1 /* 2 * linux/arch/mips/dec/kn02xa-berr.c 3 * 4 * Bus error event handling code for 5000-series systems equipped 5 * with parity error detection logic, i.e. DECstation/DECsystem 6 * 5000/120, /125, /133 (KN02-BA), 5000/150 (KN04-BA) and Personal 7 * DECstation/DECsystem 5000/20, /25, /33 (KN02-CA), 5000/50 8 * (KN04-CA) systems. 9 * 10 * Copyright (c) 2005 Maciej W. Rozycki 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #include <linux/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/kernel.h> 21 #include <linux/types.h> 22 23 #include <asm/addrspace.h> 24 #include <asm/irq_regs.h> 25 #include <asm/ptrace.h> 26 #include <asm/system.h> 27 #include <asm/traps.h> 28 29 #include <asm/dec/kn02ca.h> 30 #include <asm/dec/kn02xa.h> 31 #include <asm/dec/kn05.h> 32 33 static inline void dec_kn02xa_be_ack(void) 34 { 35 volatile u32 *mer = (void *)CKSEG1ADDR(KN02XA_MER); 36 volatile u32 *mem_intr = (void *)CKSEG1ADDR(KN02XA_MEM_INTR); 37 38 *mer = KN02CA_MER_INTR; /* Clear errors; keep the ARC IRQ. */ 39 *mem_intr = 0; /* Any write clears the bus IRQ. */ 40 iob(); 41 } 42 43 static int dec_kn02xa_be_backend(struct pt_regs *regs, int is_fixup, 44 int invoker) 45 { 46 volatile u32 *kn02xa_mer = (void *)CKSEG1ADDR(KN02XA_MER); 47 volatile u32 *kn02xa_ear = (void *)CKSEG1ADDR(KN02XA_EAR); 48 49 static const char excstr[] = "exception"; 50 static const char intstr[] = "interrupt"; 51 static const char cpustr[] = "CPU"; 52 static const char mreadstr[] = "memory read"; 53 static const char readstr[] = "read"; 54 static const char writestr[] = "write"; 55 static const char timestr[] = "timeout"; 56 static const char paritystr[] = "parity error"; 57 static const char lanestat[][4] = { " OK", "BAD" }; 58 59 const char *kind, *agent, *cycle, *event; 60 unsigned long address; 61 62 u32 mer = *kn02xa_mer; 63 u32 ear = *kn02xa_ear; 64 int action = MIPS_BE_FATAL; 65 66 /* Ack ASAP, so that any subsequent errors get caught. */ 67 dec_kn02xa_be_ack(); 68 69 kind = invoker ? intstr : excstr; 70 71 /* No DMA errors? */ 72 agent = cpustr; 73 74 address = ear & KN02XA_EAR_ADDRESS; 75 76 /* Low 256MB is decoded as memory, high -- as TC. */ 77 if (address < 0x10000000) { 78 cycle = mreadstr; 79 event = paritystr; 80 } else { 81 cycle = invoker ? writestr : readstr; 82 event = timestr; 83 } 84 85 if (is_fixup) 86 action = MIPS_BE_FIXUP; 87 88 if (action != MIPS_BE_FIXUP) 89 printk(KERN_ALERT "Bus error %s: %s %s %s at %#010lx\n", 90 kind, agent, cycle, event, address); 91 92 if (action != MIPS_BE_FIXUP && address < 0x10000000) 93 printk(KERN_ALERT " Byte lane status %#3x -- " 94 "#3: %s, #2: %s, #1: %s, #0: %s\n", 95 (mer & KN02XA_MER_BYTERR) >> 8, 96 lanestat[(mer & KN02XA_MER_BYTERR_3) != 0], 97 lanestat[(mer & KN02XA_MER_BYTERR_2) != 0], 98 lanestat[(mer & KN02XA_MER_BYTERR_1) != 0], 99 lanestat[(mer & KN02XA_MER_BYTERR_0) != 0]); 100 101 return action; 102 } 103 104 int dec_kn02xa_be_handler(struct pt_regs *regs, int is_fixup) 105 { 106 return dec_kn02xa_be_backend(regs, is_fixup, 0); 107 } 108 109 irqreturn_t dec_kn02xa_be_interrupt(int irq, void *dev_id) 110 { 111 struct pt_regs *regs = get_irq_regs(); 112 int action = dec_kn02xa_be_backend(regs, 0, 1); 113 114 if (action == MIPS_BE_DISCARD) 115 return IRQ_HANDLED; 116 117 /* 118 * FIXME: Find the affected processes and kill them, otherwise 119 * we must die. 120 * 121 * The interrupt is asynchronously delivered thus EPC and RA 122 * may be irrelevant, but are printed for a reference. 123 */ 124 printk(KERN_ALERT "Fatal bus interrupt, epc == %08lx, ra == %08lx\n", 125 regs->cp0_epc, regs->regs[31]); 126 die("Unrecoverable bus error", regs); 127 } 128 129 130 void __init dec_kn02xa_be_init(void) 131 { 132 volatile u32 *mbcs = (void *)CKSEG1ADDR(KN4K_SLOT_BASE + KN4K_MB_CSR); 133 134 /* For KN04 we need to make sure EE (?) is enabled in the MB. */ 135 if (current_cpu_type() == CPU_R4000SC) 136 *mbcs |= KN4K_MB_CSR_EE; 137 fast_iob(); 138 139 /* Clear any leftover errors from the firmware. */ 140 dec_kn02xa_be_ack(); 141 } 142