pcibr_intr.c

一个2.4.21版本的嵌入式linux内核

/*
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2001-2002 Silicon Graphics, Inc. All rights reserved.
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <asm/sn/sgi.h>
#include <asm/sn/sn_cpuid.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
#include <asm/sn/iograph.h>
#include <asm/sn/invent.h>
#include <asm/sn/hcl.h>
#include <asm/sn/labelcl.h>
#include <asm/sn/xtalk/xwidget.h>
#include <asm/sn/pci/bridge.h>
#include <asm/sn/pci/pciio.h>
#include <asm/sn/pci/pcibr.h>
#include <asm/sn/pci/pcibr_private.h>
#include <asm/sn/pci/pci_defs.h>
#include <asm/sn/prio.h>
#include <asm/sn/xtalk/xbow.h>
#include <asm/sn/ioc3.h>
#include <asm/sn/eeprom.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_private.h>

#ifdef __ia64
#define rmallocmap atemapalloc
#define rmfreemap atemapfree
#define rmfree atefree
#define rmalloc atealloc
#endif

unsigned		pcibr_intr_bits(pciio_info_t info, pciio_intr_line_t lines, int nslots);
pcibr_intr_t            pcibr_intr_alloc(devfs_handle_t, device_desc_t, pciio_intr_line_t, devfs_handle_t);
void                    pcibr_intr_free(pcibr_intr_t);
void              pcibr_setpciint(xtalk_intr_t);
int                     pcibr_intr_connect(pcibr_intr_t, intr_func_t, intr_arg_t);
void                    pcibr_intr_disconnect(pcibr_intr_t);

devfs_handle_t            pcibr_intr_cpu_get(pcibr_intr_t);
void                    pcibr_xintr_preset(void *, int, xwidgetnum_t, iopaddr_t, xtalk_intr_vector_t);
void                    pcibr_intr_func(intr_arg_t);

extern pcibr_info_t      pcibr_info_get(devfs_handle_t);

/* =====================================================================
 *    INTERRUPT MANAGEMENT
 */

unsigned
pcibr_intr_bits(pciio_info_t info,
		pciio_intr_line_t lines, int nslots)
{
    pciio_slot_t            slot = PCIBR_INFO_SLOT_GET_INT(info);
    unsigned		    bbits = 0;

    /*
     * Currently favored mapping from PCI
     * slot number and INTA/B/C/D to Bridge
     * PCI Interrupt Bit Number:
     *
     *     SLOT     A B C D
     *      0       0 4 0 4
     *      1       1 5 1 5
     *      2       2 6 2 6
     *      3       3 7 3 7
     *      4       4 0 4 0
     *      5       5 1 5 1
     *      6       6 2 6 2
     *      7       7 3 7 3
     */

    if (slot < nslots) {
	if (lines & (PCIIO_INTR_LINE_A| PCIIO_INTR_LINE_C))
	    bbits |= 1 << slot;
	if (lines & (PCIIO_INTR_LINE_B| PCIIO_INTR_LINE_D))
	    bbits |= 1 << (slot ^ 4);
    }
    return bbits;
}


/*
 *	Get the next wrapper pointer queued in the interrupt circular buffer.
 */
pcibr_intr_wrap_t
pcibr_wrap_get(pcibr_intr_cbuf_t cbuf)
{
    pcibr_intr_wrap_t	wrap;

	if (cbuf->ib_in == cbuf->ib_out)
	    PRINT_PANIC( "pcibr intr circular buffer empty, cbuf=0x%p, ib_in=ib_out=%d\n",
		(void *)cbuf, cbuf->ib_out);

	wrap = cbuf->ib_cbuf[cbuf->ib_out++];
	cbuf->ib_out = cbuf->ib_out % IBUFSIZE;
	return(wrap);
}

/* 
 *	Queue a wrapper pointer in the interrupt circular buffer.
 */
void
pcibr_wrap_put(pcibr_intr_wrap_t wrap, pcibr_intr_cbuf_t cbuf)
{
	int	in;
	int	s;

	/*
	 * Multiple CPUs could be executing this code simultaneously
	 * if a handler has registered multiple interrupt lines and
	 * the interrupts are directed to different CPUs.
	 */
	s = mutex_spinlock(&cbuf->ib_lock);
	in = (cbuf->ib_in + 1) % IBUFSIZE;
	if (in == cbuf->ib_out) 
	    PRINT_PANIC( "pcibr intr circular buffer full, cbuf=0x%p, ib_in=%d\n",
		(void *)cbuf, cbuf->ib_in);

	cbuf->ib_cbuf[cbuf->ib_in] = wrap;
	cbuf->ib_in = in;
	mutex_spinunlock(&cbuf->ib_lock, s);
	return;
}

