/*
   *	linux/arch/alpha/kernel/sys_eiger.c
   *
   *	Copyright (C) 1995 David A Rusling
   *	Copyright (C) 1996, 1999 Jay A Estabrook
   *	Copyright (C) 1998, 1999 Richard Henderson
   *	Copyright (C) 1999 Iain Grant
   *
   * Code supporting the EIGER (EV6+TSUNAMI).
   */
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/mm.h>
  #include <linux/sched.h>
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/bitops.h>
  
  #include <asm/ptrace.h>
  #include <asm/system.h>
  #include <asm/dma.h>
  #include <asm/irq.h>
  #include <asm/mmu_context.h>
  #include <asm/io.h>
  #include <asm/pci.h>
  #include <asm/pgtable.h>
  #include <asm/core_tsunami.h>
  #include <asm/hwrpb.h>
  #include <asm/tlbflush.h>
  
  #include "proto.h"
  #include "irq_impl.h"
  #include "pci_impl.h"
  #include "machvec_impl.h"
  
  
  /* Note that this interrupt code is identical to TAKARA.  */
  
  /* Note mask bit is true for DISABLED irqs.  */
  static unsigned long cached_irq_mask[2] = { -1, -1 };
  
  static inline void
  eiger_update_irq_hw(unsigned long irq, unsigned long mask)
  {
  	int regaddr;
  
  	mask = (irq >= 64 ? mask << 16 : mask >> ((irq - 16) & 0x30));
  	regaddr = 0x510 + (((irq - 16) >> 2) & 0x0c);
  	outl(mask & 0xffff0000UL, regaddr);
  }
  
  static inline void
  eiger_enable_irq(unsigned int irq)
  {
  	unsigned long mask;
  	mask = (cached_irq_mask[irq >= 64] &= ~(1UL << (irq & 63)));
  	eiger_update_irq_hw(irq, mask);
  }
  
  static void
  eiger_disable_irq(unsigned int irq)
  {
  	unsigned long mask;
  	mask = (cached_irq_mask[irq >= 64] |= 1UL << (irq & 63));
  	eiger_update_irq_hw(irq, mask);
  }
  
  static unsigned int
  eiger_startup_irq(unsigned int irq)
  {
  	eiger_enable_irq(irq);
  	return 0; /* never anything pending */
  }
  
  static void
  eiger_end_irq(unsigned int irq)
  {
  	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  		eiger_enable_irq(irq);
  }
  
  static struct hw_interrupt_type eiger_irq_type = {
  	.typename	= "EIGER",
  	.startup	= eiger_startup_irq,
  	.shutdown	= eiger_disable_irq,
  	.enable		= eiger_enable_irq,
  	.disable	= eiger_disable_irq,
  	.ack		= eiger_disable_irq,
  	.end		= eiger_end_irq,
  };
  
  static void

  eiger_device_interrupt(unsigned long vector)

  {
  	unsigned intstatus;
  
  	/*
  	 * The PALcode will have passed us vectors 0x800 or 0x810,
  	 * which are fairly arbitrary values and serve only to tell
  	 * us whether an interrupt has come in on IRQ0 or IRQ1. If
  	 * it's IRQ1 it's a PCI interrupt; if it's IRQ0, it's
  	 * probably ISA, but PCI interrupts can come through IRQ0
  	 * as well if the interrupt controller isn't in accelerated
  	 * mode.
  	 *
  	 * OTOH, the accelerator thing doesn't seem to be working
  	 * overly well, so what we'll do instead is try directly
  	 * examining the Master Interrupt Register to see if it's a
  	 * PCI interrupt, and if _not_ then we'll pass it on to the
  	 * ISA handler.
  	 */
  
  	intstatus = inw(0x500) & 15;
  	if (intstatus) {
  		/*
  		 * This is a PCI interrupt. Check each bit and
  		 * despatch an interrupt if it's set.
  		 */

  		if (intstatus & 8) handle_irq(16+3);
  		if (intstatus & 4) handle_irq(16+2);
  		if (intstatus & 2) handle_irq(16+1);
  		if (intstatus & 1) handle_irq(16+0);

