Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 1 | /* |
| 2 | * OMAP hardware spinlock driver |
| 3 | * |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 4 | * Copyright (C) 2010-2015 Texas Instruments Incorporated - http://www.ti.com |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 5 | * |
| 6 | * Contact: Simon Que <sque@ti.com> |
| 7 | * Hari Kanigeri <h-kanigeri2@ti.com> |
| 8 | * Ohad Ben-Cohen <ohad@wizery.com> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU General Public License |
| 12 | * version 2 as published by the Free Software Foundation. |
| 13 | * |
| 14 | * This program is distributed in the hope that it will be useful, but |
| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | * General Public License for more details. |
| 18 | */ |
| 19 | |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/device.h> |
| 23 | #include <linux/delay.h> |
| 24 | #include <linux/io.h> |
| 25 | #include <linux/bitops.h> |
| 26 | #include <linux/pm_runtime.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/spinlock.h> |
| 29 | #include <linux/hwspinlock.h> |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 30 | #include <linux/of.h> |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 31 | #include <linux/platform_device.h> |
| 32 | |
| 33 | #include "hwspinlock_internal.h" |
| 34 | |
| 35 | /* Spinlock register offsets */ |
| 36 | #define SYSSTATUS_OFFSET 0x0014 |
| 37 | #define LOCK_BASE_OFFSET 0x0800 |
| 38 | |
| 39 | #define SPINLOCK_NUMLOCKS_BIT_OFFSET (24) |
| 40 | |
| 41 | /* Possible values of SPINLOCK_LOCK_REG */ |
| 42 | #define SPINLOCK_NOTTAKEN (0) /* free */ |
| 43 | #define SPINLOCK_TAKEN (1) /* locked */ |
| 44 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 45 | static int omap_hwspinlock_trylock(struct hwspinlock *lock) |
| 46 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 47 | void __iomem *lock_addr = lock->priv; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 48 | |
| 49 | /* attempt to acquire the lock by reading its value */ |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 50 | return (SPINLOCK_NOTTAKEN == readl(lock_addr)); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 51 | } |
| 52 | |
| 53 | static void omap_hwspinlock_unlock(struct hwspinlock *lock) |
| 54 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 55 | void __iomem *lock_addr = lock->priv; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 56 | |
| 57 | /* release the lock by writing 0 to it */ |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 58 | writel(SPINLOCK_NOTTAKEN, lock_addr); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | /* |
| 62 | * relax the OMAP interconnect while spinning on it. |
| 63 | * |
| 64 | * The specs recommended that the retry delay time will be |
| 65 | * just over half of the time that a requester would be |
| 66 | * expected to hold the lock. |
| 67 | * |
| 68 | * The number below is taken from an hardware specs example, |
| 69 | * obviously it is somewhat arbitrary. |
| 70 | */ |
| 71 | static void omap_hwspinlock_relax(struct hwspinlock *lock) |
| 72 | { |
| 73 | ndelay(50); |
| 74 | } |
| 75 | |
| 76 | static const struct hwspinlock_ops omap_hwspinlock_ops = { |
| 77 | .trylock = omap_hwspinlock_trylock, |
| 78 | .unlock = omap_hwspinlock_unlock, |
| 79 | .relax = omap_hwspinlock_relax, |
| 80 | }; |
| 81 | |
Bill Pemberton | 5712910 | 2012-11-19 13:23:22 -0500 | [diff] [blame] | 82 | static int omap_hwspinlock_probe(struct platform_device *pdev) |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 83 | { |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 84 | struct device_node *node = pdev->dev.of_node; |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 85 | struct hwspinlock_device *bank; |
| 86 | struct hwspinlock *hwlock; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 87 | struct resource *res; |
| 88 | void __iomem *io_base; |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 89 | int num_locks, i, ret; |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 90 | /* Only a single hwspinlock block device is supported */ |
| 91 | int base_id = 0; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 92 | |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 93 | if (!node) |
Ohad Ben-Cohen | c3c1250 | 2011-09-05 23:15:06 +0300 | [diff] [blame] | 94 | return -ENODEV; |
| 95 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 96 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 97 | if (!res) |
| 98 | return -ENODEV; |
| 99 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 100 | io_base = ioremap(res->start, resource_size(res)); |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 101 | if (!io_base) |
| 102 | return -ENOMEM; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 103 | |
Suman Anna | e1e4528 | 2014-07-02 18:00:59 -0500 | [diff] [blame] | 104 | /* |
| 105 | * make sure the module is enabled and clocked before reading |
| 106 | * the module SYSSTATUS register |
| 107 | */ |
| 108 | pm_runtime_enable(&pdev->dev); |
| 109 | ret = pm_runtime_get_sync(&pdev->dev); |
| 110 | if (ret < 0) { |
