drivers/irqchip/irq-bcm2836.c - linux - Git at Google

 /*
  * Root interrupt controller for the BCM2836 (Raspberry Pi 2).
  *
  * Copyright 2015 Broadcom
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/cpu.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
 #include <linux/irqchip/irq-bcm2836.h>

 #include <asm/exception.h>

 struct bcm2836_arm_irqchip_intc {
 	struct irq_domain *domain;
 	void __iomem *base;
 };

 static struct bcm2836_arm_irqchip_intc intc  __read_mostly;

 static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
 						 unsigned int bit,
 						 int cpu)
 {
 	void __iomem *reg = intc.base + reg_offset + 4 * cpu;

 	writel(readl(reg) & ~BIT(bit), reg);
 }

 static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
 						   unsigned int bit,
 						 int cpu)
 {
 	void __iomem *reg = intc.base + reg_offset + 4 * cpu;

 	writel(readl(reg) | BIT(bit), reg);
 }

 static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
 {
 	bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
 					     d->hwirq - LOCAL_IRQ_CNTPSIRQ,
 					     smp_processor_id());
 }

 static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
 {
 	bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
 					       d->hwirq - LOCAL_IRQ_CNTPSIRQ,
 					       smp_processor_id());
 }

 static struct irq_chip bcm2836_arm_irqchip_timer = {
 	.name		= "bcm2836-timer",
 	.irq_mask	= bcm2836_arm_irqchip_mask_timer_irq,
 	.irq_unmask	= bcm2836_arm_irqchip_unmask_timer_irq,
 };

 static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
 {
 	writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
 }

 static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
 {
 	writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
 }

 static struct irq_chip bcm2836_arm_irqchip_pmu = {
 	.name		= "bcm2836-pmu",
 	.irq_mask	= bcm2836_arm_irqchip_mask_pmu_irq,
 	.irq_unmask	= bcm2836_arm_irqchip_unmask_pmu_irq,
 };

 static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
 {
 }

 static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
 {
 }

 static struct irq_chip bcm2836_arm_irqchip_gpu = {
 	.name		= "bcm2836-gpu",
 	.irq_mask	= bcm2836_arm_irqchip_mask_gpu_irq,
 	.irq_unmask	= bcm2836_arm_irqchip_unmask_gpu_irq,
 };

 static int bcm2836_map(struct irq_domain *d, unsigned int irq,
 		       irq_hw_number_t hw)
 {
 	struct irq_chip *chip;

 	switch (hw) {
 	case LOCAL_IRQ_CNTPSIRQ:
 	case LOCAL_IRQ_CNTPNSIRQ:
 	case LOCAL_IRQ_CNTHPIRQ:
 	case LOCAL_IRQ_CNTVIRQ:
 		chip = &bcm2836_arm_irqchip_timer;
 		break;
 	case LOCAL_IRQ_GPU_FAST:
 		chip = &bcm2836_arm_irqchip_gpu;
 		break;
 	case LOCAL_IRQ_PMU_FAST:
 		chip = &bcm2836_arm_irqchip_pmu;
 		break;
 	default:
 		pr_warn_once("Unexpected hw irq: %lu\n", hw);
 		return -EINVAL;
 	}

 	irq_set_percpu_devid(irq);
 	irq_domain_set_info(d, irq, hw, chip, d->host_data,
 			    handle_percpu_devid_irq, NULL, NULL);
 	irq_set_status_flags(irq, IRQ_NOAUTOEN);

 	return 0;
 }

 static void
 __exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
 {
 	int cpu = smp_processor_id();
 	u32 stat;

 	stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
 	if (stat & BIT(LOCAL_IRQ_MAILBOX0)) {
 #ifdef CONFIG_SMP
 		void __iomem *mailbox0 = (intc.base +
 					  LOCAL_MAILBOX0_CLR0 + 16 * cpu);
 		u32 mbox_val = readl(mailbox0);
 		u32 ipi = ffs(mbox_val) - 1;

 		writel(1 << ipi, mailbox0);
 		handle_IPI(ipi, regs);
 #endif
 	} else if (stat) {
 		u32 hwirq = ffs(stat) - 1;

 		handle_domain_irq(intc.domain, hwirq, regs);
 	}
 }

 #ifdef CONFIG_SMP
 static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask,
 					 unsigned int ipi)
 {
 	int cpu;
 	void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;

