1// SPDX-License-Identifier: GPL-2.0+
2/* Microchip Sparx5 Switch Reset driver
3 *
4 * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries.
5 *
6 * The Sparx5 Chip Register Model can be browsed at this location:
7 * https://github.com/microchip-ung/sparx-5_reginfo
8 */
9#include <linux/mfd/syscon.h>
10#include <linux/of.h>
11#include <linux/module.h>
12#include <linux/platform_device.h>
13#include <linux/property.h>
14#include <linux/regmap.h>
15#include <linux/reset-controller.h>
16
17struct reset_props {
18	u32 protect_reg;
19	u32 protect_bit;
20	u32 reset_reg;
21	u32 reset_bit;
22};
23
24struct mchp_reset_context {
25	struct regmap *cpu_ctrl;
26	struct regmap *gcb_ctrl;
27	struct reset_controller_dev rcdev;
28	const struct reset_props *props;
29};
30
31static struct regmap_config sparx5_reset_regmap_config = {
32	.reg_bits	= 32,
33	.val_bits	= 32,
34	.reg_stride	= 4,
35};
36
37static int sparx5_switch_reset(struct mchp_reset_context *ctx)
38{
39	u32 val;
40
41	/* Make sure the core is PROTECTED from reset */
42	regmap_update_bits(ctx->cpu_ctrl, ctx->props->protect_reg,
43			   ctx->props->protect_bit, ctx->props->protect_bit);
44
45	/* Start soft reset */
46	regmap_write(ctx->gcb_ctrl, ctx->props->reset_reg,
47		     ctx->props->reset_bit);
48
49	/* Wait for soft reset done */
50	return regmap_read_poll_timeout(ctx->gcb_ctrl, ctx->props->reset_reg, val,
51					(val & ctx->props->reset_bit) == 0,
52					1, 100);
53}
54
55static int sparx5_reset_noop(struct reset_controller_dev *rcdev,
56			     unsigned long id)
57{
58	return 0;
59}
60
61static const struct reset_control_ops sparx5_reset_ops = {
62	.reset = sparx5_reset_noop,
63};
64
65static int mchp_sparx5_map_syscon(struct platform_device *pdev, char *name,
66				  struct regmap **target)
67{
68	struct device_node *syscon_np;
69	struct regmap *regmap;
70	int err;
71
72	syscon_np = of_parse_phandle(pdev->dev.of_node, name, 0);
73	if (!syscon_np)
74		return -ENODEV;
75	regmap = syscon_node_to_regmap(syscon_np);
76	of_node_put(syscon_np);
77	if (IS_ERR(regmap)) {
78		err = PTR_ERR(regmap);
79		dev_err(&pdev->dev, "No '%s' map: %d\n", name, err);
80		return err;
81	}
82	*target = regmap;
83	return 0;
84}
85
86static int mchp_sparx5_map_io(struct platform_device *pdev, int index,
87			      struct regmap **target)
88{
89	struct resource *res;
90	struct regmap *map;
91	void __iomem *mem;
92
93	mem = devm_platform_get_and_ioremap_resource(pdev, index, &res);
94	if (IS_ERR(mem)) {
95		dev_err(&pdev->dev, "Could not map resource %d\n", index);
96		return PTR_ERR(mem);
97	}
98	sparx5_reset_regmap_config.name = res->name;
99	map = devm_regmap_init_mmio(&pdev->dev, mem, &sparx5_reset_regmap_config);
100	if (IS_ERR(map))
101		return PTR_ERR(map);
102	*target = map;
103	return 0;
104}
105
106static int mchp_sparx5_reset_probe(struct platform_device *pdev)
107{
108	struct device_node *dn = pdev->dev.of_node;
109	struct mchp_reset_context *ctx;
110	int err;
111
112	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
113	if (!ctx)
114		return -ENOMEM;
115
116	err = mchp_sparx5_map_syscon(pdev, "cpu-syscon", &ctx->cpu_ctrl);
117	if (err)
118		return err;
119	err = mchp_sparx5_map_io(pdev, 0, &ctx->gcb_ctrl);
120	if (err)
121		return err;
122
123	ctx->rcdev.owner = THIS_MODULE;
124	ctx->rcdev.nr_resets = 1;
125	ctx->rcdev.ops = &sparx5_reset_ops;
126	ctx->rcdev.of_node = dn;
127	ctx->props = device_get_match_data(&pdev->dev);
128
129	/* Issue the reset very early, our actual reset callback is a noop. */
130	err = sparx5_switch_reset(ctx);
131	if (err)
132		return err;
133
134	return devm_reset_controller_register(&pdev->dev, &ctx->rcdev);
135}
136
137static const struct reset_props reset_props_sparx5 = {
138	.protect_reg    = 0x84,
139	.protect_bit    = BIT(10),
140	.reset_reg      = 0x0,
141	.reset_bit      = BIT(1),
142};
143
144static const struct reset_props reset_props_lan966x = {
145	.protect_reg    = 0x88,
146	.protect_bit    = BIT(5),
147	.reset_reg      = 0x0,
148	.reset_bit      = BIT(1),
149};
150
151static const struct of_device_id mchp_sparx5_reset_of_match[] = {
152	{
153		.compatible = "microchip,sparx5-switch-reset",
154		.data = &reset_props_sparx5,
155	}, {
156		.compatible = "microchip,lan966x-switch-reset",
157		.data = &reset_props_lan966x,
158	},
159	{ }
160};
161
162static struct platform_driver mchp_sparx5_reset_driver = {
163	.probe = mchp_sparx5_reset_probe,
164	.driver = {
165		.name = "sparx5-switch-reset",
166		.of_match_table = mchp_sparx5_reset_of_match,
167	},
168};
169
170static int __init mchp_sparx5_reset_init(void)
171{
172	return platform_driver_register(&mchp_sparx5_reset_driver);
173}
174
175/*
176 * Because this is a global reset, keep this postcore_initcall() to issue the
177 * reset as early as possible during the kernel startup.
178 */
179postcore_initcall(mchp_sparx5_reset_init);
180
181MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
182MODULE_AUTHOR("Steen Hegelund <steen.hegelund@microchip.com>");
183