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 **/
hub_pio_map(nasid_t nasid,xwidgetnum_t widget,unsigned long xtalk_addr,size_t size)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 */
hub_setup_prb(nasid_t nasid,int prbnum,int credits)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 **/
hub_set_piomode(nasid_t nasid)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 */
hub_pio_init(nasid_t nasid)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
