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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
* linux/arch/mips/dec/kn01-berr.c
*
* Bus error event handling code for DECstation/DECsystem 3100
* and 2100 (KN01) systems equipped with parity error detection
* logic.
*
* Copyright (c) 2005 Maciej W. Rozycki
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/inst.h>
#include <asm/irq_regs.h>
#include <asm/mipsregs.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/dec/kn01.h>
/* CP0 hazard avoidance. */
#define BARRIER \
__asm__ __volatile__( \
".set push\n\t" \
".set noreorder\n\t" \
"nop\n\t" \
".set pop\n\t")
/*
* Bits 7:0 of the Control Register are write-only -- the
* corresponding bits of the Status Register have a different
* meaning. Hence we use a cache. It speeds up things a bit
* as well.
*
* There is no default value -- it has to be initialized.
*/
u16 cached_kn01_csr;
DEFINE_SPINLOCK(kn01_lock);
static inline void dec_kn01_be_ack(void)
{
volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
unsigned long flags;
spin_lock_irqsave(&kn01_lock, flags);
*csr = cached_kn01_csr | KN01_CSR_MEMERR; /* Clear bus IRQ. */
iob();
spin_unlock_irqrestore(&kn01_lock, flags);
}
static int dec_kn01_be_backend(struct pt_regs *regs, int is_fixup, int invoker)
{
volatile u32 *kn01_erraddr = (void *)CKSEG1ADDR(KN01_SLOT_BASE +
KN01_ERRADDR);
static const char excstr[] = "exception";
static const char intstr[] = "interrupt";
static const char cpustr[] = "CPU";
static const char mreadstr[] = "memory read";
static const char readstr[] = "read";
static const char writestr[] = "write";
static const char timestr[] = "timeout";
static const char paritystr[] = "parity error";
int data = regs->cp0_cause & 4;
unsigned int __user *pc = (unsigned int __user *)regs->cp0_epc +
((regs->cp0_cause & CAUSEF_BD) != 0);
union mips_instruction insn;
unsigned long entrylo, offset;
long asid, entryhi, vaddr;
const char *kind, *agent, *cycle, *event;
unsigned long address;
u32 erraddr = *kn01_erraddr;
int action = MIPS_BE_FATAL;
/* Ack ASAP, so that any subsequent errors get caught. */
dec_kn01_be_ack();
kind = invoker ? intstr : excstr;
agent = cpustr;
if (invoker)
address = erraddr;
else {
/* Bloody hardware doesn't record the address for reads... */
if (data) {
/* This never faults. */
__get_user(insn.word, pc);
vaddr = regs->regs[insn.i_format.rs] +
insn.i_format.simmediate;
} else
vaddr = (long)pc;
if (KSEGX(vaddr) == CKSEG0 || KSEGX(vaddr) == CKSEG1)
address = CPHYSADDR(vaddr);
else {
/* Peek at what physical address the CPU used. */
asid = read_c0_entryhi();
entryhi = asid & (PAGE_SIZE - 1);
entryhi |= vaddr & ~(PAGE_SIZE - 1);
write_c0_entryhi(entryhi);
BARRIER;
tlb_probe();
/* No need to check for presence. */
tlb_read();
entrylo = read_c0_entrylo0();
write_c0_entryhi(asid);
offset = vaddr & (PAGE_SIZE - 1);
address = (entrylo & ~(PAGE_SIZE - 1)) | offset;
}
}
/* Treat low 256MB as memory, high -- as I/O. */
if (address < 0x10000000) {
cycle = mreadstr;
event = paritystr;
} else {
cycle = invoker ? writestr : readstr;
event = timestr;
}
if (is_fixup)
action = MIPS_BE_FIXUP;
if (action != MIPS_BE_FIXUP)
printk(KERN_ALERT "Bus error %s: %s %s %s at %#010lx\n",
kind, agent, cycle, event, address);
return action;
}
int dec_kn01_be_handler(struct pt_regs *regs, int is_fixup)
{
return dec_kn01_be_backend(regs, is_fixup, 0);
}
irqreturn_t dec_kn01_be_interrupt(int irq, void *dev_id)
{
volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
struct pt_regs *regs = get_irq_regs();
int action;
if (!(*csr & KN01_CSR_MEMERR))
return IRQ_NONE; /* Must have been video. */
action = dec_kn01_be_backend(regs, 0, 1);
if (action == MIPS_BE_DISCARD)
return IRQ_HANDLED;
/*
* FIXME: Find the affected processes and kill them, otherwise
* we must die.
*
* The interrupt is asynchronously delivered thus EPC and RA
* may be irrelevant, but are printed for a reference.
*/
printk(KERN_ALERT "Fatal bus interrupt, epc == %08lx, ra == %08lx\n",
regs->cp0_epc, regs->regs[31]);
die("Unrecoverable bus error", regs);
}
void __init dec_kn01_be_init(void)
{
volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
unsigned long flags;
spin_lock_irqsave(&kn01_lock, flags);
/* Preset write-only bits of the Control Register cache. */
cached_kn01_csr = *csr;
cached_kn01_csr &= KN01_CSR_STATUS | KN01_CSR_PARDIS | KN01_CSR_TXDIS;
cached_kn01_csr |= KN01_CSR_LEDS;
/* Enable parity error detection. */
cached_kn01_csr &= ~KN01_CSR_PARDIS;
*csr = cached_kn01_csr;
iob();
spin_unlock_irqrestore(&kn01_lock, flags);
/* Clear any leftover errors from the firmware. */
dec_kn01_be_ack();
}
|
