path: root/arch/ia64/sn/io/sn2/pcibr/pcibr_rrb.c

/*
 *
 * 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>

void              do_pcibr_rrb_clear(bridge_t *, int);
void              do_pcibr_rrb_flush(bridge_t *, int);
int               do_pcibr_rrb_count_valid(bridge_t *, pciio_slot_t, int);
int               do_pcibr_rrb_count_avail(bridge_t *, pciio_slot_t);
int               do_pcibr_rrb_alloc(bridge_t *, pciio_slot_t, int, int);
int               do_pcibr_rrb_free(bridge_t *, pciio_slot_t, int, int);
void		  do_pcibr_rrb_free_all(pcibr_soft_t, bridge_t *, pciio_slot_t);

void              do_pcibr_rrb_autoalloc(pcibr_soft_t, int, int, int);

int		  pcibr_wrb_flush(devfs_handle_t);
int               pcibr_rrb_alloc(devfs_handle_t, int *, int *);
int               pcibr_rrb_check(devfs_handle_t, int *, int *, int *, int *);
void              pcibr_rrb_flush(devfs_handle_t);
int		  pcibr_slot_initial_rrb_alloc(devfs_handle_t,pciio_slot_t);

void		  pcibr_rrb_debug(char *, pcibr_soft_t);

/*
 * RRB Management
 *
 * All the do_pcibr_rrb_ routines manipulate the Read Response Buffer (rrb)
 * registers within the Bridge.	 Two 32 registers (b_rrb_map[2] also known
 * as the b_even_resp & b_odd_resp registers) are used to allocate the 16
 * rrbs to devices.  The b_even_resp register represents even num devices,
 * and b_odd_resp represent odd number devices.	 Each rrb is represented by
 * 4-bits within a register.
 *   BRIDGE & XBRIDGE:	1 enable bit, 1 virtual channel bit, 2 device bits
 *   PIC:		1 enable bit, 2 virtual channel bits, 1 device bit
 * PIC has 4 devices per bus, and 4 virtual channels (1 normal & 3 virtual)
 * per device.	BRIDGE & XBRIDGE have 8 devices per bus and 2 virtual
 * channels (1 normal & 1 virtual) per device.	See the BRIDGE and PIC ASIC
 * Programmers Reference guides for more information.
 */ 
 
#define RRB_MASK (0xf)			/* mask a single rrb within reg */
#define RRB_SIZE (4)			/* sizeof rrb within reg (bits) */
 
#define RRB_ENABLE_BIT(bridge)		(0x8)  /* [BRIDGE | PIC]_RRB_EN */
#define NUM_PDEV_BITS(bridge)		(is_pic((bridge)) ? 1 : 2)
#define NUM_VDEV_BITS(bridge)		(is_pic((bridge)) ? 2 : 1)
#define NUMBER_VCHANNELS(bridge)	(is_pic((bridge)) ? 4 : 2)
#define SLOT_2_PDEV(bridge, slot)	((slot) >> 1)
#define SLOT_2_RRB_REG(bridge, slot)	((slot) & 0x1)
 
/* validate that the slot and virtual channel are valid for a given bridge */
#define VALIDATE_SLOT_n_VCHAN(bridge, s, v) \
  (is_pic((bridge)) ? \
    (((((s) != PCIIO_SLOT_NONE) && ((s) <= (pciio_slot_t)3)) && (((v) >= 0) && ((v) <= 3))) ? 1 : 0) : \
    (((((s) != PCIIO_SLOT_NONE) && ((s) <= (pciio_slot_t)7)) && (((v) >= 0) && ((v) <= 1))) ? 1 : 0))
 
/*  
 * Count how many RRBs are marked valid for the specified PCI slot
 * and virtual channel.	 Return the count.
 */ 
int
do_pcibr_rrb_count_valid(bridge_t *bridge,
			 pciio_slot_t slot,
			 int vchan)
{
    bridgereg_t tmp;
    uint16_t enable_bit, vchan_bits, pdev_bits, rrb_bits;
    int rrb_index, cnt=0;

    if (!VALIDATE_SLOT_n_VCHAN(bridge, slot, vchan)) {
	printk(KERN_WARNING "do_pcibr_rrb_count_valid() invalid slot/vchan [%d/%d]\n", slot, vchan);
	return 0;
    }
    
    enable_bit = RRB_ENABLE_BIT(bridge);
    vchan_bits = vchan << NUM_PDEV_BITS(bridge);
    pdev_bits = SLOT_2_PDEV(bridge, slot);
    rrb_bits = enable_bit | vchan_bits | pdev_bits;
    
    if ( is_pic(bridge) ) {
	tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		tmp = BRIDGE_REG_GET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg));
	} else {
		tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
	}
    }

    for (rrb_index = 0; rrb_index < 8; rrb_index++) {
	if ((tmp & RRB_MASK) == rrb_bits)
	    cnt++;
	tmp = (tmp >> RRB_SIZE);
    }
    return cnt;
}
 
