71efb063f4
Now that we can execute a CONFIG_SMP kernel on a uniprocessor system, extra care has to be taken in the PMU IRQ affinity setting code to ensure that we don't always fail to initialise. This patch changes the CPU PMU initialisation code so that when we only have a single IRQ, whose affinity can not be changed at the controller, we report success (0) rather than -EINVAL. Reported-by: Avik Sil <avik.sil@linaro.org> Acked-by: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
149 lines
3 KiB
C
149 lines
3 KiB
C
/*
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* linux/arch/arm/kernel/pmu.c
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*
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* Copyright (C) 2009 picoChip Designs Ltd, Jamie Iles
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* Copyright (C) 2010 ARM Ltd, Will Deacon
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define pr_fmt(fmt) "PMU: " fmt
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#include <linux/cpumask.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <asm/pmu.h>
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static volatile long pmu_lock;
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static struct platform_device *pmu_devices[ARM_NUM_PMU_DEVICES];
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static int __devinit pmu_device_probe(struct platform_device *pdev)
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{
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if (pdev->id < 0 || pdev->id >= ARM_NUM_PMU_DEVICES) {
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pr_warning("received registration request for unknown "
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"device %d\n", pdev->id);
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return -EINVAL;
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}
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if (pmu_devices[pdev->id])
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pr_warning("registering new PMU device type %d overwrites "
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"previous registration!\n", pdev->id);
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else
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pr_info("registered new PMU device of type %d\n",
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pdev->id);
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pmu_devices[pdev->id] = pdev;
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return 0;
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}
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static struct platform_driver pmu_driver = {
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.driver = {
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.name = "arm-pmu",
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},
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.probe = pmu_device_probe,
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};
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static int __init register_pmu_driver(void)
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{
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return platform_driver_register(&pmu_driver);
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}
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device_initcall(register_pmu_driver);
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struct platform_device *
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reserve_pmu(enum arm_pmu_type device)
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{
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struct platform_device *pdev;
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if (test_and_set_bit_lock(device, &pmu_lock)) {
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pdev = ERR_PTR(-EBUSY);
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} else if (pmu_devices[device] == NULL) {
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clear_bit_unlock(device, &pmu_lock);
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pdev = ERR_PTR(-ENODEV);
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} else {
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pdev = pmu_devices[device];
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}
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return pdev;
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}
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EXPORT_SYMBOL_GPL(reserve_pmu);
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int
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release_pmu(struct platform_device *pdev)
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{
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if (WARN_ON(pdev != pmu_devices[pdev->id]))
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return -EINVAL;
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clear_bit_unlock(pdev->id, &pmu_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(release_pmu);
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static int
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set_irq_affinity(int irq,
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unsigned int cpu)
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{
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#ifdef CONFIG_SMP
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int err = irq_set_affinity(irq, cpumask_of(cpu));
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if (err)
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pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
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irq, cpu);
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return err;
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#else
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return -EINVAL;
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#endif
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}
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static int
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init_cpu_pmu(void)
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{
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int i, irqs, err = 0;
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struct platform_device *pdev = pmu_devices[ARM_PMU_DEVICE_CPU];
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if (!pdev)
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return -ENODEV;
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irqs = pdev->num_resources;
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/*
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* If we have a single PMU interrupt that we can't shift, assume that
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* we're running on a uniprocessor machine and continue.
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*/
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if (irqs == 1 && !irq_can_set_affinity(platform_get_irq(pdev, 0)))
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return 0;
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for (i = 0; i < irqs; ++i) {
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err = set_irq_affinity(platform_get_irq(pdev, i), i);
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if (err)
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break;
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}
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return err;
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}
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int
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init_pmu(enum arm_pmu_type device)
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{
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int err = 0;
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switch (device) {
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case ARM_PMU_DEVICE_CPU:
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err = init_cpu_pmu();
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break;
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default:
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pr_warning("attempt to initialise unknown device %d\n",
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device);
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err = -EINVAL;
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(init_pmu);
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