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 17 struct reset_props { 18 u32 protect_reg; 19 u32 protect_bit; 20 u32 reset_reg; 21 u32 reset_bit; 22 }; 23 24 struct 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 31 static struct regmap_config sparx5_reset_regmap_config = { 32 .reg_bits = 32, 33 .val_bits = 32, 34 .reg_stride = 4, 35 }; 36 37 static 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 55 static int sparx5_reset_noop(struct reset_controller_dev *rcdev, 56 unsigned long id) 57 { 58 return 0; 59 } 60 61 static const struct reset_control_ops sparx5_reset_ops = { 62 .reset = sparx5_reset_noop, 63 }; 64 65 static 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 86 static 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 } 105 106 static 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 } 136 137 static 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 }; 143 144 static 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 }; 150 151 static 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 }; 161 162 static 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 }; 169 170 static 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 */ 179 postcore_initcall(mchp_sparx5_reset_init); 180 181 MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver"); 182 MODULE_AUTHOR("Steen Hegelund <steen.hegelund@microchip.com>"); 183