 
/*  
 * Count how many RRBs are available to be allocated to the specified
 * slot.  Return the count.
 */ 
int
do_pcibr_rrb_count_avail(bridge_t *bridge,
			 pciio_slot_t slot)
{
    bridgereg_t tmp;
    uint16_t enable_bit;
    int rrb_index, cnt=0;
    
    if (!VALIDATE_SLOT_n_VCHAN(bridge, slot, 0)) {
	printk(KERN_WARNING "do_pcibr_rrb_count_avail() invalid slot/vchan");
	return 0;
    }
    
    enable_bit = RRB_ENABLE_BIT(bridge);

    if ( is_pic(bridge) ) {
	tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		tmp = BRIDGE_REG_GET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg));
	} else {
		tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
	}
    }

    for (rrb_index = 0; rrb_index < 8; rrb_index++) {
	if ((tmp & enable_bit) != enable_bit)
	    cnt++;
	tmp = (tmp >> RRB_SIZE);
    }
    return cnt;
}
 
 
/*  
 * Allocate some additional RRBs for the specified slot and the specified
 * virtual channel.  Returns -1 if there were insufficient free RRBs to
 * satisfy the request, or 0 if the request was fulfilled.
 *
 * Note that if a request can be partially filled, it will be, even if
 * we return failure.
 */ 
int
do_pcibr_rrb_alloc(bridge_t *bridge,
		   pciio_slot_t slot,
		   int vchan,
		   int more)
{
    bridgereg_t reg, tmp = (bridgereg_t)0;
    uint16_t enable_bit, vchan_bits, pdev_bits, rrb_bits;
    int rrb_index;
    
    if (!VALIDATE_SLOT_n_VCHAN(bridge, slot, vchan)) {
	printk(KERN_WARNING "do_pcibr_rrb_alloc() invalid slot/vchan");
	return -1;
    }
    
    enable_bit = RRB_ENABLE_BIT(bridge);
    vchan_bits = vchan << NUM_PDEV_BITS(bridge);
    pdev_bits = SLOT_2_PDEV(bridge, slot);
    rrb_bits = enable_bit | vchan_bits | pdev_bits;

    if ( is_pic(bridge) ) {
	reg = tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		reg = tmp = BRIDGE_REG_GET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg));
	} else {
		reg = tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
	}
    }
    
    for (rrb_index = 0; ((rrb_index < 8) && (more > 0)); rrb_index++) {
	if ((tmp & enable_bit) != enable_bit) {
	    /* clear the rrb and OR in the new rrb into 'reg' */
	    reg = reg & ~(RRB_MASK << (RRB_SIZE * rrb_index));
	    reg = reg | (rrb_bits << (RRB_SIZE * rrb_index));
	    more--;
	}
	tmp = (tmp >> RRB_SIZE);
    }

    if ( is_pic(bridge) ) {
	bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg = reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		BRIDGE_REG_SET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg)) = reg;
	} else {
		bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg = reg;
	}
    }
    return (more ? -1 : 0);
}
 
 
/*  
 * Release some of the RRBs that have been allocated for the specified
 * slot. Returns zero for success, or negative if it was unable to free
 * that many RRBs.
 *
 * Note that if a request can be partially fulfilled, it will be, even
 * if we return failure.
 */ 
int
do_pcibr_rrb_free(bridge_t *bridge,
		  pciio_slot_t slot,
		  int vchan,
		  int less)
{
    bridgereg_t reg, tmp = (bridgereg_t)0, clr = 0;
    uint16_t enable_bit, vchan_bits, pdev_bits, rrb_bits;
    int rrb_index;
    
    if (!VALIDATE_SLOT_n_VCHAN(bridge, slot, vchan)) {
	printk(KERN_WARNING "do_pcibr_rrb_free() invalid slot/vchan");
	return -1;
    }
    
    enable_bit = RRB_ENABLE_BIT(bridge);
    vchan_bits = vchan << NUM_PDEV_BITS(bridge);
    pdev_bits = SLOT_2_PDEV(bridge, slot);
    rrb_bits = enable_bit | vchan_bits | pdev_bits;

    if ( is_pic(bridge) ) {
	reg = tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		reg = BRIDGE_REG_GET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg));
	} else {
		reg = tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;
	}
    }
    
