
122*4882a593Smuzhiyun MODULE_LICENSE("GPL");
123