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