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