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