ip27-hubio.c
4.87 KB
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/*
* Copyright (C) 1992-1997, 2000-2003 Silicon Graphics, Inc.
* Copyright (C) 2004 Christoph Hellwig.
* Released under GPL v2.
*
* Support functions for the HUB ASIC - mostly PIO mapping related.
*/
#include <linux/bitops.h>
#include <linux/string.h>
#include <linux/mmzone.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
#include <asm/sn/hub.h>
static int force_fire_and_forget = 1;
/**
* hub_pio_map - establish a HUB PIO mapping
*
* @hub: hub to perform PIO mapping on
* @widget: widget ID to perform PIO mapping for
* @xtalk_addr: xtalk_address that needs to be mapped
* @size: size of the PIO mapping
*
**/
unsigned long hub_pio_map(cnodeid_t cnode, xwidgetnum_t widget,
unsigned long xtalk_addr, size_t size)
{
nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode);
unsigned i;
/* use small-window mapping if possible */
if ((xtalk_addr % SWIN_SIZE) + size <= SWIN_SIZE)
return NODE_SWIN_BASE(nasid, widget) + (xtalk_addr % SWIN_SIZE);
if ((xtalk_addr % BWIN_SIZE) + size > BWIN_SIZE) {
printk(KERN_WARNING "PIO mapping at hub %d widget %d addr 0x%lx"
" too big (%ld)\n",
nasid, widget, xtalk_addr, size);
return 0;
}
xtalk_addr &= ~(BWIN_SIZE-1);
for (i = 0; i < HUB_NUM_BIG_WINDOW; i++) {
if (test_and_set_bit(i, hub_data(cnode)->h_bigwin_used))
continue;
/*
* The code below does a PIO write to setup an ITTE entry.
*
* We need to prevent other CPUs from seeing our updated
* memory shadow of the ITTE (in the piomap) until the ITTE
* entry is actually set up; otherwise, another CPU might
* attempt a PIO prematurely.
*
* Also, the only way we can know that an entry has been
* received by the hub and can be used by future PIO reads/
* writes is by reading back the ITTE entry after writing it.
*
* For these two reasons, we PIO read back the ITTE entry
* after we write it.
*/
IIO_ITTE_PUT(nasid, i, HUB_PIO_MAP_TO_MEM, widget, xtalk_addr);
(void) HUB_L(IIO_ITTE_GET(nasid, i));
return NODE_BWIN_BASE(nasid, widget) + (xtalk_addr % BWIN_SIZE);
}
printk(KERN_WARNING "unable to establish PIO mapping for at"
" hub %d widget %d addr 0x%lx\n",
nasid, widget, xtalk_addr);
return 0;
}
/*
* hub_setup_prb(nasid, prbnum, credits, conveyor)
*
* Put a PRB into fire-and-forget mode if conveyor isn't set. Otherwise,
* put it into conveyor belt mode with the specified number of credits.
*/
static void hub_setup_prb(nasid_t nasid, int prbnum, int credits)
{
iprb_t prb;
int prb_offset;
/*
* Get the current register value.
*/
prb_offset = IIO_IOPRB(prbnum);
prb.iprb_regval = REMOTE_HUB_L(nasid, prb_offset);
/*
* Clear out some fields.
*/
prb.iprb_ovflow = 1;
prb.iprb_bnakctr = 0;
prb.iprb_anakctr = 0;
/*
* Enable or disable fire-and-forget mode.
*/
prb.iprb_ff = force_fire_and_forget ? 1 : 0;
/*
* Set the appropriate number of PIO cresits for the widget.
*/
prb.iprb_xtalkctr = credits;
/*
* Store the new value to the register.
*/
REMOTE_HUB_S(nasid, prb_offset, prb.iprb_regval);
}
/**
* hub_set_piomode - set pio mode for a given hub
*
* @nasid: physical node ID for the hub in question
*
* Put the hub into either "PIO conveyor belt" mode or "fire-and-forget" mode.
* To do this, we have to make absolutely sure that no PIOs are in progress
* so we turn off access to all widgets for the duration of the function.
*
* XXX - This code should really check what kind of widget we're talking
* to. Bridges can only handle three requests, but XG will do more.
* How many can crossbow handle to widget 0? We're assuming 1.
*
* XXX - There is a bug in the crossbow that link reset PIOs do not
* return write responses. The easiest solution to this problem is to
* leave widget 0 (xbow) in fire-and-forget mode at all times. This
* only affects pio's to xbow registers, which should be rare.
**/
static void hub_set_piomode(nasid_t nasid)
{
hubreg_t ii_iowa;
hubii_wcr_t ii_wcr;
unsigned i;
ii_iowa = REMOTE_HUB_L(nasid, IIO_OUTWIDGET_ACCESS);
REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, 0);
ii_wcr.wcr_reg_value = REMOTE_HUB_L(nasid, IIO_WCR);
if (ii_wcr.iwcr_dir_con) {
/*
* Assume a bridge here.
*/
hub_setup_prb(nasid, 0, 3);
} else {
/*
* Assume a crossbow here.
*/
hub_setup_prb(nasid, 0, 1);
}
/*
* XXX - Here's where we should take the widget type into
* when account assigning credits.
*/
for (i = HUB_WIDGET_ID_MIN; i <= HUB_WIDGET_ID_MAX; i++)
hub_setup_prb(nasid, i, 3);
REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, ii_iowa);
}
/*
* hub_pio_init - PIO-related hub initialization
*
* @hub: hubinfo structure for our hub
*/
void hub_pio_init(cnodeid_t cnode)
{
nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode);
unsigned i;
/* initialize big window piomaps for this hub */
bitmap_zero(hub_data(cnode)->h_bigwin_used, HUB_NUM_BIG_WINDOW);
for (i = 0; i < HUB_NUM_BIG_WINDOW; i++)
IIO_ITTE_DISABLE(nasid, i);
hub_set_piomode(nasid);
}