text: /*
   * arch/powerpc/platforms/embedded6xx/flipper-pic.c
   *
   * Nintendo GameCube/Wii "Flipper" interrupt controller support.
   * Copyright (C) 2004-2009 The GameCube Linux Team
   * Copyright (C) 2007,2008,2009 Albert Herranz
   *
   * 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.
   *
   */
  #define DRV_MODULE_NAME "flipper-pic"
  #define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/irq.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  #include <asm/io.h>
  
  #include "flipper-pic.h"
  
  #define FLIPPER_NR_IRQS		32
  
  /*
   * Each interrupt has a corresponding bit in both
   * the Interrupt Cause (ICR) and Interrupt Mask (IMR) registers.
   *
   * Enabling/disabling an interrupt line involves setting/clearing
   * the corresponding bit in IMR.
   * Except for the RSW interrupt, all interrupts get deasserted automatically
   * when the source deasserts the interrupt.
   */
  #define FLIPPER_ICR		0x00
  #define FLIPPER_ICR_RSS		(1<<16) /* reset switch state */
  
  #define FLIPPER_IMR		0x04
  
  #define FLIPPER_RESET		0x24
  
  
  /*
   * IRQ chip hooks.
   *
   */
  
  static void flipper_pic_mask_and_ack(struct irq_data *d)
  {
  	int irq = irqd_to_hwirq(d);
  	void __iomem *io_base = irq_data_get_irq_chip_data(d);
  	u32 mask = 1 << irq;
  
  	clrbits32(io_base + FLIPPER_IMR, mask);
  	/* this is at least needed for RSW */
  	out_be32(io_base + FLIPPER_ICR, mask);
  }
  
  static void flipper_pic_ack(struct irq_data *d)
  {
  	int irq = irqd_to_hwirq(d);
  	void __iomem *io_base = irq_data_get_irq_chip_data(d);
  
  	/* this is at least needed for RSW */
  	out_be32(io_base + FLIPPER_ICR, 1 << irq);
  }
  
  static void flipper_pic_mask(struct irq_data *d)
  {
  	int irq = irqd_to_hwirq(d);
  	void __iomem *io_base = irq_data_get_irq_chip_data(d);
  
  	clrbits32(io_base + FLIPPER_IMR, 1 << irq);
  }
  
  static void flipper_pic_unmask(struct irq_data *d)
  {
  	int irq = irqd_to_hwirq(d);
  	void __iomem *io_base = irq_data_get_irq_chip_data(d);
  
  	setbits32(io_base + FLIPPER_IMR, 1 << irq);
  }
  
  
  static struct irq_chip flipper_pic = {
  	.name		= "flipper-pic",
  	.irq_ack	= flipper_pic_ack,
  	.irq_mask_ack	= flipper_pic_mask_and_ack,
  	.irq_mask	= flipper_pic_mask,
  	.irq_unmask	= flipper_pic_unmask,
  };
  
  /*
   * IRQ host hooks.
   *
   */
  
  static struct irq_domain *flipper_irq_host;
  
  static int flipper_pic_map(struct irq_domain *h, unsigned int virq,
  			   irq_hw_number_t hwirq)
  {
  	irq_set_chip_data(virq, h->host_data);
  	irq_set_status_flags(virq, IRQ_LEVEL);
  	irq_set_chip_and_handler(virq, &flipper_pic, handle_level_irq);
  	return 0;
  }
  
  static int flipper_pic_match(struct irq_domain *h, struct device_node *np,
  			     enum irq_domain_bus_token bus_token)
  {
  	return 1;
  }
  
  
  static const struct irq_domain_ops flipper_irq_domain_ops = {
  	.map = flipper_pic_map,
  	.match = flipper_pic_match,
  };
  
  /*
   * Platform hooks.
   *
   */
  
  static void __flipper_quiesce(void __iomem *io_base)
  {
  	/* mask and ack all IRQs */
  	out_be32(io_base + FLIPPER_IMR, 0x00000000);
  	out_be32(io_base + FLIPPER_ICR, 0xffffffff);
  }
  
  struct irq_domain * __init flipper_pic_init(struct device_node *np)
  {
  	struct device_node *pi;
  	struct irq_domain *irq_domain = NULL;
  	struct resource res;
  	void __iomem *io_base;
  	int retval;
  
  	pi = of_get_parent(np);
  	if (!pi) {
  		pr_err("no parent found\n");
  		goto out;
  	}
  	if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
  		pr_err("unexpected parent compatible\n");
  		goto out;
  	}
  
  	retval = of_address_to_resource(pi, 0, &res);
  	if (retval) {
  		pr_err("no io memory range found\n");
  		goto out;
  	}
  	io_base = ioremap(res.start, resource_size(&res));
  
  	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
  
  	__flipper_quiesce(io_base);
  
  	irq_domain = irq_domain_add_linear(np, FLIPPER_NR_IRQS,
  				  &flipper_irq_domain_ops, io_base);
  	if (!irq_domain) {
  		pr_err("failed to allocate irq_domain\n");
  		return NULL;
  	}
  
  out:
  	return irq_domain;
  }
  
  unsigned int flipper_pic_get_irq(void)
  {
  	void __iomem *io_base = flipper_irq_host->host_data;
  	int irq;
  	u32 irq_status;
  
  	irq_status = in_be32(io_base + FLIPPER_ICR) &
  		     in_be32(io_base + FLIPPER_IMR);
  	if (irq_status == 0)
  		return NO_IRQ;	/* no more IRQs pending */
  
  	irq = __ffs(irq_status);
  	return irq_linear_revmap(flipper_irq_host, irq);
  }
  
  /*
   * Probe function.
   *
   */
  
  void __init flipper_pic_probe(void)
  {
  	struct device_node *np;
  
  	np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
  	BUG_ON(!np);
  
  	flipper_irq_host = flipper_pic_init(np);
  	BUG_ON(!flipper_irq_host);
  
  	irq_set_default_host(flipper_irq_host);
  
  	of_node_put(np);
  }
  
  /*
   * Misc functions related to the flipper chipset.
   *
   */
  
  /**
   * flipper_quiesce() - quiesce flipper irq controller
   *
   * Mask and ack all interrupt sources.
   *
   */
  void flipper_quiesce(void)
  {
  	void __iomem *io_base = flipper_irq_host->host_data;
  
  	__flipper_quiesce(io_base);
  }
  
  /*
   * Resets the platform.
   */
  void flipper_platform_reset(void)
  {
  	void __iomem *io_base;
  
  	if (flipper_irq_host && flipper_irq_host->host_data) {
  		io_base = flipper_irq_host->host_data;
  		out_8(io_base + FLIPPER_RESET, 0x00);
  	}
  }
  
  /*
   * Returns non-zero if the reset button is pressed.
   */
  int flipper_is_reset_button_pressed(void)
  {
  	void __iomem *io_base;
  	u32 icr;
  
  	if (flipper_irq_host && flipper_irq_host->host_data) {
  		io_base = flipper_irq_host->host_data;
  		icr = in_be32(io_base + FLIPPER_ICR);
  		return !(icr & FLIPPER_ICR_RSS);
  	}
  	return 0;
  }
  
  