/* * SIRF hardware spinlock driver * * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company. * * Licensed under GPLv2. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/device.h> #include <linux/io.h> #include <linux/pm_runtime.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/hwspinlock.h> #include <linux/platform_device.h> #include <linux/of.h> #include <linux/of_address.h> #include "hwspinlock_internal.h" struct sirf_hwspinlock { void __iomem *io_base; struct hwspinlock_device bank; }; /* Number of Hardware Spinlocks*/ #define HW_SPINLOCK_NUMBER 30 /* Hardware spinlock register offsets */ #define HW_SPINLOCK_BASE 0x404 #define HW_SPINLOCK_OFFSET(x) (HW_SPINLOCK_BASE + 0x4 * (x)) static int sirf_hwspinlock_trylock(struct hwspinlock *lock) { void __iomem *lock_addr = lock->priv; /* attempt to acquire the lock by reading value == 1 from it */ return !!readl(lock_addr); } static void sirf_hwspinlock_unlock(struct hwspinlock *lock) { void __iomem *lock_addr = lock->priv; /* release the lock by writing 0 to it */ writel(0, lock_addr); } static const struct hwspinlock_ops sirf_hwspinlock_ops = { .trylock = sirf_hwspinlock_trylock, .unlock = sirf_hwspinlock_unlock, }; static int sirf_hwspinlock_probe(struct platform_device *pdev) { struct sirf_hwspinlock *hwspin; struct hwspinlock *hwlock; int idx, ret; if (!pdev->dev.of_node) return -ENODEV; hwspin = devm_kzalloc(&pdev->dev, sizeof(*hwspin) + sizeof(*hwlock) * HW_SPINLOCK_NUMBER, GFP_KERNEL); if (!hwspin) return -ENOMEM; /* retrieve io base */ hwspin->io_base = of_iomap(pdev->dev.of_node, 0); if (!hwspin->io_base) return -ENOMEM; for (idx = 0; idx < HW_SPINLOCK_NUMBER; idx++) { hwlock = &hwspin->bank.lock[idx]; hwlock->priv = hwspin->io_base + HW_SPINLOCK_OFFSET(idx); } platform_set_drvdata(pdev, hwspin); pm_runtime_enable(&pdev->dev); ret = hwspin_lock_register(&hwspin->bank, &pdev->dev, &sirf_hwspinlock_ops, 0, HW_SPINLOCK_NUMBER); if (ret) goto reg_failed; return 0; reg_failed: pm_runtime_disable(&pdev->dev); iounmap(hwspin->io_base); return ret; } static int sirf_hwspinlock_remove(struct platform_device *pdev) { struct sirf_hwspinlock *hwspin = platform_get_drvdata(pdev); int ret; ret = hwspin_lock_unregister(&hwspin->bank); if (ret) { dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret); return ret; } pm_runtime_disable(&pdev->dev); iounmap(hwspin->io_base); return 0; } static const struct of_device_id sirf_hwpinlock_ids[] = { { .compatible = "sirf,hwspinlock", }, {}, }; MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids); static struct platform_driver sirf_hwspinlock_driver = { .probe = sirf_hwspinlock_probe, .remove = sirf_hwspinlock_remove, .driver = { .name = "atlas7_hwspinlock", .of_match_table = of_match_ptr(sirf_hwpinlock_ids), }, }; module_platform_driver(sirf_hwspinlock_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("SIRF Hardware spinlock driver"); MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");