summaryrefslogtreecommitdiffstats
path: root/drivers/misc/sgi-xp/xp_sn2.c
blob: 1fcfdebca2c5637395d7d43e376553b022183624 (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
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
 */

/*
 * Cross Partition (XP) sn2-based functions.
 *
 *      Architecture specific implementation of common functions.
 */

#include <linux/device.h>
#include <asm/sn/bte.h>
#include <asm/sn/sn_sal.h>
#include "xp.h"

/*
 * The export of xp_nofault_PIOR needs to happen here since it is defined
 * in drivers/misc/sgi-xp/xp_nofault.S. The target of the nofault read is
 * defined here.
 */
EXPORT_SYMBOL_GPL(xp_nofault_PIOR);

u64 xp_nofault_PIOR_target;
EXPORT_SYMBOL_GPL(xp_nofault_PIOR_target);

/*
 * Register a nofault code region which performs a cross-partition PIO read.
 * If the PIO read times out, the MCA handler will consume the error and
 * return to a kernel-provided instruction to indicate an error. This PIO read
 * exists because it is guaranteed to timeout if the destination is down
 * (amo operations do not timeout on at least some CPUs on Shubs <= v1.2,
 * which unfortunately we have to work around).
 */
static enum xp_retval
xp_register_nofault_code_sn2(void)
{
	int ret;
	u64 func_addr;
	u64 err_func_addr;

	func_addr = *(u64 *)xp_nofault_PIOR;
	err_func_addr = *(u64 *)xp_error_PIOR;
	ret = sn_register_nofault_code(func_addr, err_func_addr, err_func_addr,
				       1, 1);
	if (ret != 0) {
		dev_err(xp, "can't register nofault code, error=%d\n", ret);
		return xpSalError;
	}
	/*
	 * Setup the nofault PIO read target. (There is no special reason why
	 * SH_IPI_ACCESS was selected.)
	 */
	if (is_shub1())
		xp_nofault_PIOR_target = SH1_IPI_ACCESS;
	else if (is_shub2())
		xp_nofault_PIOR_target = SH2_IPI_ACCESS0;

	return xpSuccess;
}

void
xp_unregister_nofault_code_sn2(void)
{
	u64 func_addr = *(u64 *)xp_nofault_PIOR;
	u64 err_func_addr = *(u64 *)xp_error_PIOR;

	/* unregister the PIO read nofault code region */
	(void)sn_register_nofault_code(func_addr, err_func_addr,
				       err_func_addr, 1, 0);
}

/*
 * Wrapper for bte_copy().
 *
 *	vdst - virtual address of the destination of the transfer.
 *	psrc - physical address of the source of the transfer.
 *	len - number of bytes to transfer from source to destination.
 *
 * Note: xp_remote_memcpy_sn2() should never be called while holding a spinlock.
 */
static enum xp_retval
xp_remote_memcpy_sn2(void *vdst, const void *psrc, size_t len)
{
	bte_result_t ret;
	u64 pdst = ia64_tpa(vdst);
	/* >>> What are the rules governing the src and dst addresses passed in?
	 * >>> Currently we're assuming that dst is a virtual address and src
	 * >>> is a physical address, is this appropriate? Can we allow them to
	 * >>> be whatever and we make the change here without damaging the
	 * >>> addresses?
	 */

	/*
	 * Ensure that the physically mapped memory is contiguous.
	 *
	 * We do this by ensuring that the memory is from region 7 only.
	 * If the need should arise to use memory from one of the other
	 * regions, then modify the BUG_ON() statement to ensure that the
	 * memory from that region is always physically contiguous.
	 */
	BUG_ON(REGION_NUMBER(vdst) != RGN_KERNEL);

	ret = bte_copy((u64)psrc, pdst, len, (BTE_NOTIFY | BTE_WACQUIRE), NULL);
	if (ret == BTE_SUCCESS)
		return xpSuccess;

	if (is_shub2())
		dev_err(xp, "bte_copy() on shub2 failed, error=0x%x\n", ret);
	else
		dev_err(xp, "bte_copy() failed, error=%d\n", ret);

	return xpBteCopyError;
}

enum xp_retval
xp_init_sn2(void)
{
	BUG_ON(!is_shub());

	xp_max_npartitions = XP_MAX_NPARTITIONS_SN2;

	xp_remote_memcpy = xp_remote_memcpy_sn2;

	return xp_register_nofault_code_sn2();
}

void
xp_exit_sn2(void)
{
	BUG_ON(!is_shub());

	xp_unregister_nofault_code_sn2();
}