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 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 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 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 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 } 127 128 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 } 147 148 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 }; 213 214 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