  	} else {

  		isa_device_interrupt(vector);

  	}
  }
  
  static void

  eiger_srm_device_interrupt(unsigned long vector)

  {
  	int irq = (vector - 0x800) >> 4;

  	handle_irq(irq);

  }
  
  static void __init
  eiger_init_irq(void)
  {
  	long i;
  
  	outb(0, DMA1_RESET_REG);
  	outb(0, DMA2_RESET_REG);
  	outb(DMA_MODE_CASCADE, DMA2_MODE_REG);
  	outb(0, DMA2_MASK_REG);
  
  	if (alpha_using_srm)
  		alpha_mv.device_interrupt = eiger_srm_device_interrupt;
  
  	for (i = 16; i < 128; i += 16)
  		eiger_update_irq_hw(i, -1);
  
  	init_i8259a_irqs();
  
  	for (i = 16; i < 128; ++i) {
  		irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;

  		irq_desc[i].chip = &eiger_irq_type;

  	}
  }
  
  static int __init
  eiger_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
  {
  	u8 irq_orig;
  
  	/* The SRM console has already calculated out the IRQ value's for
  	   option cards. As this works lets just read in the value already
  	   set and change it to a useable value by Linux.
  
  	   All the IRQ values generated by the console are greater than 90,
  	   so we subtract 80 because it is (90 - allocated ISA IRQ's).  */
  
  	pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq_orig);
  
  	return irq_orig - 0x80;
  }
  
  static u8 __init
  eiger_swizzle(struct pci_dev *dev, u8 *pinp)
  {
  	struct pci_controller *hose = dev->sysdata;
  	int slot, pin = *pinp;
  	int bridge_count = 0;
  
  	/* Find the number of backplane bridges.  */
  	int backplane = inw(0x502) & 0x0f;
  
  	switch (backplane)
  	{
  	   case 0x00: bridge_count = 0; break; /* No bridges */
  	   case 0x01: bridge_count = 1; break; /* 1 */
  	   case 0x03: bridge_count = 2; break; /* 2 */
  	   case 0x07: bridge_count = 3; break; /* 3 */
  	   case 0x0f: bridge_count = 4; break; /* 4 */
  	};
  
  	slot = PCI_SLOT(dev->devfn);
  	while (dev->bus->self) {
  		/* Check for built-in bridges on hose 0. */
  		if (hose->index == 0
  		    && (PCI_SLOT(dev->bus->self->devfn)
  			> 20 - bridge_count)) {
  			slot = PCI_SLOT(dev->devfn);
  			break;
  		}
  		/* Must be a card-based bridge.  */
  		pin = bridge_swizzle(pin, PCI_SLOT(dev->devfn));
  
  		/* Move up the chain of bridges.  */
  		dev = dev->bus->self;
  	}
  	*pinp = pin;
  	return slot;
  }
  
  /*
   * The System Vectors
   */
  
  struct alpha_machine_vector eiger_mv __initmv = {
  	.vector_name		= "Eiger",
  	DO_EV6_MMU,
  	DO_DEFAULT_RTC,
  	DO_TSUNAMI_IO,
  	.machine_check		= tsunami_machine_check,
  	.max_isa_dma_address	= ALPHA_MAX_ISA_DMA_ADDRESS,
  	.min_io_address		= DEFAULT_IO_BASE,
  	.min_mem_address	= DEFAULT_MEM_BASE,
  	.pci_dac_offset		= TSUNAMI_DAC_OFFSET,
  
  	.nr_irqs		= 128,
  	.device_interrupt	= eiger_device_interrupt,
  
  	.init_arch		= tsunami_init_arch,
  	.init_irq		= eiger_init_irq,
  	.init_rtc		= common_init_rtc,
  	.init_pci		= common_init_pci,
  	.kill_arch		= tsunami_kill_arch,
  	.pci_map_irq		= eiger_map_irq,
  	.pci_swizzle		= eiger_swizzle,
  };
  ALIAS_MV(eiger)