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