// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Generic Broadcom Set Top Box Level 2 Interrupt controller driver
   *

   * Copyright (C) 2014-2017 Broadcom

   */
  
  #define pr_fmt(fmt)	KBUILD_MODNAME	": " fmt
  
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>

  #include <linux/spinlock.h>

  #include <linux/of.h>
  #include <linux/of_irq.h>
  #include <linux/of_address.h>
  #include <linux/of_platform.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/io.h>
  #include <linux/irqdomain.h>
  #include <linux/irqchip.h>
  #include <linux/irqchip/chained_irq.h>

  struct brcmstb_intc_init_params {
  	irq_flow_handler_t handler;
  	int cpu_status;
  	int cpu_clear;
  	int cpu_mask_status;
  	int cpu_mask_set;
  	int cpu_mask_clear;
  };
  
  /* Register offsets in the L2 latched interrupt controller */
  static const struct brcmstb_intc_init_params l2_edge_intc_init = {
  	.handler		= handle_edge_irq,
  	.cpu_status		= 0x00,
  	.cpu_clear		= 0x08,
  	.cpu_mask_status	= 0x0c,
  	.cpu_mask_set		= 0x10,
  	.cpu_mask_clear		= 0x14
  };
  
  /* Register offsets in the L2 level interrupt controller */
  static const struct brcmstb_intc_init_params l2_lvl_intc_init = {
  	.handler		= handle_level_irq,
  	.cpu_status		= 0x00,
  	.cpu_clear		= -1, /* Register not present */
  	.cpu_mask_status	= 0x04,
  	.cpu_mask_set		= 0x08,
  	.cpu_mask_clear		= 0x0C
  };

  
  /* L2 intc private data structure */
  struct brcmstb_l2_intc_data {

  	struct irq_domain *domain;

  	struct irq_chip_generic *gc;

  	int status_offset;
  	int mask_offset;

  	bool can_wake;
  	u32 saved_mask; /* for suspend/resume */
  };

  /**
   * brcmstb_l2_mask_and_ack - Mask and ack pending interrupt
   * @d: irq_data
   *
   * Chip has separate enable/disable registers instead of a single mask
   * register and pending interrupt is acknowledged by setting a bit.
   *
   * Note: This function is generic and could easily be added to the
   * generic irqchip implementation if there ever becomes a will to do so.
   * Perhaps with a name like irq_gc_mask_disable_and_ack_set().
   *
   * e.g.: https://patchwork.kernel.org/patch/9831047/
   */
  static void brcmstb_l2_mask_and_ack(struct irq_data *d)
  {
  	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
  	struct irq_chip_type *ct = irq_data_get_chip_type(d);
  	u32 mask = d->mask;
  
  	irq_gc_lock(gc);
  	irq_reg_writel(gc, mask, ct->regs.disable);
  	*ct->mask_cache &= ~mask;
  	irq_reg_writel(gc, mask, ct->regs.ack);
  	irq_gc_unlock(gc);
  }

  static void brcmstb_l2_intc_irq_handle(struct irq_desc *desc)

  {
  	struct brcmstb_l2_intc_data *b = irq_desc_get_handler_data(desc);
  	struct irq_chip *chip = irq_desc_get_chip(desc);

  	unsigned int irq;

  	u32 status;
  
  	chained_irq_enter(chip, desc);

  	status = irq_reg_readl(b->gc, b->status_offset) &
  		~(irq_reg_readl(b->gc, b->mask_offset));

  
  	if (status == 0) {

  		raw_spin_lock(&desc->lock);

  		handle_bad_irq(desc);

  		raw_spin_unlock(&desc->lock);

  		goto out;
  	}
  
  	do {
  		irq = ffs(status) - 1;

  		status &= ~(1 << irq);

  		generic_handle_irq(irq_linear_revmap(b->domain, irq));

  	} while (status);
  out:
  	chained_irq_exit(chip, desc);
  }
  
  static void brcmstb_l2_intc_suspend(struct irq_data *d)
  {
  	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);

  	struct irq_chip_type *ct = irq_data_get_chip_type(d);

  	struct brcmstb_l2_intc_data *b = gc->private;

  	unsigned long flags;

  	irq_gc_lock_irqsave(gc, flags);

  	/* Save the current mask */

  	b->saved_mask = irq_reg_readl(gc, ct->regs.mask);

  
  	if (b->can_wake) {
  		/* Program the wakeup mask */

  		irq_reg_writel(gc, ~gc->wake_active, ct->regs.disable);
  		irq_reg_writel(gc, gc->wake_active, ct->regs.enable);

  	}

  	irq_gc_unlock_irqrestore(gc, flags);

  }
  
  static void brcmstb_l2_intc_resume(struct irq_data *d)
  {
  	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);

  	struct irq_chip_type *ct = irq_data_get_chip_type(d);

  	struct brcmstb_l2_intc_data *b = gc->private;

  	unsigned long flags;

  	irq_gc_lock_irqsave(gc, flags);

  	if (ct->chip.irq_ack) {

  		/* Clear unmasked non-wakeup interrupts */
  		irq_reg_writel(gc, ~b->saved_mask & ~gc->wake_active,
  				ct->regs.ack);
  	}

