sys_dp264.c

讲述linux的初始化过程

/*
 *	linux/arch/alpha/kernel/sys_dp264.c
 *
 *	Copyright (C) 1995 David A Rusling
 *	Copyright (C) 1996, 1999 Jay A Estabrook
 *	Copyright (C) 1998, 1999 Richard Henderson
 *
 * Code supporting the DP264 (EV6+TSUNAMI).
 */

#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/dma.h>
#include <asm/irq.h>
#include <asm/bitops.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/core_tsunami.h>
#include <asm/hwrpb.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;
/* dp264 boards handle at max four CPUs */
static unsigned long cpu_irq_affinity[4] = { 0UL, 0UL, 0UL, 0UL };

spinlock_t dp264_irq_lock = SPIN_LOCK_UNLOCKED;

static void
tsunami_update_irq_hw(unsigned long mask)
{
	register tsunami_cchip *cchip = TSUNAMI_cchip;
	unsigned long isa_enable = 1UL << 55;
	register int bcpu = boot_cpuid;

#ifdef CONFIG_SMP
	register unsigned long cpm = cpu_present_mask;
	volatile unsigned long *dim0, *dim1, *dim2, *dim3;
	unsigned long mask0, mask1, mask2, mask3, dummy;

	mask &= ~isa_enable;
	mask0 = mask & cpu_irq_affinity[0];
	mask1 = mask & cpu_irq_affinity[1];
	mask2 = mask & cpu_irq_affinity[2];
	mask3 = mask & cpu_irq_affinity[3];

	if (bcpu == 0) mask0 |= isa_enable;
	else if (bcpu == 1) mask1 |= isa_enable;
	else if (bcpu == 2) mask2 |= isa_enable;
	else mask3 |= isa_enable;

	dim0 = &cchip->dim0.csr;
	dim1 = &cchip->dim1.csr;
	dim2 = &cchip->dim2.csr;
	dim3 = &cchip->dim3.csr;
	if ((cpm & 1) == 0) dim0 = &dummy;
	if ((cpm & 2) == 0) dim1 = &dummy;
	if ((cpm & 4) == 0) dim2 = &dummy;
	if ((cpm & 8) == 0) dim3 = &dummy;

	*dim0 = mask0;
	*dim1 = mask1;
	*dim2 = mask2;
	*dim3 = mask3;
	mb();
	*dim0;
	*dim1;
	*dim2;
	*dim3;
#else
	volatile unsigned long *dimB;
	if (bcpu == 0) dimB = &cchip->dim0.csr;
	else if (bcpu == 1) dimB = &cchip->dim1.csr;
	else if (bcpu == 2) dimB = &cchip->dim2.csr;
	else dimB = &cchip->dim3.csr;

	*dimB = mask | isa_enable;
	mb();
	*dimB;
#endif
}

static void
dp264_enable_irq(unsigned int irq)
{
	spin_lock(&dp264_irq_lock);
	cached_irq_mask |= 1UL << irq;
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static void
dp264_disable_irq(unsigned int irq)
{
	spin_lock(&dp264_irq_lock);
	cached_irq_mask &= ~(1UL << irq);
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static unsigned int
dp264_startup_irq(unsigned int irq)
{ 
	dp264_enable_irq(irq);
	return 0; /* never anything pending */
}

static void
dp264_end_irq(unsigned int irq)
{ 
	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
		dp264_enable_irq(irq);
}

static void
clipper_enable_irq(unsigned int irq)
{
	spin_lock(&dp264_irq_lock);
	cached_irq_mask |= 1UL << (irq - 16);
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static void
clipper_disable_irq(unsigned int irq)
{
	spin_lock(&dp264_irq_lock);
	cached_irq_mask &= ~(1UL << (irq - 16));
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static unsigned int
clipper_startup_irq(unsigned int irq)
{ 
	clipper_enable_irq(irq);
	return 0; /* never anything pending */
}