    for (rrb_index = 0; ((rrb_index < 8) && (less > 0)); rrb_index++) {
	if ((tmp & RRB_MASK) == rrb_bits) {
	   /*
	    * the old do_pcibr_rrb_free() code only clears the enable bit
	    * but I say we should clear the whole rrb (ie):
	    *	  reg = reg & ~(RRB_MASK << (RRB_SIZE * rrb_index));
	    * But to be compatible with old code we'll only clear enable.
	    */
	    reg = reg & ~(RRB_ENABLE_BIT(bridge) << (RRB_SIZE * rrb_index));
	    clr = clr | (enable_bit << (RRB_SIZE * rrb_index));
	    less--;
	}
	tmp = (tmp >> RRB_SIZE);
    }

    if ( is_pic(bridge) ) {
	bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg = reg;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		BRIDGE_REG_SET32((&bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg)) = reg;
	} else {
		bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg = reg;
	}
    }

    /* call do_pcibr_rrb_clear() for all the rrbs we've freed */
    for (rrb_index = 0; rrb_index < 8; rrb_index++) {
	int evn_odd = SLOT_2_RRB_REG(bridge, slot);
	if (clr & (enable_bit << (RRB_SIZE * rrb_index)))
	    do_pcibr_rrb_clear(bridge, (2 * rrb_index) + evn_odd);
    }
    
    return (less ? -1 : 0);
}
 
  
/*  
 * free all the rrbs (both the normal and virtual channels) for the
 * specified slot.
 */ 
void
do_pcibr_rrb_free_all(pcibr_soft_t pcibr_soft,
		      bridge_t *bridge,
		      pciio_slot_t slot)
{
    int vchan;
    int vchan_total = NUMBER_VCHANNELS(bridge);
    
    /* pretend we own all 8 rrbs and just ignore the return value */
    for (vchan = 0; vchan < vchan_total; vchan++) {
	    (void)do_pcibr_rrb_free(bridge, slot, vchan, 8);
	    pcibr_soft->bs_rrb_valid[slot][vchan] = 0;
    }
}
 
 
/*
 * Wait for the the specified rrb to have no outstanding XIO pkts
 * and for all data to be drained.  Mark the rrb as no longer being 
 * valid.
 */
void
do_pcibr_rrb_clear(bridge_t *bridge, int rrb)
{
    bridgereg_t             status;

    /* bridge_lock must be held;
     * this RRB must be disabled.
     */

    if ( is_pic(bridge) ) {
	/* wait until RRB has no outstanduing XIO packets. */
	while ((status = bridge->b_resp_status) & BRIDGE_RRB_INUSE(rrb)) {
		;				/* XXX- beats on bridge. bad idea? */
	}

	/* if the RRB has data, drain it. */
	if (status & BRIDGE_RRB_VALID(rrb)) {
		bridge->b_resp_clear = BRIDGE_RRB_CLEAR(rrb);

		/* wait until RRB is no longer valid. */
		while ((status = bridge->b_resp_status) & BRIDGE_RRB_VALID(rrb)) {
			;				/* XXX- beats on bridge. bad idea? */
		}
	}
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		while ((status = BRIDGE_REG_GET32((&bridge->b_resp_status))) & BRIDGE_RRB_INUSE(rrb)) {
			;                               /* XXX- beats on bridge. bad idea? */
		}

		/* if the RRB has data, drain it. */
		if (status & BRIDGE_RRB_VALID(rrb)) {
			BRIDGE_REG_SET32((&bridge->b_resp_clear)) = __swab32(BRIDGE_RRB_CLEAR(rrb));

			/* wait until RRB is no longer valid. */
			while ((status = BRIDGE_REG_GET32((&bridge->b_resp_status))) & BRIDGE_RRB_VALID(rrb)) {
				;                           /* XXX- beats on bridge. bad idea? */
			}
		}
	} else { /* io_get_sh_swapper(NASID_GET(bridge)) */
		while ((status = bridge->b_resp_status) & BRIDGE_RRB_INUSE(rrb)) {
			;                               /* XXX- beats on bridge. bad idea? */
		}

		/* if the RRB has data, drain it. */
		if (status & BRIDGE_RRB_VALID(rrb)) {
			bridge->b_resp_clear = BRIDGE_RRB_CLEAR(rrb);
			/* wait until RRB is no longer valid. */
			while ((status = bridge->b_resp_status) & BRIDGE_RRB_VALID(rrb)) {
				;                           /* XXX- beats on bridge. bad idea? */
			}
		}
	}
    }
}


