1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1992-1997, 2000-2003 Silicon Graphics, Inc. 4 * Copyright (C) 2004 Christoph Hellwig. 5 * 6 * Support functions for the HUB ASIC - mostly PIO mapping related. 7 */ 8 9 #include <linux/bitops.h> 10 #include <linux/string.h> 11 #include <linux/mmzone.h> 12 #include <asm/sn/addrs.h> 13 #include <asm/sn/arch.h> 14 #include <asm/sn/hub.h> 15 16 17 static int force_fire_and_forget = 1; 18 19 /** 20 * hub_pio_map - establish a HUB PIO mapping 21 * 22 * @hub: hub to perform PIO mapping on 23 * @widget: widget ID to perform PIO mapping for 24 * @xtalk_addr: xtalk_address that needs to be mapped 25 * @size: size of the PIO mapping 26 * 27 **/ 28 unsigned long hub_pio_map(cnodeid_t cnode, xwidgetnum_t widget, 29 unsigned long xtalk_addr, size_t size) 30 { 31 nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode); 32 unsigned i; 33 34 /* use small-window mapping if possible */ 35 if ((xtalk_addr % SWIN_SIZE) + size <= SWIN_SIZE) 36 return NODE_SWIN_BASE(nasid, widget) + (xtalk_addr % SWIN_SIZE); 37 38 if ((xtalk_addr % BWIN_SIZE) + size > BWIN_SIZE) { 39 printk(KERN_WARNING "PIO mapping at hub %d widget %d addr 0x%lx" 40 " too big (%ld)\n", 41 nasid, widget, xtalk_addr, size); 42 return 0; 43 } 44 45 xtalk_addr &= ~(BWIN_SIZE-1); 46 for (i = 0; i < HUB_NUM_BIG_WINDOW; i++) { 47 if (test_and_set_bit(i, hub_data(cnode)->h_bigwin_used)) 48 continue; 49 50 /* 51 * The code below does a PIO write to setup an ITTE entry. 52 * 53 * We need to prevent other CPUs from seeing our updated 54 * memory shadow of the ITTE (in the piomap) until the ITTE 55 * entry is actually set up; otherwise, another CPU might 56 * attempt a PIO prematurely. 57 * 58 * Also, the only way we can know that an entry has been 59 * received by the hub and can be used by future PIO reads/ 60 * writes is by reading back the ITTE entry after writing it. 61 * 62 * For these two reasons, we PIO read back the ITTE entry 63 * after we write it. 64 */ 65 IIO_ITTE_PUT(nasid, i, HUB_PIO_MAP_TO_MEM, widget, xtalk_addr); 66 __raw_readq(IIO_ITTE_GET(nasid, i)); 67 68 return NODE_BWIN_BASE(nasid, widget) + (xtalk_addr % BWIN_SIZE); 69 } 70 71 printk(KERN_WARNING "unable to establish PIO mapping for at" 72 " hub %d widget %d addr 0x%lx\n", 73 nasid, widget, xtalk_addr); 74 return 0; 75 } 76 77 78 /* 79 * hub_setup_prb(nasid, prbnum, credits, conveyor) 80 * 81 * Put a PRB into fire-and-forget mode if conveyor isn't set. Otherwise, 82 * put it into conveyor belt mode with the specified number of credits. 83 */ 84 static void hub_setup_prb(nasid_t nasid, int prbnum, int credits) 85 { 86 iprb_t prb; 87 int prb_offset; 88 89 /* 90 * Get the current register value. 91 */ 92 prb_offset = IIO_IOPRB(prbnum); 93 prb.iprb_regval = REMOTE_HUB_L(nasid, prb_offset); 94 95 /* 96 * Clear out some fields. 97 */ 98 prb.iprb_ovflow = 1; 99 prb.iprb_bnakctr = 0; 100 prb.iprb_anakctr = 0; 101 102 /* 103 * Enable or disable fire-and-forget mode. 104 */ 105 prb.iprb_ff = force_fire_and_forget ? 1 : 0; 106 107 /* 108 * Set the appropriate number of PIO credits for the widget. 109 */ 110 prb.iprb_xtalkctr = credits; 111 112 /* 113 * Store the new value to the register. 114 */ 115 REMOTE_HUB_S(nasid, prb_offset, prb.iprb_regval); 116 } 117 118 /** 119 * hub_set_piomode - set pio mode for a given hub 120 * 121 * @nasid: physical node ID for the hub in question 122 * 123 * Put the hub into either "PIO conveyor belt" mode or "fire-and-forget" mode. 124 * To do this, we have to make absolutely sure that no PIOs are in progress 125 * so we turn off access to all widgets for the duration of the function. 126 * 127 * XXX - This code should really check what kind of widget we're talking 128 * to. Bridges can only handle three requests, but XG will do more. 129 * How many can crossbow handle to widget 0? We're assuming 1. 130 * 131 * XXX - There is a bug in the crossbow that link reset PIOs do not 132 * return write responses. The easiest solution to this problem is to 133 * leave widget 0 (xbow) in fire-and-forget mode at all times. This 134 * only affects pio's to xbow registers, which should be rare. 135 **/ 136 static void hub_set_piomode(nasid_t nasid) 137 { 138 u64 ii_iowa; 139 hubii_wcr_t ii_wcr; 140 unsigned i; 141 142 ii_iowa = REMOTE_HUB_L(nasid, IIO_OUTWIDGET_ACCESS); 143 REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, 0); 144 145 ii_wcr.wcr_reg_value = REMOTE_HUB_L(nasid, IIO_WCR); 146 147 if (ii_wcr.iwcr_dir_con) { 148 /* 149 * Assume a bridge here. 150 */ 151 hub_setup_prb(nasid, 0, 3); 152 } else { 153 /* 154 * Assume a crossbow here. 155 */ 156 hub_setup_prb(nasid, 0, 1); 157 } 158 159 /* 160 * XXX - Here's where we should take the widget type into 161 * when account assigning credits. 162 */ 163 for (i = HUB_WIDGET_ID_MIN; i <= HUB_WIDGET_ID_MAX; i++) 164 hub_setup_prb(nasid, i, 3); 165 166 REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, ii_iowa); 167 } 168 169 /* 170 * hub_pio_init - PIO-related hub initialization 171 * 172 * @hub: hubinfo structure for our hub 173 */ 174 void hub_pio_init(cnodeid_t cnode) 175 { 176 nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode); 177 unsigned i; 178 179 /* initialize big window piomaps for this hub */ 180 bitmap_zero(hub_data(cnode)->h_bigwin_used, HUB_NUM_BIG_WINDOW); 181 for (i = 0; i < HUB_NUM_BIG_WINDOW; i++) 182 IIO_ITTE_DISABLE(nasid, i); 183 184 hub_set_piomode(nasid); 185 } 186