  
  	/* Restore the saved mask */

  	irq_reg_writel(gc, b->saved_mask, ct->regs.disable);
  	irq_reg_writel(gc, ~b->saved_mask, ct->regs.enable);

  	irq_gc_unlock_irqrestore(gc, flags);

  }

  static int __init brcmstb_l2_intc_of_init(struct device_node *np,

  					  struct device_node *parent,
  					  const struct brcmstb_intc_init_params
  					  *init_params)

  {
  	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
  	struct brcmstb_l2_intc_data *data;

  	struct irq_chip_type *ct;
  	int ret;

  	unsigned int flags;

  	int parent_irq;
  	void __iomem *base;

  
  	data = kzalloc(sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;

  	base = of_iomap(np, 0);
  	if (!base) {

  		pr_err("failed to remap intc L2 registers
  ");
  		ret = -ENOMEM;
  		goto out_free;
  	}
  
  	/* Disable all interrupts by default */

  	writel(0xffffffff, base + init_params->cpu_mask_set);

  
  	/* Wakeup interrupts may be retained from S5 (cold boot) */
  	data->can_wake = of_property_read_bool(np, "brcm,irq-can-wake");

  	if (!data->can_wake && (init_params->cpu_clear >= 0))
  		writel(0xffffffff, base + init_params->cpu_clear);

  	parent_irq = irq_of_parse_and_map(np, 0);
  	if (!parent_irq) {

  		pr_err("failed to find parent interrupt
  ");

  		ret = -EINVAL;

  		goto out_unmap;
  	}
  
  	data->domain = irq_domain_add_linear(np, 32,
  				&irq_generic_chip_ops, NULL);
  	if (!data->domain) {
  		ret = -ENOMEM;
  		goto out_unmap;
  	}

  	/* MIPS chips strapped for BE will automagically configure the
  	 * peripheral registers for CPU-native byte order.
  	 */
  	flags = 0;
  	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
  		flags |= IRQ_GC_BE_IO;

  	/* Allocate a single Generic IRQ chip for this node */
  	ret = irq_alloc_domain_generic_chips(data->domain, 32, 1,

  			np->full_name, init_params->handler, clr, 0, flags);

  	if (ret) {
  		pr_err("failed to allocate generic irq chip
  ");
  		goto out_free_domain;
  	}
  
  	/* Set the IRQ chaining logic */

  	irq_set_chained_handler_and_data(parent_irq,

  					 brcmstb_l2_intc_irq_handle, data);

  	data->gc = irq_get_domain_generic_chip(data->domain, 0);
  	data->gc->reg_base = base;
  	data->gc->private = data;

  	data->status_offset = init_params->cpu_status;
  	data->mask_offset = init_params->cpu_mask_status;

  	ct = data->gc->chip_types;

  	if (init_params->cpu_clear >= 0) {
  		ct->regs.ack = init_params->cpu_clear;
  		ct->chip.irq_ack = irq_gc_ack_set_bit;
  		ct->chip.irq_mask_ack = brcmstb_l2_mask_and_ack;
  	} else {
  		/* No Ack - but still slightly more efficient to define this */
  		ct->chip.irq_mask_ack = irq_gc_mask_disable_reg;
  	}

  
  	ct->chip.irq_mask = irq_gc_mask_disable_reg;

  	ct->regs.disable = init_params->cpu_mask_set;
  	ct->regs.mask = init_params->cpu_mask_status;

  
  	ct->chip.irq_unmask = irq_gc_unmask_enable_reg;

  	ct->regs.enable = init_params->cpu_mask_clear;

  
  	ct->chip.irq_suspend = brcmstb_l2_intc_suspend;
  	ct->chip.irq_resume = brcmstb_l2_intc_resume;

  	ct->chip.irq_pm_shutdown = brcmstb_l2_intc_suspend;

  	if (data->can_wake) {

  		/* This IRQ chip can wake the system, set all child interrupts
  		 * in wake_enabled mask
  		 */

  		data->gc->wake_enabled = 0xffffffff;

  		ct->chip.irq_set_wake = irq_gc_set_wake;
  	}

  	pr_info("registered L2 intc (%pOF, parent irq: %d)
  ", np, parent_irq);

  	return 0;
  
  out_free_domain:
  	irq_domain_remove(data->domain);
  out_unmap:

  	iounmap(base);

  out_free:
  	kfree(data);
  	return ret;
  }

  static int __init brcmstb_l2_edge_intc_of_init(struct device_node *np,

  	struct device_node *parent)
  {
  	return brcmstb_l2_intc_of_init(np, parent, &l2_edge_intc_init);
  }
  IRQCHIP_DECLARE(brcmstb_l2_intc, "brcm,l2-intc", brcmstb_l2_edge_intc_of_init);

  static int __init brcmstb_l2_lvl_intc_of_init(struct device_node *np,

  	struct device_node *parent)
  {
  	return brcmstb_l2_intc_of_init(np, parent, &l2_lvl_intc_init);
  }
  IRQCHIP_DECLARE(bcm7271_l2_intc, "brcm,bcm7271-l2-intc",
  	brcmstb_l2_lvl_intc_of_init);