Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 1 | /* |
| 2 | * OMAP hardware spinlock driver |
| 3 | * |
| 4 | * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com |
| 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> |
| 30 | #include <linux/platform_device.h> |
| 31 | |
| 32 | #include "hwspinlock_internal.h" |
| 33 | |
| 34 | /* Spinlock register offsets */ |
| 35 | #define SYSSTATUS_OFFSET 0x0014 |
| 36 | #define LOCK_BASE_OFFSET 0x0800 |
| 37 | |
| 38 | #define SPINLOCK_NUMLOCKS_BIT_OFFSET (24) |
| 39 | |
| 40 | /* Possible values of SPINLOCK_LOCK_REG */ |
| 41 | #define SPINLOCK_NOTTAKEN (0) /* free */ |
| 42 | #define SPINLOCK_TAKEN (1) /* locked */ |
| 43 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 44 | static int omap_hwspinlock_trylock(struct hwspinlock *lock) |
| 45 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 46 | void __iomem *lock_addr = lock->priv; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 47 | |
| 48 | /* attempt to acquire the lock by reading its value */ |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 49 | return (SPINLOCK_NOTTAKEN == readl(lock_addr)); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 50 | } |
| 51 | |
| 52 | static void omap_hwspinlock_unlock(struct hwspinlock *lock) |
| 53 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 54 | void __iomem *lock_addr = lock->priv; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 55 | |
| 56 | /* release the lock by writing 0 to it */ |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 57 | writel(SPINLOCK_NOTTAKEN, lock_addr); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 58 | } |
| 59 | |
| 60 | /* |
| 61 | * relax the OMAP interconnect while spinning on it. |
| 62 | * |
| 63 | * The specs recommended that the retry delay time will be |
| 64 | * just over half of the time that a requester would be |
| 65 | * expected to hold the lock. |
| 66 | * |
| 67 | * The number below is taken from an hardware specs example, |
| 68 | * obviously it is somewhat arbitrary. |
| 69 | */ |
| 70 | static void omap_hwspinlock_relax(struct hwspinlock *lock) |
| 71 | { |
| 72 | ndelay(50); |
| 73 | } |
| 74 | |
| 75 | static const struct hwspinlock_ops omap_hwspinlock_ops = { |
| 76 | .trylock = omap_hwspinlock_trylock, |
| 77 | .unlock = omap_hwspinlock_unlock, |
| 78 | .relax = omap_hwspinlock_relax, |
| 79 | }; |
| 80 | |
| 81 | static int __devinit omap_hwspinlock_probe(struct platform_device *pdev) |
| 82 | { |
Ohad Ben-Cohen | c3c1250 | 2011-09-05 23:15:06 +0300 | [diff] [blame] | 83 | struct hwspinlock_pdata *pdata = pdev->dev.platform_data; |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 84 | struct hwspinlock_device *bank; |
| 85 | struct hwspinlock *hwlock; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 86 | struct resource *res; |
| 87 | void __iomem *io_base; |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 88 | int num_locks, i, ret; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 89 | |
Ohad Ben-Cohen | c3c1250 | 2011-09-05 23:15:06 +0300 | [diff] [blame] | 90 | if (!pdata) |
| 91 | return -ENODEV; |
| 92 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 93 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 94 | if (!res) |
| 95 | return -ENODEV; |
| 96 | |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 97 | io_base = ioremap(res->start, resource_size(res)); |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 98 | if (!io_base) |
| 99 | return -ENOMEM; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 100 | |
| 101 | /* Determine number of locks */ |
| 102 | i = readl(io_base + SYSSTATUS_OFFSET); |
| 103 | i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET; |
| 104 | |
| 105 | /* one of the four lsb's must be set, and nothing else */ |
| 106 | if (hweight_long(i & 0xf) != 1 || i > 8) { |
| 107 | ret = -EINVAL; |
| 108 | goto iounmap_base; |
| 109 | } |
| 110 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 111 | num_locks = i * 32; /* actual number of locks in this device */ |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 112 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 113 | bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL); |
| 114 | if (!bank) { |
Ohad Ben-Cohen | c97f6dd | 2011-09-05 17:30:34 +0300 | [diff] [blame] | 115 | ret = -ENOMEM; |
| 116 | goto iounmap_base; |
| 117 | } |
| 118 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 119 | platform_set_drvdata(pdev, bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 120 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 121 | for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++) |
| 122 | hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 123 | |
| 124 | /* |
| 125 | * runtime PM will make sure the clock of this module is |
| 126 | * enabled iff at least one lock is requested |
| 127 | */ |
| 128 | pm_runtime_enable(&pdev->dev); |
| 129 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 130 | ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops, |
| 131 | pdata->base_id, num_locks); |
| 132 | if (ret) |
| 133 | goto reg_fail; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 134 | |
| 135 | return 0; |
| 136 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 137 | reg_fail: |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 138 | pm_runtime_disable(&pdev->dev); |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 139 | kfree(bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 140 | iounmap_base: |
| 141 | iounmap(io_base); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 142 | return ret; |
| 143 | } |
| 144 | |
Ohad Ben-Cohen | 9efb4a1 | 2011-09-11 18:54:50 +0300 | [diff] [blame^] | 145 | static int __devexit omap_hwspinlock_remove(struct platform_device *pdev) |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 146 | { |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 147 | struct hwspinlock_device *bank = platform_get_drvdata(pdev); |
| 148 | void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET; |
| 149 | int ret; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 150 | |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 151 | ret = hwspin_lock_unregister(bank); |
| 152 | if (ret) { |
| 153 | dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret); |
| 154 | return ret; |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | pm_runtime_disable(&pdev->dev); |
Ohad Ben-Cohen | 300bab9 | 2011-09-06 15:39:21 +0300 | [diff] [blame] | 158 | iounmap(io_base); |
| 159 | kfree(bank); |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 160 | |
| 161 | return 0; |
| 162 | } |
| 163 | |
| 164 | static struct platform_driver omap_hwspinlock_driver = { |
| 165 | .probe = omap_hwspinlock_probe, |
Ohad Ben-Cohen | 9efb4a1 | 2011-09-11 18:54:50 +0300 | [diff] [blame^] | 166 | .remove = __devexit_p(omap_hwspinlock_remove), |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 167 | .driver = { |
| 168 | .name = "omap_hwspinlock", |
Ohad Ben-Cohen | e467b64 | 2011-09-05 16:42:36 +0300 | [diff] [blame] | 169 | .owner = THIS_MODULE, |
Simon Que | 70ba4cc | 2011-02-17 09:52:03 -0800 | [diff] [blame] | 170 | }, |
| 171 | }; |
| 172 | |
| 173 | static int __init omap_hwspinlock_init(void) |
| 174 | { |
| 175 | return platform_driver_register(&omap_hwspinlock_driver); |
| 176 | } |
| 177 | /* board init code might need to reserve hwspinlocks for predefined purposes */ |
| 178 | postcore_initcall(omap_hwspinlock_init); |
| 179 | |
| 180 | static void __exit omap_hwspinlock_exit(void) |
| 181 | { |
| 182 | platform_driver_unregister(&omap_hwspinlock_driver); |
| 183 | } |
| 184 | module_exit(omap_hwspinlock_exit); |
| 185 | |
| 186 | MODULE_LICENSE("GPL v2"); |
| 187 | MODULE_DESCRIPTION("Hardware spinlock driver for OMAP"); |
| 188 | MODULE_AUTHOR("Simon Que <sque@ti.com>"); |
| 189 | MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>"); |
| 190 | MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>"); |