summaryrefslogtreecommitdiff
path: root/arch/mips/sgi-ip27/ip27-hubio.c
blob: a1fa4abb3f6a719ad0122a0861f3b2d659d293a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/*
 * 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);
	volatile hubreg_t junk;
	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);
		junk = 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);
}