/* 
 * Flush the specified rrb by calling do_pcibr_rrb_clear().  This
 * routine is just a wrapper to make sure the rrb is disabled 
 * before calling do_pcibr_rrb_clear().
 */
void
do_pcibr_rrb_flush(bridge_t *bridge, int rrbn)
{
    reg_p	 rrbp = &bridge->b_rrb_map[rrbn & 1].reg;
    bridgereg_t	 rrbv;
    int		 shft = (RRB_SIZE * (rrbn >> 1));
    unsigned long	 ebit = RRB_ENABLE_BIT(bridge) << shft;

    if ( is_pic(bridge) ) {
	rrbv = *rrbp;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		rrbv = BRIDGE_REG_GET32((&rrbp));
	} else {
		rrbv = *rrbp;
	}
    }

    if (rrbv & ebit) {
    	if ( is_pic(bridge) ) {
		*rrbp = rrbv & ~ebit;
	}
	else {
		if (io_get_sh_swapper(NASID_GET(bridge))) {
			BRIDGE_REG_SET32((&rrbp)) = __swab32((rrbv & ~ebit));
		} else {
			*rrbp = rrbv & ~ebit;
		}
	}
    }

    do_pcibr_rrb_clear(bridge, rrbn);

    if (rrbv & ebit) {
	if ( is_pic(bridge) ) {
		*rrbp = rrbv;
	}
	else {
		if (io_get_sh_swapper(NASID_GET(bridge))) {
			BRIDGE_REG_SET32((&rrbp)) = __swab32(rrbv);
		} else {
			*rrbp = rrbv;
		}
	}
    }
}


void
do_pcibr_rrb_autoalloc(pcibr_soft_t pcibr_soft,
		       int slot,
		       int vchan, 
		       int more_rrbs)
{
    bridge_t               *bridge = pcibr_soft->bs_base;
    int                     got;

    for (got = 0; got < more_rrbs; ++got) {
	if (pcibr_soft->bs_rrb_res[slot] > 0)
	    pcibr_soft->bs_rrb_res[slot]--;
	else if (pcibr_soft->bs_rrb_avail[slot & 1] > 0)
	    pcibr_soft->bs_rrb_avail[slot & 1]--;
	else
	    break;
	if (do_pcibr_rrb_alloc(bridge, slot, vchan, 1) < 0)
	    break;

	pcibr_soft->bs_rrb_valid[slot][vchan]++;
    }

    PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_soft->bs_vhdl,
		"do_pcibr_rrb_autoalloc: added %d (of %d requested) RRBs "
		"to slot %d, vchan %d\n", got, more_rrbs, 
		PCIBR_DEVICE_TO_SLOT(pcibr_soft, slot), vchan));

    pcibr_rrb_debug("do_pcibr_rrb_autoalloc", pcibr_soft);
}


/*
 * Flush all the rrb's assigned to the specified connection point.
 */
void
pcibr_rrb_flush(devfs_handle_t pconn_vhdl)
{
    pciio_info_t  pciio_info = pciio_info_get(pconn_vhdl);
    pcibr_soft_t  pcibr_soft = (pcibr_soft_t)pciio_info_mfast_get(pciio_info);
    pciio_slot_t  slot = PCIBR_INFO_SLOT_GET_INT(pciio_info);
    bridge_t	 *bridge = pcibr_soft->bs_base;

    bridgereg_t tmp;
    uint16_t enable_bit, pdev_bits, rrb_bits, rrb_mask;
    int rrb_index;
    unsigned long s;

    enable_bit = RRB_ENABLE_BIT(bridge);
    pdev_bits = SLOT_2_PDEV(bridge, slot);
    rrb_bits = enable_bit | pdev_bits;
    rrb_mask = enable_bit | ((NUM_PDEV_BITS(bridge) << 1) - 1);

    tmp = bridge->b_rrb_map[SLOT_2_RRB_REG(bridge, slot)].reg;

    s = pcibr_lock(pcibr_soft);
    for (rrb_index = 0; rrb_index < 8; rrb_index++) {
	int evn_odd = SLOT_2_RRB_REG(bridge, slot);
	if ((tmp & rrb_mask) == rrb_bits)
	    do_pcibr_rrb_flush(bridge, (2 * rrb_index) + evn_odd);
	tmp = (tmp >> RRB_SIZE);
    }
    pcibr_unlock(pcibr_soft, s);
}


/*
 * Device driver interface to flush the write buffers for a specified
 * device hanging off the bridge.
 */
int
pcibr_wrb_flush(devfs_handle_t pconn_vhdl)
{
    pciio_info_t            pciio_info = pciio_info_get(pconn_vhdl);
    pciio_slot_t            pciio_slot = PCIBR_INFO_SLOT_GET_INT(pciio_info);
    pcibr_soft_t            pcibr_soft = (pcibr_soft_t) pciio_info_mfast_get(pciio_info);
    bridge_t               *bridge = pcibr_soft->bs_base;
    volatile bridgereg_t   *wrb_flush;

    wrb_flush = &(bridge->b_wr_req_buf[pciio_slot].reg);
    if ( IS_PIC_SOFT(pcibr_soft) ) {
	while (*wrb_flush)
		;
    }
    else {
	if (io_get_sh_swapper(NASID_GET(bridge))) {
		while (BRIDGE_REG_GET32((wrb_flush)));
	} else {
		while (*wrb_flush)
			;
	}
    }
    return(0);
}

