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/of_address.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/property.h>
15 #include <linux/regmap.h>
16 #include <linux/reset-controller.h>
17
18 struct reset_props {
19 u32 protect_reg;
20 u32 protect_bit;
21 u32 reset_reg;
22 u32 reset_bit;
23 };
24
25 struct mchp_reset_context {
26 struct regmap *cpu_ctrl;
27 struct regmap *gcb_ctrl;
28 struct reset_controller_dev rcdev;
29 const struct reset_props *props;
30 };
31
32 static struct regmap_config sparx5_reset_regmap_config = {
33 .reg_bits = 32,
34 .val_bits = 32,
35 .reg_stride = 4,
36 };
37
sparx5_switch_reset(struct mchp_reset_context * ctx)38 static int sparx5_switch_reset(struct mchp_reset_context *ctx)
39 {
40 u32 val;
41
42 /* Make sure the core is PROTECTED from reset */
43 regmap_update_bits(ctx->cpu_ctrl, ctx->props->protect_reg,
44 ctx->props->protect_bit, ctx->props->protect_bit);
45
46 /* Start soft reset */
47 regmap_write(ctx->gcb_ctrl, ctx->props->reset_reg,
48 ctx->props->reset_bit);
49
50 /* Wait for soft reset done */
51 return regmap_read_poll_timeout(ctx->gcb_ctrl, ctx->props->reset_reg, val,
52 (val & ctx->props->reset_bit) == 0,
53 1, 100);
54 }
55
sparx5_reset_noop(struct reset_controller_dev * rcdev,unsigned long id)56 static int sparx5_reset_noop(struct reset_controller_dev *rcdev,
57 unsigned long id)
58 {
59 return 0;
60 }
61
62 static const struct reset_control_ops sparx5_reset_ops = {
63 .reset = sparx5_reset_noop,
64 };
65
66 static const struct regmap_config mchp_lan966x_syscon_regmap_config = {
67 .reg_bits = 32,
68 .val_bits = 32,
69 .reg_stride = 4,
70 };
71
mchp_lan966x_syscon_to_regmap(struct device * dev,struct device_node * syscon_np)72 static struct regmap *mchp_lan966x_syscon_to_regmap(struct device *dev,
73 struct device_node *syscon_np)
74 {
75 struct regmap_config regmap_config = mchp_lan966x_syscon_regmap_config;
76 struct resource res;
77 void __iomem *base;
78 int err;
79
80 err = of_address_to_resource(syscon_np, 0, &res);
81 if (err)
82 return ERR_PTR(err);
83
84 /* It is not possible to use devm_of_iomap because this resource is
85 * shared with other drivers.
86 */
87 base = devm_ioremap(dev, res.start, resource_size(&res));
88 if (!base)
89 return ERR_PTR(-ENOMEM);
90
91 regmap_config.max_register = resource_size(&res) - 4;
92
93 return devm_regmap_init_mmio(dev, base, ®map_config);
94 }
95
mchp_sparx5_map_syscon(struct platform_device * pdev,char * name,struct regmap ** target)96 static int mchp_sparx5_map_syscon(struct platform_device *pdev, char *name,
97 struct regmap **target)
98 {
99 struct device_node *syscon_np;
100 struct regmap *regmap;
101 int err;
102
103 syscon_np = of_parse_phandle(pdev->dev.of_node, name, 0);
104 if (!syscon_np)
105 return -ENODEV;
106
107 /*
108 * The syscon API doesn't support syscon device removal.
109 * When used in LAN966x PCI device, the cpu-syscon device needs to be
110 * removed when the PCI device is removed.
111 * In case of LAN966x, map the syscon device locally to support the
112 * device removal.
