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