/*
 * Device driver interface to request RRBs for a specified device
 * hanging off a Bridge.  The driver requests the total number of
 * RRBs it would like for the normal channel (vchan0) and for the
 * "virtual channel" (vchan1).  The actual number allocated to each
 * channel is returned.
 *
 * If we cannot allocate at least one RRB to a channel that needs
 * at least one, return -1 (failure).  Otherwise, satisfy the request
 * as best we can and return 0.
 */
int
pcibr_rrb_alloc(devfs_handle_t pconn_vhdl,
		int *count_vchan0,
		int *count_vchan1)
{
    pciio_info_t            pciio_info = pciio_info_get(pconn_vhdl);
    pciio_slot_t            pciio_slot = PCIBR_INFO_SLOT_GET_INT(pciio_info);
    pcibr_soft_t            pcibr_soft = (pcibr_soft_t) pciio_info_mfast_get(pciio_info);
    bridge_t               *bridge = pcibr_soft->bs_base;
    int                     desired_vchan0;
    int                     desired_vchan1;
    int                     orig_vchan0;
    int                     orig_vchan1;
    int                     delta_vchan0;
    int                     delta_vchan1;
    int                     final_vchan0;
    int                     final_vchan1;
    int                     avail_rrbs;
    int                     res_rrbs;
    int			    vchan_total;
    int			    vchan;
    unsigned long                s;
    int                     error;

    /*
     * TBD: temper request with admin info about RRB allocation,
     * and according to demand from other devices on this Bridge.
     *
     * One way of doing this would be to allocate two RRBs
     * for each device on the bus, before any drivers start
     * asking for extras. This has the weakness that one
     * driver might not give back an "extra" RRB until after
     * another driver has already failed to get one that
     * it wanted.
     */

    s = pcibr_lock(pcibr_soft);

    vchan_total = NUMBER_VCHANNELS(bridge);

    /* Save the boot-time RRB configuration for this slot */
    if (pcibr_soft->bs_rrb_valid_dflt[pciio_slot][VCHAN0] < 0) {
	for (vchan = 0; vchan < vchan_total; vchan++) 
	    pcibr_soft->bs_rrb_valid_dflt[pciio_slot][vchan] =
		    pcibr_soft->bs_rrb_valid[pciio_slot][vchan];
        pcibr_soft->bs_rrb_res_dflt[pciio_slot] =
                pcibr_soft->bs_rrb_res[pciio_slot];
                  
    }

    /* How many RRBs do we own? */
    orig_vchan0 = pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN0];
    orig_vchan1 = pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN1];

    /* How many RRBs do we want? */
    desired_vchan0 = count_vchan0 ? *count_vchan0 : orig_vchan0;
    desired_vchan1 = count_vchan1 ? *count_vchan1 : orig_vchan1;

    /* How many RRBs are free? */
    avail_rrbs = pcibr_soft->bs_rrb_avail[pciio_slot & 1]
	+ pcibr_soft->bs_rrb_res[pciio_slot];

    /* Figure desired deltas */
    delta_vchan0 = desired_vchan0 - orig_vchan0;
    delta_vchan1 = desired_vchan1 - orig_vchan1;

    /* Trim back deltas to something
     * that we can actually meet, by
     * decreasing the ending allocation
     * for whichever channel wants
     * more RRBs. If both want the same
     * number, cut the second channel.
     * NOTE: do not change the allocation for
     * a channel that was passed as NULL.
     */
    while ((delta_vchan0 + delta_vchan1) > avail_rrbs) {
	if (count_vchan0 &&
	    (!count_vchan1 ||
	     ((orig_vchan0 + delta_vchan0) >
	      (orig_vchan1 + delta_vchan1))))
	    delta_vchan0--;
	else
	    delta_vchan1--;
    }

    /* Figure final RRB allocations
     */
    final_vchan0 = orig_vchan0 + delta_vchan0;
    final_vchan1 = orig_vchan1 + delta_vchan1;

    /* If either channel wants RRBs but our actions
     * would leave it with none, declare an error,
     * but DO NOT change any RRB allocations.
     */
    if ((desired_vchan0 && !final_vchan0) ||
	(desired_vchan1 && !final_vchan1)) {

	error = -1;

