/*
 *	linux/arch/alpha/kernel/sys_alcor.c
 *
 *	Copyright (C) 1995 David A Rusling
 *	Copyright (C) 1996 Jay A Estabrook
 *	Copyright (C) 1998, 1999 Richard Henderson
 *
 * Code supporting the ALCOR and XLT (XL-300/366/433).
 */

#include <linux/config.h>
#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 <asm/ptrace.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/bitops.h>
#include <asm/mmu_context.h>
#include <asm/irq.h>
#include <asm/pgtable.h>
#include <asm/core_cia.h>

#include "proto.h"
#include "irq_impl.h"
#include "pci_impl.h"
#include "machvec_impl.h"


/* Note mask bit is true for ENABLED irqs.  */
static unsigned long cached_irq_mask;

static inline void
alcor_update_irq_hw(unsigned long mask)
{
	*(vuip)GRU_INT_MASK = mask;
	mb();
}

static inline void
alcor_enable_irq(unsigned int irq)
{
	alcor_update_irq_hw(cached_irq_mask |= 1UL << (irq - 16));
}

static void
alcor_disable_irq(unsigned int irq)
{
	alcor_update_irq_hw(cached_irq_mask &= ~(1UL << (irq - 16)));
}

static void
alcor_mask_and_ack_irq(unsigned int irq)
{
	alcor_disable_irq(irq);

	/* On ALCOR/XLT, need to dismiss interrupt via GRU. */
	*(vuip)GRU_INT_CLEAR = 1 << (irq - 16); mb();
	*(vuip)GRU_INT_CLEAR = 0; mb();
}

static unsigned int
alcor_startup_irq(unsigned int irq)
{
	alcor_enable_irq(irq);
	return 0;
}

static void
alcor_isa_mask_and_ack_irq(unsigned int irq)
{
	i8259a_mask_and_ack_irq(irq);

	/* On ALCOR/XLT, need to dismiss interrupt via GRU. */
	*(vuip)GRU_INT_CLEAR = 0x80000000; mb();
	*(vuip)GRU_INT_CLEAR = 0; mb();
}

static void
alcor_end_irq(unsigned int irq)
{
	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
		alcor_enable_irq(irq);
}

static struct hw_interrupt_type alcor_irq_type = {
	typename:	"ALCOR",
	startup:	alcor_startup_irq,
	shutdown:	alcor_disable_irq,
	enable:		alcor_enable_irq,
	disable:	alcor_disable_irq,
	ack:		alcor_mask_and_ack_irq,
	end:		alcor_end_irq,
};

static void
alcor_device_interrupt(unsigned long vector, struct pt_regs *regs)
{
	unsigned long pld;
	unsigned int i;

	/* Read the interrupt summary register of the GRU */
	pld = (*(vuip)GRU_INT_REQ) & GRU_INT_REQ_BITS;

	/*
	 * Now for every possible bit set, work through them and call
	 * the appropriate interrupt handler.
	 */
	while (pld) {
		i = ffz(~pld);
		pld &= pld - 1; /* clear least bit set */
		if (i == 31) {
			isa_device_interrupt(vector, regs);
		} else {
			handle_irq(16 + i, regs);
		}
	}
}

static void __init
alcor_init_irq(void)
{
	long i;

	if (alpha_using_srm)
		alpha_mv.device_interrupt = srm_device_interrupt;

	*(vuip)GRU_INT_MASK  = 0; mb();			/* all disabled */
	*(vuip)GRU_INT_EDGE  = 0; mb();			/* all are level */
	*(vuip)GRU_INT_HILO  = 0x80000000U; mb();	/* ISA only HI */
	*(vuip)GRU_INT_CLEAR = 0; mb();			/* all clear */

	for (i = 16; i < 48; ++i) {
		/* On Alcor, at least, lines 20..30 are not connected
		   and can generate spurrious interrupts if we turn them
		   on while IRQ probing.  */
		if (i >= 16+20 && i <= 16+30)
			continue;
		irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;
		irq_desc[i].handler = &alcor_irq_type;
	}
	i8259a_irq_type.ack = alcor_isa_mask_and_ack_irq;

	init_i8259a_irqs();
	common_init_isa_dma();

