1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Spreadtrum hardware spinlock driver
4  * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.com
5  */
6 
7 #include <linux/bitops.h>
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/device.h>
11 #include <linux/hwspinlock.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/slab.h>
20 
21 #include "hwspinlock_internal.h"
22 
23 /* hwspinlock registers definition */
24 #define HWSPINLOCK_RECCTRL		0x4
25 #define HWSPINLOCK_MASTERID(_X_)	(0x80 + 0x4 * (_X_))
26 #define HWSPINLOCK_TOKEN(_X_)		(0x800 + 0x4 * (_X_))
27 
28 /* unlocked value */
29 #define HWSPINLOCK_NOTTAKEN		0x55aa10c5
30 /* bits definition of RECCTRL reg */
31 #define HWSPINLOCK_USER_BITS		0x1
32 
33 /* hwspinlock number */
34 #define SPRD_HWLOCKS_NUM		32
35 
36 struct sprd_hwspinlock_dev {
37 	void __iomem *base;
38 	struct clk *clk;
39 	struct hwspinlock_device bank;
40 };
41 
42 /* try to lock the hardware spinlock */
43 static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
44 {
45 	struct sprd_hwspinlock_dev *sprd_hwlock =
46 		dev_get_drvdata(lock->bank->dev);
47 	void __iomem *addr = lock->priv;
48 	int user_id, lock_id;
49 
50 	if (!readl(addr))
51 		return 1;
52 
53 	lock_id = hwlock_to_id(lock);
54 	/* get the hardware spinlock master/user id */
55 	user_id = readl(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
56 	dev_warn(sprd_hwlock->bank.dev,
57 		 "hwspinlock [%d] lock failed and master/user id = %d!\n",
58 		 lock_id, user_id);
59 	return 0;
60 }
61 
62 /* unlock the hardware spinlock */
63 static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
64 {
65 	void __iomem *lock_addr = lock->priv;
66 
67 	writel(HWSPINLOCK_NOTTAKEN, lock_addr);
68 }
69 
70 /* The specs recommended below number as the retry delay time */
71 static void sprd_hwspinlock_relax(struct hwspinlock *lock)
72 {
73 	ndelay(10);
74 }
75 
76 static const struct hwspinlock_ops sprd_hwspinlock_ops = {
77 	.trylock = sprd_hwspinlock_trylock,
78 	.unlock = sprd_hwspinlock_unlock,
79 	.relax = sprd_hwspinlock_relax,
80 };
81 
82 static int sprd_hwspinlock_probe(struct platform_device *pdev)
83 {
84 	struct sprd_hwspinlock_dev *sprd_hwlock;
85 	struct hwspinlock *lock;
86 	struct resource *res;
87 	int i, ret;
88 
89 	if (!pdev->dev.of_node)
90 		return -ENODEV;
91 
92 	sprd_hwlock = devm_kzalloc(&pdev->dev,
93 				   sizeof(struct sprd_hwspinlock_dev) +
94 				   SPRD_HWLOCKS_NUM * sizeof(*lock),
95 				   GFP_KERNEL);
96 	if (!sprd_hwlock)
97 		return -ENOMEM;
98 
99 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
100 	sprd_hwlock->base = devm_ioremap_resource(&pdev->dev, res);
101 	if (IS_ERR(sprd_hwlock->base))
102 		return PTR_ERR(sprd_hwlock->base);
103 
104 	sprd_hwlock->clk = devm_clk_get(&pdev->dev, "enable");
105 	if (IS_ERR(sprd_hwlock->clk)) {
106 		dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
107 		return PTR_ERR(sprd_hwlock->clk);
108 	}
109 
110 	clk_prepare_enable(sprd_hwlock->clk);
111 
112 	/* set the hwspinlock to record user id to identify subsystems */
113 	writel(HWSPINLOCK_USER_BITS, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
114 
115 	for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
116 		lock = &sprd_hwlock->bank.lock[i];
117 		lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
118 	}
119 
120 	platform_set_drvdata(pdev, sprd_hwlock);
121 	pm_runtime_enable(&pdev->dev);
122 
123 	ret = hwspin_lock_register(&sprd_hwlock->bank, &pdev->dev,
124 				   &sprd_hwspinlock_ops, 0, SPRD_HWLOCKS_NUM);
125 	if (ret) {
126 		pm_runtime_disable(&pdev->dev);
127 		clk_disable_unprepare(sprd_hwlock->clk);
128 		return ret;
129 	}
130 
131 	return 0;
132 }
133 
134 static int sprd_hwspinlock_remove(struct platform_device *pdev)
135 {
136 	struct sprd_hwspinlock_dev *sprd_hwlock = platform_get_drvdata(pdev);
137 
138 	hwspin_lock_unregister(&sprd_hwlock->bank);
139 	pm_runtime_disable(&pdev->dev);
140 	clk_disable_unprepare(sprd_hwlock->clk);
141 	return 0;
142 }
143 
144 static const struct of_device_id sprd_hwspinlock_of_match[] = {
145 	{ .compatible = "sprd,hwspinlock-r3p0", },
146 	{ /* sentinel */ }
147 };
148 MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
149 
150 static struct platform_driver sprd_hwspinlock_driver = {
151 	.probe = sprd_hwspinlock_probe,
152 	.remove = sprd_hwspinlock_remove,
153 	.driver = {
154 		.name = "sprd_hwspinlock",
155 		.of_match_table = of_match_ptr(sprd_hwspinlock_of_match),
156 	},
157 };
158 
159 static int __init sprd_hwspinlock_init(void)
160 {
161 	return platform_driver_register(&sprd_hwspinlock_driver);
162 }
163 postcore_initcall(sprd_hwspinlock_init);
164 
165 static void __exit sprd_hwspinlock_exit(void)
166 {
167 	platform_driver_unregister(&sprd_hwspinlock_driver);
168 }
169 module_exit(sprd_hwspinlock_exit);
170 
171 MODULE_LICENSE("GPL v2");
172 MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
173 MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");
174 MODULE_AUTHOR("Lanqing Liu <lanqing.liu@spreadtrum.com>");
175 MODULE_AUTHOR("Long Cheng <aiden.cheng@spreadtrum.com>");
176