    } else {

	/* Commit the allocations: free, then alloc.
	 */
	if (delta_vchan0 < 0)
	    (void) do_pcibr_rrb_free(bridge, pciio_slot, VCHAN0, -delta_vchan0);
	if (delta_vchan1 < 0)
	    (void) do_pcibr_rrb_free(bridge, pciio_slot, VCHAN1, -delta_vchan1);

	if (delta_vchan0 > 0)
	    (void) do_pcibr_rrb_alloc(bridge, pciio_slot, VCHAN0, delta_vchan0);
	if (delta_vchan1 > 0)
	    (void) do_pcibr_rrb_alloc(bridge, pciio_slot, VCHAN1, delta_vchan1);

	/* Return final values to caller.
	 */
	if (count_vchan0)
	    *count_vchan0 = final_vchan0;
	if (count_vchan1)
	    *count_vchan1 = final_vchan1;

	/* prevent automatic changes to this slot's RRBs
	 */
	pcibr_soft->bs_rrb_fixed |= 1 << pciio_slot;

	/* Track the actual allocations, release
	 * any further reservations, and update the
	 * number of available RRBs.
	 */

	pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN0] = final_vchan0;
	pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN1] = final_vchan1;
	pcibr_soft->bs_rrb_avail[pciio_slot & 1] =
	    pcibr_soft->bs_rrb_avail[pciio_slot & 1]
	    + pcibr_soft->bs_rrb_res[pciio_slot]
	    - delta_vchan0
	    - delta_vchan1;
	pcibr_soft->bs_rrb_res[pciio_slot] = 0;

        /*
         * Reserve enough RRBs so this slot's RRB configuration can be
         * reset to its boot-time default following a hot-plug shut-down
         */
	res_rrbs = (pcibr_soft->bs_rrb_res_dflt[pciio_slot] -
		    pcibr_soft->bs_rrb_res[pciio_slot]);
	for (vchan = 0; vchan < vchan_total; vchan++) {
	    res_rrbs += (pcibr_soft->bs_rrb_valid_dflt[pciio_slot][vchan] -
			 pcibr_soft->bs_rrb_valid[pciio_slot][vchan]);
	}

	if (res_rrbs > 0) {
            pcibr_soft->bs_rrb_res[pciio_slot] = res_rrbs;
            pcibr_soft->bs_rrb_avail[pciio_slot & 1] =
                pcibr_soft->bs_rrb_avail[pciio_slot & 1]
                - res_rrbs;
        }
 
	pcibr_rrb_debug("pcibr_rrb_alloc", pcibr_soft);

	error = 0;
    }

    pcibr_unlock(pcibr_soft, s);

    return error;
}

/*
 * Device driver interface to check the current state
 * of the RRB allocations.
 *
 *   pconn_vhdl is your PCI connection point (specifies which
 *      PCI bus and which slot).
 *
 *   count_vchan0 points to where to return the number of RRBs
 *      assigned to the primary DMA channel, used by all DMA
 *      that does not explicitly ask for the alternate virtual
 *      channel.
 *
 *   count_vchan1 points to where to return the number of RRBs
 *      assigned to the secondary DMA channel, used when
 *      PCIBR_VCHAN1 and PCIIO_DMA_A64 are specified.
 *
 *   count_reserved points to where to return the number of RRBs
 *      that have been automatically reserved for your device at
 *      startup, but which have not been assigned to a
 *      channel. RRBs must be assigned to a channel to be used;
 *      this can be done either with an explicit pcibr_rrb_alloc
 *      call, or automatically by the infrastructure when a DMA
 *      translation is constructed. Any call to pcibr_rrb_alloc
 *      will release any unassigned reserved RRBs back to the
 *      free pool.
 *
 *   count_pool points to where to return the number of RRBs
 *      that are currently unassigned and unreserved. This
 *      number can (and will) change as other drivers make calls
 *      to pcibr_rrb_alloc, or automatically allocate RRBs for
 *      DMA beyond their initial reservation.
 *
 * NULL may be passed for any of the return value pointers
 * the caller is not interested in.
 *
 * The return value is "0" if all went well, or "-1" if
 * there is a problem. Additionally, if the wrong vertex
 * is passed in, one of the subsidiary support functions
 * could panic with a "bad pciio fingerprint."
 */

int
pcibr_rrb_check(devfs_handle_t pconn_vhdl,
		int *count_vchan0,
		int *count_vchan1,
		int *count_reserved,
		int *count_pool)
{
    pciio_info_t            pciio_info;
    pciio_slot_t            pciio_slot;
    pcibr_soft_t            pcibr_soft;
    unsigned long                s;
    int                     error = -1;

    if ((pciio_info = pciio_info_get(pconn_vhdl)) &&
	(pcibr_soft = (pcibr_soft_t) pciio_info_mfast_get(pciio_info)) &&
	((pciio_slot = PCIBR_INFO_SLOT_GET_INT(pciio_info)) < PCIBR_NUM_SLOTS(pcibr_soft))) {

