drivers/irqchip/irq-bcm2835.c - linux - Git at Google

 /*
  * Copyright 2010 Broadcom
  * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
  *
  * 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.
  *
  * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
  *
  * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
  * on bank 0 is set to signify that an interrupt in bank 1 has fired, and
  * to look in the bank 1 status register for more information.
  *
  * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
  * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
  * status register, but bank 0 bit 8 is _not_ set.
  *
  * Quirk 2: You can't mask the register 1/2 pending interrupts
  *
  * In a proper cascaded interrupt controller, the interrupt lines with
  * cascaded interrupt controllers on them are just normal interrupt lines.
  * You can mask the interrupts and get on with things. With this controller
  * you can't do that.
  *
  * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
  *
  * Those interrupts that have shortcuts can only be masked/unmasked in
  * their respective banks' enable/disable registers. Doing so in the bank 0
  * enable/disable registers has no effect.
  *
  * The FIQ control register:
  *  Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
  *  Bit    7: Enable FIQ generation
  *  Bits  8+: Unused
  *
  * An interrupt must be disabled before configuring it for FIQ generation
  * otherwise both handlers will fire at the same time!
  */

 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>

 #include <asm/exception.h>

 /* Put the bank and irq (32 bits) into the hwirq */
 #define MAKE_HWIRQ(b, n)	((b << 5) | (n))
 #define HWIRQ_BANK(i)		(i >> 5)
 #define HWIRQ_BIT(i)		BIT(i & 0x1f)

 #define NR_IRQS_BANK0		8
 #define BANK0_HWIRQ_MASK	0xff
 /* Shortcuts can't be disabled so any unknown new ones need to be masked */
 #define SHORTCUT1_MASK		0x00007c00
 #define SHORTCUT2_MASK		0x001f8000
 #define SHORTCUT_SHIFT		10
 #define BANK1_HWIRQ		BIT(8)
 #define BANK2_HWIRQ		BIT(9)
 #define BANK0_VALID_MASK	(BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \
 					| SHORTCUT1_MASK | SHORTCUT2_MASK)

 #define REG_FIQ_CONTROL		0x0c

 #define NR_BANKS		3
 #define IRQS_PER_BANK		32

 static const int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
 static const int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
 static const int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
 static const int bank_irqs[] __initconst = { 8, 32, 32 };

 static const int shortcuts[] = {
 	7, 9, 10, 18, 19,		/* Bank 1 */
 	21, 22, 23, 24, 25, 30		/* Bank 2 */
 };

 struct armctrl_ic {
 	void __iomem *base;
 	void __iomem *pending[NR_BANKS];
 	void __iomem *enable[NR_BANKS];
 	void __iomem *disable[NR_BANKS];
 	struct irq_domain *domain;
 };

 static struct armctrl_ic intc __read_mostly;
 static void __exception_irq_entry bcm2835_handle_irq(
 	struct pt_regs *regs);
 static void bcm2836_chained_handle_irq(struct irq_desc *desc);

 static void armctrl_mask_irq(struct irq_data *d)
 {
 	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
 }

 static void armctrl_unmask_irq(struct irq_data *d)
 {
 	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
 }

 static struct irq_chip armctrl_chip = {
 	.name = "ARMCTRL-level",
 	.irq_mask = armctrl_mask_irq,
 	.irq_unmask = armctrl_unmask_irq
 };

 static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
 	const u32 *intspec, unsigned int intsize,
 	unsigned long *out_hwirq, unsigned int *out_type)
 {
 	if (WARN_ON(intsize != 2))
 		return -EINVAL;

 	if (WARN_ON(intspec[0] >= NR_BANKS))
 		return -EINVAL;

 	if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
 		return -EINVAL;

 	if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
 		return -EINVAL;

 	*out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
 	*out_type = IRQ_TYPE_NONE;
 	return 0;
 }

 static const struct irq_domain_ops armctrl_ops = {
 	.xlate = armctrl_xlate
 };

 static int __init armctrl_of_init(struct device_node *node,
 				  struct device_node *parent,
 				  bool is_2836)
 {
 	void __iomem *base;
 	int irq, b, i;

 	base = of_iomap(node, 0);
 	if (!base)
 		panic("%pOF: unable to map IC registers\n", node);

 	intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
 			&armctrl_ops, NULL);
 	if (!intc.domain)
 		panic("%pOF: unable to create IRQ domain\n", node);

 	for (b = 0; b < NR_BANKS; b++) {
 		intc.pending[b] = base + reg_pending[b];
 		intc.enable[b] = base + reg_enable[b];
 		intc.disable[b] = base + reg_disable[b];

 		for (i = 0; i < bank_irqs[b]; i++) {
 			irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
 			BUG_ON(irq <= 0);
 			irq_set_chip_and_handler(irq, &armctrl_chip,
 				handle_level_irq);
 			irq_set_probe(irq);
 		}
 	}

 	if (is_2836) {
 		int parent_irq = irq_of_parse_and_map(node, 0);

 		if (!parent_irq) {
 			panic("%pOF: unable to get parent interrupt.\n",
 			      node);
 		}
 		irq_set_chained_handler(parent_irq, bcm2836_chained_handle_irq);
 	} else {
 		set_handle_irq(bcm2835_handle_irq);
 	}

 	return 0;
 }

 static int __init bcm2835_armctrl_of_init(struct device_node *node,
 					  struct device_node *parent)
 {
 	return armctrl_of_init(node, parent, false);
 }

 static int __init bcm2836_armctrl_of_init(struct device_node *node,
 					  struct device_node *parent)
 {
 	return armctrl_of_init(node, parent, true);
 }


