1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
2 /*
3  * Microsemi MIPS SoC reset driver
4  *
5  * License: Dual MIT/GPL
6  * Copyright (c) 2017 Microsemi Corporation
7  */
8 #include <linux/delay.h>
9 #include <linux/io.h>
10 #include <linux/notifier.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/platform_device.h>
14 #include <linux/property.h>
15 #include <linux/reboot.h>
16 #include <linux/regmap.h>
17 
18 struct reset_props {
19 	const char *syscon;
20 	u32 protect_reg;
21 	u32 vcore_protect;
22 	u32 if_si_owner_bit;
23 };
24 
25 struct ocelot_reset_context {
26 	void __iomem *base;
27 	struct regmap *cpu_ctrl;
28 	const struct reset_props *props;
29 	struct notifier_block restart_handler;
30 };
31 
32 #define BIT_OFF_INVALID				32
33 
34 #define SOFT_CHIP_RST BIT(0)
35 
36 #define ICPU_CFG_CPU_SYSTEM_CTRL_GENERAL_CTRL	0x24
37 #define IF_SI_OWNER_MASK			GENMASK(1, 0)
38 #define IF_SI_OWNER_SISL			0
39 #define IF_SI_OWNER_SIBM			1
40 #define IF_SI_OWNER_SIMC			2
41 
ocelot_restart_handle(struct notifier_block * this,unsigned long mode,void * cmd)42 static int ocelot_restart_handle(struct notifier_block *this,
43 				 unsigned long mode, void *cmd)
44 {
45 	struct ocelot_reset_context *ctx = container_of(this, struct
46 							ocelot_reset_context,
47 							restart_handler);
48 	u32 if_si_owner_bit = ctx->props->if_si_owner_bit;
49 
50 	/* Make sure the core is not protected from reset */
51 	regmap_update_bits(ctx->cpu_ctrl, ctx->props->protect_reg,
52 			   ctx->props->vcore_protect, 0);
53 
54 	/* Make the SI back to boot mode */
55 	if (if_si_owner_bit != BIT_OFF_INVALID)
56 		regmap_update_bits(ctx->cpu_ctrl,
57 				   ICPU_CFG_CPU_SYSTEM_CTRL_GENERAL_CTRL,
58 				   IF_SI_OWNER_MASK << if_si_owner_bit,
59 				   IF_SI_OWNER_SIBM << if_si_owner_bit);
60 
61 	pr_emerg("Resetting SoC\n");
62 
63 	writel(SOFT_CHIP_RST, ctx->base);
64 
65 	pr_emerg("Unable to restart system\n");
66 	return NOTIFY_DONE;
67 }
68 
ocelot_reset_probe(struct platform_device * pdev)69 static int ocelot_reset_probe(struct platform_device *pdev)
70 {
71 	struct ocelot_reset_context *ctx;
72 	struct device *dev = &pdev->dev;
73 	int err;
74 
75 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
76 	if (!ctx)
77 		return -ENOMEM;
78 
79 	ctx->base = devm_platform_ioremap_resource(pdev, 0);
80 	if (IS_ERR(ctx->base))
81 		return PTR_ERR(ctx->base);
82 
83 	ctx->props = device_get_match_data(dev);
84 
85 	ctx->cpu_ctrl = syscon_regmap_lookup_by_compatible(ctx->props->syscon);
86 	if (IS_ERR(ctx->cpu_ctrl)) {
87 		dev_err(dev, "No syscon map: %s\n", ctx->props->syscon);
88 		return PTR_ERR(ctx->cpu_ctrl);
89 	}
90 
91 	ctx->restart_handler.notifier_call = ocelot_restart_handle;
92 	ctx->restart_handler.priority = 192;
93 	err = register_restart_handler(&ctx->restart_handler);
94 	if (err)
95 		dev_err(dev, "can't register restart notifier (err=%d)\n", err);
96 
97 	return err;
98 }
99 
100 static const struct reset_props reset_props_jaguar2 = {
101 	.syscon		 = "mscc,ocelot-cpu-syscon",
102 	.protect_reg     = 0x20,
103 	.vcore_protect   = BIT(2),
104 	.if_si_owner_bit = 6,
105 };
106 
107 static const struct reset_props reset_props_luton = {
108 	.syscon		 = "mscc,ocelot-cpu-syscon",
109 	.protect_reg     = 0x20,
110 	.vcore_protect   = BIT(2),
111 	.if_si_owner_bit = BIT_OFF_INVALID, /* n/a */
112 };
113 
114 static const struct reset_props reset_props_ocelot = {
115 	.syscon		 = "mscc,ocelot-cpu-syscon",
116 	.protect_reg     = 0x20,
117 	.vcore_protect   = BIT(2),
118 	.if_si_owner_bit = 4,
119 };
120 
121 static const struct reset_props reset_props_sparx5 = {
122 	.syscon		 = "microchip,sparx5-cpu-syscon",
123 	.protect_reg     = 0x84,
124 	.vcore_protect   = BIT(10),
125 	.if_si_owner_bit = 6,
126 };
127 
128 static const struct of_device_id ocelot_reset_of_match[] = {
129 	{
130 		.compatible = "mscc,jaguar2-chip-reset",
131 		.data = &reset_props_jaguar2
132 	}, {
133 		.compatible = "mscc,luton-chip-reset",
134 		.data = &reset_props_luton
135 	}, {
136 		.compatible = "mscc,ocelot-chip-reset",
137 		.data = &reset_props_ocelot
138 	}, {
139 		.compatible = "microchip,sparx5-chip-reset",
140 		.data = &reset_props_sparx5
141 	},
142 	{ /*sentinel*/ }
143 };
144 
145 static struct platform_driver ocelot_reset_driver = {
146 	.probe = ocelot_reset_probe,
147 	.driver = {
148 		.name = "ocelot-chip-reset",
149 		.of_match_table = ocelot_reset_of_match,
150 	},
151 };
152 builtin_platform_driver(ocelot_reset_driver);
153