1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Bus error event handling code for 5000-series systems equipped 4 * with parity error detection logic, i.e. DECstation/DECsystem 5 * 5000/120, /125, /133 (KN02-BA), 5000/150 (KN04-BA) and Personal 6 * DECstation/DECsystem 5000/20, /25, /33 (KN02-CA), 5000/50 7 * (KN04-CA) systems. 8 * 9 * Copyright (c) 2005 Maciej W. Rozycki 10 */ 11 12 #include <linux/init.h> 13 #include <linux/interrupt.h> 14 #include <linux/kernel.h> 15 #include <linux/types.h> 16 17 #include <asm/addrspace.h> 18 #include <asm/cpu-type.h> 19 #include <asm/irq_regs.h> 20 #include <asm/ptrace.h> 21 #include <asm/traps.h> 22 23 #include <asm/dec/kn02ca.h> 24 #include <asm/dec/kn02xa.h> 25 #include <asm/dec/kn05.h> 26 27 static inline void dec_kn02xa_be_ack(void) 28 { 29 volatile u32 *mer = (void *)CKSEG1ADDR(KN02XA_MER); 30 volatile u32 *mem_intr = (void *)CKSEG1ADDR(KN02XA_MEM_INTR); 31 32 *mer = KN02CA_MER_INTR; /* Clear errors; keep the ARC IRQ. */ 33 *mem_intr = 0; /* Any write clears the bus IRQ. */ 34 iob(); 35 } 36 37 static int dec_kn02xa_be_backend(struct pt_regs *regs, int is_fixup, 38 int invoker) 39 { 40 volatile u32 *kn02xa_mer = (void *)CKSEG1ADDR(KN02XA_MER); 41 volatile u32 *kn02xa_ear = (void *)CKSEG1ADDR(KN02XA_EAR); 42 43 static const char excstr[] = "exception"; 44 static const char intstr[] = "interrupt"; 45 static const char cpustr[] = "CPU"; 46 static const char mreadstr[] = "memory read"; 47 static const char readstr[] = "read"; 48 static const char writestr[] = "write"; 49 static const char timestr[] = "timeout"; 50 static const char paritystr[] = "parity error"; 51 static const char lanestat[][4] = { " OK", "BAD" }; 52 53 const char *kind, *agent, *cycle, *event; 54 unsigned long address; 55 56 u32 mer = *kn02xa_mer; 57 u32 ear = *kn02xa_ear; 58 int action = MIPS_BE_FATAL; 59 60 /* Ack ASAP, so that any subsequent errors get caught. */ 61 dec_kn02xa_be_ack(); 62 63 kind = invoker ? intstr : excstr; 64 65 /* No DMA errors? */ 66 agent = cpustr; 67 68 address = ear & KN02XA_EAR_ADDRESS; 69 70 /* Low 256MB is decoded as memory, high -- as TC. */ 71 if (address < 0x10000000) { 72 cycle = mreadstr; 73 event = paritystr; 74 } else { 75 cycle = invoker ? writestr : readstr; 76 event = timestr; 77 } 78 79 if (is_fixup) 80 action = MIPS_BE_FIXUP; 81 82 if (action != MIPS_BE_FIXUP) 83 printk(KERN_ALERT "Bus error %s: %s %s %s at %#010lx\n", 84 kind, agent, cycle, event, address); 85 86 if (action != MIPS_BE_FIXUP && address < 0x10000000) 87 printk(KERN_ALERT " Byte lane status %#3x -- " 88 "#3: %s, #2: %s, #1: %s, #0: %s\n", 89 (mer & KN02XA_MER_BYTERR) >> 8, 90 lanestat[(mer & KN02XA_MER_BYTERR_3) != 0], 91 lanestat[(mer & KN02XA_MER_BYTERR_2) != 0], 92 lanestat[(mer & KN02XA_MER_BYTERR_1) != 0], 93 lanestat[(mer & KN02XA_MER_BYTERR_0) != 0]); 94 95 return action; 96 } 97 98 int dec_kn02xa_be_handler(struct pt_regs *regs, int is_fixup) 99 { 100 return dec_kn02xa_be_backend(regs, is_fixup, 0); 101 } 102 103 irqreturn_t dec_kn02xa_be_interrupt(int irq, void *dev_id) 104 { 105 struct pt_regs *regs = get_irq_regs(); 106 int action = dec_kn02xa_be_backend(regs, 0, 1); 107 108 if (action == MIPS_BE_DISCARD) 109 return IRQ_HANDLED; 110 111 /* 112 * FIXME: Find the affected processes and kill them, otherwise 113 * we must die. 114 * 115 * The interrupt is asynchronously delivered thus EPC and RA 116 * may be irrelevant, but are printed for a reference. 117 */ 118 printk(KERN_ALERT "Fatal bus interrupt, epc == %08lx, ra == %08lx\n", 119 regs->cp0_epc, regs->regs[31]); 120 die("Unrecoverable bus error", regs); 121 } 122 123 124 void __init dec_kn02xa_be_init(void) 125 { 126 volatile u32 *mbcs = (void *)CKSEG1ADDR(KN4K_SLOT_BASE + KN4K_MB_CSR); 127 128 /* For KN04 we need to make sure EE (?) is enabled in the MB. */ 129 if (current_cpu_type() == CPU_R4000SC) 130 *mbcs |= KN4K_MB_CSR_EE; 131 fast_iob(); 132 133 /* Clear any leftover errors from the firmware. */ 134 dec_kn02xa_be_ack(); 135 } 136