 /*
  * Handle each interrupt across the entire interrupt controller.  This reads the
  * status register before handling each interrupt, which is necessary given that
  * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
  */

 static u32 armctrl_translate_bank(int bank)
 {
 	u32 stat = readl_relaxed(intc.pending[bank]);

 	return MAKE_HWIRQ(bank, ffs(stat) - 1);
 }

 static u32 armctrl_translate_shortcut(int bank, u32 stat)
 {
 	return MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
 }

 static u32 get_next_armctrl_hwirq(void)
 {
 	u32 stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK;

 	if (stat == 0)
 		return ~0;
 	else if (stat & BANK0_HWIRQ_MASK)
 		return MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
 	else if (stat & SHORTCUT1_MASK)
 		return armctrl_translate_shortcut(1, stat & SHORTCUT1_MASK);
 	else if (stat & SHORTCUT2_MASK)
 		return armctrl_translate_shortcut(2, stat & SHORTCUT2_MASK);
 	else if (stat & BANK1_HWIRQ)
 		return armctrl_translate_bank(1);
 	else if (stat & BANK2_HWIRQ)
 		return armctrl_translate_bank(2);
 	else
 		BUG();
 }

 static void __exception_irq_entry bcm2835_handle_irq(
 	struct pt_regs *regs)
 {
 	u32 hwirq;

 	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
 		handle_domain_irq(intc.domain, hwirq, regs);
 }

 static void bcm2836_chained_handle_irq(struct irq_desc *desc)
 {
 	u32 hwirq;

 	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
 		generic_handle_irq(irq_linear_revmap(intc.domain, hwirq));
 }

 IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic",
 		bcm2835_armctrl_of_init);
 IRQCHIP_DECLARE(bcm2836_armctrl_ic, "brcm,bcm2836-armctrl-ic",
 		bcm2836_armctrl_of_init);
	/*
	* Copyright 2010 Broadcom
	* Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
	*
	* 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.
	*
	* Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
	*
	* If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
	* on bank 0 is set to signify that an interrupt in bank 1 has fired, and
	* to look in the bank 1 status register for more information.
	*
	* If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
	* shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
	* status register, but bank 0 bit 8 is _not_ set.
	*
	* Quirk 2: You can't mask the register 1/2 pending interrupts
	*
	* In a proper cascaded interrupt controller, the interrupt lines with
	* cascaded interrupt controllers on them are just normal interrupt lines.
	* You can mask the interrupts and get on with things. With this controller
	* you can't do that.
	*
	* Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
	*
	* Those interrupts that have shortcuts can only be masked/unmasked in
	* their respective banks' enable/disable registers. Doing so in the bank 0
	* enable/disable registers has no effect.
	*
	* The FIQ control register:
	* Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
	* Bit 7: Enable FIQ generation
	* Bits 8+: Unused
	*
	* An interrupt must be disabled before configuring it for FIQ generation
	* otherwise both handlers will fire at the same time!
	*/

	#include <linux/io.h>
	#include <linux/slab.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/irqchip.h>
	#include <linux/irqdomain.h>

	#include <asm/exception.h>

	/* Put the bank and irq (32 bits) into the hwirq */
	#define MAKE_HWIRQ(b, n) ((b << 5) \| (n))
	#define HWIRQ_BANK(i) (i >> 5)
	#define HWIRQ_BIT(i) BIT(i & 0x1f)

	#define NR_IRQS_BANK0 8
	#define BANK0_HWIRQ_MASK 0xff
	/* Shortcuts can't be disabled so any unknown new ones need to be masked */
	#define SHORTCUT1_MASK 0x00007c00
	#define SHORTCUT2_MASK 0x001f8000
	#define SHORTCUT_SHIFT 10
	#define BANK1_HWIRQ BIT(8)
	#define BANK2_HWIRQ BIT(9)
	#define BANK0_VALID_MASK (BANK0_HWIRQ_MASK \| BANK1_HWIRQ \| BANK2_HWIRQ \
	\| SHORTCUT1_MASK \| SHORTCUT2_MASK)