 	/*
 	 * Ensure that stores to normal memory are visible to the
 	 * other CPUs before issuing the IPI.
 	 */
 	smp_wmb();

 	for_each_cpu(cpu, mask)	{
 		writel(1 << ipi, mailbox0_base + 16 * cpu);
 	}
 }

 static int bcm2836_cpu_starting(unsigned int cpu)
 {
 	bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
 					       cpu);
 	return 0;
 }

 static int bcm2836_cpu_dying(unsigned int cpu)
 {
 	bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
 					     cpu);
 	return 0;
 }
 #endif

 static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
 	.xlate = irq_domain_xlate_onetwocell,
 	.map = bcm2836_map,
 };

 static void
 bcm2836_arm_irqchip_smp_init(void)
 {
 #ifdef CONFIG_SMP
 	/* Unmask IPIs to the boot CPU. */
 	cpuhp_setup_state(CPUHP_AP_IRQ_BCM2836_STARTING,
 			  "irqchip/bcm2836:starting", bcm2836_cpu_starting,
 			  bcm2836_cpu_dying);

 	set_smp_cross_call(bcm2836_arm_irqchip_send_ipi);
 #endif
 }

 /*
  * The LOCAL_IRQ_CNT* timer firings are based off of the external
  * oscillator with some scaling.  The firmware sets up CNTFRQ to
  * report 19.2Mhz, but doesn't set up the scaling registers.
  */
 static void bcm2835_init_local_timer_frequency(void)
 {
 	/*
 	 * Set the timer to source from the 19.2Mhz crystal clock (bit
 	 * 8 unset), and only increment by 1 instead of 2 (bit 9
 	 * unset).
 	 */
 	writel(0, intc.base + LOCAL_CONTROL);

 	/*
 	 * Set the timer prescaler to 1:1 (timer freq = input freq *
 	 * 2**31 / prescaler)
 	 */
 	writel(0x80000000, intc.base + LOCAL_PRESCALER);
 }

 static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
 						      struct device_node *parent)
 {
 	intc.base = of_iomap(node, 0);
 	if (!intc.base) {
 		panic("%pOF: unable to map local interrupt registers\n", node);
 	}

 	bcm2835_init_local_timer_frequency();

 	intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
 					    &bcm2836_arm_irqchip_intc_ops,
 					    NULL);
 	if (!intc.domain)
 		panic("%pOF: unable to create IRQ domain\n", node);

 	bcm2836_arm_irqchip_smp_init();

 	set_handle_irq(bcm2836_arm_irqchip_handle_irq);
 	return 0;
 }

 IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
 		bcm2836_arm_irqchip_l1_intc_of_init);
	/*
	* Root interrupt controller for the BCM2836 (Raspberry Pi 2).
	*
	* Copyright 2015 Broadcom
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/cpu.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/irqchip.h>
	#include <linux/irqdomain.h>
	#include <linux/irqchip/irq-bcm2836.h>

	#include <asm/exception.h>

	struct bcm2836_arm_irqchip_intc {
	struct irq_domain *domain;
	void __iomem *base;
	};

	static struct bcm2836_arm_irqchip_intc intc __read_mostly;

	static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
	unsigned int bit,
	int cpu)
	{
	void __iomem reg = intc.base + reg_offset + 4 cpu;

	writel(readl(reg) & ~BIT(bit), reg);
	}

	static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
	unsigned int bit,
	int cpu)
	{
	void __iomem reg = intc.base + reg_offset + 4 cpu;

	writel(readl(reg) \| BIT(bit), reg);
	}

	static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
	{
	bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
	d->hwirq - LOCAL_IRQ_CNTPSIRQ,
	smp_processor_id());
	}

	static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
	{
	bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
	d->hwirq - LOCAL_IRQ_CNTPSIRQ,
	smp_processor_id());
	}

	static struct irq_chip bcm2836_arm_irqchip_timer = {
	.name = "bcm2836-timer",
	.irq_mask = bcm2836_arm_irqchip_mask_timer_irq,
	.irq_unmask = bcm2836_arm_irqchip_unmask_timer_irq,
	};

	static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
	{
	writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
	}

	static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
	{
	writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
	}

	static struct irq_chip bcm2836_arm_irqchip_pmu = {
	.name = "bcm2836-pmu",
	.irq_mask = bcm2836_arm_irqchip_mask_pmu_irq,
	.irq_unmask = bcm2836_arm_irqchip_unmask_pmu_irq,
	};

	static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
	{
	}

	static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
	{
	}

	static struct irq_chip bcm2836_arm_irqchip_gpu = {
	.name = "bcm2836-gpu",
	.irq_mask = bcm2836_arm_irqchip_mask_gpu_irq,
	.irq_unmask = bcm2836_arm_irqchip_unmask_gpu_irq,
	};

