reset-microchip-sparx5.c

  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
 18struct reset_props {
 19	u32 protect_reg;
 20	u32 protect_bit;
 21	u32 reset_reg;
 22	u32 reset_bit;
 23};
 24
 25struct 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
 32static struct regmap_config sparx5_reset_regmap_config = {
 33	.reg_bits	= 32,
 34	.val_bits	= 32,
 35	.reg_stride	= 4,
 36};
 37
 38static 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
 56static int sparx5_reset_noop(struct reset_controller_dev *rcdev,
 57			     unsigned long id)
 58{
 59	return 0;
 60}
 61
 62static const struct reset_control_ops sparx5_reset_ops = {
 63	.reset = sparx5_reset_noop,
 64};
 65
 66static const struct regmap_config mchp_lan966x_syscon_regmap_config = {
 67	.reg_bits = 32,
 68	.val_bits = 32,
 69	.reg_stride = 4,
 70};
 71
 72static 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, &regmap_config);
 94}
 95
 96static 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
128static 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
148static 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
180static 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
187static 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
194static 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};
204MODULE_DEVICE_TABLE(of, mchp_sparx5_reset_of_match);
205
206static 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
214static 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 */
223postcore_initcall(mchp_sparx5_reset_init);
224
225MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
226MODULE_AUTHOR("Steen Hegelund <steen.hegelund@microchip.com>");
227MODULE_LICENSE("GPL");