113 */
114 if (of_device_is_compatible(pdev->dev.of_node, "microchip,lan966x-switch-reset"))
115 regmap = mchp_lan966x_syscon_to_regmap(&pdev->dev, syscon_np);
116 else
117 regmap = syscon_node_to_regmap(syscon_np);
118 of_node_put(syscon_np);
119 if (IS_ERR(regmap)) {
120 err = PTR_ERR(regmap);
121 dev_err(&pdev->dev, "No '%s' map: %d\n", name, err);
122 return err;
123 }
124 *target = regmap;
125 return 0;
126 }
127
mchp_sparx5_map_io(struct platform_device * pdev,int index,struct regmap ** target)128 static int mchp_sparx5_map_io(struct platform_device *pdev, int index,
129 struct regmap **target)
130 {
131 struct resource *res;
132 struct regmap *map;
133 void __iomem *mem;
134
135 mem = devm_platform_get_and_ioremap_resource(pdev, index, &res);
136 if (IS_ERR(mem)) {
137 dev_err(&pdev->dev, "Could not map resource %d\n", index);
138 return PTR_ERR(mem);
139 }
140 sparx5_reset_regmap_config.name = res->name;
141 map = devm_regmap_init_mmio(&pdev->dev, mem, &sparx5_reset_regmap_config);
142 if (IS_ERR(map))
143 return PTR_ERR(map);
144 *target = map;
145 return 0;
146 }
147
mchp_sparx5_reset_probe(struct platform_device * pdev)148 static int mchp_sparx5_reset_probe(struct platform_device *pdev)
149 {
150 struct device_node *dn = pdev->dev.of_node;
151 struct mchp_reset_context *ctx;
152 int err;
153
154 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
155 if (!ctx)
156 return -ENOMEM;
157
158 err = mchp_sparx5_map_syscon(pdev, "cpu-syscon", &ctx->cpu_ctrl);
159 if (err)
160 return err;
161 err = mchp_sparx5_map_io(pdev, 0, &ctx->gcb_ctrl);
162 if (err)
163 return err;
164
165 ctx->rcdev.owner = THIS_MODULE;
166 ctx->rcdev.dev = &pdev->dev;
167 ctx->rcdev.nr_resets = 1;
168 ctx->rcdev.ops = &sparx5_reset_ops;
169 ctx->rcdev.of_node = dn;
170 ctx->props = device_get_match_data(&pdev->dev);
171
172 /* Issue the reset very early, our actual reset callback is a noop. */
173 err = sparx5_switch_reset(ctx);
174 if (err)
175 return err;
176
177 return devm_reset_controller_register(&pdev->dev, &ctx->rcdev);
178 }
179
180 static const struct reset_props reset_props_sparx5 = {
181 .protect_reg = 0x84,
182 .protect_bit = BIT(10),
183 .reset_reg = 0x0,
184 .reset_bit = BIT(1),
185 };
186
187 static const struct reset_props reset_props_lan966x = {
188 .protect_reg = 0x88,
189 .protect_bit = BIT(5),
190 .reset_reg = 0x0,
191 .reset_bit = BIT(1),
192 };
193
194 static const struct of_device_id mchp_sparx5_reset_of_match[] = {
195 {
196 .compatible = "microchip,sparx5-switch-reset",
197 .data = &reset_props_sparx5,
198 }, {
199 .compatible = "microchip,lan966x-switch-reset",
200 .data = &reset_props_lan966x,
201 },
202 { }
203 };
204 MODULE_DEVICE_TABLE(of, mchp_sparx5_reset_of_match);
205
206 static struct platform_driver mchp_sparx5_reset_driver = {
207 .probe = mchp_sparx5_reset_probe,
208 .driver = {
209 .name = "sparx5-switch-reset",
210 .of_match_table = mchp_sparx5_reset_of_match,
211 },
212 };
213
mchp_sparx5_reset_init(void)214 static int __init mchp_sparx5_reset_init(void)
215 {
216 return platform_driver_register(&mchp_sparx5_reset_driver);
217 }
218
219 /*
220 * Because this is a global reset, keep this postcore_initcall() to issue the
221 * reset as early as possible during the kernel startup.
222 */
223 postcore_initcall(mchp_sparx5_reset_init);
224
225 MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
226 MODULE_AUTHOR("Steen Hegelund <steen.hegelund@microchip.com>");
227 MODULE_LICENSE("GPL");
228