	s = pcibr_lock(pcibr_soft);

	if (count_vchan0)
	    *count_vchan0 =
		pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN0];

	if (count_vchan1)
	    *count_vchan1 =
		pcibr_soft->bs_rrb_valid[pciio_slot][VCHAN1];

	if (count_reserved)
	    *count_reserved =
		pcibr_soft->bs_rrb_res[pciio_slot];

	if (count_pool)
	    *count_pool =
		pcibr_soft->bs_rrb_avail[pciio_slot & 1];

	error = 0;

	pcibr_unlock(pcibr_soft, s);
    }
    return error;
}

/*
 * pcibr_slot_initial_rrb_alloc
 *	Allocate a default number of rrbs for this slot on 
 * 	the two channels.  This is dictated by the rrb allocation
 * 	strategy routine defined per platform.
 */

int
pcibr_slot_initial_rrb_alloc(devfs_handle_t pcibr_vhdl,
			     pciio_slot_t slot)
{
    pcibr_soft_t	 pcibr_soft;
    pcibr_info_h	 pcibr_infoh;
    pcibr_info_t	 pcibr_info;
    bridge_t		*bridge;
    int 		 vchan_total;
    int			 vchan;
    int                  chan[4];

    pcibr_soft = pcibr_soft_get(pcibr_vhdl);

    if (!pcibr_soft)
	return(EINVAL);

    if (!PCIBR_VALID_SLOT(pcibr_soft, slot))
	return(EINVAL);

    bridge = pcibr_soft->bs_base;

    /* How many RRBs are on this slot? */
    vchan_total = NUMBER_VCHANNELS(bridge);
    for (vchan = 0; vchan < vchan_total; vchan++) 
        chan[vchan] = do_pcibr_rrb_count_valid(bridge, slot, vchan);

    if (IS_PIC_SOFT(pcibr_soft)) {
 	PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_vhdl,
	    "pcibr_slot_initial_rrb_alloc: slot %d started with %d+%d+%d+%d\n",
	    PCIBR_DEVICE_TO_SLOT(pcibr_soft, slot), 
	    chan[VCHAN0], chan[VCHAN1], chan[VCHAN2], chan[VCHAN3]));
    } else {
	PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_vhdl,
	    "pcibr_slot_initial_rrb_alloc: slot %d started with %d+%d\n",
	    PCIBR_DEVICE_TO_SLOT(pcibr_soft, slot), 
	    chan[VCHAN0], chan[VCHAN1]));
    }

    /* Do we really need any?
     */
    pcibr_infoh = pcibr_soft->bs_slot[slot].bss_infos;
    pcibr_info = pcibr_infoh[0];

    if (PCIBR_WAR_ENABLED(PV856866, pcibr_soft) && IS_PIC_SOFT(pcibr_soft) &&
                        (slot == 2 || slot == 3) &&
                        (pcibr_info->f_vendor == PCIIO_VENDOR_ID_NONE) &&
                        !pcibr_soft->bs_slot[slot].has_host) {

        for (vchan = 0; vchan < 2; vchan++) {
            do_pcibr_rrb_free(bridge, slot, vchan, 8);
            pcibr_soft->bs_rrb_valid[slot][vchan] = 0;
        }

        pcibr_soft->bs_rrb_valid[slot][3] = chan[3];

        return(ENODEV);
    }

    for (vchan = 0; vchan < vchan_total; vchan++)
        pcibr_soft->bs_rrb_valid[slot][vchan] = chan[vchan];

    return(0);
}

void
rrb_reserved_free(pcibr_soft_t pcibr_soft, int slot)
{
        int res = pcibr_soft->bs_rrb_res[slot];

        if (res) {
                 pcibr_soft->bs_rrb_avail[slot & 1] += res;
                 pcibr_soft->bs_rrb_res[slot] = 0;
        }
}

/*
 * pcibr_initial_rrb
 *      Assign an equal total number of RRBs to all candidate slots, 
 *      where the total is the sum of the number of RRBs assigned to
 *      the normal channel, the number of RRBs assigned to the virtual
 *      channels, and the number of RRBs assigned as reserved. 
 *
 *      A candidate slot is any existing (populated or empty) slot.
 *      Empty SN1 slots need RRBs to support hot-plug operations.
 */

int
pcibr_initial_rrb(devfs_handle_t pcibr_vhdl,
			     pciio_slot_t first, pciio_slot_t last)
{
    pcibr_soft_t            pcibr_soft = pcibr_soft_get(pcibr_vhdl);
    bridge_t               *bridge = pcibr_soft->bs_base;
    pciio_slot_t            slot;
    int			    rrb_total;
    int			    vchan_total;
    int			    vchan;
    int                     have[2][3];
    int                     res[2];
    int                     eo;

    have[0][0] = have[0][1] = have[0][2] = 0;
    have[1][0] = have[1][1] = have[1][2] = 0;
    res[0] = res[1] = 0;

    vchan_total = NUMBER_VCHANNELS(bridge);

    for (slot = pcibr_soft->bs_min_slot; 
			slot < PCIBR_NUM_SLOTS(pcibr_soft); ++slot) {
        /* Initial RRB management; give back RRBs in all non-existent slots */
        (void) pcibr_slot_initial_rrb_alloc(pcibr_vhdl, slot);

