exynos-pm-domains.c

  1// SPDX-License-Identifier: GPL-2.0
  2//
  3// Exynos Generic power domain support.
  4//
  5// Copyright (c) 2012 Samsung Electronics Co., Ltd.
  6//		http://www.samsung.com
  7//
  8// Implementation of Exynos specific power domain control which is used in
  9// conjunction with runtime-pm. Support for both device-tree and non-device-tree
 10// based power domain support is included.
 11
 12#include <linux/io.h>
 13#include <linux/err.h>
 14#include <linux/platform_device.h>
 15#include <linux/slab.h>
 16#include <linux/pm_domain.h>
 17#include <linux/delay.h>
 18#include <linux/of.h>
 19#include <linux/of_address.h>
 20#include <linux/pm_runtime.h>
 21
 22struct exynos_pm_domain_config {
 23	/* Value for LOCAL_PWR_CFG and STATUS fields for each domain */
 24	u32 local_pwr_cfg;
 25};
 26
 27/*
 28 * Exynos specific wrapper around the generic power domain
 29 */
 30struct exynos_pm_domain {
 31	void __iomem *base;
 32	struct generic_pm_domain pd;
 33	u32 local_pwr_cfg;
 34};
 35
 36static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
 37{
 38	struct exynos_pm_domain *pd;
 39	void __iomem *base;
 40	u32 timeout, pwr;
 41	char *op;
 42
 43	pd = container_of(domain, struct exynos_pm_domain, pd);
 44	base = pd->base;
 45
 46	pwr = power_on ? pd->local_pwr_cfg : 0;
 47	writel_relaxed(pwr, base);
 48
 49	/* Wait max 1ms */
 50	timeout = 10;
 51
 52	while ((readl_relaxed(base + 0x4) & pd->local_pwr_cfg) != pwr) {
 53		if (!timeout) {
 54			op = (power_on) ? "enable" : "disable";
 55			pr_err("Power domain %s %s failed\n", domain->name, op);
 56			return -ETIMEDOUT;
 57		}
 58		timeout--;
 59		cpu_relax();
 60		usleep_range(80, 100);
 61	}
 62
 63	return 0;
 64}
 65
 66static int exynos_pd_power_on(struct generic_pm_domain *domain)
 67{
 68	return exynos_pd_power(domain, true);
 69}
 70
 71static int exynos_pd_power_off(struct generic_pm_domain *domain)
 72{
 73	return exynos_pd_power(domain, false);
 74}
 75
 76static const struct exynos_pm_domain_config exynos4210_cfg = {
 77	.local_pwr_cfg		= 0x7,
 78};
 79
 80static const struct exynos_pm_domain_config exynos5433_cfg = {
 81	.local_pwr_cfg		= 0xf,
 82};
 83
 84static const struct of_device_id exynos_pm_domain_of_match[] = {
 85	{
 86		.compatible = "samsung,exynos4210-pd",
 87		.data = &exynos4210_cfg,
 88	}, {
 89		.compatible = "samsung,exynos5433-pd",
 90		.data = &exynos5433_cfg,
 91	},
 92	{ },
 93};
 94
 95static const char *exynos_get_domain_name(struct device *dev,
 96					  struct device_node *node)
 97{
 98	const char *name;
 99
100	if (of_property_read_string(node, "label", &name) < 0)
101		name = kbasename(node->full_name);
102	return devm_kstrdup_const(dev, name, GFP_KERNEL);
103}
104
105static int exynos_pd_probe(struct platform_device *pdev)
106{
107	const struct exynos_pm_domain_config *pm_domain_cfg;
108	struct device *dev = &pdev->dev;
109	struct device_node *np = dev->of_node;
110	struct of_phandle_args child, parent;
111	struct exynos_pm_domain *pd;
112	int on, ret;
113
114	pm_domain_cfg = of_device_get_match_data(dev);
115	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
116	if (!pd)
117		return -ENOMEM;
118
119	pd->pd.name = exynos_get_domain_name(dev, np);
120	if (!pd->pd.name)
121		return -ENOMEM;
122
123	pd->base = of_iomap(np, 0);
124	if (!pd->base)
125		return -ENODEV;
126
127	pd->pd.power_off = exynos_pd_power_off;
128	pd->pd.power_on = exynos_pd_power_on;
129	pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
130
131	/*
132	 * Some Samsung platforms with bootloaders turning on the splash-screen
133	 * and handing it over to the kernel, requires the power-domains to be
134	 * reset during boot.
135	 */
136	if (IS_ENABLED(CONFIG_ARM) &&
137	    of_device_is_compatible(np, "samsung,exynos4210-pd"))
138		exynos_pd_power_off(&pd->pd);
139
140	on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
141
142	pm_genpd_init(&pd->pd, NULL, !on);
143	ret = of_genpd_add_provider_simple(np, &pd->pd);
144
145	if (ret == 0 && of_parse_phandle_with_args(np, "power-domains",
146				      "#power-domain-cells", 0, &parent) == 0) {
147		child.np = np;
148		child.args_count = 0;
149
150		if (of_genpd_add_subdomain(&parent, &child))
151			pr_warn("%pOF failed to add subdomain: %pOF\n",
152				parent.np, child.np);
153		else
154			pr_info("%pOF has as child subdomain: %pOF.\n",
155				parent.np, child.np);
156	}
157
158	pm_runtime_enable(dev);
159	return ret;
160}
161
162static struct platform_driver exynos_pd_driver = {
163	.probe	= exynos_pd_probe,
164	.driver	= {
165		.name		= "exynos-pd",
166		.of_match_table	= exynos_pm_domain_of_match,
167		.suppress_bind_attrs = true,
168	}
169};
170
171static __init int exynos4_pm_init_power_domain(void)
172{
173	return platform_driver_register(&exynos_pd_driver);
174}
175core_initcall(exynos4_pm_init_power_domain);