1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2018-2020 Broadcom */
3
4#include <linux/device.h>
5#include <linux/iopoll.h>
6#include <linux/module.h>
7#include <linux/of.h>
8#include <linux/platform_device.h>
9#include <linux/reset-controller.h>
10
11#define BRCM_RESCAL_START	0x0
12#define  BRCM_RESCAL_START_BIT	BIT(0)
13#define BRCM_RESCAL_CTRL	0x4
14#define BRCM_RESCAL_STATUS	0x8
15#define  BRCM_RESCAL_STATUS_BIT	BIT(0)
16
17struct brcm_rescal_reset {
18	void __iomem *base;
19	struct device *dev;
20	struct reset_controller_dev rcdev;
21};
22
23static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
24				 unsigned long id)
25{
26	struct brcm_rescal_reset *data =
27		container_of(rcdev, struct brcm_rescal_reset, rcdev);
28	void __iomem *base = data->base;
29	u32 reg;
30	int ret;
31
32	reg = readl(base + BRCM_RESCAL_START);
33	writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
34	reg = readl(base + BRCM_RESCAL_START);
35	if (!(reg & BRCM_RESCAL_START_BIT)) {
36		dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
37		return -EIO;
38	}
39
40	ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
41				 (reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
42	if (ret) {
43		dev_err(data->dev, "time out on SATA/PCIe rescal\n");
44		return ret;
45	}
46
47	reg = readl(base + BRCM_RESCAL_START);
48	writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
49
50	dev_dbg(data->dev, "SATA/PCIe rescal success\n");
51
52	return 0;
53}
54
55static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
56				   const struct of_phandle_args *reset_spec)
57{
58	/* This is needed if #reset-cells == 0. */
59	return 0;
60}
61
62static const struct reset_control_ops brcm_rescal_reset_ops = {
63	.reset = brcm_rescal_reset_set,
64};
65
66static int brcm_rescal_reset_probe(struct platform_device *pdev)
67{
68	struct brcm_rescal_reset *data;
69
70	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
71	if (!data)
72		return -ENOMEM;
73
74	data->base = devm_platform_ioremap_resource(pdev, 0);
75	if (IS_ERR(data->base))
76		return PTR_ERR(data->base);
77
78	data->rcdev.owner = THIS_MODULE;
79	data->rcdev.nr_resets = 1;
80	data->rcdev.ops = &brcm_rescal_reset_ops;
81	data->rcdev.of_node = pdev->dev.of_node;
82	data->rcdev.of_xlate = brcm_rescal_reset_xlate;
83	data->dev = &pdev->dev;
84
85	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
86}
87
88static const struct of_device_id brcm_rescal_reset_of_match[] = {
89	{ .compatible = "brcm,bcm7216-pcie-sata-rescal" },
90	{ },
91};
92MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
93
94static struct platform_driver brcm_rescal_reset_driver = {
95	.probe = brcm_rescal_reset_probe,
96	.driver = {
97		.name	= "brcm-rescal-reset",
98		.of_match_table	= brcm_rescal_reset_of_match,
99	}
100};
101module_platform_driver(brcm_rescal_reset_driver);
102
103MODULE_AUTHOR("Broadcom");
104MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
105MODULE_LICENSE("GPL v2");
106