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

static void
cpu_set_irq_affinity(unsigned int irq, unsigned long affinity)
{
	int cpu;

	for (cpu = 0; cpu < 4; cpu++) {
		unsigned long aff = cpu_irq_affinity[cpu];
		if (affinity & (1UL << cpu))
			aff |= 1UL << irq;
		else
			aff &= ~(1UL << irq);
		cpu_irq_affinity[cpu] = aff;
	}
}

static void
dp264_set_affinity(unsigned int irq, unsigned long affinity)
{ 
	spin_lock(&dp264_irq_lock);
	cpu_set_irq_affinity(irq, affinity);
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static void
clipper_set_affinity(unsigned int irq, unsigned long affinity)
{ 
	spin_lock(&dp264_irq_lock);
	cpu_set_irq_affinity(irq - 16, affinity);
	tsunami_update_irq_hw(cached_irq_mask);
	spin_unlock(&dp264_irq_lock);
}

static struct hw_interrupt_type dp264_irq_type = {
	typename:	"DP264",
	startup:	dp264_startup_irq,
	shutdown:	dp264_disable_irq,
	enable:		dp264_enable_irq,
	disable:	dp264_disable_irq,
	ack:		dp264_disable_irq,
	end:		dp264_end_irq,
	set_affinity:	dp264_set_affinity,
};

static struct hw_interrupt_type clipper_irq_type = {
	typename:	"CLIPPER",
	startup:	clipper_startup_irq,
	shutdown:	clipper_disable_irq,
	enable:		clipper_enable_irq,
	disable:	clipper_disable_irq,
	ack:		clipper_disable_irq,
	end:		clipper_end_irq,
	set_affinity:	clipper_set_affinity,
};

static void
dp264_device_interrupt(unsigned long vector, struct pt_regs * regs)
{
#if 1
	printk("dp264_device_interrupt: NOT IMPLEMENTED YET!! \n");
#else
	unsigned long pld;
	unsigned int i;

	/* Read the interrupt summary register of TSUNAMI */
	pld = TSUNAMI_cchip->dir0.csr;

	/*
	 * 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 == 55)
			isa_device_interrupt(vector, regs);
		else
			handle_irq(16 + i, 16 + i, regs);
#if 0
		TSUNAMI_cchip->dir0.csr = 1UL << i; mb();
		tmp = TSUNAMI_cchip->dir0.csr;
#endif
	}
#endif
}

static void 
dp264_srm_device_interrupt(unsigned long vector, struct pt_regs * regs)
{
	int irq;

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

	/*
	 * The SRM console reports PCI interrupts with a vector calculated by:
	 *
	 *	0x900 + (0x10 * DRIR-bit)
	 *
	 * So bit 16 shows up as IRQ 32, etc.
	 * 
	 * On DP264/BRICK/MONET, we adjust it down by 16 because at least
	 * that many of the low order bits of the DRIR are not used, and
	 * so we don't count them.
	 */
	if (irq >= 32)
		irq -= 16;

	handle_irq(irq, regs);
}

static void 
clipper_srm_device_interrupt(unsigned long vector, struct pt_regs * regs)
{
	int irq;

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

/*
	 * The SRM console reports PCI interrupts with a vector calculated by:
	 *
	 *	0x900 + (0x10 * DRIR-bit)
	 *
	 * So bit 16 shows up as IRQ 32, etc.
	 * 
	 * CLIPPER uses bits 8-47 for PCI interrupts, so we do not need
	 * to scale down the vector reported, we just use it.
	 *
	 * Eg IRQ 24 is DRIR bit 8, etc, etc
	 */
	handle_irq(irq, regs);
}

static void __init
init_tsunami_irqs(struct hw_interrupt_type * ops, int imin, int imax)
{
	long i;
	for (i = imin; i <= imax; ++i) {
		irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;
		irq_desc[i].handler = ops;
	}
}

static void __init
dp264_init_irq(void)
{
	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 = dp264_srm_device_interrupt;

	tsunami_update_irq_hw(0);

	init_i8259a_irqs();
	init_tsunami_irqs(&dp264_irq_type, 16, 47);
}

static void __init
clipper_init_irq(void)
{
	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 = clipper_srm_device_interrupt;