/*
 *	There are end cases where a deadlock can occur if interrupt 
 *	processing completes and the Bridge b_int_status bit is still set.
 *
 *	One scenerio is if a second PCI interrupt occurs within 60ns of
 *	the previous interrupt being cleared. In this case the Bridge
 *	does not detect the transition, the Bridge b_int_status bit
 *	remains set, and because no transition was detected no interrupt
 *	packet is sent to the Hub/Heart.
 *
 *	A second scenerio is possible when a b_int_status bit is being
 *	shared by multiple devices:
 *						Device #1 generates interrupt
 *						Bridge b_int_status bit set
 *						Device #2 generates interrupt
 *		interrupt processing begins
 *		  ISR for device #1 runs and
 *			clears interrupt
 *						Device #1 generates interrupt
 *		  ISR for device #2 runs and
 *			clears interrupt
 *						(b_int_status bit still set)
 *		interrupt processing completes
 *		  
 *	Interrupt processing is now complete, but an interrupt is still
 *	outstanding for Device #1. But because there was no transition of
 *	the b_int_status bit, no interrupt packet will be generated and
 *	a deadlock will occur.
 *
 *	To avoid these deadlock situations, this function is used
 *	to check if a specific Bridge b_int_status bit is set, and if so,
 *	cause the setting of the corresponding interrupt bit.
 *
 *	On a XBridge (SN1), we do this by writing the appropriate Bridge Force 
 *	Interrupt register. On SN0, or SN1 with an older Bridge, the Bridge 
 *	Force Interrupt register does not exist, so we write the Hub 
 *	INT_PEND_MOD register directly. Likewise for Octane, where we write the 
 *	Heart Set Interrupt Status register directly.
 */
void
pcibr_force_interrupt(pcibr_intr_wrap_t wrap)
{
#ifdef PIC_LATER
	unsigned	bit;
	pcibr_soft_t    pcibr_soft = wrap->iw_soft;
	bridge_t       *bridge = pcibr_soft->bs_base;

	bit = wrap->iw_ibit;

	PCIBR_DEBUG((PCIBR_DEBUG_INTR, pcibr_soft->bs_vhdl,
		    "pcibr_force_interrupt: bit=0x%x\n", bit));

	if (IS_XBRIDGE_OR_PIC_SOFT(pcibr_soft)) {
	    bridge->b_force_pin[bit].intr = 1;
	} else if ((1 << bit) & *wrap->iw_stat) {
	    cpuid_t	    cpu;
	    unsigned        intr_bit;
	    xtalk_intr_t    xtalk_intr =
				pcibr_soft->bs_intr[bit].bsi_xtalk_intr;

	    intr_bit = (short) xtalk_intr_vector_get(xtalk_intr);
	    cpu = xtalk_intr_cpuid_get(xtalk_intr);
	    REMOTE_CPU_SEND_INTR(cpu, intr_bit);
	}
#endif	/* PIC_LATER */
}

/*ARGSUSED */
pcibr_intr_t
pcibr_intr_alloc(devfs_handle_t pconn_vhdl,
		 device_desc_t dev_desc,
		 pciio_intr_line_t lines,
		 devfs_handle_t owner_dev)
{
    pcibr_info_t            pcibr_info = pcibr_info_get(pconn_vhdl);
    pciio_slot_t            pciio_slot = PCIBR_INFO_SLOT_GET_INT(pcibr_info);
    pcibr_soft_t            pcibr_soft = (pcibr_soft_t) pcibr_info->f_mfast;
    devfs_handle_t            xconn_vhdl = pcibr_soft->bs_conn;
    bridge_t               *bridge = pcibr_soft->bs_base;
    int                     is_threaded = 0;

    xtalk_intr_t           *xtalk_intr_p;
    pcibr_intr_t           *pcibr_intr_p;
    pcibr_intr_list_t      *intr_list_p;

    unsigned                pcibr_int_bits;
    unsigned                pcibr_int_bit;
    xtalk_intr_t            xtalk_intr = (xtalk_intr_t)0;
    hub_intr_t		    hub_intr;
    pcibr_intr_t            pcibr_intr;
    pcibr_intr_list_t       intr_entry;
    pcibr_intr_list_t       intr_list;
    bridgereg_t             int_dev;


    PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_INTR_ALLOC, pconn_vhdl,
    		"pcibr_intr_alloc: %s%s%s%s%s\n",
		!(lines & 15) ? " No INTs?" : "",
		lines & 1 ? " INTA" : "",
		lines & 2 ? " INTB" : "",
		lines & 4 ? " INTC" : "",
		lines & 8 ? " INTD" : ""));

