diff options
Diffstat (limited to 'kernel/arch/mips/sgi-ip27/ip27-hubio.c')
| -rw-r--r-- | kernel/arch/mips/sgi-ip27/ip27-hubio.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/kernel/arch/mips/sgi-ip27/ip27-hubio.c b/kernel/arch/mips/sgi-ip27/ip27-hubio.c new file mode 100644 index 000000000..328ceb3c8 --- /dev/null +++ b/kernel/arch/mips/sgi-ip27/ip27-hubio.c @@ -0,0 +1,185 @@ +/* + * 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); +} |