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