sys_rawhide.c

讲述linux的初始化过程

/*
 *	linux/arch/alpha/kernel/sys_rawhide.c
 *
 *	Copyright (C) 1995 David A Rusling
 *	Copyright (C) 1996 Jay A Estabrook
 *	Copyright (C) 1998, 1999 Richard Henderson
 *
 * Code supporting the RAWHIDE.
 */

#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/mmu_context.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/core_mcpcia.h>

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


/*
 * HACK ALERT! only the boot cpu is used for interrupts.
 */


/* Note mask bit is true for ENABLED irqs.  */

static unsigned int hose_irq_masks[4] = {
	0xff0000, 0xfe0000, 0xff0000, 0xff0000
};
static unsigned int cached_irq_masks[4];
spinlock_t rawhide_irq_lock = SPIN_LOCK_UNLOCKED;

static inline void
rawhide_update_irq_hw(int hose, int mask)
{
	*(vuip)MCPCIA_INT_MASK0(MCPCIA_HOSE2MID(hose)) = mask;
	mb();
	*(vuip)MCPCIA_INT_MASK0(MCPCIA_HOSE2MID(hose));
}

static inline void 
rawhide_enable_irq(unsigned int irq)
{
	unsigned int mask, hose;

	irq -= 16;
	hose = irq / 24;
	irq -= hose * 24;

	spin_lock(&rawhide_irq_lock);
	mask = cached_irq_masks[hose] |= 1 << irq;
	mask |= hose_irq_masks[hose];
	rawhide_update_irq_hw(hose, mask);
	spin_unlock(&rawhide_irq_lock);
}

static void 
rawhide_disable_irq(unsigned int irq)
{
	unsigned int mask, hose;

	irq -= 16;
	hose = irq / 24;
	irq -= hose * 24;

	spin_lock(&rawhide_irq_lock);
	mask = cached_irq_masks[hose] &= ~(1 << irq);
	mask |= hose_irq_masks[hose];
	rawhide_update_irq_hw(hose, mask);
	spin_unlock(&rawhide_irq_lock);
}


static unsigned int
rawhide_startup_irq(unsigned int irq)
{
	rawhide_enable_irq(irq);
	return 0;
}

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

static struct hw_interrupt_type rawhide_irq_type = {
	typename:	"RAWHIDE",
	startup:	rawhide_startup_irq,
	shutdown:	rawhide_disable_irq,
	enable:		rawhide_enable_irq,
	disable:	rawhide_disable_irq,
	ack:		rawhide_disable_irq,
	end:		rawhide_end_irq,
};

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

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

        /*
         * The RAWHIDE SRM console reports PCI interrupts with a vector
	 * 0x80 *higher* than one might expect, as PCI IRQ 0 (ie bit 0)
	 * shows up as IRQ 24, etc, etc. We adjust it down by 8 to have
	 * it line up with the actual bit numbers from the REQ registers,
	 * which is how we manage the interrupts/mask. Sigh...
	 *
	 * Also, PCI #1 interrupts are offset some more... :-(
         */

	if (irq == 52) {
		/* SCSI on PCI1 is special.  */
		irq = 72;
	}

	/* Adjust by which hose it is from.  */
	irq -= ((irq + 16) >> 2) & 0x38;

	handle_irq(irq, regs);
}

static void __init
rawhide_init_irq(void)
{
	struct pci_controler *hose;
	long i;

	mcpcia_init_hoses();

	for (hose = hose_head; hose; hose = hose->next) {
		int h = hose->index;
		rawhide_update_irq_hw(h, hose_irq_masks[h]);
	}

	for (i = 16; i < 128; ++i) {
		irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;
		irq_desc[i].handler = &rawhide_irq_type;
	}

	init_i8259a_irqs();
	common_init_isa_dma();
}

/*
 * PCI Fixup configuration.
 *
 * Summary @ MCPCIA_PCI0_INT_REQ:
 * Bit      Meaning
 * 0        Interrupt Line A from slot 2 PCI0
 * 1        Interrupt Line B from slot 2 PCI0
 * 2        Interrupt Line C from slot 2 PCI0
 * 3        Interrupt Line D from slot 2 PCI0
 * 4        Interrupt Line A from slot 3 PCI0
 * 5        Interrupt Line B from slot 3 PCI0
 * 6        Interrupt Line C from slot 3 PCI0
 * 7        Interrupt Line D from slot 3 PCI0
 * 8        Interrupt Line A from slot 4 PCI0
 * 9        Interrupt Line B from slot 4 PCI0
 * 10       Interrupt Line C from slot 4 PCI0
 * 11       Interrupt Line D from slot 4 PCI0
 * 12       Interrupt Line A from slot 5 PCI0
 * 13       Interrupt Line B from slot 5 PCI0
 * 14       Interrupt Line C from slot 5 PCI0
 * 15       Interrupt Line D from slot 5 PCI0
 * 16       EISA interrupt (PCI 0) or SCSI interrupt (PCI 1)
 * 17-23    NA
 *
 * IdSel	
 *   1	 EISA bridge (PCI bus 0 only)
 *   2 	 PCI option slot 2
 *   3	 PCI option slot 3
 *   4   PCI option slot 4
 *   5   PCI option slot 5
 * 
 */

static int __init
rawhide_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
{
	static char irq_tab[5][5] __initdata = {
		/*INT    INTA   INTB   INTC   INTD */
		{ 16+16, 16+16, 16+16, 16+16, 16+16}, /* IdSel 1 SCSI PCI 1 */
		{ 16+ 0, 16+ 0, 16+ 1, 16+ 2, 16+ 3}, /* IdSel 2 slot 2 */
		{ 16+ 4, 16+ 4, 16+ 5, 16+ 6, 16+ 7}, /* IdSel 3 slot 3 */
		{ 16+ 8, 16+ 8, 16+ 9, 16+10, 16+11}, /* IdSel 4 slot 4 */
		{ 16+12, 16+12, 16+13, 16+14, 16+15}  /* IdSel 5 slot 5 */
	};
	const long min_idsel = 1, max_idsel = 5, irqs_per_slot = 5;

	struct pci_controler *hose = dev->sysdata;
	int irq = COMMON_TABLE_LOOKUP;
	if (irq >= 0)
		irq += 24 * hose->index;
	return irq;
}


/*
 * The System Vector
 */

struct alpha_machine_vector rawhide_mv __initmv = {
	vector_name:		"Rawhide",
	DO_EV5_MMU,
	DO_DEFAULT_RTC,
	DO_MCPCIA_IO,
	DO_MCPCIA_BUS,
	machine_check:		mcpcia_machine_check,
	max_dma_address:	ALPHA_MAX_DMA_ADDRESS,
	min_io_address:		DEFAULT_IO_BASE,
	min_mem_address:	MCPCIA_DEFAULT_MEM_BASE,

	nr_irqs:		128,
	device_interrupt:	rawhide_srm_device_interrupt,

	init_arch:		mcpcia_init_arch,
	init_irq:		rawhide_init_irq,
	init_rtc:		common_init_rtc,
	init_pci:		common_init_pci,
	kill_arch:		NULL,
	pci_map_irq:		rawhide_map_irq,
	pci_swizzle:		common_swizzle,
};
ALIAS_MV(rawhide)