        /* Base calculations only on existing slots */
        if ((slot >= first) && (slot <= last)) {
	    rrb_total = 0;
	    for (vchan = 0; vchan < vchan_total; vchan++) 
		rrb_total += pcibr_soft->bs_rrb_valid[slot][vchan];

            if (rrb_total < 3)
                have[slot & 1][rrb_total]++;
        }
    }

    /* Initialize even/odd slot available RRB counts */
    pcibr_soft->bs_rrb_avail[0] = do_pcibr_rrb_count_avail(bridge, 0);
    pcibr_soft->bs_rrb_avail[1] = do_pcibr_rrb_count_avail(bridge, 1);

    /*
     * Calculate reserved RRBs for slots based on current RRB usage
     */
    for (eo = 0; eo < 2; eo++) {
        if ((3 * have[eo][0] + 2 * have[eo][1] + have[eo][2]) <= pcibr_soft->bs_rrb_avail[eo])
            res[eo] = 3;
        else if ((2 * have[eo][0] + have[eo][1]) <= pcibr_soft->bs_rrb_avail[eo])
            res[eo] = 2;
        else if (have[eo][0] <= pcibr_soft->bs_rrb_avail[eo])
            res[eo] = 1;
        else
            res[eo] = 0;

    }

    /* Assign reserved RRBs to existing slots */
    for (slot = first; slot <= last; ++slot) {
        int                     r;

	rrb_total = 0;
	for (vchan = 0; vchan < vchan_total; vchan++)
		rrb_total += pcibr_soft->bs_rrb_valid[slot][vchan];

        r = res[slot & 1] - (rrb_total);

        if (r > 0) {
            pcibr_soft->bs_rrb_res[slot] = r;
            pcibr_soft->bs_rrb_avail[slot & 1] -= r;
        }
    }

    pcibr_rrb_debug("pcibr_initial_rrb", pcibr_soft);

    return 0;

}

/*
 * Dump the pcibr_soft_t RRB state variable
 */
void
pcibr_rrb_debug(char *calling_func, pcibr_soft_t pcibr_soft)
{
    pciio_slot_t slot;
    char tmp_str[256];
    
    if (pcibr_debug_mask & PCIBR_DEBUG_RRB) {
        PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_soft->bs_vhdl,
                    "%s: rrbs available, even=%d, odd=%d\n", calling_func,
                    pcibr_soft->bs_rrb_avail[0], pcibr_soft->bs_rrb_avail[1]));

        if (IS_PIC_SOFT(pcibr_soft)) {
            PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_soft->bs_vhdl,
                        "\tslot\tvchan0\tvchan1\tvchan2\tvchan3\treserved\n"));
        } else {
	    PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_soft->bs_vhdl,
		        "\tslot\tvchan0\tvchan1\treserved\n"));
        }

        for (slot=0; slot < PCIBR_NUM_SLOTS(pcibr_soft); slot++) {
	    /*
             * The kernel only allows functions to have so many variable args,
             * attempting to call PCIBR_DEBUG_ALWAYS() with more than 5 printf
             * arguments fails so sprintf() it into a temporary string.
             */
	    if (IS_PIC_SOFT(pcibr_soft)) {
                sprintf(tmp_str, "\t %d\t  %d\t  %d\t  %d\t  %d\t  %d\n", 
		        PCIBR_DEVICE_TO_SLOT(pcibr_soft, slot),
                        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN0],
                        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN1],
                        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN2],
                        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN3],
                        pcibr_soft->bs_rrb_res[slot]);
	    } else {
	        sprintf(tmp_str, "\t %d\t  %d\t  %d\t  %d\n", 
		        PCIBR_DEVICE_TO_SLOT(pcibr_soft, slot),
		        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN0],
		        0xFFF & pcibr_soft->bs_rrb_valid[slot][VCHAN1],
		        pcibr_soft->bs_rrb_res[slot]);
	    }
    
            PCIBR_DEBUG_ALWAYS((PCIBR_DEBUG_RRB, pcibr_soft->bs_vhdl,
                        "%s", tmp_str));
        }
    }
}