	setup_irq(16+31, &isa_cascade_irqaction);
}


/*
 * PCI Fixup configuration.
 *
 * Summary @ GRU_INT_REQ:
 * Bit      Meaning
 * 0        Interrupt Line A from slot 2
 * 1        Interrupt Line B from slot 2
 * 2        Interrupt Line C from slot 2
 * 3        Interrupt Line D from slot 2
 * 4        Interrupt Line A from slot 1
 * 5        Interrupt line B from slot 1
 * 6        Interrupt Line C from slot 1
 * 7        Interrupt Line D from slot 1
 * 8        Interrupt Line A from slot 0
 * 9        Interrupt Line B from slot 0
 *10        Interrupt Line C from slot 0
 *11        Interrupt Line D from slot 0
 *12        Interrupt Line A from slot 4
 *13        Interrupt Line B from slot 4
 *14        Interrupt Line C from slot 4
 *15        Interrupt Line D from slot 4
 *16        Interrupt Line D from slot 3
 *17        Interrupt Line D from slot 3
 *18        Interrupt Line D from slot 3
 *19        Interrupt Line D from slot 3
 *20-30     Reserved
 *31        EISA interrupt
 *
 * The device to slot mapping looks like:
 *
 * Slot     Device
 *  6       built-in TULIP (XLT only)
 *  7       PCI on board slot 0
 *  8       PCI on board slot 3
 *  9       PCI on board slot 4
 * 10       PCEB (PCI-EISA bridge)
 * 11       PCI on board slot 2
 * 12       PCI on board slot 1
 *   
 *
 * This two layered interrupt approach means that we allocate IRQ 16 and 
 * above for PCI interrupts.  The IRQ relates to which bit the interrupt
 * comes in on.  This makes interrupt processing much easier.
 */

static int __init
alcor_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
{
	static char irq_tab[7][5] __initlocaldata = {
		/*INT    INTA   INTB   INTC   INTD */
		/* note: IDSEL 17 is XLT only */
		{16+13, 16+13, 16+13, 16+13, 16+13},	/* IdSel 17,  TULIP  */
		{ 16+8,  16+8,  16+9, 16+10, 16+11},	/* IdSel 18,  slot 0 */
		{16+16, 16+16, 16+17, 16+18, 16+19},	/* IdSel 19,  slot 3 */
		{16+12, 16+12, 16+13, 16+14, 16+15},	/* IdSel 20,  slot 4 */
		{   -1,    -1,    -1,    -1,    -1},	/* IdSel 21,  PCEB   */
		{ 16+0,  16+0,  16+1,  16+2,  16+3},	/* IdSel 22,  slot 2 */
		{ 16+4,  16+4,  16+5,  16+6,  16+7},	/* IdSel 23,  slot 1 */
	};
	const long min_idsel = 6, max_idsel = 12, irqs_per_slot = 5;
	return COMMON_TABLE_LOOKUP;
}

static void
alcor_kill_arch(int mode)
{
	/* Who said DEC engineer's have no sense of humor? ;-)  */
	if (alpha_using_srm) {
		*(vuip) GRU_RESET = 0x0000dead;
		mb();
	}
}


/*
 * The System Vectors
 */

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_ALCOR)
struct alpha_machine_vector alcor_mv __initmv = {
	vector_name:		"Alcor",
	DO_EV5_MMU,
	DO_DEFAULT_RTC,
	DO_CIA_IO,
	DO_CIA_BUS,
	machine_check:		cia_machine_check,
	max_dma_address:	ALPHA_MAX_DMA_ADDRESS,
	min_io_address:		EISA_DEFAULT_IO_BASE,
	min_mem_address:	CIA_DEFAULT_MEM_BASE,

	nr_irqs:		48,
	device_interrupt:	alcor_device_interrupt,

	init_arch:		cia_init_arch,
	init_irq:		alcor_init_irq,
	init_rtc:		common_init_rtc,
	init_pci:		cia_init_pci,
	kill_arch:		alcor_kill_arch,
	pci_map_irq:		alcor_map_irq,
	pci_swizzle:		common_swizzle,

	sys: { cia: {
	    gru_int_req_bits:	ALCOR_GRU_INT_REQ_BITS
	}}
};
ALIAS_MV(alcor)
#endif

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_XLT)
struct alpha_machine_vector xlt_mv __initmv = {
	vector_name:		"XLT",
	DO_EV5_MMU,
	DO_DEFAULT_RTC,
	DO_CIA_IO,
	DO_CIA_BUS,
	machine_check:		cia_machine_check,
	max_dma_address:	ALPHA_MAX_DMA_ADDRESS,
	min_io_address:		EISA_DEFAULT_IO_BASE,
	min_mem_address:	CIA_DEFAULT_MEM_BASE,

	nr_irqs:		48,
	device_interrupt:	alcor_device_interrupt,

	init_arch:		cia_init_arch,
	init_irq:		alcor_init_irq,
	init_rtc:		common_init_rtc,
	init_pci:		cia_init_pci,
	kill_arch:		alcor_kill_arch,
	pci_map_irq:		alcor_map_irq,
	pci_swizzle:		common_swizzle,

	sys: { cia: {
	    gru_int_req_bits:	XLT_GRU_INT_REQ_BITS
	}}
};
ALIAS_MV(xlt)
#endif