1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.
4  * Copyright (c) 2014,2015, Linaro Ltd.
5  *
6  * SAW power controller driver
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/io.h>
12 #include <linux/slab.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/of_device.h>
16 #include <linux/err.h>
17 #include <linux/platform_device.h>
18 #include <linux/cpuidle.h>
19 #include <linux/cpu_pm.h>
20 #include <linux/firmware/qcom/qcom_scm.h>
21 #include <soc/qcom/spm.h>
22 
23 #include <asm/proc-fns.h>
24 #include <asm/suspend.h>
25 
26 #include "dt_idle_states.h"
27 
28 struct cpuidle_qcom_spm_data {
29 	struct cpuidle_driver cpuidle_driver;
30 	struct spm_driver_data *spm;
31 };
32 
33 static int qcom_pm_collapse(unsigned long int unused)
34 {
35 	qcom_scm_cpu_power_down(QCOM_SCM_CPU_PWR_DOWN_L2_ON);
36 
37 	/*
38 	 * Returns here only if there was a pending interrupt and we did not
39 	 * power down as a result.
40 	 */
41 	return -1;
42 }
43 
44 static int qcom_cpu_spc(struct spm_driver_data *drv)
45 {
46 	int ret;
47 
48 	spm_set_low_power_mode(drv, PM_SLEEP_MODE_SPC);
49 	ret = cpu_suspend(0, qcom_pm_collapse);
50 	/*
51 	 * ARM common code executes WFI without calling into our driver and
52 	 * if the SPM mode is not reset, then we may accidently power down the
53 	 * cpu when we intended only to gate the cpu clock.
54 	 * Ensure the state is set to standby before returning.
55 	 */
56 	spm_set_low_power_mode(drv, PM_SLEEP_MODE_STBY);
57 
58 	return ret;
59 }
60 
61 static __cpuidle int spm_enter_idle_state(struct cpuidle_device *dev,
62 					  struct cpuidle_driver *drv, int idx)
63 {
64 	struct cpuidle_qcom_spm_data *data = container_of(drv, struct cpuidle_qcom_spm_data,
65 							  cpuidle_driver);
66 
67 	return CPU_PM_CPU_IDLE_ENTER_PARAM(qcom_cpu_spc, idx, data->spm);
68 }
69 
70 static struct cpuidle_driver qcom_spm_idle_driver = {
71 	.name = "qcom_spm",
72 	.owner = THIS_MODULE,
73 	.states[0] = {
74 		.enter			= spm_enter_idle_state,
75 		.exit_latency		= 1,
76 		.target_residency	= 1,
77 		.power_usage		= UINT_MAX,
78 		.name			= "WFI",
79 		.desc			= "ARM WFI",
80 	}
81 };
82 
83 static const struct of_device_id qcom_idle_state_match[] = {
84 	{ .compatible = "qcom,idle-state-spc", .data = spm_enter_idle_state },
85 	{ },
86 };
87 
88 static int spm_cpuidle_register(struct device *cpuidle_dev, int cpu)
89 {
90 	struct platform_device *pdev = NULL;
91 	struct device_node *cpu_node, *saw_node;
92 	struct cpuidle_qcom_spm_data *data = NULL;
93 	int ret;
94 
95 	cpu_node = of_cpu_device_node_get(cpu);
96 	if (!cpu_node)
97 		return -ENODEV;
98 
99 	saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
100 	if (!saw_node)
101 		return -ENODEV;
102 
103 	pdev = of_find_device_by_node(saw_node);
104 	of_node_put(saw_node);
105 	of_node_put(cpu_node);
106 	if (!pdev)
107 		return -ENODEV;
108 
109 	data = devm_kzalloc(cpuidle_dev, sizeof(*data), GFP_KERNEL);
110 	if (!data)
111 		return -ENOMEM;
112 
113 	data->spm = dev_get_drvdata(&pdev->dev);
114 	if (!data->spm)
115 		return -EINVAL;
116 
117 	data->cpuidle_driver = qcom_spm_idle_driver;
118 	data->cpuidle_driver.cpumask = (struct cpumask *)cpumask_of(cpu);
119 
120 	ret = dt_init_idle_driver(&data->cpuidle_driver,
121 				  qcom_idle_state_match, 1);
122 	if (ret <= 0)
123 		return ret ? : -ENODEV;
124 
125 	return cpuidle_register(&data->cpuidle_driver, NULL);
126 }
127 
128 static int spm_cpuidle_drv_probe(struct platform_device *pdev)
129 {
130 	int cpu, ret;
131 
132 	if (!qcom_scm_is_available())
133 		return -EPROBE_DEFER;
134 
135 	ret = qcom_scm_set_warm_boot_addr(cpu_resume_arm);
136 	if (ret)
137 		return dev_err_probe(&pdev->dev, ret, "set warm boot addr failed");
138 
139 	for_each_possible_cpu(cpu) {
140 		ret = spm_cpuidle_register(&pdev->dev, cpu);
141 		if (ret && ret != -ENODEV) {
142 			dev_err(&pdev->dev,
143 				"Cannot register for CPU%d: %d\n", cpu, ret);
144 		}
145 	}
146 
147 	return 0;
148 }
149 
150 static struct platform_driver spm_cpuidle_driver = {
151 	.probe = spm_cpuidle_drv_probe,
152 	.driver = {
153 		.name = "qcom-spm-cpuidle",
154 		.suppress_bind_attrs = true,
155 	},
156 };
157 
158 static bool __init qcom_spm_find_any_cpu(void)
159 {
160 	struct device_node *cpu_node, *saw_node;
161 
162 	for_each_of_cpu_node(cpu_node) {
163 		saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
164 		if (of_device_is_available(saw_node)) {
165 			of_node_put(saw_node);
166 			of_node_put(cpu_node);
167 			return true;
168 		}
169 		of_node_put(saw_node);
170 	}
171 	return false;
172 }
173 
174 static int __init qcom_spm_cpuidle_init(void)
175 {
176 	struct platform_device *pdev;
177 	int ret;
178 
179 	ret = platform_driver_register(&spm_cpuidle_driver);
180 	if (ret)
181 		return ret;
182 
183 	/* Make sure there is actually any CPU managed by the SPM */
184 	if (!qcom_spm_find_any_cpu())
185 		return 0;
186 
187 	pdev = platform_device_register_simple("qcom-spm-cpuidle",
188 					       -1, NULL, 0);
189 	if (IS_ERR(pdev)) {
190 		platform_driver_unregister(&spm_cpuidle_driver);
191 		return PTR_ERR(pdev);
192 	}
193 
194 	return 0;
195 }
196 device_initcall(qcom_spm_cpuidle_init);
197