    NEW(pcibr_intr);
    if (!pcibr_intr)
	return NULL;

    pcibr_intr->bi_dev = pconn_vhdl;
    pcibr_intr->bi_lines = lines;
    pcibr_intr->bi_soft = pcibr_soft;
    pcibr_intr->bi_ibits = 0;		/* bits will be added below */
    pcibr_intr->bi_func = 0;            /* unset until connect */
    pcibr_intr->bi_arg = 0;             /* unset until connect */
    pcibr_intr->bi_flags = is_threaded ? 0 : PCIIO_INTR_NOTHREAD;
    pcibr_intr->bi_mustruncpu = CPU_NONE;
    pcibr_intr->bi_ibuf.ib_in = 0;
    pcibr_intr->bi_ibuf.ib_out = 0;
    mutex_spinlock_init(&pcibr_intr->bi_ibuf.ib_lock);
    pcibr_int_bits = pcibr_soft->bs_intr_bits((pciio_info_t)pcibr_info, lines, 
		PCIBR_NUM_SLOTS(pcibr_soft));


    /*
     * For each PCI interrupt line requested, figure
     * out which Bridge PCI Interrupt Line it maps
     * to, and make sure there are xtalk resources
     * allocated for it.
     */
    PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_INTR_ALLOC, pconn_vhdl,
		"pcibr_intr_alloc: pcibr_int_bits: 0x%x\n", pcibr_int_bits));
    for (pcibr_int_bit = 0; pcibr_int_bit < 8; pcibr_int_bit ++) {
	if (pcibr_int_bits & (1 << pcibr_int_bit)) {
	    xtalk_intr_p = &pcibr_soft->bs_intr[pcibr_int_bit].bsi_xtalk_intr;

	    xtalk_intr = *xtalk_intr_p;

	    if (xtalk_intr == NULL) {
		/*
		 * This xtalk_intr_alloc is constrained for two reasons:
		 * 1) Normal interrupts and error interrupts need to be delivered
		 *    through a single xtalk target widget so that there aren't any
		 *    ordering problems with DMA, completion interrupts, and error
		 *    interrupts. (Use of xconn_vhdl forces this.)
		 *
		 * 2) On SN1, addressing constraints on SN1 and Bridge force
		 *    us to use a single PI number for all interrupts from a
		 *    single Bridge. (SN1-specific code forces this).
		 */

		/*
		 * All code dealing with threaded PCI interrupt handlers
		 * is located at the pcibr level. Because of this,
		 * we always want the lower layers (hub/heart_intr_alloc, 
		 * intr_level_connect) to treat us as non-threaded so we
		 * don't set up a duplicate threaded environment. We make
		 * this happen by calling a special xtalk interface.
		 */
		xtalk_intr = xtalk_intr_alloc_nothd(xconn_vhdl, dev_desc, 
			owner_dev);

		PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_INTR_ALLOC, pconn_vhdl,
			    "pcibr_intr_alloc: xtalk_intr=0x%x\n", xtalk_intr));

		/* both an assert and a runtime check on this:
		 * we need to check in non-DEBUG kernels, and
		 * the ASSERT gets us more information when
		 * we use DEBUG kernels.
		 */
		ASSERT(xtalk_intr != NULL);
		if (xtalk_intr == NULL) {
		    /* it is quite possible that our
		     * xtalk_intr_alloc failed because
		     * someone else got there first,
		     * and we can find their results
		     * in xtalk_intr_p.
		     */
		    if (!*xtalk_intr_p) {
#ifdef SUPPORT_PRINTING_V_FORMAT
			printk(KERN_ALERT  
				"pcibr_intr_alloc %v: unable to get xtalk interrupt resources",
				xconn_vhdl);
#else
			printk(KERN_ALERT  
				"pcibr_intr_alloc 0x%p: unable to get xtalk interrupt resources",
				(void *)xconn_vhdl);
#endif
			/* yes, we leak resources here. */
			return 0;
		    }
		} else if (compare_and_swap_ptr((void **) xtalk_intr_p, NULL, xtalk_intr)) {
		    /*
		     * now tell the bridge which slot is
		     * using this interrupt line.
		     */
		    int_dev = bridge->b_int_device;
		    int_dev &= ~BRIDGE_INT_DEV_MASK(pcibr_int_bit);
		    int_dev |= pciio_slot << BRIDGE_INT_DEV_SHFT(pcibr_int_bit);
		    bridge->b_int_device = int_dev;	/* XXXMP */

		    PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_INTR_ALLOC, pconn_vhdl,