| 111 | pm_runtime_put_noidle(&pdev->dev); |
| 112 | goto iounmap_base; |
| 113 | } |
| 114 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 115 | /* Determine number of locks */ |
| 116 | i = readl(io_base + SYSSTATUS_OFFSET); |
| 117 | i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET; |
| 118 | |
Suman Anna | e1e4528 | 2014-07-02 18:00:59 -0500 | [diff] [blame] | 119 | /* |
| 120 | * runtime PM will make sure the clock of this module is |
| 121 | * enabled again iff at least one lock is requested |
| 122 | */ |
| 123 | ret = pm_runtime_put(&pdev->dev); |
| 124 | if (ret < 0) |
| 125 | goto iounmap_base; |
| 126 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 127 | /* one of the four lsb's must be set, and nothing else */ |
| 128 | if (hweight_long(i & 0xf) != 1 || i > 8) { |
| 129 | ret = -EINVAL; |
| 130 | goto iounmap_base; |
| 131 | } |
| 132 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 133 | num_locks = i * 32; /* actual number of locks in this device */ |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 134 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 135 | bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL); |
| 136 | if (!bank) { |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 137 | ret = -ENOMEM; |
| 138 | goto iounmap_base; |
| 139 | } |
| 140 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 141 | platform_set_drvdata(pdev, bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 142 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 143 | for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++) |
| 144 | hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 145 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 146 | ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops, |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 147 | base_id, num_locks); |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 148 | if (ret) |
| 149 | goto reg_fail; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 150 | |
| 151 | return 0; |
| 152 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 153 | reg_fail: |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 154 | kfree(bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 155 | iounmap_base: |
Suman Anna | e1e4528 | 2014-07-02 18:00:59 -0500 | [diff] [blame] | 156 | pm_runtime_disable(&pdev->dev); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 157 | iounmap(io_base); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 158 | return ret; |
| 159 | } |
| 160 | |
Bill Pemberton | e533a34 | 2012-11-19 13:25:52 -0500 | [diff] [blame] | 161 | static int omap_hwspinlock_remove(struct platform_device *pdev) |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 162 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 163 | struct hwspinlock_device *bank = platform_get_drvdata(pdev); |
| 164 | void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET; |
| 165 | int ret; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 166 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 167 | ret = hwspin_lock_unregister(bank); |
| 168 | if (ret) { |
| 169 | dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret); |
| 170 | return ret; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 171 | } |
| 172 | |
| 173 | pm_runtime_disable(&pdev->dev); |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 174 | iounmap(io_base); |
| 175 | kfree(bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 180 | static const struct of_device_id omap_hwspinlock_of_match[] = { |
| 181 | { .compatible = "ti,omap4-hwspinlock", }, |
| 182 | { /* end */ }, |
| 183 | }; |
| 184 | MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match); |
| 185 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 186 | static struct platform_driver omap_hwspinlock_driver = { |
| 187 | .probe = omap_hwspinlock_probe, |
Bill Pemberton | 9eb26bd | 2012-11-19 13:20:13 -0500 | [diff] [blame] | 188 | .remove = omap_hwspinlock_remove, |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 189 | .driver = { |
| 190 | .name = "omap_hwspinlock", |
Suman Anna | 65bd434 | 2015-03-04 20:01:16 -0600 | [diff] [blame^] | 191 | .of_match_table = of_match_ptr(omap_hwspinlock_of_match), |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 192 | }, |
| 193 | }; |
| 194 | |
| 195 | static int __init omap_hwspinlock_init(void) |
| 196 | { |
| 197 | return platform_driver_register(&omap_hwspinlock_driver); |
| 198 | } |
| 199 | /* board init code might need to reserve hwspinlocks for predefined purposes */ |
| 200 | postcore_initcall(omap_hwspinlock_init); |
| 201 | |
| 202 | static void __exit omap_hwspinlock_exit(void) |
| 203 | { |
| 204 | platform_driver_unregister(&omap_hwspinlock_driver); |
| 205 | } |
| 206 | module_exit(omap_hwspinlock_exit); |
| 207 | |
| 208 | MODULE_LICENSE("GPL v2"); |
| 209 | MODULE_DESCRIPTION("Hardware spinlock driver for OMAP"); |
| 210 | MODULE_AUTHOR("Simon Que <sque@ti.com>"); |
| 211 | MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>"); |
| 212 | MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>"); |