	static int bcm2836_map(struct irq_domain *d, unsigned int irq,
	irq_hw_number_t hw)
	{
	struct irq_chip *chip;

	switch (hw) {
	case LOCAL_IRQ_CNTPSIRQ:
	case LOCAL_IRQ_CNTPNSIRQ:
	case LOCAL_IRQ_CNTHPIRQ:
	case LOCAL_IRQ_CNTVIRQ:
	chip = &bcm2836_arm_irqchip_timer;
	break;
	case LOCAL_IRQ_GPU_FAST:
	chip = &bcm2836_arm_irqchip_gpu;
	break;
	case LOCAL_IRQ_PMU_FAST:
	chip = &bcm2836_arm_irqchip_pmu;
	break;
	default:
	pr_warn_once("Unexpected hw irq: %lu\n", hw);
	return -EINVAL;
	}

	irq_set_percpu_devid(irq);
	irq_domain_set_info(d, irq, hw, chip, d->host_data,
	handle_percpu_devid_irq, NULL, NULL);
	irq_set_status_flags(irq, IRQ_NOAUTOEN);

	return 0;
	}

	static void
	__exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
	{
	int cpu = smp_processor_id();
	u32 stat;

	stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
	if (stat & BIT(LOCAL_IRQ_MAILBOX0)) {
	#ifdef CONFIG_SMP
	void __iomem *mailbox0 = (intc.base +
	LOCAL_MAILBOX0_CLR0 + 16 * cpu);
	u32 mbox_val = readl(mailbox0);
	u32 ipi = ffs(mbox_val) - 1;

	writel(1 << ipi, mailbox0);
	handle_IPI(ipi, regs);
	#endif
	} else if (stat) {
	u32 hwirq = ffs(stat) - 1;

	handle_domain_irq(intc.domain, hwirq, regs);
	}
	}

	#ifdef CONFIG_SMP
	static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask,
	unsigned int ipi)
	{
	int cpu;
	void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;

	/*
	* Ensure that stores to normal memory are visible to the
	* other CPUs before issuing the IPI.
	*/
	smp_wmb();

	for_each_cpu(cpu, mask) {
	writel(1 << ipi, mailbox0_base + 16 * cpu);
	}
	}

	static int bcm2836_cpu_starting(unsigned int cpu)
	{
	bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
	cpu);
	return 0;
	}

	static int bcm2836_cpu_dying(unsigned int cpu)
	{
	bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
	cpu);
	return 0;
	}
	#endif

	static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
	.xlate = irq_domain_xlate_onetwocell,
	.map = bcm2836_map,
	};

	static void
	bcm2836_arm_irqchip_smp_init(void)
	{
	#ifdef CONFIG_SMP
	/* Unmask IPIs to the boot CPU. */
	cpuhp_setup_state(CPUHP_AP_IRQ_BCM2836_STARTING,
	"irqchip/bcm2836:starting", bcm2836_cpu_starting,
	bcm2836_cpu_dying);

	set_smp_cross_call(bcm2836_arm_irqchip_send_ipi);
	#endif
	}

	/*
	* The LOCAL_IRQ_CNT* timer firings are based off of the external
	* oscillator with some scaling. The firmware sets up CNTFRQ to
	* report 19.2Mhz, but doesn't set up the scaling registers.
	*/
	static void bcm2835_init_local_timer_frequency(void)
	{
	/*
	* Set the timer to source from the 19.2Mhz crystal clock (bit
	* 8 unset), and only increment by 1 instead of 2 (bit 9
	* unset).
	*/
	writel(0, intc.base + LOCAL_CONTROL);

	/*
	* Set the timer prescaler to 1:1 (timer freq = input freq *
	* 2**31 / prescaler)
	*/
	writel(0x80000000, intc.base + LOCAL_PRESCALER);
	}

	static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
	struct device_node *parent)
	{
	intc.base = of_iomap(node, 0);
	if (!intc.base) {
	panic("%pOF: unable to map local interrupt registers\n", node);
	}

	bcm2835_init_local_timer_frequency();

	intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
	&bcm2836_arm_irqchip_intc_ops,
	NULL);
	if (!intc.domain)
	panic("%pOF: unable to create IRQ domain\n", node);

	bcm2836_arm_irqchip_smp_init();

	set_handle_irq(bcm2836_arm_irqchip_handle_irq);
	return 0;
	}

	IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
	bcm2836_arm_irqchip_l1_intc_of_init);