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