	#define REG_FIQ_CONTROL 0x0c

	#define NR_BANKS 3
	#define IRQS_PER_BANK 32

	static const int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
	static const int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
	static const int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
	static const int bank_irqs[] __initconst = { 8, 32, 32 };

	static const int shortcuts[] = {
	7, 9, 10, 18, 19, /* Bank 1 */
	21, 22, 23, 24, 25, 30 /* Bank 2 */
	};

	struct armctrl_ic {
	void __iomem *base;
	void __iomem *pending[NR_BANKS];
	void __iomem *enable[NR_BANKS];
	void __iomem *disable[NR_BANKS];
	struct irq_domain *domain;
	};

	static struct armctrl_ic intc __read_mostly;
	static void __exception_irq_entry bcm2835_handle_irq(
	struct pt_regs *regs);
	static void bcm2836_chained_handle_irq(struct irq_desc *desc);

	static void armctrl_mask_irq(struct irq_data *d)
	{
	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
	}

	static void armctrl_unmask_irq(struct irq_data *d)
	{
	writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
	}

	static struct irq_chip armctrl_chip = {
	.name = "ARMCTRL-level",
	.irq_mask = armctrl_mask_irq,
	.irq_unmask = armctrl_unmask_irq
	};

	static int armctrl_xlate(struct irq_domain d, struct device_node ctrlr,
	const u32 *intspec, unsigned int intsize,
	unsigned long out_hwirq, unsigned int out_type)
	{
	if (WARN_ON(intsize != 2))
	return -EINVAL;

	if (WARN_ON(intspec[0] >= NR_BANKS))
	return -EINVAL;

	if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
	return -EINVAL;

	if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
	return -EINVAL;

	*out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
	*out_type = IRQ_TYPE_NONE;
	return 0;
	}

	static const struct irq_domain_ops armctrl_ops = {
	.xlate = armctrl_xlate
	};

	static int __init armctrl_of_init(struct device_node *node,
	struct device_node *parent,
	bool is_2836)
	{
	void __iomem *base;
	int irq, b, i;

	base = of_iomap(node, 0);
	if (!base)
	panic("%pOF: unable to map IC registers\n", node);

	intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
	&armctrl_ops, NULL);
	if (!intc.domain)
	panic("%pOF: unable to create IRQ domain\n", node);

	for (b = 0; b < NR_BANKS; b++) {
	intc.pending[b] = base + reg_pending[b];
	intc.enable[b] = base + reg_enable[b];
	intc.disable[b] = base + reg_disable[b];

	for (i = 0; i < bank_irqs[b]; i++) {
	irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
	BUG_ON(irq <= 0);
	irq_set_chip_and_handler(irq, &armctrl_chip,
	handle_level_irq);
	irq_set_probe(irq);
	}
	}

	if (is_2836) {
	int parent_irq = irq_of_parse_and_map(node, 0);

	if (!parent_irq) {
	panic("%pOF: unable to get parent interrupt.\n",
	node);
	}
	irq_set_chained_handler(parent_irq, bcm2836_chained_handle_irq);
	} else {
	set_handle_irq(bcm2835_handle_irq);
	}

	return 0;
	}

	static int __init bcm2835_armctrl_of_init(struct device_node *node,
	struct device_node *parent)
	{
	return armctrl_of_init(node, parent, false);
	}

	static int __init bcm2836_armctrl_of_init(struct device_node *node,
	struct device_node *parent)
	{
	return armctrl_of_init(node, parent, true);
	}


	/*
	* Handle each interrupt across the entire interrupt controller. This reads the
	* status register before handling each interrupt, which is necessary given that
	* handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
	*/

	static u32 armctrl_translate_bank(int bank)
	{
	u32 stat = readl_relaxed(intc.pending[bank]);

	return MAKE_HWIRQ(bank, ffs(stat) - 1);
	}

	static u32 armctrl_translate_shortcut(int bank, u32 stat)
	{
	return MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
	}

	static u32 get_next_armctrl_hwirq(void)
	{
	u32 stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK;

	if (stat == 0)
	return ~0;
	else if (stat & BANK0_HWIRQ_MASK)
	return MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
	else if (stat & SHORTCUT1_MASK)
	return armctrl_translate_shortcut(1, stat & SHORTCUT1_MASK);
	else if (stat & SHORTCUT2_MASK)
	return armctrl_translate_shortcut(2, stat & SHORTCUT2_MASK);
	else if (stat & BANK1_HWIRQ)
	return armctrl_translate_bank(1);
	else if (stat & BANK2_HWIRQ)
	return armctrl_translate_bank(2);
	else
	BUG();
	}

	static void __exception_irq_entry bcm2835_handle_irq(
	struct pt_regs *regs)
	{
	u32 hwirq;

	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
	handle_domain_irq(intc.domain, hwirq, regs);
	}

	static void bcm2836_chained_handle_irq(struct irq_desc *desc)
	{
	u32 hwirq;

	while ((hwirq = get_next_armctrl_hwirq()) != ~0)
	generic_handle_irq(irq_linear_revmap(intc.domain, hwirq));
	}

	IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic",
	bcm2835_armctrl_of_init);
	IRQCHIP_DECLARE(bcm2836_armctrl_ic, "brcm,bcm2836-armctrl-ic",
	bcm2836_armctrl_of_init);