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 */
sprd_hwspinlock_trylock(struct hwspinlock * lock)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 */
sprd_hwspinlock_unlock(struct hwspinlock * lock)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 */
sprd_hwspinlock_relax(struct hwspinlock * lock)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
sprd_hwspinlock_disable(void * data)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
sprd_hwspinlock_probe(struct platform_device * pdev)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 sizeof(struct sprd_hwspinlock_dev) +
97 SPRD_HWLOCKS_NUM * sizeof(*lock),
98 GFP_KERNEL);
99 if (!sprd_hwlock)
100 return -ENOMEM;
101
102 sprd_hwlock->base = devm_platform_ioremap_resource(pdev, 0);
103 if (IS_ERR(sprd_hwlock->base))
104 return PTR_ERR(sprd_hwlock->base);
105
106 sprd_hwlock->clk = devm_clk_get(&pdev->dev, "enable");
107 if (IS_ERR(sprd_hwlock->clk)) {
108 dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
109 return PTR_ERR(sprd_hwlock->clk);
110 }
111
112 ret = clk_prepare_enable(sprd_hwlock->clk);
113 if (ret)
114 return ret;
115
116 ret = devm_add_action_or_reset(&pdev->dev, sprd_hwspinlock_disable,
117 sprd_hwlock);
118 if (ret) {
119 dev_err(&pdev->dev,
120 "Failed to add hwspinlock disable action\n");
121 return ret;
122 }
123
124 /* set the hwspinlock to record user id to identify subsystems */
125 writel(HWSPINLOCK_USER_BITS, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
126
127 for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
128 lock = &sprd_hwlock->bank.lock[i];
129 lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
130 }
131
132 platform_set_drvdata(pdev, sprd_hwlock);
133
134 return devm_hwspin_lock_register(&pdev->dev, &sprd_hwlock->bank,
135 &sprd_hwspinlock_ops, 0,
136 SPRD_HWLOCKS_NUM);
137 }
138
139 static const struct of_device_id sprd_hwspinlock_of_match[] = {
140 { .compatible = "sprd,hwspinlock-r3p0", },
141 { /* sentinel */ }
142 };
143 MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
144
145 static struct platform_driver sprd_hwspinlock_driver = {
146 .probe = sprd_hwspinlock_probe,
147 .driver = {
148 .name = "sprd_hwspinlock",
149 .of_match_table = sprd_hwspinlock_of_match,
150 },
151 };
152 module_platform_driver(sprd_hwspinlock_driver);
153
154 MODULE_LICENSE("GPL v2");
155 MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
156 MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");
157 MODULE_AUTHOR("Lanqing Liu <lanqing.liu@spreadtrum.com>");
158 MODULE_AUTHOR("Long Cheng <aiden.cheng@spreadtrum.com>");
159