• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright (C) 1992-1997, 2000-2003 Silicon Graphics, Inc.
3  * Copyright (C) 2004 Christoph Hellwig.
4  *	Released under GPL v2.
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  **/
hub_pio_map(cnodeid_t cnode,xwidgetnum_t widget,unsigned long xtalk_addr,size_t size)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 		(void) HUB_L(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  */
hub_setup_prb(nasid_t nasid,int prbnum,int credits)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 cresits 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  **/
hub_set_piomode(nasid_t nasid)136 static void hub_set_piomode(nasid_t nasid)
137 {
138 	hubreg_t 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  */
hub_pio_init(cnodeid_t cnode)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